US20070113807A1 - Internal combustion engine comprising a variable valve lift system and a variable valve timing system, and a method for such an engine - Google Patents
Internal combustion engine comprising a variable valve lift system and a variable valve timing system, and a method for such an engine Download PDFInfo
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- US20070113807A1 US20070113807A1 US11/556,726 US55672606A US2007113807A1 US 20070113807 A1 US20070113807 A1 US 20070113807A1 US 55672606 A US55672606 A US 55672606A US 2007113807 A1 US2007113807 A1 US 2007113807A1
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- Prior art keywords
- vvt
- valve lift
- engine
- mode shift
- actuator
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- 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
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- 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
- F01L1/00—Valve-gear or valve arrangements, e.g. lift-valve gear
- F01L1/02—Valve drive
- F01L1/022—Chain drive
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- 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
- F01L1/00—Valve-gear or valve arrangements, e.g. lift-valve gear
- F01L1/34—Valve-gear or valve arrangements, e.g. lift-valve gear characterised by the provision of means for changing the timing of the valves without changing the duration of opening and without affecting the magnitude of the valve lift
- F01L1/344—Valve-gear or valve arrangements, e.g. lift-valve gear characterised by the provision of means for changing the timing of the valves without changing the duration of opening and without affecting the magnitude of the valve lift changing the angular relationship between crankshaft and camshaft, e.g. using helicoidal gear
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- 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
- F01L13/0036—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 the valves being driven by two or more cams with different shape, size or timing or a single cam profiled in axial and radial direction
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- 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
- F01L1/00—Valve-gear or valve arrangements, e.g. lift-valve gear
- F01L1/02—Valve drive
- F01L1/024—Belt drive
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- 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
- F01L1/00—Valve-gear or valve arrangements, e.g. lift-valve gear
- F01L1/20—Adjusting or compensating clearance
- F01L1/22—Adjusting or compensating clearance automatically, e.g. mechanically
- F01L1/24—Adjusting or compensating clearance automatically, e.g. mechanically by fluid means, e.g. hydraulically
- F01L1/245—Hydraulic tappets
- F01L1/25—Hydraulic tappets between cam and valve stem
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- 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
- F01L13/0005—Deactivating valves
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- 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
- F01L2800/00—Methods of operation using a variable valve timing mechanism
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- 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
- F01L2820/00—Details on specific features characterising valve gear arrangements
- F01L2820/04—Sensors
- F01L2820/041—Camshafts position or phase sensors
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- 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
- F01L2820/00—Details on specific features characterising valve gear arrangements
- F01L2820/04—Sensors
- F01L2820/042—Crankshafts position
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- 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
- F02D2041/001—Controlling intake air for engines with variable valve actuation
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02D—CONTROLLING COMBUSTION ENGINES
- F02D2250/00—Engine control related to specific problems or objectives
- F02D2250/18—Control of the engine output torque
- F02D2250/21—Control of the engine output torque during a transition between engine operation modes or states
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- 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
Definitions
- the present invention relates to an internal combustion engine comprising a variable valve lift system and a variable valve timing (VVT) systems, and more particularly to operating the engine selectively in either of at least two valve lift modes.
- VVT variable valve timing
- An internal combustion engine can be provided with a variable valve lift system, for example a cam profile shift (CPS) system, and a variable valve timing (VVT) system.
- a variable valve lift system for example a cam profile shift (CPS) system
- VVT variable valve timing
- CPS cam profile shift
- VVT variable valve timing
- a mode shift in the CPS system might cause a pressure pulse, which can affect the VVT-position.
- the VVT angle can due to this effect have a control error of up to 10 CA (crankshaft angles).
- a mode shift in the CPS system might affect the VVT-position.
- the cause could be a friction change due to the different camlobes used in the CPS modes.
- a CPS mode shift can cause a voltage shift affecting the VVT position.
- this invention is directed to a method for minimizing torque steps when shifting modes in a variable valve lift system of an internal combustion engine.
- VVT variable valve timing
- the VVT actuator could be controllable by at least one control valve of a hydraulic system, the control valve being controllable by an engine control unit, whereby the control pulse is sent to the control valve.
