Information
-
Patent Grant
-
6446599
-
Patent Number
6,446,599
-
Date Filed
Thursday, October 21, 199924 years ago
-
Date Issued
Tuesday, September 10, 200221 years ago
-
Inventors
-
Original Assignees
-
Examiners
Agents
- Knobbe, Martens, Olson & Bear, LLP
-
CPC
-
US Classifications
Field of Search
-
International Classifications
-
Abstract
An idle speed control for an engine includes an improved construction. An air induction system for the engine has a plurality of main air intake passages. Each one of the intake passages has its own throttle valve therein. An idle air manifold is disposed for supplying air charges to combustion chambers of the engine through delivery conduits. Amounts of air charges flowing therethrough is controlled by a feedback control system. The sum of cross-sectional areas of the delivery conduits is greater than a cross-sectional area of an inlet portion of the idle air manifold. The respective delivery conduits have restrictions upstream of junctions to the air intake passages.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to an idle speed control for an engine, and more particularly to an improved idle speed control of an engine that is provided with an idle speed controller (ISC).
2. Description of Related Art
Internal combustion engines generally—have include air induction systems that supply air charges to combustion chambers. The air induction systems usually comprises a single main air intake passage or a plurality of main air intake passages. Throttle valves are provided therein to control amounts of air supplied to the combustion chambers. The throttle valves are generally operated by throttle control mechanisms such as accelerator pedals for automobiles and throttle levers for outboard motors.
The engines are operated often under no load, i.e., in an idle state. For instance, generally the engines require to be warmed up for a while after started without any load. Also, the operator may wish to stay an associated vehicle or watercraft without stopping the engine operations. Under the idling condition, the throttle valve is closed and hence no air charges are supplied to the combustion chamber through the main air intake passages. In order not to stop the operations, the engines must keep their own idle speeds. The engines, thus, include idle air passages additionally to the main air intake passages in the air induction systems. The idle air passages bypass the main air intake passages and communicate to combustion chambers of the engines as well as the main air intake passages.
In other occasions such as an engine start, warming up or running under very low atmospheric temperature or preventing the engine from stalling when decelerated, the engine needs a larger amount of air than under the usual idle conditions described above even the throttle control mechanism is not operated.
Conventionally, an amount of air supplied to the combustion chamber through the idle air passage to maintain the idle speed is regulated by a mechanical control system. Although the mechanical control system is simple, it is difficult to change air amounts in response to the various conditions. However, as great results of developments in connection with electronic control systems in recent years, an idle speed controller (ISC) is now added to the conventional control systems.
The ISC is a feedback control system. In this system, the idle air passage has an idle throttle valve therein. An actual idle speed is sensed by a crankshaft angle position sensor associated with a crankshaft of the engine. Meanwhile, an electronic control device stores a preset idle speed in its control map. When the actual idle speed is sensed, a signal is sent to the control device and compared with the preset idle speed. If the actual idle speed is greater than the preset idle speed, the control device will activate the idle throttle valve toward the closed position. If the actual speed is smaller than the preset speed, the control device will activate it toward the open position. The actual idle speed is accordingly maintained as almost equal to the preset idle speed. Since the control device can store multiple preset idle speeds, the ISC is quite suitable for controlling the idle throttle valve in the idle air passage under the various conditions.
On the other hand, some engines are provided with a plurality of air intake passages as noted above. Conventionally, an air manifold is provided upstream of the respective air intake passages and a common throttle valve is placed therein. Also, a single ISC is provided on an idle air passage which bypasses the throttle valve. Because this arrangement only has the single ISC, a control method for the ISC is simple. However, it requires, upstream of the air manifold, a relatively large plenum chamber in which air charges to the respective intake passages are coordinated not to interfere with each other.
Another arrangement is proposable. In this arrangement, all of the air intake passages include their own throttle valves therein separately and a plurality of idle air passages bypass the respective intake passages. In addition, each idle air passage is provided with an ISC separately. This arrangement does not need a large space for the abovenoted plenum chamber. However, the multiple ISCs, in turn, require separate controls because intake air pressures in the respective idling air passages are different from each other. Accordingly, separate control maps for the ISCs are necessary in this arrangement.
It is, therefore, a principle object of this invention to provide an engine that has a relatively compact air intake system and an ISC which can be easily controlled.
Also, if an engine has a single ISC for multiple idle air passages, air charge must be collected to the ISC and then delivered to respective combustion chambers. In this arrangement, if the delivered air charges flow rapidly in respective delivery conduits which are placed between the ISC and the respective combustion chambers, they are likely to be irregular relative to each other. As a result, the idle control by the single ISC will be unstable.
It is, therefore, another object of this invention to provide an engine that will not cause any unstable condition of an ISC even it is a single one.
Further, outboard motors, of course, may have engines which incorporate the ISC. When the ISC is incorporated in an outboard motor, another problem appears.
The outboard motor generally comprises a drive unit and a bracket assembly. The drive unit is mounted on a transom of an associated watercraft by the bracket assembly for pivotal movement about a steering axis and also about a tilt axis. The drive unit includes a power head in which the engine is placed, a driveshaft housing depending from the power head and a lower unit further depending from the driveshaft housing. The engine has an output shaft extending generally vertically. The output shaft drives a driveshaft extending generally vertically within the driveshaft housing toward the lower unit. The driveshaft, in turn, drives a propeller shaft extending generally horizontally within the lower unit through a forward, neutral and reverse transmission. The propeller shaft then drives a propulsion device such as a propeller. A shift device is provided to switchover the transmission among a forward, neutral and reverse positions. A large part of current outboard motors employ dog clutches for switchover mechanisms.
If the ISC, for example, malfunctions and increases air amounts that flow through the idle air passages without any limitation, the idle speed becomes so fast that the shift operation from the neutral position to the forward or reverse position and vice versa tends to be difficult or impossible. The switchover mechanism incorporating the dog clutch is likely to cause this accident. Also, the outboard motor is sometimes operated in the forward position with the idle speed. This is a trolling condition and the associated watercraft advances quite slowly. The inconvenience situation particularly has an inclination to happen when the switchover mechanism is operated from the forward position under this condition to the neutral position. If the idle speed exceeds over a certain range, the switchover action will be impossible.
Further, in the event of dislocation or damage of delivery conduits, non-controlled and large amounts of air will be supplied to the combustion chambers. Under this condition, the large amounts of air flow into the combustion chambers and then the idle speed surely exceeds a permissible range and the shift action of the switchover mechanism will become impossible also. The same problem may occur in seizure or damage of the ISC.
It is, therefore, a further object of this invention to provide an engine in which an idle speed will not exceed a permissible range on any occasions.
SUMMARY OF THE INVENTION
In accordance with one aspect of the present invention, an internal combustion engine comprises a cylinder body defining a plurality of cylinder bores in which pistons reciprocate. A cylinder head is affixed to an end of the cylinder body and defining combustion chambers with the pistons and the cylinder bores. A plurality of air intake passages are provided for supplying air charges to the combustion chambers. Each one of the air intake passages includes a throttle valve arranged to control an amount of the air charge that flows through each one of the air intake passages. An idle air manifold is also provided for supplying air charges to the combustion chambers. A feedback control system is arranged to control amounts of the air charges that flow through the idle air manifold based upon a difference between a preset idle speed and an actual idle speed of the engine.
