GB2604616A - Control system and method for an internal combustion engine - Google Patents
Control system and method for an internal combustion engine Download PDFInfo
- Publication number
- GB2604616A GB2604616A GB2103262.8A GB202103262A GB2604616A GB 2604616 A GB2604616 A GB 2604616A GB 202103262 A GB202103262 A GB 202103262A GB 2604616 A GB2604616 A GB 2604616A
- Authority
- GB
- United Kingdom
- Prior art keywords
- intake
- operating cycle
- combustion chamber
- during
- gases
- Prior art date
- Legal status (The legal status 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 status listed.)
- Granted
Links
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02D—CONTROLLING COMBUSTION ENGINES
- F02D35/00—Controlling engines, dependent on conditions exterior or interior to engines, not otherwise provided for
- F02D35/02—Controlling engines, dependent on conditions exterior or interior to engines, not otherwise provided for on interior conditions
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02D—CONTROLLING COMBUSTION ENGINES
- F02D35/00—Controlling engines, dependent on conditions exterior or interior to engines, not otherwise provided for
- F02D35/02—Controlling engines, dependent on conditions exterior or interior to engines, not otherwise provided for on interior conditions
- F02D35/028—Controlling engines, dependent on conditions exterior or interior to engines, not otherwise provided for on interior conditions by determining the combustion timing or phasing
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
- F01L13/00—Modifications of valve-gear to facilitate reversing, braking, starting, changing compression ratio, or other specific operations
- F01L13/0015—Modifications of valve-gear to facilitate reversing, braking, starting, changing compression ratio, or other specific operations for optimising engine performances by modifying valve lift according to various working parameters, e.g. rotational speed, load, torque
- F01L13/0031—Modifications of valve-gear to facilitate reversing, braking, starting, changing compression ratio, or other specific operations for optimising engine performances by modifying valve lift according to various working parameters, e.g. rotational speed, load, torque by modification of tappet or pushrod length
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02D—CONTROLLING COMBUSTION ENGINES
- F02D13/00—Controlling the engine output power by varying inlet or exhaust valve operating characteristics, e.g. timing
- F02D13/02—Controlling the engine output power by varying inlet or exhaust valve operating characteristics, e.g. timing during engine operation
- F02D13/0203—Variable control of intake and exhaust valves
- F02D13/0207—Variable control of intake and exhaust valves changing valve lift or valve lift and timing
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02D—CONTROLLING COMBUSTION ENGINES
- F02D35/00—Controlling engines, dependent on conditions exterior or interior to engines, not otherwise provided for
- F02D35/02—Controlling engines, dependent on conditions exterior or interior to engines, not otherwise provided for on interior conditions
- F02D35/027—Controlling engines, dependent on conditions exterior or interior to engines, not otherwise provided for on interior conditions using knock sensors
-
- 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
- F02D41/0002—Controlling intake air
-
- 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
- F02D41/0025—Controlling engines characterised by use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures
- F02D41/0047—Controlling exhaust gas recirculation [EGR]
- F02D41/006—Controlling exhaust gas recirculation [EGR] using internal EGR
-
- 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
- F02D41/30—Controlling fuel injection
- F02D41/38—Controlling fuel injection of the high pressure type
- F02D41/40—Controlling fuel injection of the high pressure type with means for controlling injection timing or duration
- F02D41/401—Controlling injection timing
-
- 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
- F02P15/00—Electric spark ignition having characteristics not provided for in, or of interest apart from, groups F02P1/00 - F02P13/00 and combined with layout of ignition circuits
- F02P15/08—Electric spark ignition having characteristics not provided for in, or of interest apart from, groups F02P1/00 - F02P13/00 and combined with layout of ignition circuits having multiple-spark ignition, i.e. ignition occurring simultaneously at different places in one engine cylinder or in two or more separate engine cylinders
-
- 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
- F02P5/045—Advancing or retarding ignition; Control therefor automatically, as a function of the working conditions of the engine or vehicle or of the atmospheric conditions combined with electronic control of other engine functions, e.g. fuel injection
-
- 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
- F02P5/152—Digital data processing dependent on pinking
- F02P5/1522—Digital data processing dependent on pinking with particular means concerning an individual cylinder
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02D—CONTROLLING COMBUSTION ENGINES
- F02D13/00—Controlling the engine output power by varying inlet or exhaust valve operating characteristics, e.g. timing
- F02D13/02—Controlling the engine output power by varying inlet or exhaust valve operating characteristics, e.g. timing during engine operation
- F02D13/0261—Controlling the valve overlap
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Signal Processing (AREA)
- Output Control And Ontrol Of Special Type Engine (AREA)
Abstract
A control system 1 and method for controlling a spark ignition, reciprocating piston internal combustion engine 10 comprising a combustion chamber 18 having an intake valve 20 and an exhaust valve 22. The control system comprises a controller 50 which controls opening and closing of the intake valve during a first operating cycle to admit a first trapped mass of intake gases into the combustion chamber. On receiving a signal identifying a pre-ignition event in the combustion chamber during the first operating cycle the controller controls admission of a second trapped mass of intake gases into the combustion chamber. The second trapped mass of intake gases is less than the first trapped mass of intake gases. The admission of the second trapped mass of intake gases may be controlled by the intake valve by retarding opening of the valve, advancing closing of the valve or by reducing the valve lift. The admission of the second trapped mass of intake gases may instead be controlled by the exhaust valve.
Description
CONTROL SYSTEM AND METHOD FOR AN INTERNAL COMBUSTION ENGINE
TECHNICAL FIELD
The present disclosure relates to a control system and method for an internal combustion engine. Aspects of the invention relate to a method of controlling an internal combustion engine; a non-transitory computer-readable medium; a control system for controlling an internal combustion engine; and a vehicle comprising a control system.
BACKGROUND
The evolving powertrains for hybrid vehicles has led to small and efficient, high compression ratio, turbo charged and electrified internal combustion engines that run under highly boosted intake manifold conditions. These boosted conditions may increase the susceptibility of the internal combustion engines to the occurrence of a pre-ignition event. Pre-ignition refers to combustion of the fuel in the combustion chamber before the ignition spark is generated. A pre-ignition event can be detected using a sensor for distinguishing sound/vibration frequencies associated with the combustion event from other combustion related noise.
The occurrence of a pre-ignition event can cause damage to engine components causing durability issues. A standard method to compensate or mitigate pre-ignition is to enrich the charge by increasing the fuel injected into the affected cylinder when it is fired one engine cycle later. The enrichment has the effect of cooling the charge to avoid further pre-ignition in subsequent operating cycles. An alternative strategy is not to inject any fuel into the affected cylinder, but this reduces the torque generated by the internal combustion engine and may be perceived as a misfire or a fault.
It is an aim of the present invention to address one or more of the disadvantages associated with the prior art.
