Voltage monitoring glow plug controller

• US 6,009,369 A
• Filed: 09/16/1997
• Issued: 12/28/1999
• Est. Priority Date: 10/31/1991
• Status: Expired due to Term

• Current Assignee: Uusi LLC (Nartron Corporation)
• Original Assignee: Nartron Corporation
• Inventors: Shank, David W., Boisvert, Mario
• Primary Examiner(s): LOUIS JACQUES, JACQUES H
• Application Number:
  US08/931,470
• Time in Patent Office: 833 Days
• Field of Search: 701/99, 701/104, 701/113, 701/114, 701/102, 123/179 H, 123/179 G, 123/145 A, 123/179.21, 123/179.6, 123/142.5 E, 123/493, 219/486, 219/492, 219/497, 219/501, 219/506, 219/202, 219/205, 219/493, 219/499, 219/508, 361/265, 361/757
• US Class Current: 701/99
• CPC Class Codes: F02P 19/026 Glow plug actuation during engine operation

Abstract

An electronic control system and a device is disclosed proving improved control and diagnostics of glow plugs as are typically energized in diesel engines prior to and during cold start and also during engine warmup, especially for motor vehicles under human operator control. These improved control functions result in: Increased life of the glow plugs, longer service life, greater reliability, a simplified maintainence diagnostic interface, greater diagnostic capability, reduced emission of undesirable hydrocarbons, reduced unburned fuel as white smoke, more complete fuel combusion, reduced lubricating oil contamination, quiter and smoother operation, increased engine power, reduced fuel consumption, and quicker engine warmup all by controlling power applied to the glow plugs based upon electronically controlled fixed and/or adaptive functional algorithms based upon input variables such as battery voltage, glow plug voltages, glow plug currents, engine temperature based upon algorithms which can correct for sensing system hysteresis and time lag, ambient air termperature ambient air density, ambient air humidity, fuel injector duration and timing, intake mass air flow, exhaust gas composition, exhaust gas temperature, alternator output, engine speed, engine torque, engine power, engine compression, engine age, fuel type, and the like for affecting an on and off cycling using open loop control and/or closed loop feedback control of glow plug power so as to maintine glow plugs more closely within an optimal temperature range specific to engine system operational conditions and consistent with improved glow plug life.

Claims

1. A glow plug controller for a motor vehicle diesel engine comprising:

a) an electric power source mounted to the motor vehicle for providing a power supply signal;

b) glow plug controller circuitry powered by the power source for determining a glow plug pre-combustion preglow energization cycle for heating one or more glow plugs;

c) a monitor coupled to the glow plug controller for providing a signal indicative of a voltage output of the electric power source;

d) a switching device coupled to the glow plug controller and the electric power source for energizing the one or more glow plugs for the preglow energization cycle prior to initiating combustion in the diesel engine; and

e) said glow plug controller including an adaptive control program for adjusting the preglow energization cycle during which the one or more glow plugs are energized prior to combustion, the preglow energization cycle being adjusted based on the voltage output of the electric power source.

2. The glow plug controller of claim 1 wherein the monitor monitors a voltage output from the electric power source.

3. The glow plug controller of claim 1 additionally comprising a temperature sensor for determining a temperature of a portion of the diesel engine and wherein the controller also energizes the one or more glow plugs after combustion for an afterglow cycle that is based on the sensed engine temperature and voltage output of the electric power source.

4. The glow plug controller of claim 1 wherein the controller senses an operational state of the motor vehicle and disables a preglow energization cycle if the diesel engine has been running or has had a preglow cycle within a specified time period.

5. The glow plug controller of claim 4 wherein the controller senses running of the diesel engine based upon an output of the motor vehicle alternator.

6. The glow plug controller of claim 1 wherein the controller comprises a microprocessor executing a control program that adjusts the preglow energization cycle based on a voltage output by the electric power source which includes a vehicle battery.

7. The glow plug controller of claim 1 further comprising means to activate a visual indicator to signal an operator that the preglow energization cycle is completed and the engine should be started.

8. The glow plug controller of claim 1 additionally comprising means for preventing damage to the switching device by application of too large a voltage signal.

9. The glow plug controller of claim 8 wherein the means for preventing damage to the switching device senses over voltage signals applied to the one or more glow plugs.

10. The glow plug controller of claim 8 wherein the means for preventing damage to the switching device senses over current signals applied to the one or more glow plugs.

11. The glow plugs controller of claim 1 further comprising an input circuit coupled to the glow plug controller circuitry for transmitting a signal to the glow plug controller circuitry indicative of an operating condition of the diesel engine and wherein the glow plug controller circuitry deactivates glow plug energization based on a sensed operating condition of the diesel engine.

