Device and method for control of motor vehicle engine idle RPM to prevent disruptive battery discharge

• US 6,573,614 B2
• Filed: 08/27/2001
• Issued: 06/03/2003
• Est. Priority Date: 08/27/2001
• Status: Expired due to Fees

• Current Assignee: Martin J. Doll
• Original Assignee: Martin J. Doll
• Inventors: Doll, Martin J.
• Primary Examiner(s): Waks, Joseph
• Application Number:
  US09/939,492
• Publication Number:
  US 20030052486A1
• Time in Patent Office: 645 Days
• Field of Search: 290/40.C, 290/40.R, 320/29, 320/25
• US Class Current: 290/40.00C
• CPC Class Codes: H02J 7/1476 by mechanical action on the generator
• CPC Class Codes: H02P 9/04 Control effected upon non-electric prime mover and dependent upon electric output value of the generator
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries

Abstract

A method and device for increasing the idling speed of an engine of a motor vehicle from a normal idle speed level to a higher preselected maximum idle speed level in response to a low output voltage from a power generating system of the engine and vehicle is disclosed for the purpose of preventing a severe discharge of a storage battery of the system to prevent disruption of engine ignition and reduced effectiveness of vehicle electrical components and to increase the service life of the battery and an electrical alternator of the system. The device can be operated in conjunction with or as a part of an conventional electronic control module (ECM) of the vehicle to take over control of the idle speed of the engine when a predetermined low output voltage of the system is sensed. Upon assuming control of the engine idle speed, the device raises the idle speed to a predetermined maximum safe level and maintains that level independent of engine loading for purposes of charging the battery to increase the system output voltage. After the system output voltage is restored to a predetermined maximum value, the device returns engine idle control to the ECM. Various features of the device are disclosed which block or terminate operation of the device when necessary for reasons of safety and engine protection.

Claims

1. A method for controlling an idle RPM level of an engine of a motor vehicle for preventing or at least limiting a disruptive discharge of a storage battery of an electrical power generating system of said vehicle, the steps of which comprise

monitoring an output voltage of an electrical power generating system of said vehicle;

determining when said output voltage is less than a first preselected minimum value;

automatically increasing an idle RPM level of said engine from a normal idle RPM level to a higher preselected maximum idle RPM level in response to said output voltage being less than said first preselected minimum value; and

maintaining said higher preselected maximum idle RPM level, independent of loading on said engine, to increase said output voltage.

2. The method of claim 1, the steps of which further comprise

monitoring a length of time since said engine has been running since said engine was last started;

blocking initiating of said step of automatically increasing until said length of time equals a first preselected minimum elapse time.

3. The method of claim 2 wherein said first preselected minimum elapse time is within range of from about 3.0 to about 5.0 minutes.

4. The method of claim 1, the steps of which further comprise

monitoring a condition of a transmission of said vehicle;

determining that said transmission is disposed in a park condition;

blocking initiation of said step of automatically increasing when said transmission is disposed in a condition other than said park condition; and

ceasing execution of said steps of increasing and maintaining immediately upon a change in said condition of said transmission from said park condition to any other condition when either of said steps of increasing and maintaining are in progress.

5. The method of claim 1 wherein the step of monitoring an RPM level of an engine comprises determining that said RPM level is greater than a crank speed of said engine which occurs during ignition starting.

6. The method of claim 1 wherein the step of monitoring an RPM level of an engine comprises determining that said RPM level is at least 600 RPM when said engine comprises an eight cylinder gasoline engine.

7. The method of claim 1 wherein said first preselected minimum value of said output voltage is about 13.0 volts when a normal maximum operating output voltage of said system is at least 13.8 volts.

8. The method of claim 1 wherein said preselected maximum RPM level is about 1300 RPM when said engine is a gasoline powered eight cylinder engine.

9. The method of claim 1 wherein said preselected maximum RPM level in about 1100 RPM when said engine is a diesel powered eight cylinder engine.

10. The method of claim 1, the steps of which further comprise releasing control of said idle RPM level to an ECM of said vehicle to permit said idle RPM level to decrease from said preselected maximum idle RPM level to said normal idle RPM level after said output voltage has increased to said preselected maximum value.

11. The method of claim 1, the steps of which further comprise

monitoring a foot brake switch position of said vehicle;

determining when a foot brake of said vehicle is activated;

blocking initiation of said step of increasing so long as said foot brake is activated; and

ceasing execution of said steps of increasing and maintaining immediately upon activation of said foot brake when said steps of increasing and of maintaining are in progress.

12. The method of claim 1, the steps of which further comprise

monitoring an elapse time from initiation of said step of automatically increasing while said step of maintaining is in progress;

determining when said elapse time is equal to a preselected elapse time;

comparing said output voltage to said preselected value at said preselected elapse time;

returning idle RPM control to an ECM of said vehicle provided that said output voltage is at least equal to said preselected value at said preselected elapse time;

indexing an elapse time monitor at said preselected elapse time; and

repeating said steps of elapse time monitoring, determining when said elapse time is equal to a preselected elapse time and comparing when said output voltage is less than said preselected value at the conclusion of said preselected elapse time provided that said output voltage is less than preselected value.

