This patent application is based on and claims priority under 35 U.S.C. § 119 to Japanese Patent Application No. 2008-015224, filed on Jan. 25, 2008, the entire contents of which is hereby expressly incorporated by reference.
The present invention relates to engine control systems and vehicles including engine control systems, and more particularly to engine control systems including a rectifier and vehicles including such engine control systems.
There is conventionally known an engine control system and a vehicle including the engine control system (see, for example, Japanese Patent Publication 2002-013459). The Japanese Patent Publication discloses a method and a system (engine control system) for controlling the ignition of an engine including an alternating current (AC) generator (power generating unit) driven by rotating a crankshaft, a regulator (rectifier) half-wave rectifying a voltage output from the AC generator, an ignition plug, an ignition coil (an operational load) to which current is supplied by the regulator, and an ignition system controlling supply and cutoff of current to the ignition coil. With this engine igniting method, the ignition plug is configured to give off sparks by generating high voltage using a change in the current when the current to be supplied to the ignition coil is cut off. Furthermore, the voltage output by the regulator is obtained by half-wave rectifying the voltage from the AC generator. A waveform of the voltage output from this regulator has an angular shape including a part having a larger change in the amount of the voltage and a part having a small change in the amount of the voltage. Furthermore, the ignition system is configured to control the ignition coil to give off sparks by generating high voltage having current change by cutting off the supply of current to the ignition coil when the waveform of the voltage output from the regulator reaches a peak portion.
However, the teachings of Japanese Patent Publication 2002-013459 do not take account a number of problems. When the waveform of the voltage output by the regulator (rectifier) reaches the peak portion, the ignition system cuts off the supply of current to the ignition coil (load). Due to this, the ignition system often controls cutoff of the supply of current to the ignition coil at a timing shifted from the timing at which the waveform of the voltage output from the regulator reaches the peak due to manufacturing error such as irregular polarization of a permanent magnet of the AC generator (power generating unit). In this case, if the ignition system controls the cutoff of the supply of current to the ignition coil at a timing shifted toward the timing at which the waveform of the voltage output from the regulator reaches the part having the large change in the amount of the voltage, the ignition system executes control of the cutoff of the supply of current to the ignition coil in a state in which the voltage output from the regulator is low. In this case, the change in the amount of the current at the time of the cutoff of the supply of current to the ignition coil is small. Due to this, the necessary voltage for the ignition plug to give off sparks may not be able to be obtained. As a result, the ignition performance of the ignition plug deteriorates, so that operation of the ignition plug (load) may become unstable.
The present invention has been made to solve, or at least ameliorate, the above-described problems. To this end, one object of the present patent document is to provide an engine control system capable of reducing the likelihood an operational load will become unstable and a vehicle including the engine control system. Other objects, features, and advantages will become apparent from the following description taken together with the drawings.
To attain the above object, according to a first aspect, an engine control system for an engine including a crankshaft is provided. In one embodiment, the control system comprises a power generating unit arranged to be driven by the crankshaft, a load electrically coupled to the power generating unit, a control module configured to control the operation of the load, and a rectifier electrically interposed between the power generating unit and the load for rectifying the output of the power generating unit, wherein the rectifier is configured to output a waveform including a plurality of waves, each wave having an asymmetrical angular shape including a peak portion, a first portion located on one side of the peak portion, and a second portion located on the other side of the peak portion and exhibiting a more rapid change in the amount of an output voltage than a change in the amount of the first portion, and the control module is configured to control the load to be turned on or off at a time of shifting of the waveform output from the rectifier from the peak portion toward the first portion of a wave by a predetermined amount. With this configuration, it is possible to prevent operation of the load from becoming unstable due to an insufficient amount of power being supplied to the load in a wider range of circumstances, thereby reducing the likelihood the operational load will become unstable during operation.
A vehicle according to a second aspect of the present invention is a vehicle which includes the above-described engine control system. With this configuration, it is possible to construct a vehicle including an engine control system which is capable of preventing operation of the load from becoming unstable.