SUMMARY OF THE INVENTION
Aspects and embodiments of the invention provide a control system, a vehicle, a method and a non-transitory computer-readable medium as claimed in the appended claims According to an aspect of the present invention there is provided a control system for controlling a spark ignition, reciprocating piston internal combustion engine comprising a combustion chamber having an intake valve and an exhaust valve, the control system comprising one or more controller configured to control opening and closing of the intake valve during a first operating cycle to admit a first trapped mass of intake gases into the combustion chamber; receive a signal identifying a pre-ignition event in the combustion chamber during the first operating cycle; and in dependence on the identification of the pre-ignition event, control opening and closing of the intake valve during a second operating cycle to admit a second trapped mass of intake gases into the combustion chamber; wherein the second trapped mass of intake gases is less than the first trapped mass of intake gases. By reducing the trapped mass of intake gases in the combustion chamber, the gases available for combustion may be reduced in the second operating cycle. The characteristics of the combustion in the combustion chamber may be controlled in the second operating cycle. At least in certain embodiments, the control strategy can mitigate or prevent occurrence of a pre-ignition event in the second operating cycle. It will be appreciated that trapping less intake gases in the affected cylinder will reduce the compression work on the charge in that cylinder, thus reducing the temperature of the charge below the charge self-ignition temperature. The other cylinders charge are substantially unaffected and, at least in certain embodiments, the inertia of the rotational parts act to smooth out any cylinder to cylinder torque imbalance.
The one or more controller may comprise at least one electronic processor having an electrical input for receiving the signal identifying the pre-ignition event from a sensor. The at least one electronic processor may comprise an electrical output for outputting a control signal to control the intake valve. The control signal may be output to control operation of the intake valve. The control signal may selectively open and close the intake valve to control the admission of the first and second quantities of intake gases into the combustion chamber.
The one or more controller may comprise at least one memory device electrically coupled to the at least one electronic processor and having instructions stored therein. The at least one electronic processor may be configured to access the at least one memory device and execute the instructions therein so as to control the intake valve.
At least in certain embodiments, the first operating cycle and the second operating cycle are consecutive operating cycles. The one or more controller is configured to control the intake valve to admit the second trapped mass of intake gas in the operating cycle immediately following the identification of the pre-ignition event. This provides the advantage that a pre-ignition event in the first operating cycle is controlled in the immediately following second operating cycle.
In certain embodiments, there may be more than one intake valve. The one or more controller may be configured to control the or each intake valve to admit the first and second quantities of intake gases. The intake gases may comprise or consist of air. The intake gases may be supplied at atmospheric pressure. Alternatively, the intake gases may be supplied at a pressure greater than atmospheric pressure, for example supplied by a turbocharger or a supercharger. Alternatively, the intake gases may be supplied at a pressure less than atmospheric pressure, for example by throttling or otherwise controlling the supply of intake gases.
The one or more controller may be configured to retard opening of the intake valve during the second operating cycle. The opening of the intake valve may be delayed compared to the opening of the intake valve in the first operating cycle. The intake valve may be opened at a first open crank angle in the first operating cycle and at a second open crank angle in the second operating cycle. The first open crank angle may be different from the second open crank angle.
The one or more controller may be configured to advance closing of the intake valve during the second operating cycle. The opening of the intake valve may occur earlier in the second operating cycle than in the first operating cycle. The intake valve may be closed at a first close crank angle in the first operating cycle and at a second first close crank angle in the second operating cycle. The first close crank angle may be different from the second close crank angle.
The one or more controller may be configured to control the intake valve to provide a first valve lift in the first operating cycle, and to provide a second valve lift in the second operating cycle. The second valve lift may be less than the first valve lift. The mass flow rate of the intake gases into the combustion chamber may be greater in the first operating cycle than in the second operating cycle.
In dependence on the identification of the pre-ignition event in the first operating cycle, the one or more controller may be configured to control the exhaust valve to reduce the trapped mass of exhaust gases exhausted from the combustion chamber. The trapped mass of exhaust gases in the combustion chamber may be increased, thereby reducing the trapped mass of intake gases admitted into the combustion chamber during the subsequent intake phase. The control of the exhaust valve may 'increase the residual' in the exhaust gas, i.e. retaining more inert gas in the combustion chamber. Accordingly, there may be a reduction in the trapped mass of intake gases inducted into the combustion chamber. At least in certain embodiments, there may be a corresponding reduction in the peak combustion pressure/temperature (whilst maintaining inlet valve motion). The induction is inversely proportional to the increase in residual gases retained in the combustion chamber. The exhaust valve may be controlled to reduce the trapped mass of exhaust gases during the first operating cycle (compared to a preceding operating cycle). This may indirectly control the second trapped mass of intake gases admitted during the second operating cycle. By reducing the trapped mass of exhaust gases expelled from the combustion chamber, the second trapped mass of intake gases admitted during the second operating cycle may be reduced.
The one or more controller may be configured to control the valve lift of the intake valve in order to control the intake of gases into the combustion chamber. The valve lift of the intake valve may be reduced to decrease the mass flow rate of the intake gases entering the combustion chamber. A first intake valve lift may be implemented for the intake valve during the first operating cycle. In dependence on the identification of the pre-ignition event in the first operating cycle, a second intake valve lift may be implemented for the intake valve. The second intake valve lift may be less than the first intake valve lift.
The one or more controller may be configured to control the valve lift of the exhaust valve in order to control the expulsion of gases from the combustion chamber. The valve lift of the exhaust valve may be reduced to decrease the mass flow rate of the exhaust gases exiting the combustion chamber. An exhaust valve lift may be implemented for the exhaust valve during an operating cycle prior to or immediately preceding the first operating cycle. In dependence on the identification of the pre-ignition event in the first operating cycle, a second exhaust valve lift may be implemented for the exhaust valve. The second exhaust valve lift may be less than the first exhaust valve lift.
In dependence on the identification of the pre-ignition event, the one or more controller may be configured to advance closure of the exhaust valve during the first operating cycle. The exhaust phase may be truncated or abbreviated by advancing closure of the exhaust valve.
The closure of the exhaust valve may be shorter than a preceding operating cycle or than a reference exhaust valve closure time.
The one or more controller may be configured to control the intake valve and the exhaust valve to reduce a duration when the intake valve and the exhaust valve are both open simultaneously. The one or more controller may control the intake valve and the exhaust valve such that the intake valve and the exhaust valve are not both open simultaneously.
At least in certain embodiments, the one or more controller may be configured, in dependence on the identification of a pre-ignition event during the first operating cycle, to control opening and closing of the intake valve during a third operating cycle to admit the second trapped mass of intake gases even if a pre-ignition event is not identified during the second operating cycle.
For example, the second trapped mass may be admitted for a predetermined number of operating cycles after identification of the pre-ignition event. The predetermined number of operating cycles will be greater than one. After the predetermined number of operating cycles, the one or more controller may be configured to select the first injection pattern.
The one or more controller may be configured, in dependence on the identification of a pre-ignition event during the first operating cycle, to control opening and closing of the intake valve during a third operating cycle to admit a third trapped mass of intake gases into the combustion chamber. The third trapped mass of intake gases may be less than the first trapped mass of intake gases. The third trapped mass of intake gases may be greater than the second trapped mass of intake gases.
The one or more controller may be configured also to control the quantity of fuel injected into the combustion chamber during the first and second operating cycles. In dependence on the identification of pre-ignition during the first operating cycle, the one or more controller may be configured to reduce the quantity of fuel injected during the second operating cycle relative to the quantity of fuel injected during the first operating cycle. The one or more controller may be configured to control operation of one or more fuel injector to control the quantity of fuel injected during each operating cycle. The one or more controller may be configured to control the injection of fuel to maintain at least substantially the same air-fuel ratio (AFR) in the first and second operating cycles. The air-fuel ratio (AFR) may be at least substantially constant. The one or more controller may control the intake valve and the one or more fuel injector to maintain air-fuel equivalence ratio, A (lambda), at least substantially equal to one (A=1) during each operating cycle.
