JP3928374B2 - Control method for starting characteristic changing means of internal combustion engine for vehicle - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for controlling a starting characteristic of an internal combustion engine, and more particularly to a method for controlling an engine starting characteristic changing means in preparation for an operation at the next engine start when the engine is stopped.
[0002]
[Prior art]
In the operation of the internal combustion engine, during normal operation after engine warm-up, the intake-compression ratio is relatively low, the engine is operated with low vibration and high fuel consumption, and when the engine is cold before engine warm-up, especially when the engine is cold Conventionally, it is known to change and control engine operating characteristics as needed so as to improve the startability of the engine by increasing the intake compression ratio during cranking. Such changes in internal combustion engine operating characteristics, such as the intake compression ratio, are also made during engine operation, but in particular, changes in operating characteristics for improving engine startability are performed when the engine is not operating prior to engine cranking. This is done by operating the engine operating characteristic changing means.
[0003]
The change in the intake compression ratio of the piston type internal combustion engine related to the engine start characteristics is made by deviating the closing phase of the intake valve back and forth by the valve opening / closing timing control device, and the appropriate phase during the transition from the intake stroke to the compression stroke The exhaust valve is temporarily opened by selecting, the intake / exhaust valve drive cam is a three-dimensional cam, and the lift is adjusted as appropriate, and the piston rod and crankshaft or the connection between the piston rod and piston can be adjusted It is possible by various methods such as providing a simple eccentric bearing.
[0004]
As an example, an example of a device that changes the intake compression ratio by biasing the closing phase of the intake valve back and forth is disclosed in Japanese Patent Application Laid-Open No. 2000-320356, filed by the same applicant as the present applicant. In order to change the intake compression ratio by this structure, the opening / closing phase of the intake valve by the intake valve opening / closing timing control device is variably controlled with respect to the rotational phase of the crankshaft as shown in FIG. As a result, the amount of intake air loaded into the cylinder chamber at the moment when the intake valve is closed is increased or decreased to variably control the intake air compression ratio. The intake valve closing phase in a four-cycle engine is generally around 70 ° measured after the bottom dead center (abdc for short), which is 110 to 120 ° by the intake valve opening / closing timing control device. When it is further increased (delayed) to the extent, the amount of intake air trapped in the cylinder chamber at the time when the intake valve is closed decreases, and the intake compression ratio decreases. By changing the intake valve closing phase by the intake valve opening / closing timing control device, the in-cylinder pressure at the end of the compression stroke changes greatly as illustrated in FIG.
[0005]
The structure is as shown in FIGS. 3 to 5, and FIGS. 4 and 5 are views showing the section AA in FIG. 3 in two modes of operation. In FIG. 3, e is an internal combustion engine, and first and second motor generators (motor generators) mg1 and mg2 having both functions of a motor and a generator on a crankshaft c are planetary gear type. A pair of wheels w are electrically driven via an axle s, a differential gear d, and a transmission t with respect to a driving regenerative device composed of an internal combustion engine and a motor generator. Drive-connected at the rotating shaft portion of the generator mg1. The motor generators mg1 and mg2 are electrically connected to the power storage device b through the inverter i, and operate as a motor or a generator according to the operation state of the vehicle.
[0006]
10 is the intake valve opening / closing timing control device, and is an intake compression ratio control means from the viewpoint of the intake compression ratio as will be described later. The intake valve opening / closing timing control device includes a gear 14 that is driven to rotate in synchronization with the crankshaft from the crankshaft c of the internal combustion engine via the endless belt 12, and an intake valve camshaft 18 that carries the intake valve operating cam 16. It has the structure of a rotary actuator that acts in between.
[0007]
An internal spline-like annular member 22 and an annular end plate 24 are combined with the gear 14 by four bolts 20 to define a working chamber space including four inward radial partition walls 26. ing. In the working chamber space, a rotor 30 fixed to one end of the camshaft 18 by a bolt 28 is provided. The rotor 30 has four blade portions 32 that operate as pistons around a central hub portion, and each blade portion is a sector shape formed between a pair of contour wall portions 26 located on both sides in the circumferential direction. 4, between the rotating position as shown in FIG. 4 and the rotating position as shown in FIG. 5, from the gear 14, the annular member 22, and the end plate 24. In the piston working chamber 34, a piston working chamber portion 34a is provided on one side of the rotor wall 26 and a piston working chamber portion 34b is provided on the other side. Is formed.
[0008]
The housing is driven in the clockwise direction as indicated by the arrows in FIGS. 4 and 5 by the endless belt 12 by the endless belt 12 with the forward rotation of the crankshaft. In this state, the camshaft 18 is in the most retarded phase with respect to the crankshaft. Conversely, in the state shown in FIG. 5, the camshaft 18 is most advanced in phase with respect to the crankshaft. Is in a state.
