WO1996001945A1 - Ignition system for an internal combustion engine - Google Patents

Ignition system for an internal combustion engine Download PDF

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Publication number
WO1996001945A1
WO1996001945A1 PCT/GB1995/001576 GB9501576W WO9601945A1 WO 1996001945 A1 WO1996001945 A1 WO 1996001945A1 GB 9501576 W GB9501576 W GB 9501576W WO 9601945 A1 WO9601945 A1 WO 9601945A1
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WO
WIPO (PCT)
Prior art keywords
cylinders
engine
predetermined
cylinder
ignition
Prior art date
Application number
PCT/GB1995/001576
Other languages
French (fr)
Inventor
Gordon Wright
James R. Clark
Mark B. Barron
Original Assignee
Ford Motor Company Limited
Ford Werke Ag
Ford France S.A.
Ford Motor Company
Ford Motor Company Of Canada Limited
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Ford Motor Company Limited, Ford Werke Ag, Ford France S.A., Ford Motor Company, Ford Motor Company Of Canada Limited filed Critical Ford Motor Company Limited
Publication of WO1996001945A1 publication Critical patent/WO1996001945A1/en

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02P—IGNITION, OTHER THAN COMPRESSION IGNITION, FOR INTERNAL-COMBUSTION ENGINES; TESTING OF IGNITION TIMING IN COMPRESSION-IGNITION ENGINES
    • F02P5/00—Advancing or retarding ignition; Control therefor
    • F02P5/04—Advancing or retarding ignition; Control therefor automatically, as a function of the working conditions of the engine or vehicle or of the atmospheric conditions
    • F02P5/145—Advancing or retarding ignition; Control therefor automatically, as a function of the working conditions of the engine or vehicle or of the atmospheric conditions using electrical means
    • F02P5/15—Digital data processing
    • F02P5/1502—Digital data processing using one central computing unit
    • F02P5/1506—Digital data processing using one central computing unit with particular means during starting
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D41/00—Electrical control of supply of combustible mixture or its constituents
    • F02D41/02—Circuit arrangements for generating control signals
    • F02D41/021—Introducing corrections for particular conditions exterior to the engine
    • F02D41/0235—Introducing corrections for particular conditions exterior to the engine in relation with the state of the exhaust gas treating apparatus
    • F02D41/024—Introducing corrections for particular conditions exterior to the engine in relation with the state of the exhaust gas treating apparatus to increase temperature of the exhaust gas treating apparatus
    • F02D41/0255—Introducing corrections for particular conditions exterior to the engine in relation with the state of the exhaust gas treating apparatus to increase temperature of the exhaust gas treating apparatus to accelerate the warming-up of the exhaust gas treating apparatus at engine start
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/10—Internal combustion engine [ICE] based vehicles
    • Y02T10/12—Improving ICE efficiencies
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/10—Internal combustion engine [ICE] based vehicles
    • Y02T10/40—Engine management systems