The trapped mass of intake gases admitted to the combustion chamber during the intake phase is controlled dynamically in dependence on the identification of a pre-ignition event. The intake gases are typically air. The trapped mass of air admitted in the combustion chamber (also referred to as the air charge) may be controlled by the intake valve and/or the exhaust valve, according to one or more of the following techniques: (i) Varying valve lift so as to increase or decrease the maximum opening of the poppet valve during an activation cycle. If the opening and closing timing is unchanged, an increased lift will increase the trapped mass of aspirated air, and a reduced lift will reduce the trapped mass of aspirated air.
(ii) Varying the duration of valve opening, either by re-timing valve opening, re-timing valve closing, or both. If the valve lift is unchanged, a longer open duration will tend to increase the trapped mass of aspirated air, and a shorter duration will tend to reduce the trapped mass of aspirated air.
(H) Varying the overlap of the intake and exhaust valves, by re-timing the opening of the inlet valve to increase or reduce overlap with phase of the exhaust valve. Reduced overlap will tend to increase the trapped mass of air available for combustion, whereas increased overlap will tend to reduce the trapped mass of air available for combustion.
The term "timing" and derivatives thereof are used herein to define the relative opening and closing of the intake valve during the one or more operating cycle. In practice, the timing is determined in dependence on a crank angle of a crankshaft provided in the internal combustion engine, for example a crank angle defined with respect to top dead centre firing.
The opening and closing timing of the intake valve may be defined with respect to first and second crank angles.
According to a further aspect of the present invention there is provided a control system for controlling a spark ignition, reciprocating piston internal combustion engine comprising a combustion chamber haying an intake valve and an exhaust valve, the control system comprising one or more controller configured to: control opening and closing of the intake valve during a first operating cycle to admit a first trapped mass of intake gases into the combustion chamber; control opening and closing of the exhaust valve during the first operating cycle to expel a first trapped mass of exhaust gases from the combustion chamber; control opening and closing of the intake valve during a second operating cycle to admit a second trapped mass of intake gases into the combustion chamber; receive a signal identifying a pre-ignition event in the combustion chamber during the second operating cycle; and in dependence on the identification of the pre-ignition event, control opening and closing of the exhaust valve during the second operating cycle to expel a second trapped mass of exhaust gases from the combustion chamber; wherein the second trapped mass of exhaust gases is less than the first trapped mass of exhaust gases.
It will be understood that the process described herein may be repeated until one or more operating cycle is performed without detecting a pre-ignition event. The one or more controller may revert to admitting the first trapped mass of intake gases into the combustion chamber during each operating cycle.
According to a further aspect of the present invention there is provided a vehicle comprising a control system as described herein.
According to a further aspect of the present invention there is provided a method of controlling a spark ignition, reciprocating piston internal combustion engine having a combustion chamber for performing at least first and second operating cycles each comprising fuel injection and combustion, the method comprising: during a first operating cycle, admitting a first trapped mass of intake gases into the combustion chamber in a first intake phase, injecting fuel into the combustion chamber in a first fuel injection, generating a first ignition spark for igniting fuel in the combustion chamber, and exhausting gases from the combustion chamber in a first exhaust phase; identifying pre-ignition in the combustion chamber during the first operating cycle; and during a second operating cycle, admitting a second trapped mass of intake gases into the combustion chamber in a second intake phase, injecting fuel into the combustion chamber in a second fuel injection, generating a second ignition spark for igniting fuel in the combustion chamber, and exhausting gases from the combustion chamber in a second exhaust phase; wherein, in dependence on the identification of pre-ignition during the first operating cycle, the method comprises reducing the second trapped mass of intake gases admitted during the second operating cycle relative to the first trapped mass of intake gases admitted during the first operating cycle.
The first operating cycle and the second operating cycle may be consecutive operating cycles. In other words, the first operating cycle and the second operating cycle may occur one after the other.
The method may comprise reducing the second trapped mass of intake gases admitted during the second operating cycle comprises controlling the second intake phase.
Controlling the second intake phase may comprise retarding initiation of the second intake phase and/or advancing completion of the second intake phase.
The method may comprise controlling a valve lift of the intake valve to control the trapped mass of intake gases in the combustion chamber. The valve lift may be reduced during the second operating cycle to reduce the trapped mass of gases in the combustion chamber.
The valve closing may be performed in the compression stroke of the operating cycle, for example the valve closing may be significantly later than bottom dead centre and preferably approaching top dead centre firing. A portion of the intake gases inducted into the combustion chamber may be expelled out of the combustion chamber and back into the intake manifold during the compression stroke before the inlet valve is closed. This may reduce the trapped mass of intake gases. The valve lift may optionally be increased in the second operating cycle.
At least in certain embodiments, this may reduce the trapped mass of gases.
The method may comprise reducing the trapped mass of exhaust gases exhausted from the combustion chamber during the first operating cycle. This process may indirectly control the second trapped mass of intake gases admitted during the second operating cycle.
The method of reducing the trapped mass of exhaust gases exhausted from the combustion chamber during the first operating cycle may comprise retarding initiation of the first exhaust phase. Alternatively, or in addition, the process of reducing the trapped mass of exhaust gases exhausted from the combustion chamber during the first operating cycle may comprise advancing completion of the first exhaust phase.
The method of reducing the second trapped mass of intake gases admitted during the second operating cycle may comprise reducing an overlap of the first exhaust phase and the second intake phase.
At least in certain embodiments, the method may comprise, in dependence on the identification of a pre-ignition event during the first operating cycle, admitting the second trapped mass of intake gases during a third operating cycle even if a pre-ignition event is not identified during the second operating cycle. For example, the second trapped mass may be admitted for a predetermined number of operating cycles after identification of the pre-ignition event. The predetermined number of operating cycles may be greater than or equal to one.
After the predetermined number of operating cycles, the one or more controller may be configured to select the first injection pattern.
The method may comprise, in dependence on the identification of pre-ignition during the first operating cycle, reducing a third trapped mass of intake gases in the combustion chamber during a third operating cycle relative to the first trapped mass of intake gases admitted during the first operating cycle. The third trapped mass of intake gases may be greater than the second trapped mass of intake gases.
The method may comprise controlling the quantity of fuel injected into the combustion chamber during the first and second operating cycles. In dependence on the identification of pre-ignition during the first operating cycle, the method may comprise reducing the quantity of fuel injected during the second operating cycle relative to the quantity of fuel injected during the first operating cycle. The method may comprise controlling one or more fuel injector to control the quantity of fuel injected during each operating cycle. The method may comprise controlling the injection of fuel to maintain at least substantially the same air-fuel ratio (AFR) in the first and second operating cycles. The air-fuel ratio (AFR) may be at least substantially constant. The method may comprise controlling the intake valve and the one or more fuel injector to maintain air-fuel equivalence ratio, A (lambda), at least substantially equal to one (A=1) during each operating cycle.