[0009]
One of the blade portions 32 is provided with a stepped cylinder hole 36, and a lock pin 40 engaged in a piston manner with a large diameter head portion 38 at a large diameter portion in the stepped cylinder hole. It is inset. The small-diameter portion 42 of the lock pin 40 engages with the small-diameter portion of the stepped cylinder hole 36 and is guided to slide along it. The small diameter portion 42 is formed when the camshaft 18 is advanced most with respect to the crankshaft, that is, when the blade portion 32 of the rotor 30 comes to the rotational position shown in FIG. The gear 14 can be fitted into a recessed hole 44 provided at a corresponding position. The lock pin 40 is urged toward the recess hole 44 by a compression coil spring 46, and an annular working chamber (formed between the head portion 38 of the lock pin 40 in the large diameter portion of the stepped cylinder hole 36 ( When the hydraulic pressure is not supplied in the manner described later in the drawing position 36, when the rotor 30 reaches the most advanced angle position as shown in FIG. Due to the spring force of the compression coil spring 46, the end portion of the small diameter portion 42 is dropped into the recess hole 44, and the relative rotational positional relationship of the cam shaft 18 with respect to the crankshaft is locked to the most advanced position. ing.
[0010]
For each of the piston working chambers 34 formed between adjacent ones of the four wall portions 26 of the annular member 22, this is made into the annular member 22 with respect to the blade portion 32 of the rotor 30 disposed therein. On the other hand, as shown in FIG. 4 or 5, the first port 48 that supplies hydraulic pressure to drive in the counterclockwise direction (that is, opens to the working chamber portion 34 a), and conversely, the blade portion 32 with respect to the annular member 22, is used In view of this, a second port 50 that supplies hydraulic pressure to drive in the clockwise direction (that is, opens to the working chamber 34b) is open. The first port 48 communicates with the annular oil passage 52, and the second port 50 communicates with the annular oil passage 54. The oil passage 52 further communicates with the annular working chamber (drawing position of reference numeral 36) of the stepped cylinder hole 36. The annular groove 52 communicates with an annular oil passage 60 formed in a bearing portion 58 for the cam shaft 18 formed in the cylinder head portion of the internal combustion engine via an oil passage 56 formed in the end portion of the cam shaft 18. Yes. On the other hand, the annular oil passage 54 communicates with an annular oil passage 64 formed in the bearing portion 58 via oil passages 61 and 62 similarly formed in the end portion of the cam shaft 18. The annular oil passage 60 is connected to a first port 72 of an electromagnetically operated hydraulic switching valve 70 through a port 66 and an oil passage 68 connected thereto, while the annular oil passage 64 is connected to the oil passage 76 from the port 74. Then, it is connected to the second port 78 of the electromagnetic switching valve.
[0011]
In addition to the ports 72 and 78 described above, the electromagnetic hydraulic pressure switching valve 70 is configured to release the hydraulic port 82 that receives the discharge hydraulic pressure from the hydraulic pump 80 and the first port 72 toward the oil reservoir 84 selectively. A valve housing 90 having a second drain port 86 and a second drain port 88 for selectively releasing the second port 78 toward the oil reservoir 84; and a solenoid 92 and a compression coil spring 94 in the valve housing. And a valve spool 96 that reciprocates under the action to control the communication between the ports.
[0012]
The operation of the solenoid 92 is controlled by a command signal from a vehicle operation control unit (ECU) 98 incorporating a computer. When the solenoid 92 is not energized, the valve spool 96 is in a position fully displaced to the right as shown in the figure by the action of the compression coil spring 94. At this time, the second port 78 is communicated with the hydraulic port 82, One port 72 communicates with the first drain port 86. Accordingly, when the pump 80 is operated in such a state, the hydraulic pressure supplied through the oil passage 76 is supplied from the port 74 to the oil passage 62 through the annular oil passage 64, and from there through the oil passage 61. 54 and further supplied to the working chamber 34 via the port 50. Accordingly, at this time, the blade portion 32 of the rotor 30 is driven in the clockwise direction as viewed in FIG. 4 or 5 with respect to the annular member 22, and the intake valve closing phase is advanced. When the drive in the advance direction reaches the end, the lock pin 40 is aligned with the recess hole 44, and the lock pin is driven rightward as viewed in FIG. The camshaft 18 is inserted into the recess hole 44 and is locked at the most advanced angle position with respect to the crankshaft. However, since the hydraulic pressure discharged from the hydraulic pump 80 has not yet risen when the engine is started, the maximum hydraulic pressure is applied. The advance to the angular position does not occur when the engine is started.