Definitions

  • This invention relates generally to electronic engine control systems and more particularly to methods and apparatus for controlling ignition timing in response to changing engine operating conditions.
  • Electronic engine control systems typically respond to sensed conditions, such as engine speed and load, operating temperatures and pressures, accelerator position, and exhaust oxygen levels, in order to properly adjust ignition timing and the rate at which fuel and air are delivered to the engine.
  • Electronic control systems can significantly improve engine efficiency while minimising undesired exhaust emissions under changing operating conditions.
  • Such multifunction electronic engine control systems are preferably implemented with integrated circuit microcontrollers operating under stored program control.
  • Suitable microcontrollers are available from a variety of sources and include the devices described in Motorola ' s Microcontroller and Microprocessor Families , Volume 1 (1988), published by Motorola, Inc., Microcontroller Division, Oak Hill, Texas.
  • the microcontroller in an electronic engine control generates timed output control signals which operate the engine's electronic ignition and fuel injection systems. These control signals are typically synchronised by event signals from one or more sensors which indicate crankshaft position. Commonly called PIPS (Piston Interrupt Signals) , these position sensing signals typically initiate microcontroller interrupt-handling routines to perform a variety of control functions synchronised to the engine's rotation.
  • PIPS Proton Interrupt Signals
  • the microcontroller processes additional analogue signal values from other sensors which are converted into digital quantities by analogue-to-digital (A-D) converters within the microcontroller.
  • Electronic engine control systems perform elaborate control functions by processing available digital values which describe the engine's operating condition to vary control inputs which determine the engine's operation. Increasingly sophisticated mechanisms may accordingly be implemented at little additional manufacturing cost to optimise engine performance over a wide range of operating conditions.
  • the engine control system typically varies the timing of ignition with respect to piston motion to enhance engine performance. Normally, spark timing is adjusted uniformly for all cylinders, varying the time of ignition with respect to the top-dead-centre position of the firing cylinder to optimise performance.
  • electronic control systems include instrumentalities that may be readily adapted to provide cylinder-by-cylinder control of spark timing in order to equalise burn-rates or to retard the spark for knock-prone cylinders, these techniques are unnecessary for well-designed and well-maintained engines. Cylinder-by- cylinder ignition timing control can, however, yield significant benefits in other ways by following the principles of the present invention.
  • methods and apparatus are used to vary the time at which the fuel mixture is ignited in one or more predetermined cylinders of the engine in response to at least one predetermined sensed engine operating condition.
  • the ignition timing signals delivered to selected cylinders are retarded by a significant time delay interval, without correspondingly delaying the ignition signals delivered to the remaining cylinders, to more quickly increase the temperature of the exhaust system. Delaying the ignition timing increases the flow of heat to the engine's exhaust system, especially during cold start conditions, without significantly degrading combustion quality.
  • the more rapid increase in engine exhaust temperatures (1) improves the performance of the exhaust catalyst system, (2) increases the burn-up of hydrocarbons and carbon monoxide at the engine's exhaust port during cold idle and drive-away conditions, and (3) facilitates the use of exhaust gas recirculation (EGR) during cold-start conditions to enhance fuel preparation and reduce undesired emissions.
  • EGR exhaust gas recirculation
  • the selective retardation of ignition of predetermined cylinders typically reduces feedgas nitrous oxide emissions by reducing the in-cylinder residence time during which chemical reactions which produce such emissions can occur, and permits the air/fuel ratio to be increased during cold engine conditions to increase hydrocarbon oxidation in the catalyst system.
  • FIG. 1 of the drawings is a pictorial schematic illustration of a vehicle engine control system embodying the principles of the invention
  • Figure 2 is timing diagram illustrating the manner in which the time of ignition may be retarded for selected cylinders only to promote exhaust system heating as contemplated by the invention.
  • Figures 3 and 4 are flow charts illustrating the operation of a preferred mechanism for selectively delaying the ignition time for selected cylinders.
  • FIG. 1 of the drawings shows an electronic engine control (EEC) module within the dashed-line rectangle 10 connected to supply ignition signals to a four-cylinder, four-stroke internal combustion engine indicated generally at 20.
  • the control module 10 consists of an engine data acquisition mechanism 12, an electronic distributor 14, a common cylinder ignition retard control mechanism 15, and an individual cylinder ignition retard control mechanism
  • the distributor 14 produces ignition pulses on four parallel output lines 18 which are respectively connected to the spark plugs of four cylinders indicated at 21-24 in Fig. 1.
  • the timing of the ignition pulses supplied to the cylinders is determined in the first instance by the common retard mechanism 15.
  • the ignitions signals are then further delayed, on a cylinder-by-cylinder basis by individual delay intervals DT 1; DT 2 , DT 3 and DT 4 for cylinders 21-24 respectively, as schematically illustrated by delay mechanisms shown within the dashed-line rectangle 19 in Fig. 1.
  • the data acquisition mechanism 12, the common retard control 15, and the electronic distributor 14 within the control module 10 preferably take the form of the pre ⁇ existing conventional components of the EEC module 10 which operate without modification.
  • the engine data acquisition unit 12 receives signal values via an accelerator angle sensor input 30, a temperature sensor input 31 (connected to receive sensor inputs indicating coolant temperature, fuel temperature, exhaust port temperature, etc.), an engine load (air mass flow rate) sensor input 32, and an engine speed / crankshaft position tachometer input 33.
  • the signals supplied via input 33 typically comprises one or more pulse trains (derived from timing marks on the flywheel or the like) from which engine speed (RPM) , engine acceleration and deceleration, and the rotational position of the crankshaft (and hence the position of the piston in each cylinder) can be derived.