According to a further aspect of the present invention there is provided a non-transitory computer-readable medium having a set of instructions stored therein which, when executed, cause a processor to perform the method described herein.
Any control unit or controller described herein may suitably comprise a computational device having one or more electronic processors. The system may comprise a single control unit or electronic controller or alternatively different functions of the controller may be embodied in, or hosted in, different control units or controllers. As used herein the term "controller" or "control unit" will be understood to include both a single control unit or controller and a plurality of control units or controllers collectively operating to provide any stated control functionality.
To configure a controller or control unit, a suitable set of instructions may be provided which, when executed, cause said control unit or computational device to implement the control techniques specified herein. The set of instructions may suitably be embedded in said one or more electronic processors. Alternatively, the set of instructions may be provided as software saved on one or more memory associated with said controller to be executed on said computational device. The control unit or controller may be implemented in software run on one or more processors. One or more other control unit or controller may be implemented in software run on one or more processors, optionally the same one or more processors as the first controller. Other suitable arrangements may also be used.
Within the scope of this application it is expressly intended that the various aspects, embodiments, examples and alternatives set out in the preceding paragraphs, in the claims and/or in the following description and drawings, and in particular the individual features thereof, may be taken independently or in any combination. That is, all embodiments and/or features of any embodiment can be combined in any way and/or combination, unless such features are incompatible. The applicant reserves the right to change any originally filed claim or file any new claim accordingly, including the right to amend any originally filed claim to depend from and/or incorporate any feature of any other claim although not originally claimed in that manner.
BRIEF DESCRIPTION OF THE DRAWINGS
One or more embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 shows a vehicle incorporating an internal combustion engine configured to operate in accordance with an embodiment of the present invention; Figure 2 shows a cylinder of the internal combustion engine shown in Figure 1; Figure 3 shows a schematic representation of an electronic control unit for controlling the internal combustion engine in accordance with an embodiment of the present invention Figure 4 shows a schematic representation of a first intake valve control function for the cylinder shown in Figure 2; Figure 5 shows a schematic representation of a second intake valve control function for the cylinder shown in Figure 2; Figure 6 shows a block diagram of the method according to an embodiment of the present invention; Figure 7 shows a first control strategy having a shortened intake valve open interval according to an embodiment of the present invention; Figure 8 shows a second control strategy having a throttled intake valve according to an embodiment of the present invention; Figure 9 shows a third control strategy having a late closure of the intake valve according to an embodiment of the present invention; and Figure 10 shows a fourth control strategy having a late opening of the intake valve according to an embodiment of the present invention.
DETAILED DESCRIPTION
A control system 1 and a method for controlling operation of an internal combustion engine 10 according to an embodiment of the invention will now be described.
As shown in Figure 1, the engine 10 in the present embodiment is installed in a road vehicle V, such as an automobile or a sports utility vehicle. The engine 10 in the present embodiment is a spark ignition, reciprocating piston internal combustion engine. The engine 10 comprises a plurality of cylinders 12. By way of example, the engine 10 may comprise four (4), six (6) or eight (8) cylinders. As shown schematically in Figure 2, the engine 10 comprises a crankshaft 14 connected to a plurality of pistons 16. The pistons 16 are each associated with a respective one of the cylinders 12. The cylinders 12 and the pistons 16 collectively form combustion chambers 18.
The combustion chamber 18 in each cylinder 12 is defined above the piston 16. An intake valve 20 is provided to control the supply of air into the combustion chamber 18 from an inlet port 22. As described herein, the intake valve 20 controls the quantity (trapped mass) of air admitted into the combustion chamber 18 in an air charge. The intake valve 20 in the present embodiment comprises a first poppet valve 20. The inlet port 22 is fed from an inlet manifold 24 having a throttle valve 26. The intake valve 20 is closed by a spring (not shown) and is opened by action of a rotatable cam 28 which is conventionally provided by a lobe of a camshaft (not shown). A first tappet 30 is provided between the intake valve 20 and the cam 28. The first tappet 30 is active, and adjustable in length by relative inward and outward movement of the components thereof, so that the lift of the intake valve 20 may be varied between minimum and maximum. The valve lift may be controllably varied at each successive opening thereof, if required. By way of example, a schematic electro-hydraulic tappet 30 having a hydraulic chamber 32 supplied with oil at a steady rate and a solenoid operated bleed valve 34 to allow a varying volume of oil to escape, as indicated by arrow 36.
An exhaust valve 40 is provided to control the exhausting of gases from the combustion chamber 18 from an exhaust port 42. The exhaust valve 40 in the present embodiment comprises a second poppet valve. The exhaust valve 40 is selectively opened and closed. A second tappet (not shown) is provided for controlling operation of the exhaust valve 40. The second tappet may, for example, have the same configuration as the first tappet 30. It will be understood that other types of electro-hydraulic and electro-mechanical actuators may be used selectively to control the opening and closing of the first and exhaust valves 20, 40. One or more fuel injector 46 is associated with each cylinder 12. The one or more fuel injector 46 is configured to inject fuel into the cylinder 12 for combustion. The fuel in the present embodiment is gasoline (petrol).
During operation of the engine 10, fuel is injected into the cylinders 12 and combusted to force the pistons 16 down and rotate the crankshaft 14. Each operating cycle of fuel injection and combustion takes two full revolutions of the crankshaft 14. For a given cylinder 12, the first revolution comprises an intake stroke (piston descending) for taking in air, and a compression stroke (piston ascending) for compressing an air/fuel mixture before ignition. The second revolution starts with an ignition spark and comprises a power stroke (piston descending) for combusting the fuel and forcing the piston downwards, and an exhaust stroke (piston ascending) for expelling exhaust gasses. The full operating cycle (comprising intake, compression, power and exhaust strokes) is continually repeated during operation of the engine 10.
The control system 1 comprises an electronic control unit (ECU) 50. As described herein, the ECU 50 is configured to control operation of the engine 10. The ECU 50 is configured to control the intake valve 20, the exhaust valve 40, and the one or more fuel injector 46. The operation of the ECU 50 will now be described in more detail.
In use, the admission of air into the engine 10 is controlled via the throttle valve 26, which is controlled by the ECU 50 according to conventional control parameters, such as accelerator pedal position, altitude, air temperature and the like. An alteration of the position of the throttle valve 26 changes the rate of air inflow but does not immediately influence the amount of air admitted to the combustion chamber because of the air volume contained in the inlet manifold 24. The intake valve 20 controls the trapped mass of air admitted into the combustion chamber 18 during each operating cycle of the engine 10. The intake valve 20 can be actively controlled to admit a metered charge of air into the combustion chamber 18. The ECU 50 controls the first tappet 30 to control operation of the intake valve 20, thereby controlling the amount of air admitted into the combustion chamber 18 during an intake phase of the operating cycle. The ECU 50 may reduce the interval during which the intake valve 20 is open during an intake phase of the operating cycle in order to reduce the amount of air admitted into the combustion chamber 18. The ECU 50 can selectively delay (retard) opening of the intake valve 20. Alternatively, or in addition, the ECU 50 can selectively advance closing of the intake valve 20. Alternatively, or in addition, the ECU 50 can advance closure of the exhaust valve 40, thereby retaining exhaust gases in the combustion chamber 18 to reduce the trapped mass of air drawn into the combustion chamber 18 in the subsequent intake phase.
