Information
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Patent Grant
-
6768221
-
Patent Number
6,768,221
-
Date Filed
Tuesday, February 12, 200222 years ago
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Date Issued
Tuesday, July 27, 200420 years ago
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Inventors
-
Original Assignees
-
Examiners
- Sircus; Brian
- Rios; Roberto J
Agents
- Calfa; Jeffrey P.
- Sullivan; Dennis Kelly
- Lukasik; Susan L.
-
CPC
-
US Classifications
Field of Search
US
- 307 107
- 123 198 DC
- 180 272
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International Classifications
-
Abstract
A motor vehicle engine is under control of an engine control system (18) that performs an idle shutdown function to shut down the engine via a programmable output (50) of an electronic module of the control system after the engine has been idling for some amount of time. An ignition switch (14) is turned on and off for signaling the engine control system to turn the engine on and off. Relays (30, 40) are connected between the ignition switch and load circuits of the vehicle electrical system and to the programmable output of the module to allow the load circuits to be fed when the ignition switch is on and the programmable output of the module is not signaling an idle shutdown and to disallow feeding when the programmable output of the module is signaling an idle shutdown.
Description
FIELD OF THE INVENTION
This invention relates generally to electrical systems of motor vehicles. More particularly, the invention relates to a circuit that prevents battery drain that might otherwise occur after an idling engine has been automatically shut down by an idle shutdown timer.
BACKGROUND AND SUMMARY OF THE INVENTION
Certain motor vehicles that have diesel engines for their motors include idle shutdown timers that shut down the motors when the motors have been idling for some specified amount of time. In some vehicles that have electronic engine control systems, the idle shutdown function is embodied by electronics in an electronic module of the control system.
When an individual, such as the driver, is not present at idle shutdown, the switch that turns the engine on and off will remain on. Such a switch is typically key-operated and is commonly referred to as an ignition switch. Even if a person were present at idle shutdown, he or she might not turn the ignition switch off.
The present invention arises through the recognition that after an engine has been automatically shutdown by an idle shutdown timer, certain electric circuits in the vehicle may remain energized through the ignition switch, consuming energy from one or more DC storage batteries in the vehicle electrical system in the process. An ignition switch that remains on after idle shutdown may therefore cause a battery drain, and if the drain continues long enough, insufficient battery power may be available when it is desired to re-start the engine.
The present invention relates to a circuit that is associated with an ignition switch and an electronic module of an engine control system in a motor vehicle to prevent battery drain caused by the ignition switch remaining on after the idling engine has been automatically shutdown by a shutdown timing function performed by the engine control system.
A preferred embodiment of the inventive circuit employs two relays through which the ignition switch feeds various circuits of the vehicle electrical system when the ignition switch is on and the engine is running. When the engine has been running at idle for some specified amount of time, as monitored by the engine control system, an electronic module of the engine control system operates the relays in a way that causes them to interrupt the feeds to the various electrical system circuits, thereby preventing battery draining that would otherwise occur because of failure to turn the ignition switch off.
The invention provides a cost-efficient solution for avoiding battery draining, and the possible inconvenience of having to jump-start the engine, replace one or more batteries, or perhaps even tow the vehicle.
One general aspect of the invention relates to a motor vehicle comprising an engine whose operation is under control of an engine control system that performs an idle shutdown function to shut down the engine via a programmable output of an electronic module of the control system after the engine has been running in idle without interruption for some amount of time. An ignition switch can be operated on and off for signaling the engine control system to turn the engine on and off. Load circuits are fed through the ignition switch when the ignition switch is on. An interface is connected between the ignition switch and the load circuits and to the programmable output of the module for controlling feeding of the load circuits from the ignition switch by allowing the feeding when the ignition switch is on and the programmable output of the module is not signaling an idle shutdown and by disallowing the feeding when the programmable output of the module is signaling an idle shutdown.
According to a disclosed embodiment of the invention, the interface comprises one or more relays.
Another general aspect of the invention relates to a method for preventing battery drain caused by an ignition switch through which load circuits are fed remaining on after an engine that has been idling continuously in a motor vehicle for some amount of time has been automatically shutdown by an idle shutdown timing function performed by an engine control system. The method comprises programming a programmable output of a module of the engine control system to deliver an idle shutdown signal upon the idle shutdown timing function signaling an idle shutdown. The method further comprises connecting an interface between the ignition switch and the load circuits and to the programmable output of the module to control feeding of the load circuits from the ignition switch by allowing the feeding when the ignition switch is on and the programmable output of the module is not signaling an idle shutdown and by disallowing the feeding upon the programmable output signaling an idle shutdown.
According to a disclosed embodiment of the invention, the method interface comprises operating one or more relays from a condition allowing the feeding to a condition disallowing the feeding when idle shutdown is signaled.
The foregoing, along with further aspects, features, and advantages of the invention, will be seen in the following disclosure of a presently preferred embodiment of the invention depicting the best mode contemplated at this time for carrying out the invention. The disclosure includes a drawing, briefly described as follows.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1
is a schematic electrical diagram of a preferred embodiment of circuit in a motor vehicle according to principles of the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
FIG. 1
shows a portion of a motor vehicle electrical system
10
that incorporates circuit devices according to principles of the present invention. Electrical system
10
comprises a source of electricity, such as one or more DC storage batteries
12
. When the vehicle engine is running, the battery or batteries is or are kept charged by a charging system (not shown).