- the variable valve lift system comprises a valve lift shift actuator controllable by the same hydraulic system, a pressure pulse, positive or negative, caused by changing the valve lift mode and the physical connection by the hydraulic system between the VVT actuator and the valve lift shift actuator, can be counteracted by the provided control pulse, so that the VVT position is not affected.
- VVT actuator could be controlled by some other type of system.
- the VVT actuator could use an electric power supply which is controlled by an engine control unit.
- the control pulse is sent after a time interval (Dt) following a signal for the valve lift mode shift.
- the signal for the valve lift mode shift could be a signal from which a valve lift mode shift can be predicted.
- the signal could be in the form of an internal command in an engine control unit.
- the control pulse could be terminated by a decrement function.
- FIG. 1 is a schematic view of parts of an internal combustion engine, including a variable valve timing system and a variable valve lift system, the latter in a low lift position,
- FIG. 2 is a detail of the view in FIG. 1 , where the cam profiles have been shifted to a high lift position
- FIGS. 3 and 4 are diagrams of engine control signals as functions of time.
- FIG. 1 shows schematically parts of an internal combustion engine.
- a camshaft I is driven by a crankshaft 2 via a belt (or chain) 3 , a crankshaft wheel 3 a , and a camshaft wheel 3 b in a manner known in the art.
- the engine comprises a variable valve lift in the form of a cam profile shifting (CPS) system 4 , adapted to shift the lift profile of intake and/or exhaust valves of the engine, by changing the valve lift provided by camlobes 6 a , 6 b on the camshaft 1 .
- CPS cam profile shifting
- FIG. 1 only one valve, in the form of an intake valve 5 at a cylinder 5 a is shown. In this example, for each valve 5 there is provided one low lift camlobe 6 a and two high lift camlobes 6 b.
- each of the camlobes 6 a , 6 b acts on valve actuators 4 a , 4 b , in the form of valve tappets, located between the camlobes and the valve.
- the valve actuators can be fixed to each other by a valve lift shift actuator 4 c , here also referred to as a CPS actuator 4 c , in turn controllable by a hydraulic system 9 , indicated in FIG. 1 with broken lines.
- the hydraulic system 9 can be, as is known in the art, used for manoeuvring a plurality of units of the engine, and comprises a hydraulic pump 9 a .
- the CPS system 4 For control of the CPS actuator(s) 4 c , the CPS system 4 comprises a CPS actuator control valve 9 b in the hydraulic system 9 .
- the CPS actuator control valve 9 b is controllable by an engine control unit (ECU) 7 .
- the CPS actuator control valve 9 b can be of a known type, for example a solenoid valve, not further described here.
- the ECU 7 has, as known, computational capabilities and storage capabilities, and can be formed by one device, or more than one physically separate, but logically connected devices.
- valve actuators 4 a , 4 b are not fixed to each other by the CPS actuator 4 c , which results in the valve lift being controlled by the low lift camlobe 6 a .
- the valve actuators 4 a , 4 b are fixed to each other by the CPS actuator 4 c , so that the valve motion is controlled by the high lift camlobes 6 b.
- the CPS system can be provided in a variety of manners known in the art, for example as described in US5950583A.
- the CPS actuator can be provided in alternative manners, and the CPS system can be adapted to assume more than two valve lift modes.
- the engine also comprises a variable valve timing (VVT) system 8 , which is adapted to adjust the VVT position, i.e. set the camshaft I at desired angular positions in relation to the camshaft wheel 3 b .
- VVT variable valve timing
- the VVT system comprises a VVT actuator 8 a , for example of the type described in US6135077A, at the camshaft wheel 3 b .
- the VVT actuator 8 a is adapted to mechanically change the VVT position, and is controllable by the hydraulic system 9 .
- the VVT system comprises a VVT actuator control valve 9 c in the hydraulic system 9 , which could be of the same type as the CPS actuator control valve 9 b .
- the VVT actuator control valve 9 c is also controllable by the ECU 7 . Also, by means of a connection 8 c to a cam phase detector and a connection 8 d to a crankshaft position detector, the ECU can determine a current value of the VVT position.