The ECU 50 is configured to control the introduction of air into the combustion chamber 18 in dependence on detection of an abnormal combustion event in the preceding combustion phase. In particular, the ECU 50 is configured to control the intake valve 20 to admit a modified air charge following detection of an abnormal combustion event in the form of pre-ignition. The modified air charge consists of a smaller amount of air than the standard (default) air charge admitted during normal operation of the engine 10. By way of example, during normal operation of the engine 10, the ECU 50 controls the intake valve 20 to admit a first air charge into the combustion chamber 18 during a first operating cycle. Following detection of a pre-ignition event, the ECU 50 controls the intake valve 20 to admit a second air charge into the combustion chamber 18 during a second operating cycle. The first air charge consists of a first trapped mass of air; and the second air charge consists of a second trapped mass of air. The second trapped mass of air is less than the first trapped mass of air. The first and second operating cycles in this example may be successive operating cycles, i.e. the second operating cycle may follow immediately after the first operating cycle. In certain embodiments, the ECU 50 may control the intake valve 20 to admit the second air charge into the combustion chamber 18 during one or more one successive operating cycle. Thus, a reduced trapped mass of air may be admitted into the combustion chamber during two or more operating cycles after the operating cycle in which the pre-ignition event is detected. The ECU 50 is configured to control the intake valve 20 to revert to admitting the first air charge into the combustion chamber 18 after one or more subsequent operating cycle.
The engine 10 comprises a sensor Si for detecting pre-ignition. The combustion process generates a sound or vibrations which can be detected by the sensor Si. The sensor Si in the present embodiment comprises a noise sensor (audio transducer) for detecting sounds generated when combustion occurs in the combustion chamber 18. In a variant, the sensor Si may comprise a vibration sensor for detecting vibrations resulting from the combustion process. The sensor Si generates a sound signal which may comprise signal characteristics, such as one or more peak, which indicate that a combustion event has occurred. The sound signal is analysed to identify any such signal characteristics to determine that a combustion event has occurred. The timing of the combustion event is compared to that of the spark ignition for that cylinder 12. If the combustion event occurred before ignition in that cylinder 12, a determination is made that the pre-ignition occurred in the cylinder 12. The sensor Si outputs an electrical signal SIN-1 indicating the occurrence of the pre-ignition during an operating cycle. The sensor Si is configured to output the electronic signal SIN-1 to the ECU 50 indicating detection of pre-ignition. This process is performed for each operating cycle to identify any abnormal combustion events. It will be understood that additional processing may optionally be performed on the audio signal generated by the sensor Si, for example to ensure that the signal characteristics have a magnitude greater than a level indicative of background noise.
The ECU 50 is configured to control the opening and closing of the intake valve 20 to deliver a metered charge of air into the combustion chamber 18. In dependence on receipt of the electronic signal SIN-1, the ECU 50 is configured to reduce the trapped mass of air admitted into the combustion chamber 18 of the affected cylinder 12 during the next operating cycle of the engine 10. By reducing the trapped mass of air admitted into the combustion chamber 18, the characteristics of the combustion process are controlled to mitigate against or prevent pre-ignition in the next operating cycle. The ECU 50 is configured to control the intake valve 20 to reduce the interval during which air is admitted into the combustion chamber 18 during the intake phase of the operating cycle. The trapped mass of air admitted into the combustion chamber 18 is thereby modified to deliver a reduced trapped mass of air for combustion following detection of a pre-ignition.
In the present embodiment, the ECU 50 is configured to retard opening of the intake valve 20 to delay admission of air into the combustion chamber 18 during the intake phase. Reducing the interval that the intake valve 20 is open, causes a proportional reduction in the trapped mass of air admitted into the combustion chamber 18. The ECU 50 may be configured to close the intake valve 20 at substantially the same crank angle in each operating cycle. Alternatively, or in addition, the ECU 50 may advance closing of the intake valve 20 during the intake phase. Thus, the intake valve 20 may be closed early to reduce the trapped mass of air admitted into the combustion chamber 18. The reduced trapped mass of air admitted into the combustion chamber 18 reduces the oxygen available for combustion during the subsequent combustion process. However, stoichiometric combustion is at least substantially maintained. This is achieved by controlling the quantity of fuel injected into the combustion chamber 18 during the operating cycle. The fuel injected may be reduced in the substantially same proportion as the reduction of air, thereby maintaining the air fuel ratio (AFR) substantially unchanged. The ECU 50 may be configured to control operation of the one or more fuel injector 46 to control the quantity of fuel injected during each operating cycle. The air-fuel equivalence ratio, A (lambda), is maintained at least substantially equal to one (A=1). The air-fuel equivalence ratio, A (lambda) is the ratio of the actual air-fuel ratio (AFR) to stoichiometry for a given mixture. The intake valve 20 is controlled to maintain the air-fuel equivalence ratio at least substantially equal to one (i.e. A=1.0) in the first and second operating cycles.
As shown in Figure 3, the ECU 50 comprises a controller 52 having at least one processor 54 and a system memory 56. The processor 54 is an electronic processor and is configured to implement a set of computational instructions stored in the system memory 56. When executed, the computational instructions cause the electrical processor 54 to implement the method(s) described herein. The at least one electrical processor 54 has at least one electrical input 58A for receiving the input signal SIN-n; and at least one electrical output 58B for outputting one or more output signal SOUT-n. The first input signal SI N-n may comprise the electrical signal from the sensor Si indicating detection of a pre-ignition event. The first output signal SOUT-n may comprise a request to select one of the first and second intake valve control functions.
A first intake profile defines a first intake valve control function for opening and closing the intake valve 20 to admit the first trapped mass of air. A second intake profile defines a second intake valve control function for opening and closing the intake valve 20 to admit the second trapped mass of air. The second trapped mass of air is less than the first trapped mass of air. The ECU 50 is configured selectively to implement one of the first and second intake valve control functions. The ECU 50 defaults to the first intake valve control function. Thus, during normal operation of the engine 10 (when pre-ignition has not been detected), the ECU 50 implements the first intake valve control function. If, however, pre-ignition is detected, the ECU 50 is configured implement the second intake valve control function to reduce the trapped mass of air admitted into the combustion chamber 18. At least in certain embodiments, the second intake valve control function can be implemented in the next, successive operating cycle. For example, if pre-ignition is detected in a first operating cycle, the ECU 50 is configured to implement the second intake valve control function during a successive second operating cycle. The ECU 50 may optionally be configured to apply the second intake valve control function in a plurality of consecutive operating cycles following detection of a pre-ignition event. The trapped mass of air admitted to the combustion chamber 18 following detection of a pre-ignition event may be the same in each of the modified operating cycles; or the trapped mass of air may vary, for example progressively increasing over successive operating cycles to return to the standard (default) trapped mass of air. The ECU 50 may continue to apply the second intake valve control function in the event that pre-ignition is detected in one or more successive operating cycle.