[0013]
On the other hand, when the solenoid 92 is continuously energized, the valve spool 96 is driven to the left as viewed in FIG. 3 against the action of the compression coil spring 94. At this time, the first port 72 communicates with the hydraulic port 82 and the second port 78 communicates with the second drain port 88. When the valve spool 96 is in such a position, when the hydraulic pump 80 is operated, the hydraulic pressure generated by the hydraulic pump 80 is supplied from the port 66 to the annular oil passage 60 via the oil passage 68, from which the oil passage 56 and the annular oil are supplied. At the same time as being supplied from the port 48 to the piston working chamber 34 via the passage 52, it is also supplied to the annular working chamber of the stepped cylinder hole 36. Accordingly, at this time, the lock pin 40 is driven to the position shown in FIG. 3 against the action of the compression coil spring 46, and when the small diameter end portion 42 is fitted in the recess hole 44, the fitting is released. At the same time, the blade portion 32 of the rotor 30 is driven in the counterclockwise direction as viewed in FIG. 4 or 5 with respect to the annular member 22, and the camshaft 18 is displaced in the retarding direction with respect to the crankshaft.
[0014]
When energization of the solenoid 92 is controlled as on / off pulse energization, the valve spool 96 is set to an arbitrary intermediate position between the two extreme positions according to the duty ratio of the pulse current, and accordingly, the rotor 30 The hydraulic pressure acting on both sides of the blade portion 32 is relatively balanced and the relative angular position of the camshaft 18 with respect to the crankshaft is set to an arbitrary intermediate position between the most advanced angle position and the most retarded angle position. Is set.
[0015]
The vehicle operation control unit (ECU) 98 has a vehicle key switch (not shown in the figure) turned on and turned to a cranking position for cranking the engine. Is supplied with a signal Sk representing the amount of depression of the accelerator pedal, a signal Da representing the amount of depression of the accelerator pedal, a signal Ve representing the vehicle speed, a signal Ne representing the engine speed, a signal Te representing the engine temperature, a signal Ac representing the crank angle, etc. Based on these input signals, the control device 98 performs a control calculation based on a predetermined control program, and controls the operation of the solenoid 92 as described above to control the opening / closing timing of the intake valve with respect to the reciprocation of the piston. .
[0016]
[Problems to be solved by the invention]
An eco-run car that stops the internal combustion engine when the vehicle is temporarily stopped, such as when waiting for a signal, and a hybrid that mixes the drive by the internal combustion engine and the drive by the electric motor as appropriate. The vehicle is provided with a means for changing the intake air compression ratio, and cranking start with different intake air compression ratios at the time of engine cold start at the start of vehicle operation and at the time of engine restart due to engine temporary stop during vehicle operation is performed. If the engine can be operated, the engine is started by increasing the intake air compression ratio at the time of cold start of the engine at the start of vehicle operation, and the restart after the engine temporary stop in the engine warm-up state that frequently occurs after the engine warm-up is reduced. Smooth and quiet cranking by the intake compression ratio can be achieved.
[0017]
In this case, in the example shown in FIGS. 3 to 5 above, the engine restart after the temporary stop of the engine may be performed as it is from the state shown in FIG. 4, but the engine is in a cold state. In order to increase the intake compression ratio, the intake valve opening / closing timing control device is shown in FIG. 4 at the start of the vehicle operation or when the engine has cooled down while the vehicle is in operation, even if the vehicle is temporarily stopped. It is necessary to switch from the state shown to the state shown in FIG. However, when the engine is not in operation before starting the engine, the advance angle control of the intake valve opening / closing timing control device based on the hydraulic pressure of the hydraulic pump 80 is not yet obtained. The crankshaft c is actuated to rotate in the reverse rotation direction first, and the housing member composed of the gear 14, the annular member 22, and the annular end plate 24 is rotated in the delay direction with respect to the rotor 30 that is stopped. An operation for mechanically locking the intake valve opening / closing timing control device at the most advanced angle position by rotating the housing relative to the housing in the advancing direction and dropping the small-diameter end 42 of the lock pin 40 into the recessed hole 44. Is done.
[0018]
When the internal combustion engine is temporarily stopped during the operation of the vehicle in an eco-run vehicle or a hybrid vehicle due to the automatic control judgment action of the vehicle operation control device, the engine stop time is relatively short, and when the engine is restarted, Is still warm-up, and the engine starts easily and smoothly even when the intake compression ratio is lowered. Therefore, the engine restart after the automatic temporary stop of the engine is performed while the intake air compression ratio is lowered, that is, in the example shown in FIGS. You may be ranked. However, in general, when the engine is stopped by the driver turning off the key switch, or even if the engine is temporarily stopped due to automatic control judgment of the vehicle operation control device, the engine will be restarted at the next engine restart. In this case, it is preferable that the engine is started with a high intake compression ratio.
[0019]
  When the intake air compression ratio is changed and controlled by a hydraulic pressure (generally, hydraulic pressure) type device as in the structure of FIGS. 3 to 5 illustrated above, oil (working liquid) is contained in the device. If the device cools while the engine is full, the viscosity of the oil increases, and there is a possibility that the control may not be effective depending on the motor drive when the engine is cold. That is, in the above example, when the valve opening / closing timing control device is cooled in the state shown in FIG. 4 and the piston working chamber 34 is cooled and filled with oil having increased viscosity, the engine cold start is started. Motor generator mg1 or mg2If the crankshaft is driven in reverse to change the device from the state shown in FIG. 4 to the state shown in FIG. If possible, it may take a long time.
