Control method for spark-ignition engines

• US 6,032,640 A
• Filed: 10/02/1998
• Issued: 03/07/2000
• Est. Priority Date: 10/02/1998
• Status: Expired due to Term

• Current Assignee: R. L. Evans And Associates, Ltd.
• Original Assignee: University of British Columbia
• Inventors: Evans, Robert Lancelot
• Primary Examiner(s): ARGENBRIGHT, TONY MICHAEL
• Application Number:
  US09/165,197
• Time in Patent Office: 522 Days
• Field of Search: 123/27 GE, 123/295, 123/297, 123/299, 123/300, 123/399, 123/430, 123/431, 123/478, 123/486, 123/526, 123/525, 123/527, 123/305
• US Class Current: 123/295
• CPC Class Codes: F02D 41/2422 Selective use of one or more tables
• CPC Class Codes: F02D 41/402 Multiple injections
• CPC Class Codes: F02P 5/045 combined with electronic control of other engine functions, e.g. fuel injection in general F02D37/02
• CPC Class Codes: Y02T 10/40 Engine management systems

Abstract

The control system disconnects the throttle from direct connection with the accelerator pedal, which sets the power requirements or demand. The demand signal passes to a computer control or microprocessor which electronically controls the throttle as a function of the engine operating conditions and pre-established values for controlled parameters stored in bitmaps in the microprocessor'"'"'s memory. It is preferred to use a fuel injecting stratified charge spark plug in conjunction with the electronic control system and use the electronic control system to control the primary and auxiliary fuel injection systems as well as the ignition timing to permit the engine to run under very lean conditions to produce low levels of emissions such as nitrogen oxides, hydrocarbons, and carbon monoxide.

Claims

1. A computer control method for controlling a stratified charge fuel injected spark ignited internal combustion engine having at least one cylinder each of said at least one cylinders having a spark plug, said engine having a primary fuel injector and a separate auxiliary fuel injector for each of said at least one cylinder for injecting a small quantity of fuel into each cylinder of said at least one cylinder adjacent to its spark plug, said method comprising monitoring at least the parameters of the group comprising engine rpm, air mass flow into the engine, air fuel ratio, power demand and engine crank angle and continuously sending signals defining the conditions of each of the parameters at that point in time to a control computer, inputting a change in power demand signal to said control computer, changing primary fuel supply in accordance with said change in power demand signal and adjusting air mass flow rate to obtain a desired primary air fuel ratio fed to said engine provided the then current air mass flow rate is not at one of its extreme operating conditions and the required adjustment of air mass flow would exceed such operating condition, said control computer being pre-programmed with predetermined bit maps of rate of fuel supply, spark ignition and air mass flow rate for different values of said operating parameters and said control computer controlling said engine based on said predetermined bitmaps, said computer controlling the amounts and timings of primary and auxiliary fuel injected by said primary and auxiliary fuel injectors based on said monitored parameters and said predetermined bitmap to obtain an auxiliary air fuel mixture adjacent to said spark plug in said at least one cylinder having an air fuel ratio lower than that of a primary air fuel mixture formed by fuel injected by said primary injector, co-ordinating timing of auxiliary fuel injection with timing of spark discharge of said spark plug in each of said at least one cylinders, igniting said auxiliary air-fuel mixture and said ignited auxiliary air-fuel mixture igniting said primary air-fuel mixture.

2. A computer control method as defined in claim 1 wherein said change in primary fuel supply is controlled by said computer by changing the timing of the beginning of primary fuel injection and duration of primary fuel injection.

3. A computer control method as defined in claim 1 wherein said injection of said auxiliary fuel is through a fuel injection spark plug.

4. A computer control method as defined in claim 1 wherein said change in primary fuel supply injection is followed by a change in said adjusting air mass flow rate.

5. A computer control method as defined in claim 2 wherein said change in primary fuel supply injection is followed by a change in said adjusting air mass flow rate.

6. A computer control method as defined in claim 3 wherein said change in primary fuel supply injection is followed by a change in said adjusting air mass flow rate.

7. A computer control method as defined in claim 1 wherein said spark discharge comprises a multiple spark discharge.

8. A computer control method as defined in claim 2 wherein said spark discharge comprises a multiple spark discharge.

9. A computer control method as defined in claim 3 wherein said spark discharge comprises a multiple spark discharge.

10. A computer control method as defined in claim 4 wherein said spark discharge comprises a multiple spark discharge.

11. A computer control method as defined in claim 5 wherein said spark discharge comprises a multiple spark discharge.

12. A computer control method as defined in claim 6 wherein said spark discharge comprises a multiple spark discharge.