It is convenient to represent the intake valve control functions with reference to a single revolution represented by a circle. Points on the circle are used to represent the instant at which, during the first revolution, the intake valve 20 is opened and closed. A representation of this kind is provided in Figures 4 and 5. The timing of the admission of air into the combustion chamber is expressed by way of the piston position in the revolution before the ignition spark (which is delivered at the top of the circle at the 12 o'clock position). That is, the timings of the injections are expressed as a crank angle, for example before a 'top dead centre firing' crank angle ('degrees BTDC').
Figure 4 represents a first intake valve control function 55 for application in a first operating cycle. In the present embodiment, the first intake valve control function comprises or consists of a standard (or default) air intake function for the engine 10. The standard fuel intake valve control function may, for example, be defined to control combustion in the combustion chamber to reduce or minimise emissions. The first intake valve control function consists of a first interval 4a during which the intake valve 20 is open to admit air into the combustion chamber 18. The first intake valve control function defines a first open crank angle al for opening the intake valve 20; and a first close crank angle a2 for closing the intake valve 20. The first open crank angle al and the first close crank angle a2 are both measured from a reference crank angle a0, for example corresponding to top dead centre firing. The first interval Au is the difference between the first open crank angle al and the first close crank angle a2 (Au = a2 -al). The first interval Au corresponds to the intake phase in the first operating cycle during which intake gases are inducted into the combustion chamber.
Figure 5 represents a second intake valve control function 65 for application in a second operating cycle. The second intake valve control function comprises or consists of a modified air intake function for the engine 10. The modified fuel intake valve control function is defined to control combustion in the combustion chamber 18 to mitigate or prevent pre-ignition. The second intake valve control function consists of a second interval 413 during which the intake valve 20 is open to admit air into the combustion chamber 18. The second intake valve control function defines a second open crank angle p1 for opening the intake valve 20; and a second close crank angle 132 for closing the intake valve 20. The second open crank angle 131 and the second close crank angle 132 are both measured from the reference crank angle a0. The second interval AS is the difference between the second open crank angle p 1 and the second close crank angle 132 (413 =132 -[31). The second interval 413 corresponds to the intake phase in the second operating cycle during which intake gases are inducted into the combustion chamber.
The ECU 50 is configured to implement the second intake valve control function in dependence on detection of a pre-ignition event. The second intake valve control function is configured to reduce or control the occurrence of pre-ignition. The ECU 50 is configured to output the first output signal SOUT-n may comprise a request to select one of the first and second intake valve control functions.
The method according to the present invention will now be described with reference to a first block diagram 100 shown in Figure 5. The engine 10 is activated (BLOCK 105). The ECU 50 implements the first intake valve control function for a first operating cycle (BLOCK 110). The ECU 50 controls the opening and closing of the intake valve 20 according to the first intake valve control function (BLOCK 115). The sensor Si monitors combustion in the combustion chamber during the first operating cycle (BLOCK 120). During the first operating cycle, the sensor Si detects a pre-ignition event (BLOCK 125). The sensor Si outputs an electronic signal SIN-1 to the ECU 50 indicating detection of the pre-ignition event (BLOCK 130). In dependence on receipt of the electronic signal, the ECU 50 implements the second intake valve control function (BLOCK 135). The ECU 50 controls the opening and closing of the intake valve 20 according to the second intake valve control function for a second operating cycle (BLOCK 140). The first and second operating cycles may be consecutive operating cycles. The method may optionally comprise selecting the first intake valve control function for a predetermined number of operating cycle(s) (BLOCK 145). The first and second operating cycles may be spaced apart from each other. The sensor Si monitors combustion in the combustion chamber during the second operating cycle (BLOCK 150). The ECU 50 performs a check to determine if a pre-ignition event is detected in the second operating cycle (BLOCK 155). If a pre-ignition event is not detected in the second operating cycle, the ECU 50 is configured to implement the first intake valve control function for the next (third) operating cycle (BLOCK 160). If an abnormal combustion event is detected in the second operating cycle, the ECU 50 is configured to select the second intake valve control function for the next (third) operating cycle (BLOCK 165). The ECU 50 controls the fuel valve(s) to maintain the second intake valve control function for the next (third) operating cycle. The ECU 50 may be configured to implement the second intake valve control function for a predetermined number of operating cycles following detection of the pre-ignition event. The predetermined number may, for example, be two or more operating cycles. The ECU 50 is configured to implement the first injection pattern in the event that pre-ignition is not detected during the successive operating cycle. The controlled implementation of the first and second intake valve control functions continues until the engine 10 is deactivated (BLOCK 170). In this example, the operating cycles are consecutive operating cycles of the engine 10.
The first and second intake valve control functions are defined to maintain at least substantially the same air/fuel ratio in the first and second operating cycles. Although the first and second intake valve control functions have different timing schedules, the air/fuel ratio may be at least substantially the same for the first and second operating cycles. At least in certain embodiments, the first and second intake valve control functions may be configured to provide at least substantially stoichiometric combustion (A=1) in the combustion chamber during the first and second operating cycles respectively.
Alternatively, or in addition, the ECU 50 may be configured to provide indirect control of the trapped mass of air admitted into the combustion chamber by modifying the timing for opening and/or closing the second poppet control valve 40. The ECU 50 may be configured to control the exhaust valve 40 to reduce the interval that the exhaust port 42 is open for exhausting gases from the combustion chamber 18 during the exhaust phase. In dependence on identifying a pre-ignition event during an operating cycle, the ECU 50 may be configured to control the exhaust valve 40 to reduce the interval that the exhaust port 42 is open during the same operating cycle. The trapped mass of air admitted into the combustion chamber 18 in the intake phase of the subsequent operating cycle may be reduced. To reduce the interval that the exhaust valve 40 is open, the ECU 50 may be configured to retard (delay) opening of the exhaust valve 40, and/or advance closure of the exhaust valve 40. A first exhaust valve control function may define a first set of opening and closing crank angles for the exhaust valve 40; and a second exhaust valve control function may define a second set of opening and closing crank angles for the exhaust valve 40. The second set may define a shorter interval during which the exhaust valve 40 is open. The ECU 50 may be configured to select the second exhaust valve control function in dependence on identification of a pre-ignition.
The ECU 50 has been described herein as controlling the interval AA, Al3 for which the intake valve 20 is open during the intake phase of the operating cycle; and/or the interval for which the exhaust valve 40 is open during the exhaust phase of the operating cycle. Alternatively, or in addition, the ECU 50 may control the valve lift of the intake valve 20 and/or the exhaust valve 40 to modify the intake of air into the combustion chamber 18 and/or the exhaust of gases from the combustion chamber 18 respectively. The valve lift of the intake valve 20 may be reduced to reduce the mass flow rate of air entering the combustion chamber 18 through the intake port 22; and/or the valve lift of the exhaust valve 40 may be reduced to reduce the mass flow rate of exhaust gases exiting the combustion chamber through the exhaust port 42.
The second intake valve control function may define a valve lift which is less than the valve lift implemented by the first intake valve control function. Alternatively, or in addition, the first exhaust valve control function may define a valve lift which is less than the valve lift implemented by the first exhaust valve control function.
The trapped mass of air available for combustion may be reduced by directly reducing the trapped mass of a fresh air charge, or by controlling valve overlap to retain a greater proportion of combustion gases within a combustion chamber; such gases are inert and cannot contribute towards combustion.