- the VVT actuator 8 a with the VVT actuator control valve 9 c is integrating which means that a constant value of the signal from the ECU 7 to the VVT actuator control valve 9 c gives a constant flow of oil through the valve if the pressure drop over the valve is constant. Since the CPS system and the VTT system use the same hydraulic system, a CPS mode shift can result in a change of the oil pressure at the VVT actuator control valve 9 c . As described closer below, in order to compensate for this change of pressure, the VVT actuator control valve 9 c is activated so as to counteract the effect of the pressure change.
- FIG. 3 shows signals of the ECU 7 in the form of a VVT actuator control valve signal 11 , and a CPS actuator control valve signal 12 .
- a valve lift mode shift here also referred to as a cam profile mode shift
- the ECU 7 sends a control pulse 14 for the VVT actuator in this example.
- a signal is identified from which a valve lift mode shift is predicted.
- the mode shift involves changing the cam profile mode from the low lift mode to the high lift mode.
- the signal is in the form of an internal command in the ECU 7 .
- the ECU sends a signal to the CPS actuator control valve 9 b .
- the ECU 7 sends a control pulse 14 to the VVT actuator control valve 9 c.
- the ECU 7 could send the control pulse 14 to the VVT actuator control valve 9 c at the end of a time interval following a time at which the ECU sends a signal to the CPS actuator control valve 9 b.
- the control pulse 14 in this example includes a step to its maximum amplitude A, and is terminated by a decrement function F.
- the control pulse 14 in FIG. 3 is defined as positive.
- the control pulse 14 will result in a movement of the VVT actuator control valve 9 c so as for the pressure at the VVT actuator to be constant despite the pressure change in the hydraulic system caused by the CPS mode shift.
- the control pulse 14 will counteract the effect of the cam profile shift on the VVT position.
- the effect of the control pulse 14 is to counteract the influence of the cam profile mode shift on the VVT position.
- the time interval Dt, and the amplitude A and the decrement function F of the control pulse 14 could be predetermined.
- one or more of these parameters, Dt, A, F could be determined based on at least one engine operation related parameter, for example the engine speed and/or the oil temperature. Such determinations could be based on predetermined functions or tables mapping the time interval Dt, the pulse amplitude A and the pulse decrement function F to the engine operation related parameter(s).
- the time interval Dt, the pulse amplitude A, and the decrement function F, or the functions for their determination, could be calibratable, i.e., they could be adjusted before operation so that an optimal effect of the control pulse 14 is achieved. More specifically, the shape of the control pulse should adapted to a shape of a pressure pulse in the hydraulic system caused by a CPS mode shift.
- the time interval Dt is preferably chosen so that the VVT actuator 8 a response to the control pulse 14 occurs at the same time as the CPS mode shift affects the VVT position.
- the delay between the CPS mode shift control signal and the time at which the CPS mode shift affects the VVT position can be due to, for example, a pressure pulse travelling through a hydraulic system adapted to control the CPS system as well as the VVT system.
- a cam profile shift is made in the opposite direction in relation to the shift described with reference to in FIG. 3 .
- the ECU sends a signal to the CPS actuator control valve 9 b in order to change the cam profile mode from the high lift mode to the low lift mode.
- the ECU 7 sends a control pulse 14 to the VVT actuator control valve 9 c .
- the control pulse 14 in FIG. 4 is negative instead of positive. Therefore, the pressure pulse sent to the VVT actuator 8 a , will result in the VVT actuator 8 a acting in the opposite direction in relation to the actuator action following the control pulse in FIG. 3 .
- it can be suitable to provide control pulses to the VVT system having the same sign (positive or negative) for both types of CPS mode shifts, i.e. low lift to high lift and vice versa.
- control pulse can have alternative shapes, for example it can be in the form of a constant amplitude pulse.
- control pulse can be sent simultaneously as the ECU signal 12 for the cam profile shift.
- the invention is equally applicable to engines where the VVT system and the CPS system are actuated by two separate hydraulic systems, or where any or both of the systems are actuated by some other type of system, for example including electromagnetic actuators. Further, the invention is equally applicable to engines with variable valve lift systems providing more than two valve lift modes. It should also be noted that the method according to the invention is equally applicable to engines with spark ignition and engines with compression ignition.
