Microprocessor-based electronic engine control system

In an internal combustion engine having an intake system, an exhaust system, an engine block, a plurality of cylinders disposed in said engine block, a piston disposed in each of said plurality of cylinders and mounted for reciprocal movement within each of said cylinders in response to combustion of fuel and air therein, means associated with at least a predetermined one of said cylinders and responsive to said piston reciprocating therein having attained a predetermined reference position for generating an engine position signal indicative thereof, means responsive to a fuel control signal for selectively controlling the quantity of fuel supplied to a selected one or more of said plurality of cylinders, means responsive to an ignition control signal for selectively controlling the time and duration of the ignition of said fuel in said selected one or more of said plurality of cylinders, an improved microprocessor-based engine control system comprising:

• means for sensing a plurality of engine operating parameters and generating sensor output signals indicative of the value thereof;
• means for generating command signals for processing said sensor output signals;
• means for converting a selected one of said sensor output signals into one or more data words representative thereof in response to said processing signals;
• means responsive to one or more of said data words for performing predetermined programmed operations thereon in accordance with pre-programmed fuel control laws and ignition timing laws and for generating digital commands indicative of a desired control action for effecting one or more predetermined engine control functions such as fuel pulse injection or ignition timing, the operation thereof being synchronized to the generation of said engine position signals;
• means responsive to said digital commands for controlling the generation of a selected one of said fuel control signal or said ignition timing signal thereby accurately controlling the quantity of fuel supplied to a selected one or more of said plurality of cylinders or the time and duration of fuel ignition therein;
• and
• means responsive to said engine position signals for altering the rate at which said digital commands are generated such that certain control functions such as fuel control are up-dated once each revolution until a predetermined engine speed is reached and then once every other revolution thereafter, and other control functions such as ignition timing and the like are updated once every other revolution at low engine speeds and once each revolution after the engine speed reaches a second predetermined level, thereby automatically proportioning the up-dating of said data commands to effectively compensate for changing computing power per engine revolution and hence the number of computations that can be performed per revolution which inherently occur with changes in engine speed.

In an internal combustion engine having an engine block, a plurality of cylinders disposed in said engine block, a piston disposed in each of said cylinders and mounted for reciprocal movement therein in response to the combustion of air and fuel in said cylinder, means responsive to a fuel control signal for selectively controlling the supply of fuel into a selected one or more of said plurality of cylinders, means responsive to a digital fuel control command for controlling the generation of said fuel control signal, and an electronic engine control means for implementing a pre-programmed fuel control law to generate said digital fuel control command, the improvement comprising:

• external sensing means for generating a signal indicative of the value of engine temperature;
• means responsive to said signal indicative of the value of engine temperature for converting said signal into an engine temperature data word representative thereof;
• memory means for storing data representative of a look-up table having a predetermined finite number of basic fuel command modifier values representing a continuous control surface having an infinite number of such modifier values;
• means responsive to at least said engine temperature data word for addressing said look-up table to obtain at least one predetermined basic fuel command modifier value;
• means for interpolating between data representative of said addressed at least one predetermined basic modifier value and the basic modifier values adjacent thereto for accurately computing an optimal modifier value for use by said electronic engine control means in the implementation of said predetermined fuel control law;
• and
• program means for implementing said fuel control law to generate said digital fuel control command, said program means being responsive to said accurately computed optimal modifier value for modifying the value of said digital fuel control command to insure the generation of a more accurate engine temperature-compensated digital fuel control command and hence a more accurate engine temperature-compensated fuel control signal thereby insuring a more accurately controlled supply of fuel into said selected one or more cylinders.