[0020]
However, if this is dealt with and the engine is automatically returned to the state shown in FIG. 5 when the engine is stopped due to the key switch being turned off, the driver can restart the vehicle while the warm-up is still maintained. When trying to operate, the device is set to a position where the intake compression ratio is maximized, and in order to release it and displace the device to the state shown in FIG. But it takes a lot of time. If cranking is performed as it is, the advantage that a smooth and quiet engine start can be obtained with the intake compression ratio lowered when the engine is warmed up is lost.
[0021]
In view of the above circumstances, the present invention has a piston working chamber that operates a piston so that the intake compression ratio is lowered when working liquid is introduced. When the intake compression ratio is increased, the working liquid is discharged from the piston working chamber. It is an object of the present invention to provide a control method for quickly operating a starting characteristic changing means of an internal combustion engine for a vehicle that is required to increase an intake compression ratio as necessary when the engine is restarted. Yes.
[0022]
[Means for Solving the Problems]
In order to solve the above problems, the present invention provides a method of controlling the internal combustion engine operating characteristic changing means as described above, and draining the piston working chamber as the internal combustion engine stops. In this case, drainage of the piston working chamber due to the stop of the internal combustion engine may be performed at any time during the period from immediately before the stop of the internal combustion engine to immediately before the engine is restarted. As the liquid cools, the viscosity increases and the resistance to drainage increases, so the piston working chamber is drained only after the stop of the internal combustion engine immediately before the stop, the viscosity due to the temperature drop of such working liquid. It is particularly preferable that the time is within a period determined in consideration of the increase until a predetermined time elapses.
[0023]
The starting characteristic changing means is subjected to an action of enlarging the piston working chamber by rotation of the crankshaft of the engine in the forward rotation direction, and reduces the piston working chamber by rotation of the crankshaft in the reverse rotation direction. It may be designed to receive the action to be attempted.
[0024]
  Further, the start characteristic changing means is the piston working chamber as a first piston working chamber,TheWhen the internal combustion engine is stopped when the second piston working chamber acting on the piston is opposed to the first piston working chamber, the working liquid supply pump is stopped immediately before the stop, The second piston working chamber may be opened to the drainage passage. In this case, after the internal combustion engine is stopped, the first piston working chamber may be opened to the drainage passage, and the crankshaft may be driven in reverse by an electric motor (including a motor generator; the same applies hereinafter).
[0025]
Alternatively, in the above control, when the internal combustion engine is stopped, the working liquid supply source pump is stopped, and after the internal combustion engine is stopped, the second piston working chamber is opened to the drainage passage, The crankshaft may be driven in the forward direction by an electric motor. In this case, after the driving of the crankshaft in the forward direction by the electric motor is completed, the first piston working chamber may be opened to the drainage passage, and the crankshaft may be reversely driven by the electric motor.
[0026]
The starting characteristic changing means may include a locking means for locking the piston at the displacement position when the piston is displaced to a position where the first piston working chamber is reduced to a predetermined reduction degree. The rotation in the reverse direction of the crankshaft that drains the one piston working chamber may be set to a position immediately before the locking means is locked.
[0027]
The displacement of the piston that enlarges the first piston working chamber delays the closing phase of the intake valve by the start characteristic changing means, and the displacement of the piston that reduces the first piston working chamber is the intake valve by the start characteristic changing means. The closing phase may be advanced.
[0028]
[Action and effect of the invention]
As described above, it has the first piston working chamber that operates the piston so that the intake compression ratio is lowered when the working liquid is introduced. When the intake compression ratio is increased, the working liquid is discharged from the piston working chamber. When changing the starting characteristic of the internal combustion engine by the starting characteristic changing means of the internal combustion engine for a vehicle that is required, if the piston working chamber is drained when the internal combustion engine is stopped, the starting characteristic is changed. By reducing the viscous resistance of the working fluid that resists the operation of the means, the next time the engine is restarted, even if the required intake compression ratio is high or low, the start characteristic changing means is quickly adapted to it. Can be made.
[0029]
As described above, the piston working chamber may be drained at any time during the period from immediately before the internal combustion engine is stopped to just before the engine is restarted. As the working fluid cools and increases in viscosity with the passage of time, the drainage from the first piston working chamber is performed in particular within a period of time until a predetermined time elapses immediately before the stop of the internal combustion engine. In this case, the drainage can be performed quickly while the working liquid easily flows.