In accordance with another aspect of the present invention, an internal combustion engine comprising a cylinder body defining at least one cylinder bore in which a piston reciprocates. A cylinder head affixed to an end of the cylinder body and defining a combustion chamber with the piston and the cylinder bore. At least one air intake passage is provided for supplying an air charge to the combustion chamber. The the air intake passage includes a throttle valve arranged to control an amount of the air charge that flows through the air intake passage. An idle air passage bypasses the throttle valve to deliver idle air to the combustion chamber. An idle air control system is arranged to control an amount of an air charge that flows through the idle air passage. The idle air passage has a fixed cross-sectional area through which an amount of air is regulated.
In accordance with a further aspect of the present invention, an internal combustion engine comprises a cylinder body defining a plurality of cylinder bores in which pistons reciprocate. A cylinder head is affixed to an end of the cylinder body and defining combustion chambers with the pistons and the cylinder bores. A plurality of air intake passages are provided for supplying air charges to the combustion chambers. Each one of the air intake passages includes a throttle valve arranged to control an amount of the air charge that flows through each one of the air intake passages. An idle air passage bypasses the throttle valves to deliver idle air to the combustion chambers. An idle air control system is arranged to control an amount of an air charge that flows through the idle air passage. The idle air passage includes an idle air manifold having an inlet portion and a plurality of idle air delivery conduits. The idle air delivery conduits diverge from the idle air manifold and communicate with the respective air intake passages. The sum of cross-sectional areas of the idle air delivery conduits is greater than a cross-sectional area of the inlet of the idle air manifold.
Further aspects, features and advantages of this invention will become apparent from the detailed description of the preferred embodiments which follow.
BRIEF DESCRIPTION OF THE DRAWINGS
These and other features of this invention will now be described with reference to the drawings of preferred embodiments which are intended to illustrate and not to limit the invention.
FIG. 1
is a side elevational view showing an outboard motor in accordance with a first embodiment of this invention. An associated watercraft is partially shown in phantom.
FIG. 2
is an enlarged side elevational view showing a power head of the outboard motor.
FIG. 3
is an enlarged top plan view, generally taken from the line
3
—
3
in
FIG. 2
, showing the power head. A flywheel and a cover member which exist above the line
3
—
3
are also shown in phantom.
FIG. 4
is a schematic view showing an arrangement of an idle air supply unit with air intake passages in accordance with a second embodiment of the invention.
FIG. 5
is a schematic view showing an arrangement of the idle air supply unit with the air intake passages in accordance with a third embodiment of the invention.
FIG. 6
is a schematic view showing an arrangement of the idle air supply unit with the air intake passages in accordance with a fourth embodiment of the invention.
FIG. 7
is a schematic view showing an arrangement of the idle air supply unit with the air intake passages in accordance with a fifth embodiment of the invention.
FIG. 8
is a schematic view showing an arrangement of the idle air supply unit with the air intake passages in accordance with a sixth embodiment of the invention.
FIG. 9
is a schematic view showing another power head incorporating an arrangement of the idle air supply unit with the air intake passages in accordance with a seven embodiment of the invention. A protective cowling is shown in phantom.
FIG. 10
is a schematic view showing the arrangement more in detail.
FIG. 11
is a graphical view showing a relationship between idle speeds and shift loads of an switchover mechanism.
FIG. 12
is a graphical view showing a relationship between diameters of restrictions and the idle speeds.
FIG. 13
is a schematic view showing an arrangement of the idle air supply unit with an air manifold and the air intake passages in accordance with an eighth embodiment of the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION
With reference to
FIGS. 1
to
3
, an outboard motor, designated generally by reference numeral
30
, includes an internal combustion engine
32
arranged in accordance with a first embodiment of the present invention. Although the present invention is shown in the context of an engine for an outboard motor, various aspects and features of the present invention also can be employed with other engines such as for automobiles and motorcycles.
In the illustrated embodiment, the outboard motor
30
comprises a drive unit
34
and a bracket assembly
36
. The drive unit
34
includes a power head
38
, a driveshaft housing
40
and a lower unit
42
. The power head
38
is disposed atop of the drive unit
34
and includes the engine
32
, a top protective cowling
46
and a bottom protective cowling
48
.
The engine
32
operates on a four stroke cycle principle and powers a propulsion device. As seen in
FIGS. 2 and 3
, the engine has a cylinder body
50
. Although not shown, the cylinder body
50
defines four cylinder bores generally horizontally extending and spaced generally vertically with each other. A piston can reciprocate in each cylinder bore. A cylinder head member
52
is affixed to one end of the cylinder body
50
and defines four combustion chambers with the pistons and the cylinder bores. The other end of the cylinder body
50
is closed with a crankcase member
54
defining a crankcase chamber with the cylinder bores. A crankshaft or output shaft
56
extends generally vertically through the crankcase chamber. The crankshaft
56
is pivotally connected with the pistons and rotates with the reciprocal movement of the pistons. The crankcase member
54
is located at the most forward position, then the cylinder body
50
and the cylinder head member
52
extends rearwardly from the crankcase member
54
one after another.
The engine
32
includes an air induction system
60
and exhaust system (not shown). The air induction system
60
is arranged to supply air charges to the combustion chambers and comprises a plenun chamber
62
, four main air intake passages
64
and intake ports. The intake ports are defined in the cylinder head assembly
52
and opened or closed by intake valves. When the intake ports are opened, the air intake passages
64
communicate with the combustion chambers. The air induction system
60
will be described in more detail later. The exhaust system is arranged to discharge burnt charges or exhaust gasses from the combustion chambers to outside of the outboard motor
30
. Exhaust ports are defined in the cylinder head assembly
52
also and opened or closed by exhaust valves. When the exhaust ports are opened, the combustion chambers communicate with exhaust passages which lead the exhaust gasses downstream of the exhaust system.
Two camshafts
70
extend generally vertically to activate the intake valves and exhaust valves. The camshafts
70
has cam lobes thereon to push the intake and exhaust valves at certain timings to open or close the respective ports. The camshaft
70
are journaled between the cylinder head member
52
and a cylinder head cover member
72
.
The camshafts
70
are driven by the crankshaft
56
. The respective camshafts
70
have cogged pulleys
74
thereon, while the crankshaft
56
also has a cogged pulley
76
thereon. A cogged belt or chain
78
is wound around the cogged pulleys
74
,
76
. With rotation of the crankshaft
56
, therefore, the camshaft
70
rotate also.
The engine
32
has a direct fuel injection system
82
. The fuel injection system
82
includes four fuel injectors
84
and fuel delivery conduits
86
. A fuel supply tank (not shown) is placed in the hull of the associated watercraft
88
(see FIG.
1
). The fuel contained in the fuel supply tank is supplied to low pressure fuel pumps and a high pressure fuel pump both placed on the outboard motor
30
to be pressurized by them. The pressurized fuel is, then, delivered through the delivery conduits
86
to the fuel injectors
84
. The fuel is sprayed into the combustion chambers every proper timing. The injection timing is controlled by an electronic control unit (ECU) which will be described later.
Although not shown, the engine
32
further has a firing system. Four spark plugs are exposed into the respective combustion chambers and fire an air fuel charge at preset timings. This firing timing is also controlled by the ECU. The air fuel charges are formed with air charges supplied by the main air intake passages
64
and fuel charges sprayed by the fuel injectors
84
in usual states of engine operations. However, in an idle state, air charges are delivered through an idle air passage, which will be described later, and mixed with the fuel charges sprayed by the fuel injectors
84
.
A flywheel assembly
90
is affixed atop the crankshaft
56
. The flywheel assembly
90
includes a generator to supply electric power to the firing system, the ECU and other electrical equipment. A cover member
92
covers the flywheel assembly
90
as well as the pulleys
74
,
76
and the belt
78
for protection of the operator from such moving parts.