In an internal combustion engine having an intake system, an exhaust system, an engine block, a plurality of engine cylinders disposed in said engine block, a piston disposed for reciprocal movement within each of said plurality of cylinders, an output shaft responsive to the reciprocation of said pistons within said cylinders in response to the combustion of fuel and air therein for driveably rotating same, means for selectively supplying fuel into one or more of said cylinders, means responsive to an ignition control pulse for controlling the ignition of said fuel in said cylinders, means for sensing a predetermined position of said piston within said cylinder such as top-dead-center or the like for generating engine position pulses and for obtaining an indication of the speed or period of said engine, and a micro-processor-based electronic engine control system including memory means, the improvement in said microprocessor-based electronic engine control system comprising:

• memory means for storing data representative of at least one look-up table for establishing a predetermined multi-dimensional control surface representing values of modifier variables;
• means responsive to said engine speed or period for addressing said memory means for at least one look-up table and selecting a predetermined modifier variable stored therein;
• program means responsive to the addressing of said look-up table memory means for interpolating between said addressed predetermined modifier value and adjacent values for computing an optimal modifier value for use in ignition timing calculations, said program means further including means responsive to said engine speed or period and to said computed optimal modifier values for generating an ignition control word indicative of a predetermined delay interval, said ignition timing being controlled thereby such that said ignition control pulse is initiated at the end of a delay represented by said ignition control word, said program means being further effective for terminating said ignition control pulse after a second predetermined period, thereby controlling the ignition timing of said engine.

In an internal combustion engine having an intake system, an exhaust system, an engine block, a plurality of engine cylinders disposed in said engine block, a piston disposed for a reciprocal movement within each of said plurality of cylinders, an output shaft responsive to the reciprocal movement of said pistons within said cylinders in response to the combustion fuel and air therein for drivably rotating same, means for controllably supplying fuel to a selected one or more of said cylinders, sensor means associated with one or more of said pistons or said output shaft for generating engine position pulses indicative of the piston having attained a predetermined position such as top-dead-center or the like, said engine position pulse being generally indicative of engine speed or period, and a microprocessor-based engine control system including a memory means, a means responsive to an ignition control pulse for controlling the ignition of said fuel within said cylinders, the improvement comprising:

• memory means for storing data representative of at least one look-up table containing a predetermined finite number of modifier values stored in said memory means for establishing a predetermined at least two dimensional control surface representing an infinite number of modifier values which are a function of at least engine speed or period;
• means responsive to at least said engine position pulses or a speed or period value derived therefrom for addressing said look-up table to select one of said finite modifier values therefrom;
• program means for interpolating between said one selected modifier value and the addressable values adjacent thereto for computing an optimal modifier value, said program means further including means responsive at last to said accurately computed optimal modifier value for calculating a first digital ignition control word indicative of the pulse-width or duration of said ignition control pulse, said program means further including means responsive to each of said engine position pulses for initiating the start of said ignition control pulse upon receipt thereof for controlling both ignition timing and ignition dwell time.

In an internal combustion engine having an engine block, a plurality of cylinders disposed in said engine block, a piston disposed in each of said cylinders and mounted for reciprocal movement in response to the combustion of air and fuel in said cylinder, an output shaft responsive to the reciprocation of said pistons within said cylinders for drivably rotating same, means for selectively controlling the supply of fuel to one or more of said plurality of cylinders, means for generating an ignition pulse for controlling the ignition timing and ignition dwell time and therefore the ignition of said fuel within said cylinders, and a microprocessor-based engine control system for controlling the generation of said ignition pulse, said engine control system further comprising:

• sensor means operatively associated with said engine for generating an engine position pulse each time one of said pistons is near the top-dead-center position of its associated cylinder;
• program means for computing a first digital ignition control word indicative of ignition delay time and a second digital ignition control word indicative of ignition pulse-width;
• means responsive to said first and second digital ignition control words for electronically controlling the generation of said ignition control pulse for ignition timing purposes during normal engine operation;
• and
• means for detecting an engine cranking mode of operation for automatically switching the ignition timing from the control of said microprocessor-based engine control system and generating a first command signal;
• and
• means responsive to said first command signal for mechanically controlling the generation of said ignition control pulse and therefore ignition timing throughout said cranking mode of operation.

