Electronic Fuel Injection Compensation

1. An electronic engine control system for controlling the supply of fuel to an engine comprising means for measuring the time interval between engine position pulses and computing a digital number indicative of engine speed, computation means, memory means for storing a program for implementing at least one fuel control law, said program being executed by said computation means for implementing said at least one fuel control law to normally compute a primary fuel control pulse for controlling the supply of fuel to said engine, means for detecting engine operating conditions indicative of a need for acceleration enrichment and generating an acceleration enrichment request signal, means responsive to said acceleration enrichment request signal for addressing said memory means with said stored digital number indicative of engine speed for generating an acceleration enrichment modifier value signal which is a function of engine speed, said computational means executing said stored program for implementing said at least one fuel control law and programmably modifying the normally-computed primary fuel control pulse with said calculated acceleration enrichment modifier value signal for generating an elongated, acceleration enrichment-compensated primary fuel control pulse for controlling the supply of fuel to said engine to maintain smooth engine performance while avoiding "stumbling" and the like.

2. An electronic engine control system for normally generating a primary fuel injection pulse for controlling the quantity of fuel supplied to an engine including means for engine operating conditions indicative of a need for acceleration enrichment and generating an acceleration enrichment request signal in response thereto, and means responsive to said acceleration enrichment request signal for immediately generating an initial acceleration enrichment fuel injection pulse if no normally-generated primary fuel injection pulse is currently being outputted and delaying the generation of said initial acceleration enrichment fuel injection pulse whenever a normally-generated primary fuel injection pulse is being generated until immediately after the normal termination of said primary fuel injection pulse so that no portion of either said normally-generated primary fuel injection pulse or said initial acceleration enrichment fuel injection pulse is masked or lost during the outputting of the other and the total quantity of fuel supplied to said engine is sufficient to maintain smooth engine operation even during conditions of acceleration.

3. A method of operating a microprocessor-based electronic engine control system including a microprocessor means, memory means for storing at least one look-up table of modifier values computed as a function of at least one engine-operating parameter and program means for implementing at least one control law, means for measuring said at least one engine-operating parameter, said microprocessor means being responsive to said at least one measured engine-operating parameter for executing said program means for implementing said at least one control law to compute a particular engine control command, the method for addressing said look-up table and computing an exact modifier value corresponding to the actual measured value of said at least one engine-operating parameter for use in implementing said at least one control law by extending a straight line between pairs of addressed values below the correction factor of one utilizing a "unity intercept" technique to compute an overall correction factor compared to the level of "one" law to compute said program-implemented engine control command comprising the steps of: (1) assigning a desired modifier value weight at a modifier value Y.sub.1 for input address value X.sub.1 and a value of "ONE" for the modifier value at a predetermined threshhold address level X.sub.t ; (2) extending a straight line from Y.sub.1, X.sub.1 to "ONE", X.sub.t below the modifier value of "ONE"; (3) reading a Y.sub.2 modifier value (lower than ONE) at the address value X.sub.2 ; (4) interpolating between the modifier values Y.sub.1 and Y.sub.2 by linear interpolation techniques to compute an overall modifier value corresponding to the actual measured value of engine-operating parameter represented by the input address variable X; (5) comparing the computed overall modifier value Y to the value ONE; and (6) utilizing the greater of the computed modifier value Y and the value ONE to modify said programmably-computed engine control command thereby allowing any threshhold input value between the addressed values X.sub.1 and X.sub.2 to be selected regardless of the limited number of addressable locations for the variable input values corresponding to measured values of engine-operating parameters in the look-up table of modifier values stored in said memory means.

4. An electronic engine control system for use with an internal combustion engine system having an intake system, an exhaust system, an engine block, a plurality of cylinders disposed in said engine block, a piston operatively disposed within each of said plurality of cylinders for reciprocal movement therein, means responsive to fuel control signals for selectively supplying a controlled quantity of fuel to a selected one or more of said plurality of cylinders, the electronic engine control system comprising computer means, memory means operatively coupled to said computer means for storing data representative of at least one look-up table containing a control surface of modifier values computed as a function of engine speed, and program means for implementing at least one fuel control law, means for measuring engine speed and generating a signal indicative thereof, means for temporarily storing said signal indicative of engine speed, said computer means being responsive to said temporarily stored signal indicative of engine speed for addressing said at least one look-up table data of modifier values stored in said memory means and generating a signal representative of a particular modifier value corresponding to the actual measured value of engine speed represented by said temporarily stored signal, said program means utilizing said at least one fuel control law in response to said computed particular modifier value for generating a modified fuel control signal so that the controlled quantity of fuel supplied to a selected one or more of said plurality of cylinders for ignition purposes is a function of actual engine speed thereby maintaining smooth engine performance and good drivability while avoiding "stumble", "hesitation" and the like.