  • the common retard control mechanism 15 operates in accordance with conventional practice to control the electronic distributor 14 to produce, for each of the cylinders in turn, a reference ignition timing signal which establishes the minimum spark advance for best timing (MBT) under the then current engine speed, acceleration, temperature and load conditions.
  • the individual retard control circuit 16 when digital values available from the data acquisition mechanism 12 manifest predetermined engine conditions indicating cold startup, cold idle, deceleration or accelerator tip-out, the individual retard control circuit 16 introduces a significant additional spark retarding delay for selected cylinders only.
  • FIG. 2 The timing diagram seen in Fig. 2 illustrates this operation.
  • the MBT firing point established by the common retard control 15 for each of the four cylinders of a four-cylinder, four-stroke engine is shown by the position of the numbered vertical dashed lines in Fig. 2.
  • Waveforms Cl - C4 respectively illustrate the ignition timing signals supplied to the four cylinders of the engine, with the ignition signals supplied to the even- numbered cylinders C2 and C4 being delayed from their normal MBT timing by the delay intervals indicated in both Figs. 1 and 2 by DT 2 and DT 4 .
  • the ignition timing for the odd- numbered cylinders Cl and C3 remains unchanged from the MBT timing established by the common retard control mechanism 15; that is, both DT ⁇ and DT 3 are zero-valued.
  • the additional individual cylinder delay may be introduced for a predetermined actual time interval (established by a system clock, not shown) , for a predetermined amount of crankshaft rotation (determined by counting PIP pulses) , or may be terminated when defined engine operating conditions are detected (e.g., engine load or temperature values in excess of predefined threshold values) .
  • the duration of the introduced individual cylinder delay may be gradually reduced as a function of elapsed time and/or sensed engine operating conditions.
  • the first cylinder 21 is depicted near the bottom of the fuel intake stroke with the intake valve 41 open
  • the second cylinder 22 is seen near the top of its compression stroke with both valves closed
  • the third cylinder 23 is seen near the bottom of its power stroke with both valves closed
  • the fourth cylinder 24 is shown near the top of its exhaust stroke with the exhaust valve 43 open.
  • Retarding spark timing has further effects: the reaction times in which chemical kinetic reactions that produce nitrous oxide occur are reduced, knocking is suppressed, and a leaner air/fuel ratio may be used to promote hydrocarbon burning in the three-way catalyst.
  • Selective cylinder-by-cylinder modulation of the ignition timing also permits beneficial modifications to be made to the overall engine system. With the reduced expansion ratio created by retarded spark timing, the catalyst can be located farther downstream from the exhaust flange, thus improving catalyst protection for a smaller volume light-off catalyst.
  • rapid heating of the exhaust system allows exhaust gas recirculation (EGR) mechanisms to be used during cold starts, or to be activated more rapidly after startup, thereby diluting the intake charge without degrading combustion.
  • a "dual function" secondary air system can be used to deliver a higher air flow rate to those cylinders with retarded ignition timing to promote additional oxidation.
  • FIG. 3 The flowcharts of Figs. 3 and 4 illustrate an illustrative preferred implementation of a selective ignition retarding scheme embodying the principles of the invention.
  • the individual retard control mechanism illustrated schematically at 16 in Fig. 1 is preferably implemented by programming the engine control unit microcontroller (not shown) to process crankshaft position pulses consisting of a first train of pulses, each of which indicates a predetermined unit of angular rotation (e.g., 1°), in combination with one or more widely spaced pulses which indicate one or more reference position crankshaft positions (e.g., when the piston in cylinder 1 is at top- dead-centre) .
  • crankshaft rotation and reference signals are accepted and evaluated as illustrated at 50 and 51 in Fig. 3.
  • an integer value CylinderNo is incremented at 53 through the repeating succession of values 1, 2, 3, 4, 1, 2, etc. to indicate which cylinder is to receive the next ignition pulse (the distributor 14 seen in Fig. l routes the ignition pulse to the appropriate sparkplug based on the value of CylinderNo) .
  • a value IgnitionTimer indicative of engine operating conditions which will determine the spark timing for cylinder CylinderNo is set into a timing register as indicated at 55 in Fig. 3. The manner in which the value IgnitionTimer is determined is illustrated in Fig. 4, discussed below.
  • IgnitionTimer Assuming a unit rotation pulse is generated for every degree of crankshaft rotation, 89 unit pulses will be detected at 51 between each pair of reference pulses. Each of these unit pulses decrements the value of IgnitionTimer by one as seen at 56 until IgnitionTimer reaches the value zero, as detected at 57, at which time an ignition timing pulse is generated for the cylinder identified by CylinderNo as indicated at 58 in Fig. 3. The value of IgnitionTimer is then set to a high value MAX at 59 to prevent the remaining unit pulses from triggering additional ignition pulses until IgnitionTimer is again reset at 55. Thus, the numerical value IgnitionTimer initially placed in the timing register at 55 establishes the number of degrees of crankshaft rotation which will occur between the detection of the reference position pulse and the time of ignition for a given cylinder.
  • the value of IgnitionTimer as set into the timing register at 55 may be determined in the manner illustrated . by the flowchart of Fig. 4.
  • step 61 the least significant bit of CylinderNo is tested to determine if CylinderNo is odd or even.
  • the functional relationship F2 adds a significant delay to the ignition timing of the even-numbered cylinders, typically within a range between and degrees of crankshaft rotation, beginning at the time predetermined engine conditions are first detected.
  • the triggering condition may be a detected engine start, in combination with a detected engine temperature below a triggering threshold, and may further include certain detected engine running conditions, such as deceleration under low engine temperature conditions.
  • the amount of additional spark retardation added for the selected cylinders i.e., the magnitude of IgnitionTimer
  • F2 the amount of additional spark retardation added for the selected cylinders
  • variable elapsed time or angular rotation which is functionally related to: a) one or more engine operating temperatures (e.g., coolant, fuel or exhaust temperatures); b) the load on the engine (indicated, for example, by the air mass flow rate) ; c) engine acceleration or deceleration; d) accelerator angle; or e) the combination or one or more of above; or