A microprocessor-based engine control system for use in an internal combustion engine of the type having means for supplying a controlled quantity of fuel to the engine in response to a fuel control signal, means for igniting the fuel supplied to the engine in response to an ignition control signal, and means for controlling the recirculation of exhaust gases from the exhaust manifold of said engine back to the intake manifold in response to an EGR control signal, said microprocessor-based engine control system comprising:

• means for sensing a plurality of engine operating parameters such as manifold absolute pressure, air temperature, engine coolant temperature, throttle position, EGR valve position, the concentration of oxygen in the exhaust system of said engine and the like and for generating a conditioned output signal indicative thereof;
• analog-to-digital converter means including means for converting each of said conditioned sensor output signals into a corresponding DC voltage level;
• a microprocessor system including memory means and program means for implementing various control laws, arithematic functions and the like and for generating various sets of computer control signals;
• multiplexer means responsive to first computer control signals for selecting a predetermined one of said DC voltage levels;
• pulse-width to binary converter means responsive to said selected one of said DC voltage levels for generating a pulse-width indicative of said selected level and converting same into a binary number indicative thereof, said pulse-width to binary converter means being responsive to second computer control signals for transmitting said binary number to said microprocessor system;
• means responsive to the speed or period of said engine for generating various engine pulse position signals indicative thereof;
• program means within said multiprocessor for utilizing said received binary words to calculate digital control words in accordance with pre-programmed look-up tables, control laws, and data supplied thereto;
• a plurality of serial shift registers associated with predetermined control functions;
• parallel to serial converter means responsive to third computer control signals for receiving said digital control word in parallel from said microprocessor and serially transferring said control word into a selected one of said shift registers;
• means for detecting a plurality of system conditions and generating interrupt signals in response thereto, said interrupt signals being transmitted to said microprocessor unit for use therein;
• means associated with said serial shift registers for converting said binary values stored therein into a pulse-width output signal;
• and
• means responsive to predetermined ones of said pulse width output signals for generating said fuel control pulse, said ignition control pulse and said EGR control pulse for controlling the operation of the said internal combustion engine.

In an engine system having an internal combustion engine, a plurality of cylinders in said internal combustion engine, a piston mounted for reciprocal motion within each of said plurality of cylinders in response to the combustion of fuel therein, an output shaft operatively coupled to said piston and rotatably driven by the reciprocation of said pistons within said cylinders, at least one fuel injector means responsive to a fuel control pulse for injecting a controlled quantity of fuel into a selected one or more of said plurality of cylinders for combustion therein, at least one ignition means responsive to an ignition control signal for selectively controlling the timing and duration of ignition of said injected fuel within said cylinder, an improved electronic engine control system comprising:

• computer means;
• memory means operatively coupled to said computer means for storing data representative of a plurality of look-up tables representing multi-dimensional control surfaces of modifier values which are functions of at least one engine operating parameter;
• first program data means stored in said memory means for implementing a predetermined fuel control law when executed by said computer means;
• means for sensing a plurality of real time engine operating parameters, at least one of said engine operating parameters being a function of engine speed, and for generating digital words indicative of the actual measured value of said sensed engine operating parameter;
• means for generating command signals for processing data in said computer;
• second program means executable by said computer means in response to said command signals for utilizing said digital words indicative of the actual measured value of said sensed engine operating parameter for addressing said memory means for a predetermined value stored in said look-up table in said memory means and for interpolating between said predetermined stored value and addressable stored values adjacent thereto to compute an interpolated control surface value for use in executing said fuel control law to generate a compensated fuel control digital command;
• and
• means responsive to said fuel control digital command for generating said fuel control pulse to operate said at least one fuel injector means, the duration of said fuel control pulse determining the specific quantity of fuel to be injected into said selected one or more of said plurality of cylinders.