[0030]
The starting characteristics of the engine basically depend on the compression ratio of the intake air. To change the intake compression ratio of a piston-type internal combustion engine, the valve closing timing control device deviates the closing phase of the intake valve back and forth, and selects the appropriate phase during the transition from the intake stroke to the compression stroke to temporarily turn off the exhaust valve. Opening the valve, adjusting the lift of the intake / exhaust valve drive cam as a three-dimensional cam, and providing an adjustable eccentric bearing at the connecting portion between the piston rod and crankshaft or piston rod and piston, etc. Although it is possible to control the intake compression ratio in synchronism with the rotation of the crankshaft, any of these can cause some control element to follow the rotation of the crankshaft and control its following displacement. become. Therefore, the starting characteristic changing means has a structure having a second piston working chamber that acts on the piston opposite to the first piston working chamber, and the working fluid is supplied to the first piston working chamber and the second working fluid is supplied. When the working liquid is discharged from the chamber, the intake compression ratio decreases, and when the working liquid is supplied to the second working fluid chamber and the working liquid is discharged from the first working fluid chamber, the intake compression ratio increases. When the crankshaft rotates in the forward rotation direction, the piston undergoes a displacement action in the direction of lowering the intake compression ratio, and when the crankshaft rotates in the reverse rotation direction, the piston undergoes a displacement action in the direction of increasing the intake compression ratio. If this displacement action is used, the first piston working chamber is drained by rotation of the crankshaft in the reverse direction, and the second piston working chamber is drained by rotation of the crankshaft in the forward direction. It is possible.
[0031]
As one operation mode of such a configuration, when the internal combustion engine is stopped, the working liquid supply source pump is stopped immediately before the stop, and the second piston working chamber is opened to the drainage passage. The second piston working chamber can be drained by displacing the piston by a displacement action exerted on the piston from the crankshaft when the last crankshaft rotating to stop. In this case, after the internal combustion engine is stopped, the first piston working chamber can be drained by opening the first piston working chamber to the drainage passage and driving the crankshaft in reverse by the electric motor.
[0032]
Alternatively, when the internal combustion engine is stopped, the drainage fluid in the second piston working chamber stops the supply pump for the working fluid, and after the internal combustion engine stops, the second piston working chamber is opened to the drainage passage. However, this can be done by driving the crankshaft in the forward direction with an electric motor. Also in this case, after the drainage of the second piston working chamber by driving the crankshaft in the forward direction by the electric motor is completed, the first piston working chamber is opened to the drainage passage, and the crankshaft is driven by the electric motor. If it is driven in reverse, the first piston working chamber can be drained.
[0033]
When the starting characteristic changing means has a locking means for locking the piston at the displacement position when the piston is displaced to a position where the first piston working chamber is reduced to a predetermined degree of reduction. If the rotation of the crankshaft that drains the piston working chamber in the reverse direction is made to the position just before the lock means is locked, when the next engine start is cold start, the start characteristic changing means is very little by the motor. The engine is locked at the cold start position by the reverse rotation of the engine, so that the cold start of the engine can be performed quickly. Even when the next engine start is a warm-up start, the start characteristic changing means is not locked at the cold start position, and the viscosity of the hydraulic oil is low at this time. The changing means quickly displaces to the warm-up start position, and a quick warm-up start is obtained.
[0034]
In each of the above-described configurations, the displacement of the piston described in FIGS. 3 to 5 that expands the first piston working chamber is the direction that delays the closing phase of the intake valve by the start characteristic changing means, and the first piston of the piston When the displacement for reducing the working chamber is in the direction of advancing the closing phase of the intake valve by the starting characteristic changing means, it is advantageously achieved by the structure shown in FIG.
[0035]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 6 is a flowchart showing one embodiment of the control method of the starting characteristic changing means of the vehicle internal combustion engine according to the present invention. Here, the present invention will be described as being implemented in the intake valve opening / closing timing control apparatus shown in FIGS. The engine stop control operation according to this flowchart is started when the vehicle operation control device shown as 98 in FIG. 3 is instructed to start the vehicle operation by a signal representing the operation of the key switch shown as signal Sk. It's okay.
[0036]
When the control is started, various data related to the control are read in step 10. The read data includes a signal Sk representing the operation of the key switch shown in FIG. 3, a signal Da representing the depression amount of the accelerator pedal, a signal Ve representing the vehicle speed, a signal Ne representing the engine speed, an engine temperature. , A signal Eb representing the voltage of the power storage device, a signal Ta representing the air temperature, a signal Ac representing the crank angle, and the like. Based on these read data, it is determined in next step 20 whether or not an engine stop condition is satisfied. In this case, whether or not the engine stop condition is satisfied is determined by the signal Sk indicating the operation of the key switch operated by the driver, and in the case of an eco-run vehicle or a hybrid vehicle, the engine is temporarily stopped by the vehicle operation control device. It is made as a judgment whether or not to stop. As long as the answer is no, control returns to step 10 to continue updating the read data. If the answer is yes, the control proceeds to step 30, and the following series of engine stop control accompanying the engine stop is performed.
[0037]
  In step 30, the hydraulic pump 80 is stopped, and then control proceeds to step 40, where the hydraulic switching valve 70 is turned on.ProgressAngular position (switching position shown in FIG.Place)Cut intoReplacedIt is. As a result, the working chamber 34b side of the piston working chamber 34 is connected to the port 50, the oil passages 54, 61, 62, 76, and the port.78ThroughMadeIt is connected to the hydraulic pump 80 that has stopped moving.