Abstract

An electronic ignition timing control system including means (15, 16) for retarding the ignition timing for all or a predetermined subset of the cylinders (21-24) in a multi-cylinder internal combustion engine (20) during cold starts. Spark timing is reduced for a balanced subset of the cylinders (21-24) for a short time after the engine is started in order to transfer additional heat to the exhaust system to more quickly raise the temperature of the catalyst and thereby reduce undesired emissions.

Description

IGNITION SYSTEM FOR AN INTERNAL COMBUSTION ENGINE
This invention relates generally to electronic engine control systems and more particularly to methods and apparatus for controlling ignition timing in response to changing engine operating conditions.
Electronic engine control systems typically respond to sensed conditions, such as engine speed and load, operating temperatures and pressures, accelerator position, and exhaust oxygen levels, in order to properly adjust ignition timing and the rate at which fuel and air are delivered to the engine. Electronic control systems can significantly improve engine efficiency while minimising undesired exhaust emissions under changing operating conditions.
Such multifunction electronic engine control systems are preferably implemented with integrated circuit microcontrollers operating under stored program control. Suitable microcontrollers are available from a variety of sources and include the devices described in Motorola ' s Microcontroller and Microprocessor Families , Volume 1 (1988), published by Motorola, Inc., Microcontroller Division, Oak Hill, Texas.
The microcontroller in an electronic engine control generates timed output control signals which operate the engine's electronic ignition and fuel injection systems. These control signals are typically synchronised by event signals from one or more sensors which indicate crankshaft position. Commonly called PIPS (Piston Interrupt Signals) , these position sensing signals typically initiate microcontroller interrupt-handling routines to perform a variety of control functions synchronised to the engine's rotation. In addition, the microcontroller processes additional analogue signal values from other sensors which are converted into digital quantities by analogue-to-digital (A-D) converters within the microcontroller. Electronic engine control systems perform elaborate control functions by processing available digital values which describe the engine's operating condition to vary control inputs which determine the engine's operation. Increasingly sophisticated mechanisms may accordingly be implemented at little additional manufacturing cost to optimise engine performance over a wide range of operating conditions.
The engine control system typically varies the timing of ignition with respect to piston motion to enhance engine performance. Normally, spark timing is adjusted uniformly for all cylinders, varying the time of ignition with respect to the top-dead-centre position of the firing cylinder to optimise performance. Although electronic control systems include instrumentalities that may be readily adapted to provide cylinder-by-cylinder control of spark timing in order to equalise burn-rates or to retard the spark for knock-prone cylinders, these techniques are unnecessary for well-designed and well-maintained engines. Cylinder-by- cylinder ignition timing control can, however, yield significant benefits in other ways by following the principles of the present invention.
In accordance with one aspect of the invention, methods and apparatus are used to vary the time at which the fuel mixture is ignited in one or more predetermined cylinders of the engine in response to at least one predetermined sensed engine operating condition. In a preferred arrangement, the ignition timing signals delivered to selected cylinders are retarded by a significant time delay interval, without correspondingly delaying the ignition signals delivered to the remaining cylinders, to more quickly increase the temperature of the exhaust system. Delaying the ignition timing increases the flow of heat to the engine's exhaust system, especially during cold start conditions, without significantly degrading combustion quality. When used in conjunction with typical engine and exhaust systems, the more rapid increase in engine exhaust temperatures (1) improves the performance of the exhaust catalyst system, (2) increases the burn-up of hydrocarbons and carbon monoxide at the engine's exhaust port during cold idle and drive-away conditions, and (3) facilitates the use of exhaust gas recirculation (EGR) during cold-start conditions to enhance fuel preparation and reduce undesired emissions. Similarly, the selective retardation of ignition of predetermined cylinders typically reduces feedgas nitrous oxide emissions by reducing the in-cylinder residence time during which chemical reactions which produce such emissions can occur, and permits the air/fuel ratio to be increased during cold engine conditions to increase hydrocarbon oxidation in the catalyst system.
The invention will now be described further, by way of example, with reference to the accompanying drawings, in which:
Figure 1 of the drawings is a pictorial schematic illustration of a vehicle engine control system embodying the principles of the invention;
Figure 2 is timing diagram illustrating the manner in which the time of ignition may be retarded for selected cylinders only to promote exhaust system heating as contemplated by the invention; and
Figures 3 and 4 are flow charts illustrating the operation of a preferred mechanism for selectively delaying the ignition time for selected cylinders.
Figure 1 of the drawings shows an electronic engine control (EEC) module within the dashed-line rectangle 10 connected to supply ignition signals to a four-cylinder, four-stroke internal combustion engine indicated generally at 20. The control module 10 consists of an engine data acquisition mechanism 12, an electronic distributor 14, a common cylinder ignition retard control mechanism 15, and an individual cylinder ignition retard control mechanism
16.
The distributor 14 produces ignition pulses on four parallel output lines 18 which are respectively connected to the spark plugs of four cylinders indicated at 21-24 in Fig. 1. The timing of the ignition pulses supplied to the cylinders is determined in the first instance by the common retard mechanism 15. The ignitions signals are then further delayed, on a cylinder-by-cylinder basis by individual delay intervals DT1; DT2, DT3 and DT4 for cylinders 21-24 respectively, as schematically illustrated by delay mechanisms shown within the dashed-line rectangle 19 in Fig. 1.
The data acquisition mechanism 12, the common retard control 15, and the electronic distributor 14 within the control module 10 preferably take the form of the pre¬ existing conventional components of the EEC module 10 which operate without modification. The engine data acquisition unit 12 receives signal values via an accelerator angle sensor input 30, a temperature sensor input 31 (connected to receive sensor inputs indicating coolant temperature, fuel temperature, exhaust port temperature, etc.), an engine load (air mass flow rate) sensor input 32, and an engine speed / crankshaft position tachometer input 33. The signals supplied via input 33 typically comprises one or more pulse trains (derived from timing marks on the flywheel or the like) from which engine speed (RPM) , engine acceleration and deceleration, and the rotational position of the crankshaft (and hence the position of the piston in each cylinder) can be derived.
The common retard control mechanism 15 operates in accordance with conventional practice to control the electronic distributor 14 to produce, for each of the cylinders in turn, a reference ignition timing signal which establishes the minimum spark advance for best timing (MBT) under the then current engine speed, acceleration, temperature and load conditions.
In accordance with the invention, when digital values available from the data acquisition mechanism 12 manifest predetermined engine conditions indicating cold startup, cold idle, deceleration or accelerator tip-out, the individual retard control circuit 16 introduces a significant additional spark retarding delay for selected cylinders only.
The timing diagram seen in Fig. 2 illustrates this operation. As seen in Fig. 2, the MBT firing point established by the common retard control 15 for each of the four cylinders of a four-cylinder, four-stroke engine is shown by the position of the numbered vertical dashed lines in Fig. 2. Waveforms Cl - C4 respectively illustrate the ignition timing signals supplied to the four cylinders of the engine, with the ignition signals supplied to the even- numbered cylinders C2 and C4 being delayed from their normal MBT timing by the delay intervals indicated in both Figs. 1 and 2 by DT2 and DT4. The ignition timing for the odd- numbered cylinders Cl and C3 remains unchanged from the MBT timing established by the common retard control mechanism 15; that is, both DTχ and DT3 are zero-valued.