Additionally, the engine
32
has a water discharge pipe
94
through which cooling water is discharged and a blow-by gas passage
96
through which blow-by gasses returns to the crankcase chamber from recesses formed in the cylinder head member
52
.
Returning back to
FIG. 1
, the top and bottom cowlings
46
,
48
generally completely enclose the engine
32
. The top cowling
46
is detachably affixed to the bottom cowling
48
so that the operator can access to the engine
32
for maintenance or other purposes.
The driveshaft housing
40
depends from the power head
38
and supports a driveshaft
104
which is driven by the crankshaft
56
of the engine
32
. The driveshaft
104
extends generally vertically through the driveshaft housing
40
. The driveshaft housing
40
also defines internal passages which form portions of the exhaust system.
The lower unit
42
depends from the driveshaft housing
40
and supports a propeller shaft
106
which is driven by the driveshaft
104
. The propeller shaft
106
extends generally horizontally through the lower unit
42
. In the illustrated embodiment, the propulsion device includes a propeller
108
that is affixed to an outer end of the propeller shaft and is driven by the propeller shaft
106
. A transmission
110
is provided between the driveshaft
104
and the propeller
106
. The transmission
110
couples together the two shafts
104
,
106
which lie generally normal to each other (i.e., at a 90° shaft angle) with a bevel gear combination
112
. The transmission
110
has a switchover mechanism
114
to shift rotational directions of the propeller
108
to forward, neutral or reverse. The switchover mechanism
114
, although it is rather schematically illustrated, includes: a dog clutch
116
, a shift cable
118
disposed in the protective cowlings
46
,
48
. A shift rod
120
extending generally vertically is also included in the switchover mechanism
114
to connect the dog clutch
116
with the sift cable
118
. The shift cable
118
extends outwardly from the protective cowlings
46
,
47
so as to be operated by the operator. Actually, the shift rod
120
extends through a swivel bracket, which will be described shortly, and the lower unit
42
. The switchover mechanism
114
is operable at certain engine speeds less than a predetermined speed which will be described later.
The lower unit
42
also defines an internal passage that forms a discharge section of the exhaust system. At engine speed above idle, the majority of the exhaust gasses are discharged to the body of water surrounding the outboard motor
30
through the internal passage and finally through a hub
124
of the propeller
108
, as well known in the art.
The bracket assembly
36
comprises a swivel bracket
130
and a clamping bracket
132
. The swivel bracket
130
supports the drive unit
34
for pivotal movement about a generally vertically extending steering axis. The clamping bracket
132
, in turn, is affixed to a transom
134
of the associated watercraft
88
and supports the swivel bracket
130
for pivotal movement about a generally horizontally extending tilt axis, i.e., the axis of a pivot shaft
136
.
As used through this description, the terms “fore,” “forward,’ “front,” and “forwardly mean at or to the side where the clamping bracket
132
is located, and the terms “rear,” “reverse”, “back,” and “rearwardly” mean at or to the opposite side of the front side, unless indicated otherwise.
Although not shown, a hydraulic tilt system is provided between the swivel bracket
130
and the clamping bracket
132
. The hydraulic tilt system may have various arrangements. However, it basically comprises a cylinder housing, a tilt piston slidably supported in the cylinder housing and a piston rod extending from the tilt piston beyond the cylinder housing. The bottom end of the cylinder housing is affixed to the clamping bracket
132
for pivotal movement about a generally horizontally extending axis, i.e., the axis of a pivotal shaft
138
. The upper end of the piston rod is affixed to the swivel bracket
130
for pivotal movement about a generally horizontally extending axis, i.e., the axis of a pivotal shaft
140
. A powering assembly is also provided for pressurizing working fluid to move the tilt piston up and down within the cylinder housing. With this movement, the piston rod is expanded or contracted to tilt up or down. Thus, the drive unit
40
as well as the swivel bracket
130
is tilted up and down.
A steering handle
144
extends from the swivel bracket
130
forwardly so that the operator can steer the outboard motor
30
in the associated watercraft
88
. A throttle control lever (not shown) is also attached to the steering handle
144
. Throttle valves which will be described later can be operated by the operator with this throttle lever.
With reference to
FIGS. 2 and 3
, the air induction system
60
will be described in more detail.
The plenum chamber
62
is defined in a plenun chamber member
148
positioned on the port side of the crankcase member
54
. The main air intake passages
64
extend rearwardly from the plenum chamber member
148
along the cylinder body
50
and then bend toward the intake ports. The plenum chamber member
148
has an inlet opening, although it is not shown, at its front side and the plenum chamber
62
defined therein functions as an intake silencer and/or an coodination of air charges. The air intake passages
64
are actually defined by duct sections
152
which are uniformly formed with the plenum chamber member
148
, throttle bodies
154
and runners
156
. The upper two throttle bodies
154
are unified with each other. The upper two runners
56
, in turn, are uniformly formed with each other at their fore portions and then forked into two portions. The lower two throttle bodies
154
and runners
156
have the same constructions as the upper two throttle bodies
154
and runners
156
. The air intake passages
64
comprising these members
152
,
154
,
156
extend generally horizontally along the respective cylinder bores and spaced generally vertically with each other. As indicated in
FIG. 2
, the air intake passages
64
are numbered as #
1
through #
4
from the top to the bottom for convenience' sake in this description.
The respective throttle bodies
154
support butterfly-type throttle valves (not shown) therein for pivotal movement about axes of valve shafts extending generally vertically. The valve shafts are linked together to be a single valve shaft
157
that passes through all of the throttle bodies
154
. The throttle valves are operable by the operator with the aforenoted throttle control lever through a throttle cable
158
and a non linear control device
160
.
The non-linear control device
160
includes a first lever
164
and a second lever
166
joined together with each other by cam connection. The first lever
164
is pivotally connected to the throttle cable
158
and pivotally connected to a first pin
168
which is affixed to the cylinder body
50
. The first lever
164
has a cam hole
170
at the opposite end of the connection with the throttle cable
158
; The second lever
166
is generally shaped as the letter “L” and pivotally connected to a second pin
172
which is affixed to the crankcase member
54
. The second lever has a pin
174
that interfits the cam hole
170
. The other end of the second lever
166
is pivotally connected to a control rod
178
. The control rod
178
, in turn, is pivotally connected to a lever member
179
. The lever member
179
is, then, connected to the throttle valve shaft
157
via a coil spring
180
that urges the control rod
178
to be at a position as shown in FIG.
2
. At this position of the control rod
178
, the throttle valve shaft
157
is in a closed position wherein no air charge can pass through the air intake passages
64
.
When the throttle cable
158
is operated, the first lever
164
pivots about the first pin
168
anti-clockwise in FIG.
2
. The second lever
166
, then, pivots about the second pin
172
clockwise. Since the pin
174
of the second lever
166
is intermitted in the cam hole
170
, the second lever
166
moves along this cam shape. Then, the second lever
166
pushes the control rod
178
against the urge of the coil spring
180
to open the throttle valves. When the throttle cable
158
is released, the control rod
178
returns to the initial position by the force of the spring
180
and the throttle valves are closed again.
A throttle valve position sensor
182
is placed atop of the throttle valve shaft
157
. A signal from the position sensor
182
is sent to the ECU for both of the fuel injection control and the firing control.