Abstract
An internal combustion engine having a variable valve lift system whereby the engine can operate selectively in either of at least two valve lift modes, and a variable valve timing (VVT) system, as well as a method for controlling valve timing in such an engine are presented. The method comprises providing, in response to a valve lift mode shift, a control pulsing signal for the VVT actuator in order to compensate for the effects of the valve lift on the VVT system.
Description
- The present invention relates to an internal combustion engine comprising a variable valve lift system and a variable valve timing (VVT) systems, and more particularly to operating the engine selectively in either of at least two valve lift modes.
- An internal combustion engine can be provided with a variable valve lift system, for example a cam profile shift (CPS) system, and a variable valve timing (VVT) system. Such an engine is described in for example US6581564B2. In engines where one oil feed system is provided for actuation in both the CPS system and the VVT system, the physical connection between the VVT system and the CPS system via the oil system can cause the following problem: A mode shift in the CPS system might cause a pressure pulse, which can affect the VVT-position. The VVT angle can due to this effect have a control error of up to 10 CA (crankshaft angles).
- Also in engines in which the CPS system and the VVT system have separate systems for their respective actuation, whether hydraulic or not, a mode shift in the CPS system might affect the VVT-position. The cause could be a friction change due to the different camlobes used in the CPS modes. Further, where both systems are electrically actuated, a CPS mode shift can cause a voltage shift affecting the VVT position.
- This is undesirable, since the related change in the VVT position can cause a change of the volumetric efficiency of the engine, which in turn may affect vehicle driveability and driver comfort.
- Accordingly, this invention is directed to a method for minimizing torque steps when shifting modes in a variable valve lift system of an internal combustion engine.
- This is accomplished by a method for controlling valve timing in an internal combustion engine capable of operating selectively in either of at least two valve lift modes, the engine having a variable valve timing (VVT) system, the method comprising: sending a control pulsing signal to a VVT system actuator in response to a valve lift mode shift.
- Thereby, an effect on the VVT position by a valve lift mode shift can be counteracted or compensated for, so that the VVT position remains essentially the same before, during and after the mode shift.
- The VVT actuator could be controllable by at least one control valve of a hydraulic system, the control valve being controllable by an engine control unit, whereby the control pulse is sent to the control valve. In case the variable valve lift system comprises a valve lift shift actuator controllable by the same hydraulic system, a pressure pulse, positive or negative, caused by changing the valve lift mode and the physical connection by the hydraulic system between the VVT actuator and the valve lift shift actuator, can be counteracted by the provided control pulse, so that the VVT position is not affected.
- However, it should be noted that the VVT actuator could be controlled by some other type of system. For example, the VVT actuator could use an electric power supply which is controlled by an engine control unit.
- Preferably, the control pulse is sent after a time interval (Dt) following a signal for the valve lift mode shift. The signal for the valve lift mode shift could be a signal from which a valve lift mode shift can be predicted. For example, the signal could be in the form of an internal command in an engine control unit. Also, the control pulse could be terminated by a decrement function.
- The above advantages and other advantages, and features of the present invention will be readily apparent from the following detailed description of the preferred embodiments when taken in connection with the accompanying drawings, and from the claims.
