JPH0342340A - Controller for power unit - Google Patents

Abstract

PURPOSE:To decrease an engine loss by setting the control hydraulic pressure of a transmission correspondingly to the supercharging pressure of a supercharger and correcting the control hydraulic pressure correspondingly to the change over of a valve operating characteristic in a power unit including an engine in which the valve operating characteristic can be freely selected. CONSTITUTION:In a power unit in which an automatic transmission AT is connected to the output shaft of an engine E provided with a turbo unit TU comprising an operating characteristic change over mechanism VT for changing over the opening and closing timing, the opening period and the amount of lift of an air intake valve in accordance with a low rotating area and a high rotating area, a turbine 102 and a compressor 104, the mechanism VT is changed over by a hydraulic coupling change over means (not shown). The automatic transmission AT has each speed change element controlled by control hydraulic pressure set by a regulator valve RV. In this case, the regulator valve RV is constructed so as to control the control hydraulic pressure according to the supercharging pressure of the turbo unit TU and the operating hydraulic pressure of the operating characteristic change over mechanism VT.

Description

Detailed Description of the Invention A.8 Objective of the Invention (Field of Industrial Application) The present invention relates to a power unit consisting of an engine with variable valve operating characteristics and a transmission that transmits the output of this engine. .

Note that switching the valve operating characteristics refers to switching at least one of the opening/closing timing, opening period, and valve lift amount of an intake valve or exhaust valve, and refers to switching at least one of the opening/closing timing, opening period, and valve lift amount of the intake valve or exhaust valve. It also includes reducing the open period of the valve to substantially zero and switching it to a closed state.

(Prior art) An engine in which the valve operating characteristics of both or one of the intake valve and exhaust valve can be freely switched between a low-speed valve operating characteristic suitable for a low-speed range and a high-speed valve operating characteristic suitable for a high-speed range. is disclosed in Japanese Patent Publication No. 49-33289, but in this one, the low-speed valve operation characteristic is changed in the region where the engine speed is below a predetermined value and the intake negative pressure is below a predetermined value (vacuum side). In other areas, it switches to high-speed valve operation characteristics.

Further, there is a transmission controlled by hydraulic pressure, for example, as disclosed in Japanese Patent Publication No. 60-49786, in which a plurality of power transmission elements are arranged between an input shaft and an output shaft. It is set up.

Each power transmission element mainly consists of a drive gear disposed on the input shaft, a driven gear disposed on the output shaft or countershaft, and a friction element such as a hydraulic clutch for selectively operating these gear trains. Their combination constitutes one gear stage. The input shaft of the transmission connected to the output shaft of the engine rotates, and for example, in a gear position where the input shaft and the drive gear are rotatably attached, a hydraulic clutch provided between them is actuated and engaged. This rotates the driven gear that engages with the driving gear. At this time, if the driven gear is attached integrally with the output shaft, the output shaft will continue to rotate, and if the driven gear is rotatable relative to the output shaft, the hydraulic clutch provided between them will be engaged. Rotate the output shaft. In this way, the engine output is shifted and transmitted.

In addition, when the engine has a supercharger, the engagement force of the friction element of the transmission is made sufficiently large for the engine output torque increased by supercharging, and the friction element is prevented from slipping. , the control oil pressure of the transmission may be set in accordance with the boost pressure.

(Problems to be Solved and Attempted by the Invention) As described above, the engine with variable valve operating characteristics has a supercharger, and the control hydraulic pressure of the transmission is set in accordance with the supercharging pressure. The unit has the following problems.

Generally, in small vehicles such as passenger cars, superchargers are often matched to generate relatively high torque in a low engine speed range. For this reason, the maximum value of the supercharging pressure occurs in a low rotation range, and the supercharging pressure is maintained at its maximum value in a rotation range higher than the rotation speed at which the maximum supercharging pressure is reached. Therefore, in that rotation range, the transmission control oil pressure also remains almost unchanged, with the oil pressure corresponding to the maximum boost pressure. However, as mentioned above, in an engine where the engine output torque with high-speed valve operating characteristics in the high-speed region is higher than the engine output torque with low-speed valve operating characteristics in the low-speed region, the engine output torque with high-speed valve operating characteristics If the transmission control oil pressure is not set in accordance with the torque, there is a risk that the friction elements of the transmission will slip.

However, in consideration of the above problems, if the transmission control hydraulic pressure is set to a value corresponding to the maximum output torque with high-speed valve operating characteristics in the entire rotation range, the oil pressure will be higher than necessary when operating with low-speed valve operating characteristics. Since the hydraulic pressure is supplied, there is a problem of oil pump drive loss, that is, engine loss.

In view of the above problems, the present invention includes a supercharger,
It is an object of the present invention to provide a control device for a power unit in which the control hydraulic pressure of a transmission connected to an engine can be freely changed over valve operating characteristics so that the control hydraulic pressure is always an appropriate hydraulic pressure.