Running of the engine is under the control of a switch
14
that is typically key-operated and commonly referred to as an ignition switch, even in vehicle whose engine relies on compression of fuel in the engine cylinders for ignition rather than on spark ignition.
FIG. 1
shows a positive voltage electrical system where the negative battery pole is grounded and the positive battery pole is connected to one terminal
14
A of switch
14
. Switch
14
has at least two positions, and often three or four. One position is the OFF position that is illustrated by
FIG. 1
where terminal
14
A is disconnected from other switch terminals that leading to various load circuits in the vehicle.
FIG. 1
further shows switch
14
to comprise two other terminals
14
B and
14
C, each of which can be selectively connected to and disconnected from terminal
14
A depending on the position to which switch
14
is operated. The particular switch being described here can be operated to any of at least three positions: an OFF position, as shown where neither terminal
14
B nor
14
C is connected to terminal
14
A; an ON, or RUN, position; and an ACCESSORY position. In ON position, switch
14
connects each terminal
14
B,
14
C to terminal
14
A through a respective switch contact
14
E,
14
F. In ACCESSORY position, switch
14
connects only terminal
14
C to terminal
14
A via contact
14
F.
Prior to incorporation of the invention in the vehicle, terminals
14
B,
14
C were connected to a fuse block
16
containing various circuit protection devices through which various load circuits
17
in the vehicle are fed. Some of those load circuits are fed through circuit protection devices connected to terminal
14
B while others are fed through circuit protection devices connected to terminal
14
C. Simply feeding a load circuit does not necessarily mean that current is actually being drawn by that circuit because that circuit may have its own switch or other circuit component that controls the current flow through the circuit.
IF switch
14
also serves to start the engine, it will be operated to a CRANKING position for cranking the engine at starting via an electric cranking motor (not shown). In CRANKING position, switch
14
closes contact
14
E, but not contact
14
F. The switch has still another terminal and associated contact (not shown) that closes to terminal
14
A for cranking the engine, but opens upon release of the switch from CRANKING position when the switch returns to ON position. When the switch returns to ON position, contact
14
E remains closed while contact
14
F operates from open to closed. In this way, those load circuits that need to be fed while the engine is being cranked will be, but those that would impose an unnecessary drain on the electrical system are not. Once cranking has ceased and the engine has started running under its own power, both ignition and accessory load circuits are fed through switch
14
.
The vehicle also has an engine control system
18
that comprises an electronic module, or modules, containing various electronic devices arranged to exercise control over various engine functions on the basis of various data processed by the control system from various sources, including external input sources. One such external input source comes from switch
14
to an ignition input
20
of a module of engine control system
18
. That input source is a feed from terminal
14
B through a circuit protection device
22
. Therefore, closure of contact
14
E provides an input signal to engine control system
18
that is processed by the system for enabling the engine to run and for the control system to exercise control over the engine.
A running engine is shut off by operating switch
14
from ON position to OFF position to interrupt the feed from switch
14
to ignition input
20
. With the engine off, operation of switch
14
to the ACCESSORY position will close only contact
14
F, allowing only accessory load devices to be operated.
One of the functions performed by control system
18
is an idle shutdown function. The system has been programmed with a data value representing an amount of time for which the engine will be allowed to continuously idle. Whenever the engine runs at idle, control system
18
starts the idle timing function by starting a timer. Timing continues as long as the engine remains idling. Off-idle running will reset the timer. Should the engine continue to run in idle without interruption for the amount of the programmed idle time, the timer will time out and cause the engine to shut down. If no one is present at idle shutdown, switch
14
will remain in ON position, and even if someone were present, it might not occur to him or her to turn switch
14
off. As a result, the battery, or batteries, could be drained through one or more of the load circuits because of the failure to turn switch
14
off after idle shutdown.
The invention provides the following solution for avoiding battery draining after idle shutdown. Two relays
30
and
40
are connected between switch
14
and fuse block
16
. Each relay
30
,
40
comprises a respective coil
30
A,
40
A and a respective normally open contact
30
B,
40
B. Terminals
30
C,
30
D provide for connection of coil
30
A in circuit and terminals
30
E,
30
F provides for connection of contact
30
B. Terminals
40
C,
40
D provide for connection of coil
40
A in circuit and terminals
40
E,
40
F provide for connection of contact
40
B.
Although engine control system
18
provides an idle shutdown signal for shutting down the engine, a module of the system that contains programmable outputs must be configured so that an unused one of those programmable outputs is programmed to operate coils
30
A,
40
A. Such a programmable output is designated by the reference numeral
50
in FIG.
1
and shown connected to relay terminals
30
C,
40
C. Relay terminals
30
D,
40
D are grounded. In this way, relay coils
30
A,
40
A will be energized only when an energizing voltage for them is delivered to output
50
by control system
18
.