- In the following text, the invention will be described in detail with reference to the attached drawings. These drawings are used for illustration only and do not in any way limit the scope of the invention. In the drawings:
-
FIG. 1 is a schematic view of parts of an internal combustion engine, including a variable valve timing system and a variable valve lift system, the latter in a low lift position, -
FIG. 2 is a detail of the view inFIG. 1 , where the cam profiles have been shifted to a high lift position, and -
FIGS. 3 and 4 are diagrams of engine control signals as functions of time. -
FIG. 1 shows schematically parts of an internal combustion engine. A camshaft I is driven by acrankshaft 2 via a belt (or chain) 3, a crankshaft wheel 3 a, and acamshaft wheel 3 b in a manner known in the art. The engine comprises a variable valve lift in the form of a cam profile shifting (CPS)system 4, adapted to shift the lift profile of intake and/or exhaust valves of the engine, by changing the valve lift provided by camlobes 6 a, 6 b on the camshaft 1. InFIG. 1 only one valve, in the form of anintake valve 5 at acylinder 5 a is shown. In this example, for eachvalve 5 there is provided one low lift camlobe 6 a and two high lift camlobes 6 b. - In operation each of the camlobes 6 a, 6 b acts on valve actuators 4 a, 4 b, in the form of valve tappets, located between the camlobes and the valve. As depicted in the schematic presentation of
FIG. 1 and 2, the valve actuators can be fixed to each other by a valve lift shift actuator 4 c, here also referred to as a CPS actuator 4 c, in turn controllable by a hydraulic system 9, indicated inFIG. 1 with broken lines. The hydraulic system 9 can be, as is known in the art, used for manoeuvring a plurality of units of the engine, and comprises ahydraulic pump 9 a. For control of the CPS actuator(s) 4 c, theCPS system 4 comprises a CPS actuator control valve 9 b in the hydraulic system 9. The CPS actuator control valve 9 b is controllable by an engine control unit (ECU) 7. The CPS actuator control valve 9 b can be of a known type, for example a solenoid valve, not further described here. The ECU 7 has, as known, computational capabilities and storage capabilities, and can be formed by one device, or more than one physically separate, but logically connected devices. - In a low lift mode, shown in
FIG. 1 , the valve actuators 4 a, 4 b are not fixed to each other by the CPS actuator 4 c, which results in the valve lift being controlled by the low lift camlobe 6 a. As can be seen inFIG. 2 , in a high lift mode the valve actuators 4 a, 4 b are fixed to each other by the CPS actuator 4 c, so that the valve motion is controlled by the high lift camlobes 6 b. - Alternatively, still within the scope of the present invention, the CPS system can be provided in a variety of manners known in the art, for example as described in US5950583A. In particular, the CPS actuator can be provided in alternative manners, and the CPS system can be adapted to assume more than two valve lift modes.
- The engine also comprises a variable valve timing (VVT)
system 8, which is adapted to adjust the VVT position, i.e. set the camshaft I at desired angular positions in relation to thecamshaft wheel 3 b. The VVT system comprises aVVT actuator 8 a, for example of the type described in US6135077A, at thecamshaft wheel 3 b. TheVVT actuator 8 a is adapted to mechanically change the VVT position, and is controllable by the hydraulic system 9. For control of theVVT actuator 8 a, the VVT system comprises a VVT actuator control valve 9 c in the hydraulic system 9, which could be of the same type as the CPS actuator control valve 9 b. The VVT actuator control valve 9 c is also controllable by theECU 7. Also, by means of a connection 8 c to a cam phase detector and aconnection 8 d to a crankshaft position detector, the ECU can determine a current value of the VVT position. - The
VVT actuator 8 a with the VVT actuator control valve 9 c is integrating which means that a constant value of the signal from theECU 7 to the VVT actuator control valve 9 c gives a constant flow of oil through the valve if the pressure drop over the valve is constant. Since the CPS system and the VTT system use the same hydraulic system, a CPS mode shift can result in a change of the oil pressure at the VVT actuator control valve 9 c. As described closer below, in order to compensate for this change of pressure, the VVT actuator control valve 9 c is activated so as to counteract the effect of the pressure change. - Here reference is made also to
FIG. 3 , which shows signals of theECU 7 in the form of a VVT actuatorcontrol valve signal 11, and a CPS actuatorcontrol valve signal 12. In connection to a valve lift mode shift, here also referred to as a cam profile mode shift, theECU 7 sends acontrol pulse 14 for the VVT actuator in this example. In this embodiment, at the time t0, a signal is identified from which a valve lift mode shift is predicted. The mode shift involves changing the cam profile mode from the low lift mode to the high lift mode. The signal is in the form of an internal command in theECU 7. At least partly based on the internal command, the ECU sends a signal to the CPS actuator control valve 9 b. Also, according to this embodiment of the invention, at the end of a time interval Dt following the time t0 at which the signal or internal command was identified, theECU 7 sends acontrol pulse 14 to the VVT actuator control valve 9 c. - Alternatively, the