[0038]
  Control then proceeds to step 50 where the engine fuel is shut off. As a result, the engine slows down and stops, but the progress is monitored in the next step 60. Immediately after the fuel shutoff, the engine continues to rotate due to inertia, so the answer to step 60 is no, during which control returns to step 10 and circulates through steps 20-60.The
[0039]
  Before longThe engine stops and the answer to step 60 turns to yes.The
[0040]
  Next, the control proceeds to step 80, and reverse rotation driving of the crankshaft is performed by operating one or both of the motor generators mg1 and mg2 (motor reverse rotation ON). By the reverse rotation driving of the crankshaft, as described above, the housing including the gear 14, the annular member 22, and the end plate 24 rotates in the reverse rotation direction with respect to the rotor 30 connected to the intake valve camshaft 18 and having a large rotational resistance. The rotor blade portion 32 is displaced in the advance direction relative to the housing while discharging the working oil in the working chamber portion 34a from the port 48 toward the oil reservoir.At this time, the working chamber portion 34b is connected to the hydraulic pump 80 which has stopped operating via the port 50 and the oil passages 54, 62 and 76, and the working chamber portion 34b is expanded while the working chamber portion 34b is evacuated. As a result, drag is generated, but the negative pressure due to the vacuum is at most 1 atm.The reverse rotation angle of the crankshaft by such an electric motor is monitored in step 90 to determine whether or not the crankshaft rotation angle Ac (negative value) is smaller than a predetermined threshold value -Aco (larger in absolute value). Is done. The absolute value of the threshold value Aco is from the angular position shown in FIG. 4 to the angular position shown in FIG. 5 with respect to the housing in which the rotor blade portion 32 is composed of the gear 14, the annular member 22, and the end plate 24. The angle is somewhat smaller than the crankshaft rotation angle corresponding to the relative rotation. Initially, the answer is no, and the control returns to step 10 and circulates while re-reading the data. However, as the reverse rotation proceeds, the answer changes from no to yes. Accordingly, the control proceeds to step 100, and the reverse rotation driving of the electric motor is stopped. Thus, the hydraulic oil in the working chamber portion 34a is completely eliminated, and the relative position of the rotor 30 with respect to the housing composed of the gear 14, the annular member 22 and the end plate 24 is slightly displaced in the advance direction with respect to the housing. As a result, the tip 42 of the lock pin 40 can be aligned with the recessed hole 44.
[0041]
In this way, the lock pin 40 is slightly in front of the alignment position with respect to the recess hole 44, and the state in which both the working chamber portions 34 a and 34 b on both sides of the rotor blade portion 32 are exhausted in the piston working chamber 34 is as follows. This is a state before engine start that can quickly respond to both warm-up start of the engine that does not increase the intake compression ratio and cold start of the engine that increases the intake compression ratio.
[0042]
After the reverse rotation driving of the electric motor is completed in Step 100, the control proceeds to Step 110, and the control for the next engine start (control according to FIG. 8 described later) is turned on (standby state or set state), and this control is ended.
[0043]
FIG. 7 is a flowchart showing another embodiment of the control method of the starting characteristic changing means of the vehicle internal combustion engine according to the present invention in which a part of the control flow shown in FIG. 6 is changed. In the flowchart of FIG. 7, the steps corresponding to the steps in FIG. 6 are indicated by the same step numbers as in FIG. 6, and operate in the same manner as in FIG.
[0044]
In this embodiment, after the rotation of the engine is stopped in step 60, the crankshaft c is driven in the forward rotation direction by one or both of the motor generators mg1, mg2 in step 61 (motor forward rotation). on). In the embodiment shown in FIG. 6, the operation oil in the working chamber portion 34b is relied on the inertia rotation of the crankshaft, but more reliably by driving the crankshaft by an electric motor. It is. After starting forward rotation of the electric motor in step 61, the count number n is incremented by 1 from each state reset to 0 in step 62, and then in step 63, the count number n is increased to each time. Based on this, it is determined whether or not the crank angle Ac (n) at the current flowchart tour has increased with respect to the crank angle Ac (n-1) at the previous flowchart tour. If the answer is yes, it indicates that the rotor blade 32 is not yet in contact with the partition wall 26 of the housing in the retarded direction, and there is room for further discharge of hydraulic oil from the working chamber 34b. On the other hand, a negative answer indicates that the rotor is fully reversed with respect to the housing in the retarding direction. Therefore, the control continues to drive the motor in the reverse direction while the answer to step 63 is yes. If the answer is no, the control proceeds to step 64 to stop the forward drive of the motor. Thus, the working oil in the working chamber portion 34b is completely discharged toward the oil reservoir. Thereafter, the control for discharging the hydraulic oil in the working chamber portion 34a is the same as in FIG.