12. The glow plug controller of claim 11 wherein the input circuit monitors a signal related to a running status of the diesel engine.

13. The glow plug controller of claim 12 wherein the glow plug controller circuitry disables a preglow energization cycle if the engine has been sensed as running or an ignition input has been sensed within a specified time period of receipt of an additional ignition input.

14. The glow plug controller of claim 12 wherein the glow plug controller deactivates glow plug energization if an engine running condition is sensed when power is applied to the glow plug controller circuitry.

15. The glow plug controller of claim 12 wherein the glow plug controller circuitry terminates a pre-glow energization cycle of the glow plugs upon receipt of the signal indicating a running diesel engine during a pre-glow energization cycle and begins a post combustion afterglow energization cycle.

16. The glow plug controller of claim 1 additionally comprising a temperature sensor and wherein the glow plug controller circuitry briefly activates an indicator lamp if the sensed temperature is greater than a threshold temperature such that a preglow energization cycle is not needed.

17. A method for controlling a glow plug controller for a diesel engine that provides motive power to a motor vehicle, the steps of the method comprising:

a) providing a power supply source mounted to the motor vehicle, the power supply source generating a signal for energizing one or more glow plugs of a diesel engine;

b) monitoring an energization signal for energizing one or more glow plugs prior to engine combustion and providing an indication of said energization signal; and

c) activating one or more glow plugs with a timing signal derived from the energization signal for a controlled preglow cycle time before starting the diesel engine, wherein the controlled preglow cycle time is adjusted based on an output voltage of the power supply source.

18. The method of claim 17 additionally comprising the step of adjusting the controlled preglow cycle time based on a temperature of the diesel engine.

19. The method of claim 17 additionally comprising the step of applying a heating signal to the one or more glow plugs during an afterglow energization cycle after the engine has started.

20. The method of claim 19 wherein during the afterglow energization cycle the one or more the glow plugs are energized with a sequence of on and off periods wherein the one or more glow plugs are alternately energized and deenergized.

21. The method of claim 18 additionally comprising the step of adjusting the controlled cycle time based on whether the engine is running.

22. The method of claim 17 additionally comprising the step of providing a visual indication to the operator of the motor vehicle that the engine can be started after the controlled preglow energization cycle has transpired.

23. The method of claim 17 wherein the energization signal that is monitored is a voltage related to the voltage applied to the one or more glow plugs.

24. The method of claim 17 additionally comprising the step of sensing a temperature of the engine and if the sensed temperature is above a threshold temperature activating a visual indicator for a brief interval without commencing a controlled preglow energization cycle.

25. The method of claim 21 wherein if the engine is running when power is applied to a programmable controller for activating the glow plugs, the one or more glow plugs are not energized.

26. The method of claim 17 wherein a running condition of the engine is sensed and if a running condition is sensed during a controlled preglow energization cycle, the controlled preglow energization cycle is terminated and an afterglow energization cycle is commenced.

27. Apparatus for use with a motor vehicle diesel engine comprising:

a) an electric power source mounted to the motor vehicle for providing a power supply signal by means of an ignition signal;

b) controller circuitry powered by the power source for determining a glow plug pre-combustion preglow energization cycle during which one or more glow plugs are energized prior to initiating combustion of the diesel engine, the preglow energization cycle being adjusted based on power applied to the one or more glow plugs by the electric power source;

c) a monitor coupled to the controller circuitry for providing a signal indicative of power applied to the one or more glow plugs;

d) a switching device coupled to the glow plug controller and the electric power source for energizing the one or more glow plugs for the preglow energization cycle prior to initiating combustion in the diesel engine; and

e) circuitry for maintaining power to current drawing loads of the motor vehicle after removal of the ignition signal.

28. The apparatus of claim 27 wherein circuitry for maintaining power to the current drawing loads monitors a frequency output from an alternator signal to determine when to remove the alternator signal from the current drawing loads of the motor vehicle.

29. The apparatus of claim 28 additionally comprising reverse voltage protection means.

30. The apparatus of claim 27 wherein the signal provided by the monitor is indicative of a voltage output of the electric power source.

31. The apparatus of claim 30 wherein a duration of the preglow energization cycle is adjusted based the voltage output of the electric power source.

32. The apparatus of claim 30 additionally comprising a temperature sensor for determining a temperature of a portion of the diesel engine and wherein the switching device also energizes the one or more glow plugs after combustion for an afterglow cycle that is based on the sensed engine temperature and the voltage output of the electric power source.

33. The apparatus of claim 27 wherein the apparatus senses an operational state of the diesel engine and disables a preglow energization cycle if the diesel engine has been running or has had a preglow cycle within a specified time period.

34. The apparatus of claim 33 wherein the apparatus senses running of the diesel engine based upon an output of the motor vehicle alternator.