5. In an internal combustion engine system having computer means, memory means associated with said computer means, program means stored in said memory means for implementing at least one fuel control law to compute a fuel control signal, preparing a look-up table of modifier values which are a function of engine speed; storing said look-up table of modifier values which are a function of engine speed; storing said look-up table of modifier values in said memory means; and means responsive to said fuel control signal for controlling the quantity of fuel supplied to said engine, an improved method of acceleration enrichment compensation comprising the steps of: measuring the speed of said engine to obtain a vaue indicative thereof and generating a measured engine speed signal; addressing the stored look-up table of modifier values with said measured engine speed signal; generating modifier value signals by interpolating between stored modifier values to compute the particular modifier value corresponding to said measured engine speed signal; utilizing said program means including at least one fuel control law to generate said fuel control signal; and altering said at least one fuel control law by modifiying the fuel control signal with said predetermined computed modifier value signal corresponding to said measured engine speed signal to generate a compensated fuel control signal corrected for acceleration so as to maintain smooth engine performance and the like.

6. In an internal combustion engine system including means responsive to fuel control pulses for selectively controlling the quantity of fuel supplied to said engine and engine control means for normally computing primary fuel control pulses for operating said fuel supply means, an improved method of acceleration enrichment compensation comprising the steps of monitoring at least one of throttle angle and manifold absolute pressure, detecting a rapid change in said monitored one of said throttle angle and manifold absolute pressure as an indication of a need for acceleration enrichment, generating an extra additional one-time acceleration enrichment fuel control pulse in response to said detected need for acceleration enrichment, determining if the generation of said extra additional one-time acceleration enrichment fuel control pulse will occur during the normal generation of said primary fuel control pulse and generating a signal indicative thereof, immediately generating said extra additional one-time acceleration enrichment fuel control pulse in response to a signal indicating that said normally generated primary fuel control pulse is not currently being generated, and delaying the generation of said extra additional one-time acceleration enrichment fuel control pulse until immediately after the termination of said normally-generated primary fuel control pulse in response to a determination that said primary fuel control pulse is currently being generated for extending same to insure that no portion of either of said fuel control pulses is masked or lost and that said internal combustion engine receives sufficient fuel even during acceleration periods to maintain smooth engine performance and "drivability".

7. In an internal combustion engine having a control system for normally generating main fuel control pulses and means responsive to the duration of said fuel control pulses for selectively controlling the quantity of fuel supplied to said engine for combustion purposes, the improvement comprising acceleration enrichment compensation means including: means for monitoring at least one engine manifold absolute pressure and throttle angle for detecting rapid changes therein; means responsive to the detection of rapid changes in said monitored at least one of manifold absolute pressure and throttle angle for generating an acceleration enrichment enable signal indicative of a need for acceleration enrichment; means responsive to said acceleration enrichment enable signal for normally generating a one-shot additional tip-in fuel control pulse upon the leading edge of said acceleration enrichment enable signal unless one of said normally-generated main fuel control pulses is currently being generated and for otherwise generating said one-shot additional Tip-In fuel control pulse immediately upon the termination of said normally-generated main fuel control pulse for effectively extending the pulse-width thereof; and means for modifying said normally-generated main fuel control pulse for longer term acceleration enrichment correction as a function of engine speed, air temperature and the number of engine revolutions elapsed since the generation of said acceleration enrichment enable signal.