In an engine system having an internal combustion engine, a plurality of cylinders in said internal combustion engine, a piston mounted for reciprocal motion within each of said plurality of cylinders in response to the combustion of fuel therein, an output shaft operatively coupled to said piston and rotatably driven by the reciprocation of said pistons within said cylinders, at least one fuel injector means responsive to a fuel control pulse for injecting a controlled quantity of fuel into a selected one or more of said plurality of cylinders for combustion therein, at least one ignition means responsive to an ignition control signal for selectively controlling the timing and duration of ignition of said injected fuel within said cylinder, an improved electronic engine control system comprising:

• computer means;
• memory means operatively coupled to said computer means for storing data representative of a plurality of look-up tables representing multi-dimensional control surfaces of modifier values which are a function of at least one engine operating parameter;
• program means stored in said memory means for implementing a predetermined ignition control signal calculation when executed by said computer means;
• means for sensing a plurality of real time engine operating parameters at least one of which is a function of degrees of engine revolution for establishing a reference position for piston whose associated cylinder is to have the injected fuel ignited therein and for generating a reference position pulse indicative thereof;
• means for generating command signals for processing data in said computer means;
• said computer means executing said program means in response to said command signals for computing a first digital word indicative of a calculated delay time from the receipt of said reference pulse until ignition is to occur and a second separate and distinct digital word indicative of the duration of ignition of said fuel injected into said cylinder.

In combination with an internal combustion engine of the type having an engine block, a plurality of cylinders located in said engine block, a plurality of pistons each mounted in a respective cylinder for reciprocating movement therein, an output shaft operatively coupled to said plurality of pistons and rotatable upon the reciprocation of each of said pistons within said cylinders, an intake manifold common to all of said plurality of cylinders, said intake manifold having an opening therein for receiving air and means disposed within said opening for selectively varying the effective size of said opening, means for supplying fuel to a selected one or more of said plurality of engine cylinders, said fuel supply means including a fuel pump and at least one electromagnetically operated fuel injector valve adapted to operate in response to a fuel control signal, means for igniting the fuel supplied to said selected one or more of said plurality of engine cylinders, said fuel igniting means being responsive to an ignition control signal for controlling the timing and duration of admission of the fuel injected into said selected one or more of said plurality of engine cylinders, and an electrical system for controlling the operation of said fuel supply means and said igniter means to cause the combustion of fuel and air in each of said plurality of engine cylinders and thereby cause said pistons to reciprocate within said cylinders to rotate said output shaft, the improvement in said electrical system comprising:

• means for sensing various engine operating parameters on a real time basis and for producing a corresponding plurality of digital signals indicative thereof, at least one of said digital signals representing operator-commanded changes in the size of said opening in said manifold intake;
• means for generating said fuel control signal for controlling the operation of said fuel supply means in response to said plurality of digital signals, said fuel control signal generated means including means for receiving and processing said plurality of digital signals from said sensing means, said processing means including a digital data processor operating under the control of a program to convert said plurality of digital signals into a first electrical control signal for operating said fuel pump and controlling the supply of fuel to said fuel injection means, a second electrical control signal for opening said fuel injector valve for a predetermined time interval T1 for a given predetermined revolution of said output crankshaft, means responsive to said one of said digital signals representing a change in the effective size of said opening for anticipating an operator-commanded acceleration enrichment request and generating a fourth electrical control signal indicative thereof, a fourth electrical control signal responsive to said third electrical control signal for opening said fuel injector valve for at least one additional time interval T2 for each predetermined revolution period of said output shaft to increase the amount of fuel supplied to a selected one or more of said plurality of engine cylinders for acceleration enrichment purposes and then increase the rotational speed of said output shaft, another of said plurality of digital signals being representative of a sensed engine operating parameter indicative of one or more of said pistons having reached a predetermined reference position for generating successive engine position pulses, means responsive to the receipt of an engine position pulse for counting a delay time therefrom prior to generating said ignition control signal and causing the combustion of injected fuel within said selected one or more of said plurality of said cylinders, and means normally responsive to the end of said predetermined delay time interval for generating said ignition control pulse for a time interval T3 whose duration controls the time of combustion of said injected fuel within said selected engine cylinder.