As seen in
FIG. 2
, the top cowling
46
defines a pair of air intake compartments
186
with compartment members
188
and recesses at both rear sides thereof. Each air intake compartment
186
has an air funnel
190
that stands in the compartment
186
. The air intake compartments
186
, thus, communicate with the interior of the protective cowlings
46
,
48
.
Air is introduced, at first, into the air intake compartments
186
as indicated by the arrow
192
and enters into the interior of the cowlings
46
,
48
through the air funnels
190
as indicated by the arrows
196
,
198
. Then, the air goes down to the inlet opening of the plenum chamber member
148
as indicated by the arrow
200
and enters into the plenum chamber
62
. The plenum chamber
62
attenuates intake noise and delivers air charges to the respective duct sections
152
. Amounts of the air charges are controlled by the throttle valves in the throttle bodies
154
to meet the requirements for operational conditions of the engine
32
. The adjusted air charges are, then, go to the runners
156
and finally reach the intake ports. As described above, the intake valves are provided at these intake ports. Since the intake valves are opened intermittently by the cam lobes of the camshafts
70
, the air charges are finally supplied to the combustion chambers when the intake valves are opened.
The air induction system
60
further includes an idle air supply unit
210
. With still reference to
FIGS. 2 and 3
, the idle air supply unit
210
in accordance with a first embodiment of the present invention will be described.
The idle air supply unit
210
is located between the cylinder body
50
and the main air intake passages
64
. Actually, the idle air supply unit
210
is affixed to the #
1
and #
2
runners
156
. This is effective because the heat in the cylinder body
50
does not conducted to the idle air supply unit
210
. The idle air supply unit
210
comprises an idle air manifold
212
and idle speed controller (ISC)
214
. Although a detailed description in connection with the construction of the idle air supply unit
210
will be made with reference to
FIG. 4
shortly, an inlet bypass
216
, which is shown schematically with the phantom line in
FIG. 2
, connects the plenum chamber
62
with the idle air manifold
212
. A housing of the ISC
214
includes a through-passage therein. The through passage communicates with the idle air manifold
212
. A pair of outlet bypasses
218
connect the idle air manifold
212
with bypass inlet ports
222
which are positioned on the #
1
throttle body
154
and #
3
throttle body
154
downstream of the main throttle valves. The outlet bypasses
218
are delivery conduits and made of elastic material such as synthetic rubber. The inlet port
222
on the #
1
throttle body
154
communicates with the #
2
throttle body
154
by an internal passage as well as the #
1
throttle body
154
. This is shown schematically again with the dotted arrows in FIG.
2
. The other inlet port
222
on the #
3
throttle body
154
, in turn, communicates with the #
4
throttle body
154
by another internal passage as well as the #
3
throttle body
154
, although this is not shown.
The sum of cross-sectional areas of the outlet bypasses
218
is greater than a cross-sectional area of the inlet bypass
216
, more specifically, a cross-sectional area of the inlet portion of the inlet bypass
216
to the housing of the ISC
214
.
The housing of the ISC
214
has an idle throttle valve therein that is a butterfly type and placed in the through-passage. The opening of the idle throttle valve is controlled by the ECU. The term “idle speed controller” or “ISC” includes the control by the ECU. The pure mechanical part of the ISC including the housing and excluding the control by the ECU will be called as an “idle air control mechanism” in this description and Claims.
The ISC
214
is a feedback control system. An actual idle speed is sensed by a crankshaft angle position sensor (not shown) which is provided associated with the crankshaft
56
. The crankshaft angle position sensor outputs a crankshaft rotational speed signal or engine speed signal. The engine speed at an idle state is the idle speed. That is, the engine
32
operates under substantially no load in the idle state. More specifically, the changeover mechanism
114
is in the neutral position. Otherwise, the changeover mechanism
114
is in a forward position but the throttle control lever is not operated and the propeller
108
simply rotates in the trolling mode. The actual idle speed changes generally in proportion to the amounts of air charges that is regulated by the ISC
214
.
Meanwhile, the ECU stores preset idle speeds in its control map. When the actual idle speed is sensed by the crankshaft angle position sensor, a signal is sent to the ECU and compared with one of the preset idle speeds by the ECU. If the actual idle speed is greater than the preset idle speed, the ECU will activate the idle throttle valve toward the closed position. If the actual speed is smaller than the preset speed, the control device will activate it toward the open position. The actual idle speed is accordingly maintained as almost equal to the preset idle speed. The ECU can store multiple preset idle speeds which meet with various engine conditions including the engine start, the usual engine warm up, the engine warm up or running in a very cold situation, the idle state in which the switchover mechanism
114
is in the neutral position and the trolling state in which the switchover mechanism
114
is in the forward position but the engine operates still in the idle state. As aforenoted, the ECU selects one of the preset idle speeds in response to the current engine condition and control the opening of the idle throttle valve to adjust an air amount to make an actual idle speed meet the preset idle speed.
When the throttle control lever on the steering handle
144
is not operated, i.e., in the idle state, the main throttle valves in the throttle bodies
154
are closed. The idle air charge, therefore, is supplied to the combustion chambers through the idle air supply unit
210
bypassing the main air intake passages
64
. The air charge in the plenum chamber
62
goes to the housing of the ISC
214
or idle air control mechanism through the inlet bypass
216
and its amount is adjusted in response to the engine condition by the ISC
214
. The adjusted air charge, then, goes to the idle air manifold
212
to be equalized therein before delivered to the respective outlet bypasses
218
. Then, the air charge goes to the portions of the respective throttle bodies
154
that position downstream of the throttle valves through the outlet bypasses
218
and finally reaches the combustion chambers.
The air charge is mixed with the fuel charge sprayed by the fuel injectors
84
and fired by the spark plugs. The fuel charge has been also regulated in a suitable manner to make an appropriate air fuel ratio with the air charge. Burning of the air fuel charge moves the pistons down to rotate the crankshaft
56
. If the rotational speed of the crankshaft
56
, i.e., the idle speed, is faster than the preset speed, the ISC
214
activates the idle throttle valve toward the closed position and a smaller amount of air is supplied to reduce the idle speed. Meanwhile, if the rotational speed of the crankshaft
56
, i.e., the idle speed, is slower than the preset speed, the ISC
214
activates the idle throttle valve toward the open position and a larger amount of air is supplied to increase the idle speed. The actual idle speed is, thus, controlled to be consistent with the preset idle speed.
As described above, all of the main air intake passages
64
have their own throttle valves. Because the air charges that flow through the respective intake passages
64
are separately controlled by the own throttle valves, this arrangement does not need a large space for the plenum chamber
62
. In addition, the idle air manifold
212
is provided for supplying idle air charges to the combustion chambers additionally to the main air intake passages
64
. The ISC
214
is attached to the idle air manifold
212
to control amounts of the air charges flowing through the idle air manifold
212
. Since the idle air manifold
212
is provided separately from the main air intake passages
64
and air pressure of the air charge is equalized in the manifold
212
before delivered to the combustion chambers. The ISC
214
is provided on the idle air manifold
212
rather than the respective air intake passages
64
, the system will not have any problem in controlling the air amounts even with the single ISC
214
. No separate control maps are necessary for the ISC
214
in this arrangement accordingly.
Also, the sum of cross-sectional areas of the outlet bypasses
218
is greater than a cross-sectional area of the inlet portion of the inlet bypass
216
to the housing of the ISC
214
. Because of this, the air flowing through the outlet bypasses
218
reduces its speed sufficiently and hence intake air pressures in the respective air passages
64
are almost equal to each other. The single ISC
214
, therefore, will not cause any problems with the multiple air passages
64
and a common control map can be used for the ISC
214
.