Configuration of the Invention (Means for Solving the Problems) In order to solve the above problems, in the present invention, the hydraulic pressure control means of the transmission controls the control hydraulic pressure in response to the supercharging pressure of the supercharger. A control device is used in which the control hydraulic pressure is corrected in response to switching of valve operating characteristics by a valve operating characteristic switching mechanism.

(Function) When the above control device is used, for example, in a low rotation range using low-speed valve operating characteristics, the transmission control oil pressure is set corresponding to the boost pressure, and in a high-speed range using high-speed valve operating characteristics. In the rotation range, the control oil pressure is set according to the sum of the boost pressure and the working oil pressure of the valve operating characteristic switching mechanism, and these control oil pressures are set according to the engine output torque for each valve operating characteristic. Since the oil pressure is the minimum required for control, it is possible to prevent the friction elements from slipping, and it also helps to keep engine loss low.

(Example) Preferred examples of the present invention will be described below with reference to the drawings.

FIG. 1 shows the configuration of a power unit having a control device according to the present invention.

Engine E has variable valve timing/lift mechanism VT
and turbo unit) TU. The variable valve timing/lift mechanism VT switches the opening/closing timing, opening period, and lift amount of the intake valve of the engine E between a low-speed valve operating characteristic suitable for a low-speed range and a high-speed valve operating characteristic suitable for a high-speed range. mechanism, and this switching is
As will be described later, this is performed by supplying and discharging a predetermined hydraulic pressure within the rocker shaft 6 by turning on and off the switching valve 91.

The exhaust gas flow leaving the combustion chamber 101 rotates the turbine 102 of the turbo unit TU and is discharged to the outside through the exhaust pipe 103. On the other hand, the compressor 104, which rotates together with the turbine 102, compresses the intake air that has been sucked in from the air cleaner AC and entered the intake pipe 1O5, and sends it into the combustion chamber 101. Furthermore, a control valve CV for controlling the operation of each friction element is attached to the lower part of the automatic transmission AT connected to the rear end of the engine E. This control valve CV includes a regulator valve 70 that sets the control oil pressure, and the above-mentioned working oil pressure in the rocker shaft 6 and supercharging pressure are communicated through a communication oil passage 106 and a communication pipe 107, respectively. It acts on this regulator valve 70.

Next, the variable valve timing/lift mechanism VT will be explained with reference to FIGS. 2 and 3. A pair of intake valves 1a, 1b are arranged for each mechanism of the engine E, and these pair of intake valves 1a, lb are connected to a camshaft 2 that is driven at a rotation ratio of 1/2 in synchronization with the rotation of the engine. First low speed cam provided integrally3. The first cam 3' is pivotally supported by a second low-speed cam 3', a high-speed cam 5, and a rocker shaft 6 parallel to the camshaft 2. It is opened and closed by the action of the 2nd t-5 and 30th lever arms 7.8.9.

The camshaft 2 is rotatably disposed above the engine body, and the first low-speed cam 3 is connected to one intake valve 1a.
is provided integrally with the camshaft 2 at a position corresponding to
The second low-speed cam 3' is integrally provided on the camshaft 2 at a position corresponding to the other intake valve 1b. Further, the high-speed cam 5 is integrally provided on the camshaft 2 at a position corresponding to between both intake valves 1a and ib. Moreover, the first
The second low speed cams 3, 3' have high portions 3ae3a' corresponding to low speed operation of the engine.

The high-speed cam 5 has a high portion 5a suitable for high-speed operation of the engine.

First to thirtieth lever arms 7 to 9 are respectively pivotally supported on the rocker shaft 6, and the first to thirtieth lever arms 7.8
is extended to a position above each intake valve la, 1b.

Further, a cam slipper 10 that slides on the low-speed cam 3 is provided on the upper part of the 10th claw arm 7, and a cam slipper 1 that can come into contact with the second low-speed cam 4 is provided on the upper part of the 20th claw arm 8. Note that each intake valve 1a, lb is biased toward the valve closing direction, that is, upward, by valve springs 1B, 17.

The 30th claw arm 9 is connected to the first and 20th claw arms 7.
．． It is pivotally supported on the rocker shaft 6 between 8 and 8. This 30th lever arm 9 connects both intake valves la from the rocker shaft 6.
, slightly extending toward the lb side, and a cam slipper that slides into contact with the high-speed cam 5 is provided at the upper part of the cam slipper.

As shown in FIG. 3, the first to 30th claw arms 7.8.
9 are in sliding contact with each other, and a connecting means 21 that can switch between a state that allows relative angular displacement thereof and a state that integrally connects each rocker arm 7 to 9 is connected to the first to 20th rocker arms 7 to 9.
It is installed at the claw arm 7.8°9.