[0045]
FIG. 8 is a flowchart showing a mode of engine start control when the engine is stopped and the engine that has been subjected to engine stop control as shown in FIG. 6 or 7 is restarted. This engine start control indicates how convenient the restart of the engine is performed if the engine stop control according to the present invention as illustrated in FIG. 6 or FIG. 7 is performed. The control shows the effect of the engine stop control according to the present invention, and is not a part of the configuration of the present invention.
[0046]
When the illustrated engine start control is started, necessary data is read in step 210, and the control proceeds to step 220, where it is determined whether or not a condition for starting the engine is satisfied based on the read data. Is done. As long as the answer is no, the control returns to step 210 to prepare for the establishment of the engine start condition while rereading the data.
[0047]
If the answer to step 210 is yes, the control proceeds to step 230 where it is determined whether or not the engine temperature Te is equal to or higher than a predetermined threshold value Teo. This threshold temperature Teo is in an engine warm-up state in which the engine can be easily started without performing control for increasing the intake air compression ratio if the engine temperature Te is higher than that, and if the engine temperature Te is lower than that, It is the engine temperature that forms the boundary where it is desired to perform control to increase the intake compression ratio prior to cranking.
[0048]
If the answer to step 230 is yes, the control proceeds to step 240 where the electric motor is operated in the forward rotation direction and the engine is cranked as it is. When the engine is warmed up, the hydraulic oil in the intake valve opening / closing timing control device 10 is warm and low in viscosity, and the hydraulic chamber is in a state in which the hydraulic oil is excluded, so cranking starts by the electric motor, If the housing including the gear 14, the annular member 22, and the end plate 24 is driven in the forward rotation direction, the housing is initially advanced even if the intake valve opening / closing timing control device is advanced to a position slightly before the most advanced angle position. Immediately precedes the rotor 30 integrated with the cam shaft 18 whose movement is suppressed by the intake cam, the intake valve opening / closing timing control device is quickly displaced to the most retarded position, and the engine has a compression ratio. Cranked smoothly and quietly in the lowered state. Then, in order to measure the cranking time in step 250, the count value C of a counter provided in a part of the computer constituting the vehicle operation control device 98 starts from a state where it is reset to 0 and goes through the flowchart. Incremented by 1 for each control round. Control then proceeds to step 260, where it is determined whether or not the engine speed Ne has reached a predetermined threshold value Neo indicating the normal start of the engine. Initially, the answer is no, but if the engine starts normally, the answer becomes yes, so the control proceeds to step 270 and the forward rotation of the motor is stopped. Thereafter, in step 280, the engine stop control as shown in FIG. 6 or 7 may be turned on in preparation for the next engine stop.
[0049]
However, even if the engine is cranked, the engine may not start normally even if a predetermined cranking time has passed for some reason. Such a condition is that the control proceeds to NO from step 260 after a predetermined cranking time, which is detected by the answer being YES in step 290. Therefore, when such a situation occurs, control proceeds to step 300, the cranking operation of the motor is stopped and stopped, control proceeds to step 310, and an appropriate notification is given to the driver that the engine has not been started normally. The display should be turned on.
[0050]
On the other hand, if the answer to step 230 is no, the control proceeds to 320, and the crankshaft is reversely driven by the reverse rotation operation of the motor in the manner described above in order to increase the intake compression ratio prior to cranking. The rotor 30 of the valve opening / closing timing control device is displaced relative to the housing made up of the gear 14, the annular member 22, and the end plate 24 in the advance direction. However, in this case, the rotor blade 32 has already been displaced to a position immediately before the most advanced angle position as shown in FIG. 5 by the previous engine stop control. The angle at which the valve opening / closing timing control device is driven in reverse until the tip of the lock pin 40 is aligned with the recess 44 and falls into it is very small. Whether or not such small-angle reverse rotation driving has been achieved can be determined by detecting whether or not the crank angle Ac has been reverse-rotated to the corresponding negative small angle −ΔAco in step 330. Thus, the crankshaft is reversely driven by the electric motor for a very short time until the answer to step 330 changes from no to yes, and the intake valve opening / closing timing control device is locked at the most advanced angle position. To perform cranking with a higher intake compression ratio.
[0051]
While the invention has been described in detail with reference to several embodiments, it will be apparent to those skilled in the art that various modifications can be made to these embodiments within the scope of the invention.
[Brief description of the drawings]
FIG. 1 is a diagram showing a procedure for variably controlling an opening / closing phase of an intake valve together with an opening / closing phase of an exhaust valve in order to variably control an intake compression ratio.
FIG. 2 is a graph illustrating a course in which the in-cylinder pressure rises due to cranking according to the angle after the bottom dead center of the intake valve closing phase.
FIG. 3 is an explanatory view showing the basic configuration of an example of an intake valve opening / closing timing control device in an exploded view as applied to a hybrid vehicle.
4 is a view taken along the line AA of FIG. 3 showing the intake valve opening / closing timing control device of FIG. 3 in a state in which the intake valve closing phase is most retarded.