FIG. 4
illustrates another arrangement of the idle air supply unit
210
that connected to the main air intake passages
64
in accordance with a second embodiment of the present invention. The same members or components already described in connection with the first embodiment shown in
FIG. 1 through 3
will be assigned with the same numerals. The other embodiments following this second embodiment will be described in the same manner.
The idle air manifold
212
may be affixed to the #
1
and #
2
runners
156
like in the arrangement of the first embodiment. The housing of the ISC
214
is now designated with the reference numeral
230
. The through-passage and the idle throttle valve are also provided therein. The aforenoted idle air control mechanism includes the housing
230
, the though-passage, the idle throttle valve and an actuator of the idle throttle valve. The air control mechanism is now designated by the reference numeral
231
. The ECU, which is also indicated with the reference numeral
232
, is mounted on an appropriate wall portion of the engine
32
or located at any other place in the protecting cowlings
46
,
48
. The ECU
232
is connected to the idle air control mechanism
231
by a signal line
234
, which is schematically indicated, and arranged to control the idle throttle valve, more specifically, the actuator.
An inlet conduit
238
made of elastic material such as synthetic rubber is connected to the ISC housing
230
by a nipple or joint member
240
made of metal. The inlet conduit
238
communicates with the plenum chamber
62
, while the nipple
240
communicates with the through-passage in the ISC housing
230
. The ISC housing
230
is mounted on and above the idle air manifold
212
in a suitable manner. An inlet port
241
is provided at the top side of the idle air manifold
212
and the other end of the through-passage communicates with the inlet port
241
.
The idle air manifold
212
has four outlet ports
242
at both sides thereof. That is, a pair of outlet ports
242
are allotted at one side of the idle air manifold
212
, while the other pair of outlet ports
242
are allotted at the other side of the manifold
212
. The respective outlet ports
242
have nipples
246
which are also made of metal. The respective main air intake passages
64
, in turn, have inlet ports
248
and nipples
246
are fitted into the inlet ports
248
. The inlet ports
248
are positioned downstream of the throttle valves and may be formed at the runners
156
. The nipples
246
of the idle air manifold
212
and the nipples
246
of the air intake passages
64
are connected together by four delivery conduits which are made of elastic material.
The idle air manifold
212
additionally has two openings
254
,
256
. An intake air pressure sensor
258
is affixed to and below the idle air manifold
212
so that its sensor tip is exposed to the interior of the manifold
212
. The intake air pressure sensor
258
senses air pressure in the idle air manifold
212
through the opening
254
. A signal from that the sensor
258
will be sent to the ECU
232
by a signal line
265
to adjust an amount of fuel sprayed into the combustion chambers.
A nipple
264
is fitted into the other opening
256
and an elastic conduit
266
is connected to this nipple
264
. The other end of the elastic conduit
266
communicates with a fuel pressure regulator (not shown). A purpose in connecting the idle air manifold
212
with the fuel pressure regulator is to make a difference between the air pressure and the fuel pressure generally fixed at every engine speed, from low speed to high speed. This is advantageous for keeping the fuel injections under stable conditions.
Although the intake air pressure sensor
258
and the elastic conduit
266
are not shown in
FIGS. 2 and 3
, these members are provided in the arrangement of the first embodiment also.
Similar to the first embodiment, instead of the main air intake passages
64
, the idle air manifold
212
can supply idle air charges to the combustion chambers, although the runners
156
are commonly used. Also, the ISC
214
is attached to the idle air manifold
212
. Same as the first embodiment, because the idle air manifold
212
is provided separately from the main air intake passages
64
and air pressure of the air charge is equalized in the manifold
212
before delivered to the combustion chambers and the ISC
214
is provided on the idle air manifold
212
rather than the respective air intake passages
64
, the system will not have any problem in controlling the air amounts even with the single ISC
214
. No separate control maps are necessary for the ISC
214
in this arrangement also.
Alike the first embodiment, the sum of cross-sectional areas of the delivery conduits
252
are larger than a cross-sectional area of the inlet nipple
240
. The same effect described above with the first embodiment is obtained with this embodiment. In addition to that, each cross-sectional area of the delivery conduit
252
is larger than each cross-sectional area of the nipple
246
. This brings in more effective result because the length of the delivery conduit
252
is far longer than the length of the nipple
246
. It should be noted that the sum of cross-sectional areas of the nipples
246
at the outlet ports
242
is, still larger than the cross-sectional area of the inlet nipple
240
in this arrangement.
FIG. 5
illustrates an arrangement it accordance with a third embodiment of the present invention.
In this arrangement, an air rail
278
is provided as the idle air manifold. The air rail
278
extends generally vertically and four outlet ports
280
are provided to be spaced apart evenly with each other on one side of the manifold
212
that faces the air intake passages
64
, specifically, the runners
156
. The intervals of the respective outlet ports
280
are equal to the intervals of the respective inlet ports
248
of the runners
156
and the air rail
278
is positioned in the proximity to the respective runners
156
. Because of this, the outlet ports
280
of the air rail
278
are connected with the inlet ports
248
of the runners
156
directly by the nipples
246
.
An inlet port
282
is provided on the other side of the air rail
278
at the center portion thereof. The intake air pressure sensor
258
is fitted into an opening
288
which is provided directly below the opening
282
. The nipple
264
on which the delivery conduit
266
communicating with the regulator is fixed is fitted into an opening
290
provided at the top side of the air rail
278
.
FIG. 6
illustrates an arrangement in accordance with a fourth embodiment of the present invention.
The air rail
278
is again provided as the idle air manifold. The air rail
278
is spaced apart from the air intake passages
64
unlike the arrangement of the third embodiment. The nipples
246
fitted into the outlet ports
280
of the air rail
278
are, therefore, connected with the nipples
246
fitted into the inlet ports
248
of the respective runners
156
by the delivery conduits
252
. The other part of this arrangement is the same as the residual part that excludes the connections from the arrangement shown in FIG.
5
.
FIG. 7
illustrates an arrangement in accordance with a fifth embodiment of the present invention.
A slightly larger air rail
294
is provided as the idle air manifold. The ISC housing
230
is positioned atop of the air rail
294
. The delivery conduit
266
is affixed to the nipple
264
which is positioned at the center of the opposite side of the outlet ports
280
. The other part of this arrangement is the same as the residual part of the arrangement shown in FIG.
6
.
The location of the ISC housing
230
in this arrangement brings in a particular advantage. That is, because it is positioned atop of the air rail
294
, the air charge passing through the inlet conduit
238
will not be affected by the heat that is held by the surrounding air which is stagnant at the bottom of the protective cowlings
46
,
48
. The air charge to the idle air manifold
294
, therefore, will have a relatively low temperature that may equal to the atmospheric temperature. The density of the air charge will be relatively high accordingly.
FIG. 8
illustrates an arrangement in accordance with a sixth embodiment of the present invention.
The same air rail
294
is provided as the idle air manifold in this arrangement. Only difference between the arrangement of the fifth embodiment and this arrangement is that the ISC
214
, the delivery conduit
266
and the intake air pressure sensor
258
in this arrangement are disposed upside down relative to the arrangement of the fifth embodiment.
The location of the ISC housing
230
in this arrangement results in another advantage. That is, the ISC
230
and the inlet conduit
238
does not projected upwardly. This can contribute for compactness and neatness of the engine
32
.
FIGS. 9 and 10
illustrate an arrangement in accordance with a seventh embodiment of the present invention.