The additional individual cylinder delay may be introduced for a predetermined actual time interval (established by a system clock, not shown) , for a predetermined amount of crankshaft rotation (determined by counting PIP pulses) , or may be terminated when defined engine operating conditions are detected (e.g., engine load or temperature values in excess of predefined threshold values) . Alternatively, the duration of the introduced individual cylinder delay may be gradually reduced as a function of elapsed time and/or sensed engine operating conditions.
By retarding the spark on a balanced subset of the total number of cylinders for a short period of time during cold start, cold idle and cold drive-away conditions, when the engine temperature is low and reduced power demands are being placed on the engine, the rate at which the engine's exhaust system is heated can be significantly increased. The simple four cylinder, four-stroke internal combustion engine illustrated schematically in Fig. 1 illustrates some of the principles involved. As seen in Fig. 1, the first cylinder 21 is depicted near the bottom of the fuel intake stroke with the intake valve 41 open, the second cylinder 22 is seen near the top of its compression stroke with both valves closed, the third cylinder 23 is seen near the bottom of its power stroke with both valves closed, and the fourth cylinder 24 is shown near the top of its exhaust stroke with the exhaust valve 43 open. Whenever the time of ignition is intentionally retarded from its "best" timing (that is, from the timing which delivers maximum power) , several effects occur which are particularly beneficial during cold starting.
Because combustion occurs later in the power stroke and continues into the exhaust stroke when the exhaust valve is open, additional energy is transferred to the exhaust system in the form of heat, rather than being delivered to the power train and/or dissipated as heat through the cylinder walls to the engine coolant. The resulting increase in exhaust system heating during startup more quickly raises the temperature of the catalyst system (not shown) , thus reducing tailpipe emissions. Fast catalyst light-off (within 3 - 10 seconds) is typically advantageous in reducing emission levels during startup in compliance with emission regulations. In addition, increased exhaust temperatures promote increased burn-up of hydrocarbons and carbon monoxide in the exhaust port to reduce feedgas emissions. Retarding spark timing has further effects: the reaction times in which chemical kinetic reactions that produce nitrous oxide occur are reduced, knocking is suppressed, and a leaner air/fuel ratio may be used to promote hydrocarbon burning in the three-way catalyst. Selective cylinder-by-cylinder modulation of the ignition timing also permits beneficial modifications to be made to the overall engine system. With the reduced expansion ratio created by retarded spark timing, the catalyst can be located farther downstream from the exhaust flange, thus improving catalyst protection for a smaller volume light-off catalyst. In addition, rapid heating of the exhaust system allows exhaust gas recirculation (EGR) mechanisms to be used during cold starts, or to be activated more rapidly after startup, thereby diluting the intake charge without degrading combustion. Moreover, a "dual function" secondary air system can be used to deliver a higher air flow rate to those cylinders with retarded ignition timing to promote additional oxidation.
The flowcharts of Figs. 3 and 4 illustrate an illustrative preferred implementation of a selective ignition retarding scheme embodying the principles of the invention. The individual retard control mechanism illustrated schematically at 16 in Fig. 1 is preferably implemented by programming the engine control unit microcontroller (not shown) to process crankshaft position pulses consisting of a first train of pulses, each of which indicates a predetermined unit of angular rotation (e.g., 1°), in combination with one or more widely spaced pulses which indicate one or more reference position crankshaft positions (e.g., when the piston in cylinder 1 is at top- dead-centre) . These crankshaft rotation and reference signals are accepted and evaluated as illustrated at 50 and 51 in Fig. 3.
Each time the incoming pulse is identified as a reference pulse, an integer value CylinderNo is incremented at 53 through the repeating succession of values 1, 2, 3, 4, 1, 2, etc. to indicate which cylinder is to receive the next ignition pulse (the distributor 14 seen in Fig. l routes the ignition pulse to the appropriate sparkplug based on the value of CylinderNo) . After CylinderNo has been incremented at 53 to identify the next cylinder to receive an ignition pulse, a value IgnitionTimer indicative of engine operating conditions which will determine the spark timing for cylinder CylinderNo is set into a timing register as indicated at 55 in Fig. 3. The manner in which the value IgnitionTimer is determined is illustrated in Fig. 4, discussed below.
Assuming a unit rotation pulse is generated for every degree of crankshaft rotation, 89 unit pulses will be detected at 51 between each pair of reference pulses. Each of these unit pulses decrements the value of IgnitionTimer by one as seen at 56 until IgnitionTimer reaches the value zero, as detected at 57, at which time an ignition timing pulse is generated for the cylinder identified by CylinderNo as indicated at 58 in Fig. 3. The value of IgnitionTimer is then set to a high value MAX at 59 to prevent the remaining unit pulses from triggering additional ignition pulses until IgnitionTimer is again reset at 55. Thus, the numerical value IgnitionTimer initially placed in the timing register at 55 establishes the number of degrees of crankshaft rotation which will occur between the detection of the reference position pulse and the time of ignition for a given cylinder.
The value of IgnitionTimer as set into the timing register at 55 may be determined in the manner illustrated . by the flowchart of Fig. 4. First, to implement the operation of the common retard control shown at 15 in Fig. 1 and to establish the normal Minimum Best Time (MBT) for all cylinders in normal operation, conventional processing is employed at step 61 to produce a first value for IgnitionTimer in accordance with a first functional relationship Fl which produces an initial numerical value indicative of the desired minimum angular crankshaft rotation between the reference cylinder position detected at 51 and a desired MBT ignition position. Next, at 63, the least significant bit of CylinderNo is tested to determine if CylinderNo is odd or even. If CylinderNo is odd, the MBT value of IgnitionTimer established at 62 is left unchanged. However, if CylinderNo is even, IgnitionTimer is incremented by an amount determined by a second functional relationship F2 to significantly retard the ignition timing for even numbered cylinders.
The functional relationship F2 adds a significant delay to the ignition timing of the even-numbered cylinders, typically within a range between and degrees of crankshaft rotation, beginning at the time predetermined engine conditions are first detected. The triggering condition may be a detected engine start, in combination with a detected engine temperature below a triggering threshold, and may further include certain detected engine running conditions, such as deceleration under low engine temperature conditions.
Once activated, the amount of additional spark retardation added for the selected cylinders (i.e., the magnitude of IgnitionTimer) is established by the function F2 which may take one of a variety of workable forms to .lm3
A) a fixed value (thus adding a fixed angular spark retardation) maintained for the selected cylinders during a time interval which persists for either:
1) a predetermined elapsed time (determined by a system clock) ;
2) a predetermined amount of crankshaft rotation; or
3) a variable elapsed time or angular rotation which is functionally related to: a) one or more engine operating temperatures (e.g., coolant, fuel or exhaust temperatures); b) the load on the engine (indicated, for example, by the air mass flow rate) ; c) engine acceleration or deceleration; d) accelerator angle; or e) the combination or one or more of above; or
B) a variable value, producing a correspondingly variable amount of angular spark retardation, where the instantaneous magnitude of additional retardation is determined by:
1) elapsed time (gradually decreasing the amount of additional ignition retardation toward zero during a desired time interval as noted above) ;
2) the load on the engine;
3) engine acceleration or deceleration;
4) accelerator angle; or
5) a combination or one or more of above-noted variables.