Embodiments of the present invention will be described hereinafter based on the drawings.
As shown in
Further, a pivot shaft (not shown) is disposed at the rear of the upper frame portion 3a of the main frame 3. A rear arm 5 is supported at its front end by the pivot shaft so as to be able to pivot in the vertical direction. A rear wheel 6 is rotatably coupled to the rear end of the rear arm 5. A fuel tank 28 is arranged above the upper frame portion 3a of the main frame 3. A seat 7 is arranged at the rear side of the fuel tank 28.
Furthermore, a front fork 8 having suspension for absorbing impact in the vertical direction is rotatably mounted to the head pipe 2 so as to operably extend below the head pipe 2. A front wheel 9 is rotatably coupled to the bottom end of front fork 8. A front fender 10 is arranged above the front wheel 9. A number plate 11 to cover the front side of the head pipe 2 is disposed at the front side of the head pipe 2. A handle 12 is rotatably disposed above the head pipe 12.
In addition, an engine 13 is mounted below the upper side frame portion 3a of the main frame 3. An exhaust pipe 14 is attached to a front portion of the engine 13. The exhaust pipe 14 extends rearward and is connected to a muffler 15. An intake pipe 16 is attached to a rear portion of the engine 13.
In the present embodiment, a kick pedal 17 for starting the engine 13 with a user's foot is attached to a rear portion of the engine 13. Here, the kick pedal 17 is an example of a “manual start device” of the present invention. A function of kick pedal 17 is to drive a generator 37 (
As shown in
The exhaust pipe 14 is connected to the exhaust port 20b. A crankcase 24 is arranged below the cylinder 18, and a crankshaft 25 is arranged in the crankcase 24. The other end of the connecting rod 21 is rotatably attached to the crankshaft 25. The crankshaft 25 is configured to be rotatable by the movement of the connecting rod 21 in accordance with the vertical sliding of the piston 19 inside the cylinder 18. Further, an ignition plug 26 which ignites the mixture of air and fuel is operatively disposed in the cylinder head 20. It is to be noted that the ignition plug 26 is an example of a “load” according to the present invention.
In the present embodiment, the engine 13 is a four-stroke engine comprising an intake stroke, a compression stroke, a combustion (power) stroke and an exhaust stroke in accordance with the vertical sliding movement of the piston 19. Specifically, in the intake stroke, the engine 13 is configured so that the intake port 20a is opened and the air and fuel mixture flows into the combustion chamber 20c when the piston 19 slides downward and the intake valve 22 is lifted by a cam lobe. Further, the piston 19 is configured to slide down to the intake bottom dead center which is the bottom dead center of the cylinder 18.
Moreover, the engine 13 is configured so that in the compression stroke the intake port 20a is closed by the intake valve 22 and the air and fuel mixture in the cylinder 18 is compressed when the piston 19 slides upward from the intake bottom dead center. At this time, piston 19 is configured to slide up to the compression top dead center which is the top dead center of the cylinder 18.
The engine 13 is configured so that in the combustion stroke the air and fuel mixture, which is compressed by the piston 19 having arrived at the compression top dead center, is ignited with a spark generated by the ignition plug 26 at which point fuel combustion occurs. Thereafter, the piston 19 slides downward from the compression top dead center. At this time, the piston 19 is configured to slide down to the combustion bottom dead center, which is the bottom dead center of the cylinder 18 due to the combustion of the air and fuel mixture which is expanded due to the combustion of the fuel.
The engine 13 is configured so that in the exhaust stroke the exhaust port 20b is opened as the exhaust valve 23 is lifted by a cam lobe when the piston slides upward from the combustion bottom dead center. In addition, the engine 13 is configured so that the combustion gas in the combustion chamber 20c is exhausted through the exhaust port 20b by being pushed out upward by the piston 19. The piston 19 is configured to slide up to the exhaust top dead center which is the top dead center of the cylinder 18.