An internal combustion engine
300
, which is a different type from the aforedescribed engine
32
, is employed for the power head
38
. The other part of the outboard motor is the same as the motor
30
already described above. The engine
300
is a type of V
4
and includes a pair of banks both having two cylinder bores. However, it still operates on a four stroke cycle principle. The engine
300
comprises a cylinder body
302
defining the cylinder bores in which pistons reciprocate. The cylinder bores disposed each bank are spaced apart generally vertically from each other and extend generally horizontally. A pair of cylinder head assemblies
304
are affixed to the respective banks of the cylinder body
302
to define combustion chambers with the cylinder bores and the pistons. A crankcase member
306
is affixed to the other side of the engine
300
to define a crankcase chamber with the cylinder body
302
. A crankshaft, which rotates with the reciprocal movement of the pistons, extends generally vertically within the crankcase chamber.
An air induction system
308
is provided for supplying air charges to the combustion chambers. This air induction system
308
will be described shortly. An exhaust system
310
is also provided for discharging exhaust gasses from the combustion chambers. Exhaust manifolds
314
which collect exhaust gasses from respective exhaust ports are shown in FIG.
9
. The exhaust manifolds
314
are enclosed by outer covers
316
. Although the engine
300
further includes a direct fuel injection system and a firing system, these are omitted in FIG.
9
. The functions of these systems are the same as the systems that are already described.
The air induction system
308
includes the plenum chamber member
148
defining the plenum chamber
62
therein. Two pairs of main air intake passages
322
extend from both sides of the plenum chamber member
148
and communicate with the plenum chamber
62
. The air intake passages
322
disposed at each side are spaced apart generally vertically to each other. Also, they extend generally horizontally and rearwardly along the cylinder body
302
toward the combustion chambers. Intake ports are provided in the cylinder head assemblies
304
to accept end portions of the air intake passages
322
.
Each of the air intake passages
322
has a throttle body
326
in which an air passage
328
is defined. The air passages
328
communicate with the respective air intake passages
322
so that air charges flow through the air intake passages
322
all the way form the plenum chamber
62
to the combustion chambers. Butterfly-type throttle valves
340
are pivotally affixed in the respective throttle bodies
326
. Thus, amounts of the air charges supplied to the combustion chambers are regulated by the throttle valves
340
in response to various engine conditions.
Like in the already described arrangements, the air induction system
308
further includes an idle air supply unit
341
. The idle air supply unit
341
is positioned above the cylinder body
302
and connected to the plenum chamber member
148
through an inlet bypass
342
. Two outlet bypasses
343
extend from both sides of the idle air supply unit
341
and reach the respective main air intake passages
322
downstream of the throttle valves
340
.
The idle air supply unit
341
is similar to the aforenoted idle supply unit
210
. However, as seen in
FIG. 10
, the mechanical part of the ISC
214
, i.e., idle air control mechanism
231
and an air manifold section
344
are unified together in a single housing
346
. An idle throttle valve
348
projects into the air manifold section
344
from the idle air control mechanism
231
. This idle throttle valve
348
in not a butterfly-type. The valve
348
has a downwardly narrower tapered portion
350
supported on a shaft
352
. The shaft
352
is reciprocally movable along its axis as indicated by the double-headed arrows
354
. Meanwhile, the housing
346
has an recess
356
into which the tapered portion
350
enters. Because of this construction, an area of a gap
360
between the tapered portion
350
and the top of the recess
356
changes with the reciprocal movement of the valve
348
and air amounts passing through the gap
360
is adjusted. The reciprocal movement of the valve
348
is controlled by the ISC
214
with an actuator which is not shown. The aforenoted intake air pressure sensor
258
and conduit
266
to the fuel regulator are provided in this arrangement also, although these are not shown.
Actually, the outlet bypasses
343
are connected to the throttle bodies
326
directly downstream of the throttle valves
340
. As best seen in
FIG. 10
, the throttle bodies
326
on the same sides are unified with each other and the air passages
328
are defined therein and spaced apart generally vertically to each other. Delivery paths
362
are also defined therein to connect the outlet bypasses
343
with the air passages
328
. The delivery paths
362
further diverge to form inlet paths
364
and then connected to the air passages
328
.
The inlet bypass
342
and the outlet bypasses
343
are made of elastic material such as synthetic rubber. Nipples
365
made of metal are again used for connecting the inlet and outlet bypasses
342
,
343
to the housing
346
and the respective throttle bodies
326
.
As described above, if an amount of air charge supplied by the idle air supply unit
341
is excessive, idle speed of the engine
308
increases higher than a certain speed that may give rise to impossibility of the operation of the changeover mechanism
114
.
FIG. 11
illustrates a relationship between an idle speed and a shift load of the changeover mechanism
114
. When the idle speed becomes larger, the shift load also becomes larger. The change rate of this characteristic curve also becomes larger with the increase of the idle speed. If this characteristic curve exceeds over the line (A), the shift operation is no longer possible. The line (B) indicates the idle speed over which the shift operation is impossible. Particularly, since the outboard motor
30
employs the dog clutch, the shift operation from the forward (or reverse) position to the neutral position is likely to be difficult or impossible. Positions of the border lines (A) and (B) depend on shapes of the dog clutches, constructions of the switchover mechanisms, torque of engines and other various reasons.
Returning back to
FIG. 10
, the inlet paths
364
have restrictions or orifices
370
directly upstream of the air passages
328
in order to improve the situation in the shift operation. Air charges supplied to the combustion chambers through the air passages
328
are surely regulated by the restrictions
370
before entering the passages
328
. The diameters of the restrictions
370
are set to be the size that can permit air to flow therethrough to maintain the engine speed less than a predetermined speed. Because, as described above, the changeover mechanism
114
is shiftable within idle speeds less than the predetermined speed.
With Reference to
FIG. 12
, the relationship between diameters of the restrictions
370
and the engine speeds. The engine speed increases almost in proportion to the diameters of the restrictions
370
. When the diameter exceeds the line (C), the engine speed comes into the area where the shift operation by the changeover mechanism
114
becomes impossible. The area of the engine speed is over the line (B) that is also shown in FIG.
11
. This means that, inasmuch as the engine speed is regulated less than the line (B), the changeover mechanism
114
is always shiftable and that, in order to regulate the engine speed less than the line (B), the diameter of the restriction
370
should be less than the line (C). The engine speed on the line (B) is the predetermined speed.
The diameters of the restrictions
370
, on the other hand, should be a size larger than the size that can afford air amounts required for the engine start, engine warming up or running particularly under very cold conditions, maintaining idle states, preventing the engine from stalling and other various situations. The diameters of the restrictions
370
are, thus, determined to be less than the value on the line (C) and larger than the value that will be suited to such various situations by experiments or other proper methods.
Because of the restrictions
370
, amounts of idle air will never be increased over the regulated value and the shift operation by the switchover mechanism
114
will be surely made. As a result, even though disconnection or damage of the elastic conduits
343
or seizure or damage of the ISC mechanism
231
would occur, the idle speed of the engine would never exceed the predetermined speed irrespective of the intention of the operator.
Although the restrictions
370
can be disposed at any positions between the idle throttle valve
348
and the inlet portions to the air passages
328
from the inlet paths
364
, it is desirable to be positioned directly upstream of the inlet portions to the air passages
328
in the inlet paths
364
. In addition, this directly upstream arrangement is useful for preventing air intake conditions in respective air passages
328
from affecting the other passages
328
.
FIG. 13
illustrates an arrangement in accordance with an eighth embodiment of the present invention.