Claims

1. A method for increasing the temperature of the exhaust system of a multi-cylinder internal combustion engine (20) which comprises, in combination, the steps of: sensing the presence of a predetermined engine operating condition and, in response thereto, delaying the time of fuel mixture ignition in one or more predetermined cylinders (21-24) of said engine (20) .
2. A method as claimed in claim 1, wherein said step of delaying the time at which the fuel mixture is ignited is performed for a predetermined interval of time.
3. A method as claimed in claim 1 further comprising the step of detecting the onset of a second predetermined engine operating condition and performing said step of delaying the time at which the fuel mixture is ignited until said second operating condition is detected.
4. A method as claimed in claim 1, wherein said one or more predetermined cylinders comprise all of said cylinders.
5. A method as claimed in claim 1, wherein said one or more predetermined cylinders comprise a balanced subset of all of the cylinders in said multi-cylinder engine.
6. Apparatus for increasing the temperature of the exhaust system of a multi-cylinder (21-24) internal combustion engine comprising: means (33) for sensing the rotational position of the crankshaft of the engine (20) and generating an ignition pulse for each given one of said cylinders (21-24) in synchrony with the motion of the piston in said given cylinder, means (12,30,31,32) for detecting the presence of a predetermined engine operating condition indicative of an abnormally cold exhaust system, and means (16) for delaying the generation of said ignition pulses for predetermined selected ones of said cylinders by a significant delay interval such that additional combustion of the fuel supplied to said selected cylinders occurs within said exhaust system to increase the temperature of said exhaust system.
1 . Apparatus as claimed in claim 6, wherein said predetermined selected cylinders comprises all of the cylinders in said multi-cylinder engine.
8. Apparatus as claimed in claim 6, wherein said predetermined selected cylinders comprise a balanced subset of said cylinders and wherein said means for delaying delays the generation of pulses for said selected cylinders without significantly delaying the generation of said ignition signals for the remaining ones of said cylinders.
9. Apparatus as claimed in claim 6 further comprising means for terminating the operation of said means for delaying upon the expiration of a predetermined interval.
10. Apparatus as claimed in claim 6 further comprising means for varying the duration of said delay interval as a predetermined function of one or more predetermined engine operating conditions.
PCT/GB1995/001576 1994-07-08 1995-07-05 Ignition system for an internal combustion engine WO1996001945A1 (en)

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US08/272,057 US5626117A (en) 1994-07-08 1994-07-08 Electronic ignition system with modulated cylinder-to-cylinder timing