Terminal
30
E of relay
30
is wired to terminal
14
B of switch
14
, and terminal
30
F to ignition load circuits at fuse block
16
Terminal
40
E of relay
40
is wired to terminal
14
C of switch
14
, and terminal
40
F to accessory load circuits at the fuse block.
When switch
14
is operated to close contact
14
E, the voltage signal applied to ignition input
20
will cause control system
18
to deliver energizing voltage for coils
30
A,
40
A to output
50
. This causes both relay contacts
30
B,
40
B to operate from open to closed, thereby feeding both the ignition load circuits and the accessory load circuits from battery
12
through switch
14
. This condition will continue as long as switch
14
remains on, and idle shutdown does not occur. When switch
14
is turned off, the loss of voltage at ignition input
20
causes system
18
to discontinue the voltage at output
50
. Coils
30
A,
40
A then de-energize, opening contacts
30
B,
40
B, to interrupt the feeds to the idle and accessory load circuits. With the feeds interrupted, no devices in those circuits that require current can operate.
If the engine has been running in idle without interruption for the amount of the programmed idle time, the idle shutdown timer will time out and cause the engine to shut down. Control system
18
also discontinues the voltage at output
50
, causing coils
30
A,
40
A to de-energize. This opens contacts
30
B,
40
B, interrupting the feeds to the idle and accessory load circuits so that no devices in those circuits that require current can operate. In this way, the invention prevents those circuits from potentially draining the battery should ignition switch
14
remain on for an extended time after the idle shutdown.
It is believed that the invention can be advantageous for owners and operators of trucks because it can avoid having to call for service should the battery be drained because the ignition switch has been left on after an idle shutdown. It can also avoid the potential application of low voltages to the electric system as the battery drains.
While a presently preferred embodiment of the invention has been illustrated and described, it should be appreciated that principles of the invention are applicable to all embodiments that fall within the scope of the following claims.
Claims
- 1. A motor vehicle comprising:an engine whose operation is under control of an engine control system that performs an idle shutdown function to shut down the engine via a programmable output of an electronic module of the control system after the engine has been running in idle without interruption for an amount of time programmed in the module as measured from the commencement of running in idle; an ignition switch that can be operated on and off for signaling the engine control system via a feed from the ignition switch to an ignition input of the module to turn the engine on and off, load circuits that are fed through the ignition switch when the ignition switch is on; and an interface that is connected between the ignition switch an the load circuits and to the programmable output of the module for controlling feeding of the load circuits from the ignition switch by allowing the feeding when the ignition switch is on and the programmable output of the module is not signaling an idle shutdown and by disallowing the feeding when the programmable output of the module is signaling an idle shutdown, wherein the interface excludes the feed from the ignition switch to the ignition input of the module.
- 2. A motor vehicle as set forth in claim 1 in which the interface comprises one or more relays.
- 3. A motor vehicle as set forth in claim 2 in which the ignition switch comprises an ignition terminal and an accessory terminal, one relay interfaces the ignition terminal with some of the load circuits, and another relay interfaces the accessory terminal with other load circuits.
- 4. A motor vehicle as set forth in claim 3 in which both relay are energized when allowing the feeding and de-energized when disallowing the feeding.
- 5. A motor vehicle as set forth in claim 4 in which each relay comprises a coil having a terminal connected to the programmable output of the module.
- 6. A method for preventing battery drain caused by an ignition switch through which load circuits are fed remaining on after an engine that has been idling continuously in a motor vehicle for an amount of time, as measured from the commencement of running in idle, has been automatically shutdown by an idle shutdown timing function performed by an engine control system, the method comprising:programming a programmable output of a module of the engine control system to deliver an idle shutdown signal upon the idle shutdown timing function having measured the amount of time and thereupon signaling an idle shutdown; connecting an interface between the ignition switch and the load circuit and to the programmable output of the module to control feeding of the load circuits from the ignition switch by allowing the feeding when the ignition switch is on and th programmable output of the module is not signaling an idle shutdown and by disallowing the feeding upon the programmable output signaling an idle shutdown, wherein the step of connecting an interface excludes any connection that would interrupt a feed from the ignition switch of an ignition input of the module via which the ignition switch signals the engine control system to turn the ignition on and off.
- 7. A method as set forth in claim 6 in which the step of connecting an interface between the ignition switch and the load circuits and to the programmable output of the module interface comprises connecting one or more relays between the ignition switch and the load circuits and to the programmable output of the module.
- 8. A method as set forth in claim 7 in which the step of connecting one or more relays between the ignition switch and the load circuits and to the programmable output of the module comprises connecting a contact of one relay between some of the load circuits and an ignition terminal of the ignition switch and connecting a contact of another relay between other load circuits and an accessory terminal of the ignition switch.
- 9. A method as set forth in claim 8 including the steps of energizing coils of both relays to allow the feeding and de-energizing the coils to disallow the feeding.
- 10. A method as set forth in claim 9 including the step of connecting a terminal of each coil to the programmable output of the module.
US Referenced Citations (2)
Number |
Name |
Date |
Kind |
4381042 |
Perry |
Apr 1983 |
A |
5222469 |
Sutton |
Jun 1993 |
A |