A main air manifold
380
is provided upstream of main air intake passages
382
and communicates with the aforenoted plenum chamber
62
. In other words, the air intake passages
382
diverge from the air manifold
380
downstream thereof. A main throttle valve
384
is disposed in the air manifold
380
. Because of this, the air intake passages
382
have no throttle valves therein. An idle air passage
386
extends along the air manifold
380
. The idle air passage
386
is connected to the air manifold
380
at two portions so as to communicate with the manifold
380
at the upstream and downstream portions of the throttle valve
384
. That is, the idle air passage
386
bypasses the throttle valve
384
. The idle air supply unit
341
including the ISC
214
is provided in the idle air passage
386
. A restriction or orifice
388
is disposed downstream of the idle air passage
386
directly upstream of the portion where the idle air passage
386
communicates with the air manifold
380
. The aforenoted intake air pressure sensor
258
and conduit
266
to the fuel regulator are again provided in this arrangement, although these are not shown also.
The function of this restriction
388
is the same as that of the restrictions
370
and air amounts flowing into the air manifold
380
from the idle air passage
386
is regulated by the restriction
388
. Thereby, the switchover mechanism
114
can be surely operated. In addition, this arrangement is quite simple because idle air control can be made only with a single idle air passage
386
having the single idle air supply unit
341
and also the single restriction
388
.
As described above, the respective air intake passages have their own throttle valves. Thus, the air induction system does not become large. In addition, the idle air manifold is provided and the feedback control system or ISC is arranged to control amounts of the air charges that flow through the idle air manifold. The control of the ISC mechanism is simple and easy accordingly.
Also, the sum of cross-sectional areas of the delivery passages that diverge from the idle air manifold is greater than a cross-sectional area of the inlet portion of the air manifold. Since the air that pass through the delivery passages reduces its speed sufficiently, intake air pressures in the respective air passages
64
are almost equal to each other. Therefore, no unstable condition will occur with the ISC.
Further, the respective delivery passages have restrictions upstream of the junctions to the intake air passages. As a result, excessive air will not be supplied to the combustion chambers in the idle state. The idle speed, hence, will not exceed a permissible range on any occasions.
Of course, the foregoing description is that of preferred embodiments of the invention, and various changes and modifications may be made without departing from the spirit and scope of the invention, as defined by the appended claims.
Claims
- 1. An internal combustion engine comprising a cylinder body defining a plurality of cylinder bores in which pistons reciprocate, a cylinder head affixed to an end of said cylinder body and defining combustion chambers with said pistons and said cylinder bores, a plurality of air intake passages supplying air charges to said combustion chambers, said air intake passages being spaced generally vertically relative to each other, each one of said air intake passages including a throttle valve arranged to control an amount of the air charge that flows through each one of said air intake passages, an idle air manifold supplying air charges to said combustion chambers, and a feedback control system arranged to control amounts of the air charges that flow through said idle air manifold based upon a difference between a preset idle speed and an actual idle speed of said engine.
- 2. An internal combustion engine as set forth in claim 1, wherein the actual idle speed changes generally in proportion to the amounts of the air charges that flow through said idle air manifold.
- 3. An internal combustion engine as set forth in claim 1, wherein said feedback control system includes an idle air control mechanism arranged to supply the air charges to said idle air manifold.
- 4. An internal combustion engine as set forth in claim 3, wherein said idle air control mechanism is positioned upstream of said idle air manifold.
- 5. An internal combustion engine as set forth in claim 4, wherein said idle air control mechanism is placed on one side of said idle air manifold.
- 6. An internal combustion engine as set forth in claim 5, wherein said idle air manifold has outlet ports corresponding to said air intake passages on one side of said idle air manifold, and said idle air control mechanism is placed at the opposite side of said outlet ports.
- 7. An internal combustion engine as set forth in claim 5, wherein said idle air manifold includes outlet ports spaced generally vertically relative to each other, each one of said outlet ports corresponds to each one of said air intake passages, said outlet ports and said air intake passages being connected, respectively, said idle air control mechanism being disposed at generally a center position of said outlet ports.
- 8. An internal combustion engine as set forth in claim 7, wherein said respective outlet ports are disposed at generally even intervals.
- 9. An internal combustion engine as set forth in claim 4, wherein said idle air control mechanism is placed above said idle air manifold.
- 10. An internal combustion engine as set forth in claim 4, wherein said idle air control mechanism is placed below said idle air manifold.
- 11. An internal combustion engine as set forth in claim 4, wherein said idle air control mechanism includes an inlet port, said idle air manifold includes outlet ports corresponding to said air intake passages, said outlet ports and said air intake passages are connected by delivery conduits, and the sum of cross-sectional areas of said delivery conduits is greater than a cross-sectional area of said inlet port.
- 12. An internal combustion engine as set forth in claim 11, wherein said outlet ports have joint members communicating with said delivery conduits, and a cross-sectional area of each one of said delivery conduits is greater than a cross-sectional area of each one of said joint members.
- 13. An internal combustion engine as set forth in claim 3, wherein said idle air control mechanism includes an idle air passage and an idle throttle valve positioned in said idle air passage, and said feedback control system controls an opening of said idle throttle valve.
- 14. An internal combustion engine as set forth in claim 13, wherein said feedback control system includes an idle speed sensor arranged to sense a rotational speed of a crankshaft as the idle speed, said crankshaft is rotated by the reciprocal movement of said pistons, means for comparing the actual idle speed sensed by said idle speed sensor with the preset idle speed, and means for controlling the opening of said idle throttle valve based upon an output of said comparing means.
- 15. An internal combustion engine as set forth in claim 14, wherein said engine has a fuel injection system arranged to supply fuel to said combustion chambers, an air pressure sensor arranged to sense an air pressure in said idle air manifold, and an amount of the fuel is adjusted by said fuel injection system based upon a signal from said air pressure sensor.
- 16. An internal combustion engine as set forth in claim 15, wherein said air pressure sensor is affixed to said idle air manifold.
- 17. An internal combustion engine as set forth in claim 15, wherein said fuel injection system includes a fuel regulator, said fuel regulator is connected to said idle air manifold to receive air pressure therein, and said fuel regulator adjusts pressure of the fuel supplied to said combustion chamber based upon the air pressure.
- 18. An internal combustion engine as set forth in claim 1, wherein said engine further comprises delivery conduits connecting said idle air manifold with said air intake passages downstream of said throttle valves.
- 19. An internal combustion engine as set forth in claim 18, wherein said delivery conduits are connected to each one of said intake passages.
- 20. An internal combustion engine as set forth in claim 18, wherein said delivery conduits includes elastic portions.
- 21. An internal combustion engine as set forth in claim 18, wherein each one of said delivery conduits has a cross-sectional area through which an amount of air is regulated.
- 22. An internal combustion engine as set forth in claim 18, wherein each one of said delivery conduits has a restriction.
- 23. An internal combustion engine as set forth in claim 1, wherein said idle air manifold is connected to said respective air intake passages directly by joint members.
- 24. An internal combustion engine as set forth in claim 1, wherein said idle air manifold includes outlet ports spaced generally vertically relative to each other, each one of said outlet ports corresponds to each one of said air intake passages, said outlet ports and said air intake passages being connected together, repectively.
- 25. An internal combustion engine as set forth in claim 24, wherein said idle air manifold is disposed in the proximity of said air intake passages, and said respective outlet ports and said respective air intake passages are connected by joint members made of metal.