8. The improved internal combustion engine system of claim 7 wherein said engine control system includes computer means, memory means operatively coupled to said computer means, program means stored in said memory means for execution by said computer means to implement at least one fuel control law, a first look-up table containing a control surface of first acceleration enrichment modifier values which are a function of engine speed, a second look-up table containing a control surface of second acceleration enrichment modifier values which are a function of air temperature, and a third look-up table containing a control surface of third acceleration enrichment modifier values which are a function of the number of engine revolutions which have elapsed since the generation of said acceleration enrichment enable signal, said internal combustion engine system further including means for measuring the actual speed of said engine and generating a RPM signal indicative thereof, means for measuring the actual air temperature and generating a TEMP signal indicative thereof, and means for counting the number of engine revolutions elapsed since the generation of said acceleration enrichment enable signal and generating a DECAY signal indicative thereof, said means for modifying said normally-generated fuel control pulses for longer term acceleration enrichment correction including means for performing a One Factoral Enrichment of said normally-computed main fuel control pulse such that if T.sub.P (N) represents the normally-computed main fuel pulse, T.sub.P(AE) represents the total acceleration enrichment-compensated main fuel control pulse needed to supply a sufficient quantity of fuel to said engine to maintain smooth engine performance and good "dirvability" and "K" represents the factoral enrichment factor, then T.sub.P(AE) =T.sub.P(N) .times.(1+K), where K=K.sub.RPM .times.K.sub.AIR TEMP .times.K.sub.DECAY where K.sub.RPM is said first acceleration enrichment modifier value which is a function of engine speed and which is determined by addressing said first look-up table with said RPM signal and interpolating to compute the particular first acceleration enrichment modifier value corresponding thereto, where K .sub.AIR TEMP represents said second acceleration enrichment modifier value which is a function of air temperature and which is determined by addressing said second look-up table of acceleration enrichment modifier values with said TEMP signal and interpolating to calculate the particular acceleration enrichment modifier value corresponding to the actual measured value thereof, and where K.sub.DECAY represents said third acceleration enrichment modiifier value which is determined from said third look-up table by addressing said table with said DECAY signal and interpolating on said control surface to calculate the particular third acceleration enrichment modifier value corresponding to the actual number of counts having elapsed since the generation of said acceleration enrichment signal.

9. An acceleration enrichment system for use with an internal combustion engine including means responsive to the measured values of one or more engine-operating parameters for normally generating primary fuel control signals and means responsive to the duration of said fuel control signals for selectively controlling the quantity of fuel supplied to said engine and therefore the operation thereof, said acceleration enrichment system including: means for sensing engine-operating parameters and generating a signal indicative of a need for acceleration enrichment including generating an acceleration enrichment request signal in response thereto; means responsive to said acceleration enrichment request signal for generating an immediate Tip-In acceleration enrichment fuel control pulse if no main fuel control pulse if currently being generated and for delaying the generation of said Tip-In acceleration enrichment fuel control pulse until immediately after the termination of said main fuel control pulse if said normally-generated main fuel control pulse is currently being generated; and means responsive to said acceleration enrichment request for additionally modifying said normally-generated main fuel control pulse to effect a longer term, more gradual acceleration enrichment correction so as to insure smooth engine performance and good drivability.

10. The acceleration enrichment system of claim 9 wherein said means for additionally modifying said normally-generated main fuel control pulse to effect said longer-term more gradual acceleration enrichment correction includes means for correcting said normally-generated main fuel control pulse by multiplying same by a One Factoral Factor (1+K) where "K" is a factor combining a first acceleration enrichment modifier value which is a function of engine speed, a second acceleration enrichment modifier value which is a function of air temperature, and a third acceleration enrichment modifier value which is a function of the number of engine revolutions elapsed since the initiation of the present acceleration enrichment sequence.

11. In an internal combustion engine system including means for normally generating primary fuel control pulses and means responsive to the duration of said fuel control pulses for selectively controlling quantity of fuel supplied to said engine for combustion purposes, an improved acceleration enrichment compensation method comprising the steps of determining a need for acceleration enrichment, generating an initial immediate Tip-In fuel control pulse if no main fuel control pulse is presently being generated and a delayed Tip-In fuel control pulse if a main fuel control pulse is presently being generated, and modifying subsequently generated main fuel control pulses with a long term acceleration enrichment factor, said modifying said normally-generated main fuel control pulses further including computing a first acceleration enrichment multiplier value as a function of engine speed, computing a second acceleration enrichment multiplier value as a function of air temperature, computing a third acceleration enrichment multiplier value as a function of decay where decay represents the number of engine revolutions having elapsed since the initiation of the current acceleration enrichment sequence, multiplying said first, second and third acceleration enrichment modifier values to obtain said factor "K", and multiplying said normally-computed main fuel control pulse by the quantity (1+K) to arrive at said fully-acceleration-enrichment-compensated fuel control pulse for achieving said long-term gradual compensation for the detected acceleration.