In the present embodiment, an injector 27, which injects fuel to the upstream side of the intake port 20a by an amount calculated by an ECU 38 (to be described later), is arranged at the intake pipe 16 (
A pipe pressure sensor 31, which detects air pressure in the intake pipe 16, a throttle position sensor 32, which detects the extent of the opening of the throttle valve 30, an atmospheric pressure sensor 33, which detects atmospheric pressure, and an atmospheric temperature sensor 34, which detects atmospheric temperature, are operatively coupled to the intake pipe 16. Further, a water temperature sensor 35, which detects water temperature in a water jacket (not shown) which cools the cylinder 18 with coolant, and a crank angle sensor 36, which detects the rotational position of the crankshaft 25, are arranged in the engine 13. The later-mentioned ECU (Engine Control Unit) 38 (see
In the present embodiment, the generator 37, which is operated in accordance with the rotation of the crankshaft 25, is disposed inside the crankcase 24, as shown in
Further, in the present embodiment, the flywheel 37c is arranged concentrically with the core portion 37a. Since the core portion 37a is fixed to the crankcase 24 (see
An extended gap portion 37f, having an angular width of about 60° is provided on the outside of the flywheel 37c by omitting one projecting portion 37e opposite one magnet 37d. The ECU 38 (see
In the present embodiment, the ECU 38 is electrically connected to the generator 37, as shown in
Furthermore, in the present embodiment, as shown in
As shown in
As shown in
As shown in
Moreover, in the present embodiment, the ECU 38 is configured to decide the timing of controlling the ignition plug 26 and the injector 27 to be turned on or off based on the rotational angle position of the crankshaft 25 detected by the crank angle sensor 36. Specifically, the ECU 38 is configured to determine the timing of controlling the ignition plug 26 and the injector 27 to be turned on or off based on the pulse (see
Further, in the present embodiment, as shown in
Moreover, in the present embodiment, as shown in
As stated above, in the present embodiment, if the waveform of the output from the regulator 39 has the asymmetrical angular shape including the peak portion P2, the first portion P1 located on a front (left) side of the peak portion P2 and having the gentle change in voltage, and the second portion P3 located on a rear (right) side of the peak portion and having the sharp change in voltage, the ECU 38 is configured to control the injector 27 to be turned on and the ignition plug 26 to be turned off at the timings T2 and T5, respectively. Timings T2 and T5 are each shifted from the peak portion P2 of the waveform of the output from the regulator 39 toward the first portion P1 side (front side) by about a 3° shift of the rotational angle of the crankshaft 25. With this configuration, even if the position of the peak portion P2 of the waveform of the output from the regulator 39 is shifted toward the first portion P1 side or the second portion P3 side due to, for example, manufacturing error of the generator 37 or the regulator 39, the timings T2 and T5, at which the injector 27 is controlled to be turned on and the ignition plug 26 is controlled to be turned off, respectively, would shift toward the first portion P1 side or the second portion P3 side correspondingly, with the first portion P1 having the gentle change in voltage. With this arrangement, it is, therefore, possible to prevent the voltage from being reduced when the injector 27 is controlled to be turned on and the ignition plug 26 is controlled to be turned off. It is thereby possible to prevent operations performed by the injector 27 and the ignition plug 26 from becoming unstable due to the insufficient supply of power.
As stated above, in the present embodiment, the crank angle sensor 36 is capable of detecting the rotational position of the crankshaft 25 by the pulse generated whenever the crankshaft 25 rotates by about 30°, and the waveform of the output from the regulator 39 is configured to correspond to the rotational position of the crankshaft 25. Further, the ECU 38 is configured to control the injector 27 to be turned on and the ignition plug 26 to be turned off based on the rotational position of the crankshaft 25 detected by the crank angle sensor 36, and to control the injector 27 to be turned on and the ignition plug 26 to be turned off at the timings of shifting of the rotational position of the crankshaft 25 from the peak portion P2 of the waveform of the output from the regulator 39 toward the first portion P1 side (front side) by about 3°. The ECU 38 can thereby readily control the injector 27 to be turned on and the ignition plug 26 to be turned off at the timings shifted from the peak portion P2 of the waveform output from the regulator 39 toward the first portion P1 side (front side) by about 3°.