- 26. An internal combustion engine as set forth in claim 24, wherein said respective outlet ports and said respective air intake passages are connected by delivery conduits made of elastic material.
- 27. An internal combustion engine as set forth in claim 1, wherein said engine further comprises a fuel injection system arranged to supply fuel into said combustion chambers.
- 28. An internal combustion engine as set forth in claim 1 in combination with a marine propulsion device, wherein said engine powers said marine propulsion device.
- 29. An internal combustion engine comprising a cylinder body defining a plurality of cylinder bores in which pistons reciprocate, a cylinder head affixed to an end of said cylinder body and defining combustion chambers with said pistons and said cylinder bores, a plurality of air intake passages supplying air charges to said combustion chambers, each one of said air intake passages including a throttle valve arranged to control an amount of the air charge that flows through each one of said air intake passages, an idle air manifold supplying air charges to said combustion chambers, and a feedback control system arranged to control amounts of the air charges that flow through said idle air manifold based upon a difference between a preset idle speed and an actual idle speed of said engine, said air intake passages being connected to said idle air manifold with delivery conduits less than the number of said air intake passages.
- 30. An internal combustion engine comprising a cylinder body defining a plurality of cylinder bores in which pistons reciprocate, a cylinder head affixed to an end of said cylinder body and defining combustion chambers with said pistons and said cylinder bores, a plurality of air intake passages supplying air charges to said combustion chambers, each one of said air intake passages including a throttle valve arranged to control an amount of the air charge that flows through each one of said air intake passages, an idle air manifold supplying air charges to said combustion chambers, and a feedback control system arranged to control amounts of the air charges that flow through said idle air manifold based upon a difference between a preset idle speed and an actual idle speed of said engine, said air intake passages extending along said cylinder body, and said idle air manifold being placed between said air intake passages and said cylinder body.
- 31. An internal combustion engine as set forth in claim 30, wherein said idle air manifold is affixed on at least one of said air intake passages.
- 32. An internal combustion engine for a marine propulsion device comprising a cylinder body defining at least one cylinder bore in which a piston reciprocates, a cylinder head affixed to an end of said cylinder body and defining a combustion chamber with said piston and said cylinder bore, at least one air intake passage supplying an air charge to said combustion chamber, said air intake passage including a throttle valve arranged to control an amount of the air charge that flows through said air intake passage, an idle air passage bypassing said throttle valve to deliver idle air to said combustion chamber, and an idle air control system arranged to control an amount of an air charge that flows through said idle air passage, said idle air passage having a restriction through which the amount of the air charge is regulated, said marine propulsion device being shiftable at least between a neutral position and a forward position within an idle speed range less than a preset speed, and said restriction having a diameter with which the amount of the air charge maintains the idle speed less than the preset speed.
- 33. An internal combustion engine as set forth in claim 32, wherein said restriction is positioned in the proximity of a junction of said idle air passage to said air intake passage.
- 34. An internal combustion engine as set forth in claim 32, wherein said idle air passage is connected to said air intake passage downstream of said throttle valve.
- 35. An internal combustion engine as set forth in claim 32 additionally comprising a feed back control system, wherein said idle air control system has an idle throttle valve, and said feed back control system controls an opening of said idle throttle valve based upon a difference between an actual idle speed and a preset idle speed.
- 36. An internal combustion engine as set forth in claim 32, wherein the restriction is positioned downstream of said idle air control system.
- 37. An internal combustion engine for a marine propulsion device comprising a cylinder body defining a plurality of cylinder bores in which pistons reciprocate, a cylinder head affixed to an end of said cylinder body and defining combustion chambers with said pistons and said cylinder bores, a plurality of air intake passages supplying air charges to said combustion chambers, each one of said air intake passages having a throttle valve and arranged to control an amount of the air charge that flows through each one of said air intake passages, an idle air passage bypassing said throttle valves to deliver idle air to said combustion chambers, an idle air control system arranged to control amounts of air charges that flow through said idle air passage, said idle air passage including an idle air manifold and a plurality of idle air delivery conduits positioned downstream of said idle air manifold and corresponding to said respective air intake passages, each one of said idle air delivery conduits having a restriction through which the amount of the air charge is regulated, said marine propulsion device being shiftable at least between a neutral position and a forward position within an idle speed range less than a preset speed, and each one of the restrictions having a diameter with which the amount of the air charge maintains the idle speed less than the preset speed.
- 38. An internal combustion engine as set forth in claim 37, wherein said idle air manifold has an inlet, and the sum of cross-sectional areas of said idle air delivery conduits is greater than a cross-sectional area of said inlet.
- 39. An internal combustion engine comprising a cylinder body defining a plurality of cylinder bores in which pistons reciprocate, a cylinder head affixed to an end of said cylinder body and defining combustion chambers with said pistons and said cylinder bores, a plurality of air intake passages supplying air charges to said combustion chambers, each one of said air intake passages including a throttle valve arranged to control an amount of the air charge that flows through each one of said air intake passages, an idle air passage bypassing said throttle valves to deliver idle air to said combustion chambers, an idle air control system arranged to control an amount of an air charge that flows through said idle air passage, said idle air passage including an idle air manifold having an inlet portion and a plurality of idle air delivery conduits, said idle air delivery conduits diverging from said idle air manifold and communicating with said respective air intake passages, and the sum of cross-sectional areas of said idle air delivery conduits being greater than a cross-sectional area of said idle air manifold.
- 40. An internal combustion engine for a marine propulsion device comprising a cylinder body defining a plurality of cylinder bores in which pistons reciprocate, a cylinder head affixed to an end of said cylinder body and defining combustion chambers with said pistons and said cylinder bores, an air intake conduit supplying air charges to said combustion chambers, said air intake conduit including an upstream portion and a plurality of downstream portions branched off from the upstream portion toward said combustion chambers, said upstream portion having a throttle valve arranged to control amounts of the air charges that flow through said upstream portion, an idle air passage bypassing said throttle valve to deliver idle air to said downstream portions, an idle air control system arranged to control amounts of air charges that flow through said idle air passage, said idle air passage having a restriction through which the amount of the air charge is regulated, said marine propulsion device being shiftable at least between a neutral position and a forward position within an idle speed range less than a preset speed, and said restriction having a diameter with which the amount of the air charge maintains the idle speed less than the preset speed.
- 41. An internal combustion engine as set forth in claim 40, wherein said restriction is positioned downstream of the idle air control system.
- 42. An internal combustion engine comprising a cylinder body defining a plurality of cylinder bores in which pistons reciprocate, a cylinder head affixed to an end of the cylinder body and defining a plurality of combustion chambers with the pistons and the cylinder bores, a plurality of air intake passages supplying air to the combustion chambers, each one of the air intake passages including means for metering an amount of the air that flows through each one of the air intake passages, an idle air supply device bypassing the metering means, a control system arranged to control an amount of air that flows through the idle air supply device based upon a difference between a preset idle speed and an actual idle speed of the engine, and an air pressure sensor mounted on the idle air supply device to sense air pressure in the idle air supply device, the control system further controlling an operation of the engine based upon a signal from the air pressure sensor.
Priority Claims (3)
Number |
Date |
Country |
Kind |
10-307256 |
Oct 1998 |
JP |
|
10-307269 |
Oct 1998 |
JP |
|
11-043444 |
Feb 1999 |
JP |
|
US Referenced Citations (8)
Foreign Referenced Citations (3)
Number |
Date |
Country |
2 321 085 |
Jul 1998 |
GB |
61-93228 |
May 1986 |
JP |
3-121266 |
May 1991 |
JP |