ECU 7 could send thecontrol pulse 14 to the VVT actuator control valve 9 c at the end of a time interval following a time at which the ECU sends a signal to the CPS actuator control valve 9 b. - The
control pulse 14 in this example includes a step to its maximum amplitude A, and is terminated by a decrement function F. For this presentation, thecontrol pulse 14 inFIG. 3 is defined as positive. Thecontrol pulse 14 will result in a movement of the VVT actuator control valve 9 c so as for the pressure at the VVT actuator to be constant despite the pressure change in the hydraulic system caused by the CPS mode shift. Thus, thecontrol pulse 14 will counteract the effect of the cam profile shift on the VVT position. - Thus, the effect of the
control pulse 14 is to counteract the influence of the cam profile mode shift on the VVT position. The time interval Dt, and the amplitude A and the decrement function F of thecontrol pulse 14 could be predetermined. Alternatively, one or more of these parameters, Dt, A, F could be determined based on at least one engine operation related parameter, for example the engine speed and/or the oil temperature. Such determinations could be based on predetermined functions or tables mapping the time interval Dt, the pulse amplitude A and the pulse decrement function F to the engine operation related parameter(s). The time interval Dt, the pulse amplitude A, and the decrement function F, or the functions for their determination, could be calibratable, i.e., they could be adjusted before operation so that an optimal effect of thecontrol pulse 14 is achieved. More specifically, the shape of the control pulse should adapted to a shape of a pressure pulse in the hydraulic system caused by a CPS mode shift. - The time interval Dt is preferably chosen so that the
VVT actuator 8 a response to thecontrol pulse 14 occurs at the same time as the CPS mode shift affects the VVT position. The delay between the CPS mode shift control signal and the time at which the CPS mode shift affects the VVT position can be due to, for example, a pressure pulse travelling through a hydraulic system adapted to control the CPS system as well as the VVT system. - Here reference is made also to
FIG. 4 . A cam profile shift is made in the opposite direction in relation to the shift described with reference to inFIG. 3 . Thus, at the time t0, the ECU sends a signal to the CPS actuator control valve 9 b in order to change the cam profile mode from the high lift mode to the low lift mode. After a time interval Dt, theECU 7 sends acontrol pulse 14 to the VVT actuator control valve 9 c. Thecontrol pulse 14 inFIG. 4 is negative instead of positive. Therefore, the pressure pulse sent to theVVT actuator 8 a, will result in theVVT actuator 8 a acting in the opposite direction in relation to the actuator action following the control pulse inFIG. 3 . However, for certain CPS systems, not described closer here, it can be suitable to provide control pulses to the VVT system having the same sign (positive or negative) for both types of CPS mode shifts, i.e. low lift to high lift and vice versa. - Alternatives are possible to the embodiment described above. For example, the control pulse can have alternative shapes, for example it can be in the form of a constant amplitude pulse. Also, the control pulse can be sent simultaneously as the
ECU signal 12 for the cam profile shift. - The invention is equally applicable to engines where the VVT system and the CPS system are actuated by two separate hydraulic systems, or where any or both of the systems are actuated by some other type of system, for example including electromagnetic actuators. Further, the invention is equally applicable to engines with variable valve lift systems providing more than two valve lift modes. It should also be noted that the method according to the invention is equally applicable to engines with spark ignition and engines with compression ignition.
- The invention is not limited to the embodiments described above and may be varied freely within the scope of the appended claims.
Claims (10)
1. A method for controlling valve timing in an internal combustion engine capable of operating selectively in either of at least two valve lift modes, the engine having a variable valve timing (VVT) system, the method comprising:
sending a control pulsing signal to a VVT system actuator in response to a valve lift mode shift.
2. The method according to claim 1 , wherein said control pulsing signal is sent to compensate for oil pressure variation caused by said valve lift mode shift.
3. The method according to claim 2 wherein said control pulsing signal is such that a VVT position remains essentially the same before, during and after said valve lift mode shift.
4. The method according to claim 3 , wherein said control pulsing signal is sent after a predetermined time interval following a signal for said valve lift mode shift.
5. The method according to claim 4 , wherein said control pulsing signal is terminated by a decrement function.
6. An automotive system, comprising:
an internal combustion engine having a variable valve lift system whereby said engine can operate selectively in either of at least two valve lift modes,
said engine further having a variable valve timing (VVT) system comprising a VVT actuator, and
a control unit adapted to provide, in response to a valve lift mode shift, a control pulsing signal for said VVT actuator.