5 is a view taken along the line AA of FIG. 3 showing the intake valve opening / closing timing control device of FIG. 3 in a state in which the intake valve closing phase is at the most advanced angle.
FIG. 6 is a flowchart showing one embodiment of the control of the start characteristic changing means of the vehicle internal combustion engine according to the present invention.
7 is a flowchart showing another embodiment in which a part of the flowchart shown in FIG. 6 is changed.
FIG. 8 is a flowchart of an example of engine start control showing that the restart of the engine is speeded up by the control of the start characteristic changing means of the vehicle internal combustion engine according to the present invention.
[Explanation of symbols]
e ... Internal combustion engine
c ... Crankshaft
mg1, mg2 ... Motor generator
p ... Torque distributor
w ... wheel
s ... Axle
d ... Differential gear
t ... Transmission
i ... Inverter
b ... Power storage device
10. Intake valve opening / closing timing control device
12 ... Endless belt
14 ... Gear
16 ... Intake valve operation cam
18 ... Intake valve camshaft
20 ... Bolt
22 ... Spline-shaped annular member
24 ... annular end plate
26 ... Radial partition
28 ... Bolt
30 ... Rotor
32 ... feathers
34 ... Piston working chamber
36 ... Cylinder hole with steps
38 ... Large diameter head
40 ... Lock pin
42 ... Small diameter part of lock pin
44 ... hollow
46 ... Compression coil spring
48 ... Port
50 ... Port
52 ... Annular oil passage
54 ... Annular oil passage
56 ... Oilway
58 ... Bearing part
60 ... Annular oil passage
61, 62 ... Oil passage
64 ... annular oil passage
66 ... Port
68 ... Oilway
70 ... Hydraulic switching valve
72 ... Port
74 ... Port
76 ... Oilway
78 ... 78
80 ... Hydraulic pump
82 ... Hydraulic port
84 ... Oil sump
86, 88 ... Drain port
90 ... Valve housing
92 ... Solenoid
94. Compression coil spring
96 ... Valve spool
98 ... Vehicle operation control device

Claims (8)

There is a first piston working chamber that operates the piston so that the intake compression ratio decreases when the working liquid is introduced, and a second piston working chamber that acts on the piston facing the first piston working chamber. Then, when the intake compression ratio is increased, the internal combustion engine is stopped using the control method of the starting characteristic changing means of the internal combustion engine for a vehicle which requires that the working liquid be discharged from the first piston working chamber. When the operation is stopped, the working fluid supply source pump is stopped immediately before the stop, the second piston working chamber is connected to the pump , and the first piston working chamber is drained when the internal combustion engine is stopped. An internal combustion engine start characteristic changing means control method.   2. The internal combustion engine start characteristic according to claim 1, wherein the first piston working chamber is drained within a period from immediately before the internal combustion engine is stopped until a predetermined time elapses after the stop. Change means control method.   The starting characteristic changing means is subjected to an action of enlarging the first piston working chamber by the rotation of the crankshaft of the internal combustion engine in the forward rotation direction, and the first piston by the rotation of the crankshaft in the reverse rotation direction. 3. The internal combustion engine start characteristic changing means control method according to claim 1, wherein the operation chamber is subjected to an action of reducing the operating chamber. There is a first piston working chamber that operates the piston so that the intake compression ratio decreases when the working liquid is introduced, and a second piston working chamber that acts on the piston facing the first piston working chamber. Then, when the intake compression ratio is increased, the internal combustion engine is stopped using the control method of the starting characteristic changing means of the internal combustion engine for a vehicle which requires that the working liquid be discharged from the first piston working chamber. When the engine is stopped, the working fluid supply source pump is stopped immediately before the second piston working chamber is connected to the pump . After the internal combustion engine stops rotating, the first piston working chamber is discharged. 5. The internal combustion engine start characteristic changing means control method according to claim 4, wherein the crankshaft is opened to a liquid passage and reversely driven by an electric motor. After connecting the second piston working chamber to the pump, internal combustion engine starting characteristic changing means control method according to either of claims 1 to 3, characterized in that for driving the crank shaft by an electric motor in the forward direction .   6. The first piston working chamber is opened to a drainage passage after the crankshaft is driven in the forward direction by the electric motor, and the crankshaft is reversely driven by the electric motor. The internal combustion engine start characteristic changing means control method according to claim 1.   The starting characteristic changing means has locking means for locking the piston at the displacement position when the piston is displaced to a position where the first piston working chamber is reduced to a predetermined degree of reduction. The internal combustion engine start characteristic changing means according to any one of claims 1 to 6, wherein the rotation of the crankshaft that drains the piston working chamber in the reverse direction is to a position immediately before the lock means is locked. Control method.   The displacement of the piston that expands the first piston working chamber delays the closing phase of the intake valve by the start characteristic changing means, and the displacement of the piston that reduces the first piston working chamber is the intake valve by the start characteristic changing means. 8. The internal combustion engine start characteristic changing means control method according to claim 1, wherein the closing phase of the internal combustion engine is advanced.

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