It will be understood that different control strategies may be implemented to modify the trapped mass of intake gases. The embodiment herein contemplates modifying the first and second intervals Au, A13 during which the intake valve 20 is open in the first and second operating cycles respectively. Alternatively, or in addition, the valve lift of the intake valve 20 may be controlled to throttle the admittance of intake gases into the combustion chamber. Different control strategies for controlling the trapped mass of intake gases are shown in Figures 7 to 11 by way of example. The operation of the intake valve 20 in the first operating cycle is represented by a first intake valve trace IV1 in each of these figures. The operation of the intake valve 20 in the second operating cycle is represented by a second intake valve trace IV2 in each of these figures. The intake stroke is represented by the angular range 0° to 180° from TDC; and the compression stroke is represented by the angular range 180° to 360° from TDC. The different control strategies will now be described in more detail.
A first control strategy having a shortened intake valve open interval Al3 is shown in Figure 7. The intake valve 20 has at least substantially the same open crank angles al, 131 in the first and second operating cycles. The first and second open crank angles al, 131 occur at the end of the exhaust phase. The second close crank angle 132 is advanced compared to the first close crank angle a2. As such, the second interval A13 (A[3= [32-131) when the intake valve 20 is open during the second operating cycle is less than the first interval AA (AA=a2-al) when the intake valve 20 is open during the first operating cycle. As a result of the reduced second interval A13, the trapped mass of intake gas is reduced in the second operating cycle. In the illustrated example, the valve lift of the intake valve 20 is substantially unchanged between the first and second operating cycles.
A second control strategy having a throttled intake valve is shown in Figure 8. In this control strategy, the intake valve 20 is throttled to control the intake gases admitted into the combustion chamber. The intake valve 20 has at least substantially the same open crank angle al, 131 in the first and second operating cycles. The first and second open crank angles al, 131 occur at the end of the exhaust phase. The operation of the intake valve 20 is controlled to provide a reduced valve lift during the second operating cycle compared to the valve lift during the first operating cycle. The reduced valve lift restricts the admittance of intake gases into the combustion chamber, thereby reducing the trapped mass of the intake gases. In the illustrated example, the second close crank angle 132 is also advanced compared to the first close crank angle a2. It will be understood that the second close crank angle 132 may be the same as the first close crank angle 131.
A third control strategy having a late closure of the intake valve 20 is shown in Figure 9. The intake valve 20 has at least substantially the same open crank angles al, 31 in the first and second operating cycles. The first and second open crank angles al, 131 occur at the end of the exhaust phase. The second close crank angle 132 is retarded (delayed) compared to the first close crank angle a2. As such, the second interval ap (A13= 132-131)when the intake valve 20 is open during the second operating cycle is greater than the first interval AA (AA=a2-al) when the intake valve 20 is open during the first operating cycle. However, in the second operating cycle, the second close crank angle 132 occurs later in the compression phase. This results in the expulsion of some of the intake gases admitted into the combustion chamber during the preceding intake stroke. As a result, the trapped mass of intake gas is reduced in the second operating cycle. In the illustrated example, the valve lift of the intake valve 20 is substantially unchanged between the first and second operating cycles.
A fourth control strategy having a late opening of the intake valve 20 is shown in Figure 10. The intake valve 20 has different open crank angles al, 131 in the first and second operating cycles. The first open crank angle al occurs at the end of the exhaust phase. The second open crank angle 131 is retarded (delayed) and occurs later in the intake phase. The second close crank angle 132 is retarded (delayed) compared to the first close crank angle a2. As such, the second interval A13 (413= 132-131) when the intake valve 20 is open during the second operating cycle is less than the first interval AA (AA=a2-al) when the intake valve 20 is open during the first operating cycle. As a result of the reduced second interval 413, the trapped mass of intake gas is reduced in the second operating cycle. In the illustrated example, the valve lift of the intake valve 20 is substantially unchanged between the first and second operating cycles.
It will be appreciated that various changes and modifications can be made to the present invention without departing from the scope of the present application.
The following table provides labels for the block diagram 100 shown as figure 5.
Activated Select first intake valve control function for first operating cycle Admit air into combustion chamber according to first intake valve control function Monitor combustion during first operating cycle Pre-ignition event detected Output pre-ignition detected signal Select second intake valve control function for second operating cycle Admit air into combustion chamber according to second intake valve control function Optionally hold first intake valve control function for a predetermined number of operating cycle(s) Monitor combustion during operating cycle Pre-ignition event detected NO -select first intake valve control function for next operating cycle YES -select second intake valve control function for next operating cycle Deactivated
Claims (25)
- CLAIMS1. A control system for controlling a spark ignition, reciprocating piston internal combustion engine comprising a combustion chamber having an intake valve and an exhaust valve, the control system comprising one or more controller configured to: control opening and closing of the intake valve during a first operating cycle to admit a first trapped mass of intake gases into the combustion chamber; receive a signal identifying a pre-ignition event in the combustion chamber during the first operating cycle; and in dependence on the identification of the pre-ignition event, control opening and closing of the intake valve during a second operating cycle to admit a second trapped mass of intake gases into the combustion chamber; wherein the second trapped mass of intake gases is less than the first trapped mass of intake gases.
- 2. A control system as claimed in claim 1, wherein the one or more controller comprises: at least one electronic processor having an electrical input for receiving the signal identifying the pre-ignition event from a sensor, and an electrical output for outputting a control signal to control the intake valve; and at least one memory device electrically coupled to the at least one electronic processor and having instructions stored therein, and wherein the at least one electronic processor is configured to access the at least one memory device and execute the instructions therein so as to control the intake valve.
- 3. A control system as claimed in claim 1 or claim 2, wherein the first operating cycle and the second operating cycle are consecutive operating cycles.
- 4. A control system as claimed in any one of claims 1, 2 or 3, wherein the one or more controller is configured to retard opening of the intake valve during the second operating cycle.
- 5. A control system as claimed in any one of claims 1 to 4, wherein the one or more controller is configured to advance closing of the intake valve during the second operating cycle.
- 6. A control system as claimed in any one of the preceding claims, wherein the one or more controller is configured to control the intake valve to provide a first valve lift in the first operating cycle, and to provide a second valve lift in the second operating cycle wherein the second valve lift is less than the first valve lift.
- 7. A control system as claimed in any one of the preceding claims, wherein, in dependence on the identification of the pre-ignition event in the first operating cycle, the one or more controller is configured to control the exhaust valve to reduce the trapped mass of exhaust gases exhausted from the combustion chamber during the first operating cycle indirectly to control the second trapped mass of intake gases admitted during the second operating cycle.
- 8. A control system as claimed in claim 7, wherein, in dependence on the identification of the pre-ignition event, the one or more controller is configured to advance closure of the exhaust valve during the first operating cycle.
- 9. A control system as claimed in any one of the preceding claims, wherein the one or more controller is configured to control the intake valve and the exhaust valve to reduce a duration when the intake valve and the exhaust valve are both open simultaneously.
- 10. A control system as claimed in any one of the preceding claims, wherein the one or more controller is configured to control the injection of fuel to maintain at least substantially the same air-fuel ratio (AFR) in the first and second operating cycles.