7. An automotive system according to claim 6 , wherein said control pulsing signal is sent after a predetermined time interval following a signal for said valve lift mode shift.
8. An automotive system according to claim 7 , wherein said controller provides said control pulsing signal is terminated by a decrement function.
9. An automotive system according to claim 8 , wherein said controller provides said control pulsing signal to compensate for oil pressure variation caused by said valve lift mode shift.
10. An automotive system according to claim 9 , wherein said controller provides said control pulsing signal is such that a VVT position remains essentially the same before, during and after said valve lift mode shift.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP05110938A EP1788224B1 (en) | 2005-11-18 | 2005-11-18 | An internal combustion engine comprising a variable valve lift system and a variable valve timing system, and a method for such an engine |
EP05110938.7 | 2005-11-18 |
Publications (1)
Publication Number | Publication Date |
---|---|
US20070113807A1 true US20070113807A1 (en) | 2007-05-24 |
Family
ID=36129292
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US11/556,726 Abandoned US20070113807A1 (en) | 2005-11-18 | 2006-11-06 | Internal combustion engine comprising a variable valve lift system and a variable valve timing system, and a method for such an engine |
Country Status (3)
Country | Link |
---|---|
US (1) | US20070113807A1 (en) |
EP (1) | EP1788224B1 (en) |
DE (1) | DE602005010718D1 (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20080017144A1 (en) * | 2006-06-28 | 2008-01-24 | Martin Litorell | Internal combustion engine comprising a variable valve lift profile system and a method for controlling valve lift profile shifting |
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JP4416377B2 (en) * | 2002-05-16 | 2010-02-17 | 日産自動車株式会社 | Control device for internal combustion engine |
EP1788202B1 (en) | 2005-11-18 | 2009-03-25 | Ford Global Technologies, LLC | An internal combustion engine comprising a variable valve lift system and a method for controlling valve lift shifting |
-
2005
- 2005-11-18 DE DE602005010718T patent/DE602005010718D1/en active Active
- 2005-11-18 EP EP05110938A patent/EP1788224B1/en not_active Expired - Fee Related
-
2006
- 2006-11-06 US US11/556,726 patent/US20070113807A1/en not_active Abandoned
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US5287830A (en) * | 1990-02-16 | 1994-02-22 | Group Lotus | Valve control means |
US5331583A (en) * | 1992-06-19 | 1994-07-19 | Hitachi, Ltd. | Running-average/decimation filter for an oversampling A/D converter |
US5881690A (en) * | 1996-12-20 | 1999-03-16 | Hyundai Motor Company | System for variably controlling operation of an intake/exhaust valve for an internal combustion engine |
US5950583A (en) * | 1997-04-25 | 1999-09-14 | Dr. Ing. H.C.F. Porsche Ag | Valve gear of an internal-combustion engine |
US6135077A (en) * | 1997-11-07 | 2000-10-24 | Toyota Jidosha Kabushiki Kaisha | Valve timing changing apparatus for internal combustion engine |
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US6581564B2 (en) * | 2000-09-21 | 2003-06-24 | Honda Giken Kogyo Kabushiki Kaisha | Ignition time controller, ignition time control method and engine control unit for internal combustion engine |
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US20080017144A1 (en) * | 2006-06-28 | 2008-01-24 | Martin Litorell | Internal combustion engine comprising a variable valve lift profile system and a method for controlling valve lift profile shifting |
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Also Published As
Publication number | Publication date |
---|---|
EP1788224A1 (en) | 2007-05-23 |
EP1788224B1 (en) | 2008-10-29 |
DE602005010718D1 (en) | 2008-12-11 |
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Owner name: VOLVO CAR CORPORATION, SWEDEN Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:LYNGFELT, THOMAS;LITORELL, MARTIN;REEL/FRAME:018485/0953 Effective date: 20060117 Owner name: FORD GLOBAL TECHNOLOGIES, LLC, MICHIGAN Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:VOLVO CAR CORPORATION;REEL/FRAME:018485/0992 Effective date: 20060123 |
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