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Families Citing this family (65)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6243642B1 (en) 1999-03-31 2001-06-05 Detroit Diesel Corporation System and method for detecting cold engine operation
DE19952829A1 (en) * 1999-11-02 2001-05-03 Audi Ag Control for a multi-cylinder internal combustion engine with a catalyst
US6487849B1 (en) 2000-03-17 2002-12-03 Ford Global Technologies, Inc. Method and apparatus for controlling lean-burn engine based upon predicted performance impact and trap efficiency
US6308697B1 (en) 2000-03-17 2001-10-30 Ford Global Technologies, Inc. Method for improved air-fuel ratio control in engines
US6594989B1 (en) 2000-03-17 2003-07-22 Ford Global Technologies, Llc Method and apparatus for enhancing fuel economy of a lean burn internal combustion engine
US6308515B1 (en) 2000-03-17 2001-10-30 Ford Global Technologies, Inc. Method and apparatus for accessing ability of lean NOx trap to store exhaust gas constituent
US6438944B1 (en) 2000-03-17 2002-08-27 Ford Global Technologies, Inc. Method and apparatus for optimizing purge fuel for purging emissions control device
US6434930B1 (en) 2000-03-17 2002-08-20 Ford Global Technologies, Inc. Method and apparatus for controlling lean operation of an internal combustion engine
US6708483B1 (en) 2000-03-17 2004-03-23 Ford Global Technologies, Llc Method and apparatus for controlling lean-burn engine based upon predicted performance impact
US6629453B1 (en) 2000-03-17 2003-10-07 Ford Global Technologies, Llc Method and apparatus for measuring the performance of an emissions control device
US6374597B1 (en) 2000-03-17 2002-04-23 Ford Global Technologies, Inc. Method and apparatus for accessing ability of lean NOx trap to store exhaust gas constituent
US6327847B1 (en) 2000-03-17 2001-12-11 Ford Global Technologies, Inc. Method for improved performance of a vehicle
US6427437B1 (en) 2000-03-17 2002-08-06 Ford Global Technologies, Inc. Method for improved performance of an engine emission control system
US6487850B1 (en) 2000-03-17 2002-12-03 Ford Global Technologies, Inc. Method for improved engine control
US6843051B1 (en) 2000-03-17 2005-01-18 Ford Global Technologies, Llc Method and apparatus for controlling lean-burn engine to purge trap of stored NOx
US6810659B1 (en) 2000-03-17 2004-11-02 Ford Global Technologies, Llc Method for determining emission control system operability
US6539704B1 (en) 2000-03-17 2003-04-01 Ford Global Technologies, Inc. Method for improved vehicle performance
US6481199B1 (en) 2000-03-17 2002-11-19 Ford Global Technologies, Inc. Control for improved vehicle performance
US6499293B1 (en) 2000-03-17 2002-12-31 Ford Global Technologies, Inc. Method and system for reducing NOx tailpipe emissions of a lean-burn internal combustion engine
US6860100B1 (en) 2000-03-17 2005-03-01 Ford Global Technologies, Llc Degradation detection method for an engine having a NOx sensor
US6360529B1 (en) 2000-03-17 2002-03-26 Ford Global Technologies, Inc. Method and apparatus for enabling lean engine operation upon engine start-up
US6477832B1 (en) 2000-03-17 2002-11-12 Ford Global Technologies, Inc. Method for improved performance of a vehicle having an internal combustion engine
US6360530B1 (en) 2000-03-17 2002-03-26 Ford Global Technologies, Inc. Method and apparatus for measuring lean-burn engine emissions
US6491024B1 (en) 2000-10-11 2002-12-10 Ford Global Technologies, Inc. System and method for cold start control of internal combustion engines
US6691507B1 (en) 2000-10-16 2004-02-17 Ford Global Technologies, Llc Closed-loop temperature control for an emission control device
US6494277B1 (en) 2000-11-09 2002-12-17 Ford Motor Company Hybrid electric vehicle system
US6691020B2 (en) 2001-06-19 2004-02-10 Ford Global Technologies, Llc Method and system for optimizing purge of exhaust gas constituent stored in an emission control device
US6694244B2 (en) 2001-06-19 2004-02-17 Ford Global Technologies, Llc Method for quantifying oxygen stored in a vehicle emission control device
US6546718B2 (en) 2001-06-19 2003-04-15 Ford Global Technologies, Inc. Method and system for reducing vehicle emissions using a sensor downstream of an emission control device
US6463733B1 (en) 2001-06-19 2002-10-15 Ford Global Technologies, Inc. Method and system for optimizing open-loop fill and purge times for an emission control device
US6487853B1 (en) 2001-06-19 2002-12-03 Ford Global Technologies. Inc. Method and system for reducing lean-burn vehicle emissions using a downstream reductant sensor
US6453666B1 (en) 2001-06-19 2002-09-24 Ford Global Technologies, Inc. Method and system for reducing vehicle tailpipe emissions when operating lean
US6604504B2 (en) 2001-06-19 2003-08-12 Ford Global Technologies, Llc Method and system for transitioning between lean and stoichiometric operation of a lean-burn engine
US6539706B2 (en) 2001-06-19 2003-04-01 Ford Global Technologies, Inc. Method and system for preconditioning an emission control device for operation about stoichiometry
US6553754B2 (en) 2001-06-19 2003-04-29 Ford Global Technologies, Inc. Method and system for controlling an emission control device based on depletion of device storage capacity
US6650991B2 (en) 2001-06-19 2003-11-18 Ford Global Technologies, Llc Closed-loop method and system for purging a vehicle emission control
US6467259B1 (en) 2001-06-19 2002-10-22 Ford Global Technologies, Inc. Method and system for operating dual-exhaust engine
US6502387B1 (en) 2001-06-19 2003-01-07 Ford Global Technologies, Inc. Method and system for controlling storage and release of exhaust gas constituents in an emission control device
US6615577B2 (en) 2001-06-19 2003-09-09 Ford Global Technologies, Llc Method and system for controlling a regeneration cycle of an emission control device
US6490860B1 (en) 2001-06-19 2002-12-10 Ford Global Technologies, Inc. Open-loop method and system for controlling the storage and release cycles of an emission control device
US6439039B1 (en) * 2001-09-04 2002-08-27 Ford Global Technologies, Inc. Method to verify cold start spark retard
US6688411B2 (en) * 2001-11-09 2004-02-10 Ford Global Technologies, Llc Hybrid electric vehicle and a method for operating a hybrid electric vehicle
US7168239B2 (en) * 2002-06-04 2007-01-30 Ford Global Technologies, Llc Method and system for rapid heating of an emission control device
US6925982B2 (en) 2002-06-04 2005-08-09 Ford Global Technologies, Llc Overall scheduling of a lean burn engine system
US6745747B2 (en) 2002-06-04 2004-06-08 Ford Global Technologies, Llc Method for air-fuel ratio control of a lean burn engine
US6769398B2 (en) 2002-06-04 2004-08-03 Ford Global Technologies, Llc Idle speed control for lean burn engine with variable-displacement-like characteristic
US6736121B2 (en) 2002-06-04 2004-05-18 Ford Global Technologies, Llc Method for air-fuel ratio sensor diagnosis
US6735938B2 (en) 2002-06-04 2004-05-18 Ford Global Technologies, Llc Method to control transitions between modes of operation of an engine
US6736120B2 (en) * 2002-06-04 2004-05-18 Ford Global Technologies, Llc Method and system of adaptive learning for engine exhaust gas sensors
US7032572B2 (en) * 2002-06-04 2006-04-25 Ford Global Technologies, Llc Method for controlling an engine to obtain rapid catalyst heating
US6568177B1 (en) 2002-06-04 2003-05-27 Ford Global Technologies, Llc Method for rapid catalyst heating
US7111450B2 (en) * 2002-06-04 2006-09-26 Ford Global Technologies, Llc Method for controlling the temperature of an emission control device
US6758185B2 (en) * 2002-06-04 2004-07-06 Ford Global Technologies, Llc Method to improve fuel economy in lean burn engines with variable-displacement-like characteristics
US6725830B2 (en) 2002-06-04 2004-04-27 Ford Global Technologies, Llc Method for split ignition timing for idle speed control of an engine
US6868827B2 (en) * 2002-06-04 2005-03-22 Ford Global Technologies, Llc Method for controlling transitions between operating modes of an engine for rapid heating of an emission control device
US6715462B2 (en) 2002-06-04 2004-04-06 Ford Global Technologies, Llc Method to control fuel vapor purging
US7007667B2 (en) * 2003-07-22 2006-03-07 Hitachi, Ltd. Cold start fuel control system
US6814065B1 (en) * 2003-09-24 2004-11-09 Delphi Technologies, Inc. Control apparatus for staggered spark plug firing in a dual-plug spark ignition engine
US7377236B2 (en) 2005-09-09 2008-05-27 Ford Global Technologies, Llc System and method for exhaust heat generation using electrically actuated cylinder valves and variable stroke combustion cycles
US7748362B2 (en) * 2008-05-08 2010-07-06 Gm Global Technology Operations, Inc. Managing lean air/fuel transients in coordinated torque control
US9334846B2 (en) * 2014-02-07 2016-05-10 Ford Global Technologies, Llc Method and system of controlling bank to bank component temperature protection during individual cylinder knock control
US9441551B2 (en) * 2014-07-29 2016-09-13 Ford Global Technologies, Llc Method for a variable displacement engine
US9534517B2 (en) * 2014-08-12 2017-01-03 Ford Global Technologies, Llc Systems and methods for a modified cylinder firing interval in a dedicated EGR engine
JP6330748B2 (en) * 2015-07-29 2018-05-30 トヨタ自動車株式会社 Cooling device for internal combustion engine
DE102016221847A1 (en) * 2016-11-08 2018-05-09 Robert Bosch Gmbh Method for operating an internal combustion engine after a cold start