13. The method of claim 1, the steps of which further comprise monitoring a position of a throttle of said engine;

determining that said throttle is in an idle position;

blocking initiating of the step of increasing when said throttle is in a position other than said idle position; and

ceasing execution of said steps of increasing and maintaining when said throttle is in a position other than said idle position.

14. The method of claim 1, the steps of which further comprise

monitoring activation of a check engine light;

blocking initiation of the step of increasing when said check engine light is active; and

terminating execution of said steps of increasing and maintaining upon activation of said check engine light when said steps of increasing and maintaining are in progress.

15. The method of claim 1, wherein the step of maintaining includes maintaining said preselected maximum idle RPM level at least until said output voltage increases from said first value to a preselected maximum value which is greater than said first value.

16. An electronic device for controlling idle RPM of an engine of a motor vehicle to prevent or at least limit disruptive discharge of a battery of an electrical power generating system of said engine and vehicle, said device comprising

means for determining that a transmission of said vehicle is disposed in a park condition;

means for monitoring an output voltage generated by said system;

means for comparing said output voltage with a preselected minimum value;

means for increasing an idle RPM of said engine from a normal idle RPM level to a preselected maximum idle RPM level when said output voltage is less than said preselected minimum value to increase said output voltage;

means for maintaining said maximum idle RPM level, I independent of loading on said engine, at least until said output voltage increases to a preselected maximum value; and

means for decreasing an idle RPM of said engine from said preselected maximum idle RPM level to said normal idle RPM level after said output voltage increases to a preselected maximum value.

17. A device for controlling an idle speed of an engine of a motor vehicle comprising

means for monitoring an output voltage of an electrical power generating system of said vehicle;

means for determining when said output voltage is less than a first preselected minimum value;

means responsively connected to said determining means for automatically increasing an idle speed level of said engine from a normal idle speed level to a preselected maximum idle speed level when said output voltage is less than said first preselected minimum value; and

means for maintaining said maximum idle speed level independent of loading on said engine to increase said output voltage.

18. The combination of claim 17 wherein said device further comprises means for switching said relay for switching said idle control means from control by said second output signal generating means back to control by said ECM in response to a third signal from said monitoring means indicative that said output voltage is at least equal to a preselected maximum value greater than said preselected minimum value.

19. The combination of claim 17 wherein said device further comprises

second means for determining that a transmission of said vehicle is in a condition other than a park condition; and

means responsively connected to said second determining means for preventing the switching of said relay when said transmission is in a condition other than said park condition.

20. The combination of claim 17 wherein said device further comprises

second means for determining that a foot brake of said vehicle is activated;

and

means responsively connected to said second determining means for preventing the switching of said relay when said foot brake is activated.

21. The combination of claim 17 wherein said device further comprises

first timing means for determining a running time of said engine from its most recent start;

and

means responsively connected to said first timing means for preventing the switching of said relay until said running time has reached a preselected running time.

22. In combination with a conventional ECM of a motor vehicle which is used to set and maintain an idle speed of an engine of said vehicle within a normal idle speed range when said engine is operating in a normal operating temperature range, an electronic device for assuming control of said idle speed from said ECM in response to a low output voltage of an electrical power generating system of said engine and vehicle, said device comprising

first means for determining that said engine is running;

first means for monitoring an output voltage of an electrical power generating system of said engine and vehicle, said first monitoring means generating a first output signal indicative that said output voltage is less than a preselected minimum value when said engine is running;

means responsively connected to said first monitoring means for generating a second output signal for controlling an idle speed control means of said engine to increase the idle speed of said engine from said normal idle speed range to a preselected maximum idle speed in response to said output voltage being less than said preselected minimum value; and

an electrical relay for switching said idle speed control means from control by said ECM to control by said second output signal generating means in response to said output voltage being less than said preselected minimum value.

23. A device for assuming control of an idle speed control apparatus of an engine of a motor vehicle which is normally controlled by an ECM of said vehicle, said device comprising

means for monitoring an output voltage of an electrical power generating system of said engine and vehicle;

means responsively connected to said monitoring means for generating a first signal indicative that said output voltage is less than a first preselected minimum value;

means responsively connected to said first signal generating means for generating a second signal which is capable of controlling said idle speed control apparatus of said engine to increase an idle speed of said engine from a normal idle speed level to a higher preselected maximum idle speed level; and

means responsively connected to said first signal generating means for switching control of said idle speed control apparatus from said ECM to said second signal generating means in response to said first signal.

24. The device of claim 23 wherein said switching means comprises a relay.

25. The device of claim 24 wherein said relay normally connects said ECM to said apparatus when said relay is in a de-energized condition and connects said second signal generating means to said apparatus in place of said ECM when said relay is in an energized condition.

26. The device of claim 23 further comprising means responsively connected to said monitoring means for operating said switching means to return control of said idle speed control apparatus from said second signal generating means to said ECM after said output voltage has increased from less than said preselected minimum value to a higher preselected maximum value.

27. In an electronic control module of a motor vehicle, a device for controlling an idle RPM of an engine of said vehicle in response to a low output voltage of an electrical power generating system of said vehicle, said device comprising

means for monitoring an output voltage of an electrical power generating system of a motor vehicle;

means for generating a first signal in response to said output voltage being less than a first preselected minimum value; and

means responsively connected tom said first signal generating means for increasing an idle speed level of said engine from a normal idle speed level to a higher maximum idle speed level in response to said output voltage being less than said first value to increase said output voltage.