- 11. A control system as claimed in any one of the preceding claims, wherein the one or more controller is configured, in dependence on the identification of a pre-ignition event during the first operating cycle, to control opening and closing of the intake valve during a third operating cycle to admit a third trapped mass of intake gases into the combustion chamber; the third trapped mass of intake gases being less than the first trapped mass of intake gases.
- 12. A control system as claimed in claim 11, wherein the third trapped mass of intake gases is greater than the second trapped mass of intake gases.
- 13. A vehicle comprising a control system as claimed in any one of the preceding claims.
- 14. A method of controlling a spark ignition, reciprocating piston internal combustion engine having a combustion chamber for performing at least first and second operating cycles each comprising fuel injection and combustion, the method comprising: during a first operating cycle, admitting a first trapped mass of intake gases into the combustion chamber in a first intake phase, injecting fuel into the combustion chamber in a first fuel injection, generating a first ignition spark for igniting fuel in the combustion chamber, and exhausting gases from the combustion chamber in a first exhaust phase; identifying pre-ignition in the combustion chamber during the first operating cycle; and during a second operating cycle, admitting a second trapped mass of intake gases into the combustion chamber in a second intake phase, injecting fuel into the combustion chamber in a second fuel injection, generating a second ignition spark for igniting fuel in the combustion chamber, and exhausting gases from the combustion chamber in a second exhaust phase; wherein, in dependence on the identification of pre-ignition during the first operating cycle, the method comprises reducing the second trapped mass of intake gases admitted during the second operating cycle relative to the first trapped mass of intake gases admitted during the first operating cycle.
- 15. A method as claimed in claim 14 wherein the first operating cycle and the second operating cycle are consecutive operating cycles.
- 16. A method as claimed in claim 14 or claim 15, wherein reducing the second trapped mass of intake gases admitted during the second operating cycle comprises controlling the second intake phase.
- 17. A method as claimed in claim 16, wherein controlling the second intake phase comprises retarding initiation of the second intake phase and/or advancing completion of the second intake phase.
- 18. A method as claimed in any one of claims 14 to 17, comprising controlling a valve lift of the intake valve to control the trapped mass of intake gases in the combustion chamber; wherein the valve lift is reduced during the second operating cycle to reduce the trapped mass of gases in the combustion chamber.
- 19. A method as claimed in any one of claims 14 to 18 comprising reducing the trapped mass of exhaust gases exhausted from the combustion chamber during the first operating cycle indirectly to control the second trapped mass of intake gases admitted during the second operating cycle.
- 20. A method as claimed in claim 19, wherein reducing the trapped mass of exhaust gases exhausted from the combustion chamber during the first operating cycle comprises advancing completion of the first exhaust phase.
- 21. A method as claimed in any one of claims 14 to 20, wherein reducing the second trapped mass of intake gases admitted during the second operating cycle comprises reducing an overlap of the first exhaust phase and the second intake phase.
- 22. A method as claimed in any one of claims 14 to 21 comprising controlling the injection of fuel to maintain at least substantially the same air-fuel ratio (AFR) in the first and second operating cycles.
- 23. A method as claimed in any one of claims 14 to 22, wherein, in dependence on the identification of pre-ignition during the first operating cycle, the method comprises reducing a third trapped mass of intake gases in the combustion chamber during a third operating cycle relative to the first trapped mass of intake gases admitted during the first operating cycle.
- 24. A method as claimed in claim 23, wherein the third trapped mass of intake gases is greater than the second trapped mass of intake gases.
- 25. A non-transitory computer-readable medium having a set of instructions stored therein which, when executed, cause a processor to perform the method claimed in any one of the claims 14 to 24.
Priority Applications (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB2103262.8A GB2604616B (en) | 2021-03-09 | 2021-03-09 | Control system and method for an internal combustion engine |
DE102022104816.0A DE102022104816A1 (en) | 2021-03-09 | 2022-03-01 | CONTROL SYSTEM AND METHOD FOR AN INTERNAL COMBUSTION ENGINE |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB2103262.8A GB2604616B (en) | 2021-03-09 | 2021-03-09 | Control system and method for an internal combustion engine |
Publications (3)
Publication Number | Publication Date |
---|---|
GB202103262D0 GB202103262D0 (en) | 2021-04-21 |
GB2604616A true GB2604616A (en) | 2022-09-14 |
GB2604616B GB2604616B (en) | 2023-06-21 |
Family
ID=75472523
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
GB2103262.8A Active GB2604616B (en) | 2021-03-09 | 2021-03-09 | Control system and method for an internal combustion engine |
Country Status (2)
Country | Link |
---|---|
DE (1) | DE102022104816A1 (en) |
GB (1) | GB2604616B (en) |
Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20170082081A1 (en) * | 2014-11-21 | 2017-03-23 | Ford Global Technologies, Llc | Method for pre-ignition control |
US20180163649A1 (en) * | 2015-08-21 | 2018-06-14 | Ford Global Technologies, Llc | Method and system for pre-ignition control |
-
2021
- 2021-03-09 GB GB2103262.8A patent/GB2604616B/en active Active
-
2022
- 2022-03-01 DE DE102022104816.0A patent/DE102022104816A1/en active Pending
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20170082081A1 (en) * | 2014-11-21 | 2017-03-23 | Ford Global Technologies, Llc | Method for pre-ignition control |
US20180163649A1 (en) * | 2015-08-21 | 2018-06-14 | Ford Global Technologies, Llc | Method and system for pre-ignition control |
Also Published As
Publication number | Publication date |
---|---|
GB2604616B (en) | 2023-06-21 |
GB202103262D0 (en) | 2021-04-21 |
DE102022104816A1 (en) | 2022-09-15 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US8851050B2 (en) | Spark-ignition engine control method and system | |
US9970361B2 (en) | Engine control apparatus | |
US7571707B2 (en) | Engine mode transition utilizing dynamic torque control | |
US8949002B2 (en) | System and method for injecting fuel | |
RU2703872C2 (en) | Method and system for motor control | |
CN105526011B (en) | Method and system for reactivating engine cylinders | |
JP2002538366A (en) | Fuel injection method for internal combustion engine | |
US11333092B2 (en) | Control device and control method for internal combustion engine | |
US10408152B1 (en) | Methods and system for adjusting cylinder air charge of an engine | |
US20090211554A1 (en) | Control Device for Engine | |
US7406937B2 (en) | Method for operating an internal combustion engine | |
US10669953B2 (en) | Engine control system | |
US10641186B2 (en) | Internal combustion engine control apparatus | |
MX2015001616A (en) | Method and system of controlling bank to bank component temperature protection during individual cylinder knock control. | |
US20170107922A1 (en) | Control system of internal combustion engine | |
JP6090641B2 (en) | Control device for internal combustion engine | |
JP2007327399A (en) | Control device for internal combustion engine | |
CN108266277B (en) | System and method for operating an engine | |
GB2604616A (en) | Control system and method for an internal combustion engine | |
US11359573B2 (en) | Control device for internal combustion engine | |
US11390264B2 (en) | Methods and system for controlling stopping of an engine | |
US20200277903A1 (en) | Cylinder deactivation system and cylinder deactivation method | |
JP2006132399A (en) | Control device and control method for supercharged engine | |
JP5333172B2 (en) | Control device for internal combustion engine | |
CN108691663B (en) | Internal combustion engine controls |