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4351297A (en) * 1979-11-15 1982-09-28 Toyota Jidosha Kogyo Kabushiki Kaisha Method and apparatus for controlling the ignition timing of an internal combustion engine
US4574588A (en) * 1984-01-20 1986-03-11 Mazda Motor Corporation Automobile exhaust purifying system
DE4037183A1 (en) * 1989-11-22 1991-05-23 Fuji Heavy Ind Ltd SYSTEM FOR CONTROLLING A TWO-STROKE INTERNAL COMBUSTION ENGINE
EP0499207A1 (en) * 1991-02-12 1992-08-19 Nippondenso Co., Ltd. Control apparatus for speedily warming up catalyst in internal combustion engine
DE4304110A1 (en) * 1992-03-25 1993-09-30 Suzuki Motor Co Fuel injection system for IC engine - provides each cylinder with separate injection control and ignition control to produce smooth running

Family Cites Families (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3813877A (en) * 1972-08-17 1974-06-04 Matthews D Internal combustion engine controls for reduced exhaust contaminants
JPS5610459B2 (en) * 1973-03-13 1981-03-07
US3964258A (en) * 1973-08-01 1976-06-22 Exxon Research And Engineering Company Reducing undesirable components of automotive exhaust gas
US4103486A (en) * 1974-04-15 1978-08-01 Nissan Motor Company, Ltd. Method of controlling temperature in thermal reactor for engine exhaust gas and ignition system for performing same
JPS549B2 (en) * 1974-06-01 1979-01-05
US4111010A (en) * 1975-03-07 1978-09-05 Nissan Motor Company, Limited Automotive internal combustion engine
JPH0237171A (en) * 1988-07-26 1990-02-07 Fuji Heavy Ind Ltd Ignition timing controller for engine
DE4029811C2 (en) * 1990-09-20 1999-08-12 Bosch Gmbh Robert Catalyst heating function

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4351297A (en) * 1979-11-15 1982-09-28 Toyota Jidosha Kogyo Kabushiki Kaisha Method and apparatus for controlling the ignition timing of an internal combustion engine
US4574588A (en) * 1984-01-20 1986-03-11 Mazda Motor Corporation Automobile exhaust purifying system
DE4037183A1 (en) * 1989-11-22 1991-05-23 Fuji Heavy Ind Ltd SYSTEM FOR CONTROLLING A TWO-STROKE INTERNAL COMBUSTION ENGINE
EP0499207A1 (en) * 1991-02-12 1992-08-19 Nippondenso Co., Ltd. Control apparatus for speedily warming up catalyst in internal combustion engine
DE4304110A1 (en) * 1992-03-25 1993-09-30 Suzuki Motor Co Fuel injection system for IC engine - provides each cylinder with separate injection control and ignition control to produce smooth running

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