As stated above, in the present embodiment, the ECU 38 is configured to control the injector 27 to be turned on and the ignition plug 26 to be turned off at the timings T2 and T5 which are near the peak portion P2 and are shifted from the peak portion P2 of the waveform of the output from the regulator 39 toward the first portion P1 side (front side) by about 3°, respectively. The ECU 38 can thereby control the injector 27 to be turned on and the ignition plug 26 to be turned off at a voltage value that is not significantly different from the voltage value of the peak portion P2 of the waveform of the output from the regulator 39.
As stated above, in the present embodiment, the regulator 39 is implemented as a full-wave rectifier, whereby the portion of the AC voltage output from the generator 37 below the center line of the amplitude is inverted for use as DC voltage. Therefore, as compared with a half-wave rectifier that does not use the portion of the waveform of the AC voltage below the amplitude center line, the regulator 39 can rectify the AC voltage supplied from the generator 37 to DC voltage while reducing loss generated during rectification.
The embodiments disclosed herein are to be considered to be illustrative in all respects and not to be restrictive. The scope of the present invention is indicated not by the above-stated description of the embodiment but by the claims. Furthermore, equivalents of the claims and all modifications within the scope of the claims are included within the present invention.
For example, in the above-described embodiment, an example in which the vehicle according to the present invention is applied to a motorcycle has been shown. However, the invention is not limited to this embodiment but is also applicable to other vehicles such as motor vehicles, tricycles and ATVs (All Terrain Vehicles).
Moreover, in the above-described embodiment, an example in which application of the vehicle to an off-road motorcycle has been shown. However, the invention is not limited to this embodiment but is also applicable to on-road motorcycles and vehicles.
In the above-described embodiment, an example of the application of the engine control device according to the present invention to the engine of a motorcycle that is the vehicle has been shown. However, the present invention is not limited to this embodiment but is also applicable to other engines, such as engines for generators, chainsaws or the like, including a load and a power generating unit.
In the embodiment, an example of application of the present invention to a motorcycle that does not include a battery has been shown. However, the present invention is not limited to this embodiment but is also applicable to motorcycles including a battery. In this case, even if the battery is discharged, starting performance of the motorcycle can be improved by applying the present invention at the time of starting the motorcycle.
In the embodiment, an example of configuring a control module to control an injector to be turned on and an ignition plug to be turned off at the timings of the rotational position of the crankshaft about 3° before the peak portion has been shown. However, the present invention is not limited to this embodiment. The control module may execute only one of the ON-control over the injector and the OFF-control over the ignition plug at the timing of the rotational position of the crankshaft being shifted from the peak portion P2 by about 3° toward the first portion P1 having the gentle voltage change.
Moreover, the control module may be configured to control the injector to be turned on and the ignition plug to be turned off at timing of shifting the rotational position of the crankshaft by about 3° or more or less than about 3° within a shifting width of the position of the peak portion considered to be generated by manufacturing error. Further, the present invention is applicable to an alternative instance in which the waveform of the output from the regulator includes a part (a front part) having a sharp change in output value, a peak portion, a part (a rear part) having a gentle change in output value arranged in this order. In such case, it suffices to control the injector to be turned on and the ignition plug to be turned off at a timing at which the rotational position of the crankshaft is shifted from the peak portion toward the rear side by a predetermined angle (for example, about 3°).
In the embodiment above, the fuel injector and the load have been mentioned as an example of loads controlled by the ECU to be turned on or off. However, the present invention is not limited to this embodiment but is also applicable to other loads used to control driving of the engine.
It is to be clearly understood that the above description was made only for purposes of an example and not as a limitation on the scope of the invention as claimed herein below.
Number | Date | Country | Kind |
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2008-015224 | Jan 2008 | JP | national |