The connecting means 21 has a first piston 22 which is movable between a position where the first and 30th lever arms 7.9 are connected and a position where the connection is released, and a position where the third and 20th lever arms 9.8 are connected. A second piston 23 that is movable between positions where the connection is released, a stopper 24 that restricts movement of the first and second pistons 22 and 23, and a first
and a spring 25 that biases the stopper 24 to move the second piston 22, 23 to the disconnection position.

The movement of these first and second pistons 22.23 is performed by hydraulic pressure supplied into the hydraulic chamber 29 through the oil passages 31.degree. 32.30 in response to the operation of the switching valve 91.

Incidentally, such a variable valve timing/lift mechanism is disclosed in detail in, for example, Japanese Patent Laid-Open No. 121811/1983.

Next, the variable valve timing
The operation of the lift mechanism VT will be explained.

When engine E is operating at low speed, the switching valve 91 is turned OFF.
As shown in FIG. 3, the communication between the oil passage 31 and the oil pressure source (not shown) is cut off, and oil pressure is not supplied to the oil pressure chamber 29 of the connection switching means 21, and the stopper 24 is closed to the spring 25. is pressed toward the 30th lug arm 9 side. Each rocker arm 7.8.9 is therefore independently displaceable.

When the connection switching means 21 is in the disconnected state,
Due to the rotational movement of the camshaft 2, the tenth lever arm 7
swings in response to sliding contact with the first low-speed cam 3, and the 20th claw arm 8 swings in response to sliding contact with the second low-speed cam 3'. Therefore, both intake valves la and lb are opened and closed by the first and second low-speed cams 3.3'. At this time, the 30th lever arm 9 swings due to sliding contact with the high-speed cam 5, but the swinging movement is caused by both the intake valves 1a and 1.
It has no effect on the operation of b.

In this way, when the engine E is operating at low speed, the 5th A
As shown by a broken line 3 and a dashed-dotted line 3' in the figure, one intake valve 1a opens and closes at a timing and lift amount according to the shape of the first low-speed cam 3, and the other intake valve 1b operates as a second low-speed cam 3. It opens and closes with timing and lift amount depending on the shape of the cam 3'. Therefore, a mixture flow rate suitable for low-speed operation can be obtained, reducing fuel consumption and preventing sparkling, and allows optimum low-speed operation to be performed.

In addition, in order to obtain a mixture flow speed suitable for low-speed operation,
For example, as shown in FIG. 5B, the high part 3a' of the second low-speed cam 3' is lowered to lower the intake valve 1b during low-speed operation.
Alternatively, the opening time and amount of the intake valve 1b may be made very small, and furthermore, the above-mentioned high portion 3a' may be set to zero so that the intake valve 1b is not opened at all during low-speed operation to create a valve rest state. It's okay.

When the engine E is operated at high speed, the switching valve 91 is
As shown in FIG. 4, a hydraulic pressure source (not shown) and the oil passage 31 are communicated with each other by a switching valve 91, and the hydraulic pressure is supplied to the hydraulic chamber 29 of the connection switching means 21. As a result, as shown in FIG. 4, the first and second pistons 22 .
23 moves, and the first piston 22 causes the first and third pistons to move.
The 0th lever arm 7.9 is connected, and the 3rd and 20th lever arms 9.8 are connected by the second piston 23.

In this manner, when the first to thirtieth hook arms 7I8.9 are connected to each other by the connection switching means 21,
Since the amount of swing of the 30th claw arm 9 in sliding contact with the high speed cam 5 is the largest, the first and 20th claw arms 7.8 swing together with the 30th claw arm 9. Therefore, during high-speed operation of the engine E, both intake pulps la and lb are moved to the high-speed cam 5, as shown by the solid line 5 in FIG. 5A.
It opens and closes with timing and lift amount depending on the shape of the door. The timing and lift amount in this case are larger than those during low-speed operation, so that intake air suitable for high-speed operation can be obtained, and the engine output can be improved.

In the above-described operation, the opening/closing timing and lift amount of the intake valves la, lb based on the first and second low-speed cams 3, 3' are referred to as low-speed valve operating characteristics, and the intake valves la, lb based on the high-speed cams 5 are referred to as low-speed valve operating characteristics. The opening/closing timing and lift amount of lb are referred to as high-speed valve operation characteristics. Both valve operating characteristics are used separately for a low-speed operation region and a high-speed operation region, and the relationship between the engine output torque and the engine rotational speed at this time is as shown in FIG. In this figure, the characteristics in low-speed valve operation characteristic operation are shown by lines, and the characteristics in high-speed valve operation characteristic operation are shown by line H. Switching of valve operation characteristics is done at the intersection of these lines and H. This is done in C.

Next, the automatic transmission AT will be explained using FIG. 7.

This automatic transmission AT is composed of a torque converter 40 and a transmission mechanism 50, and the torque converter 40 is connected to an engine output shaft E. It consists of a pump 46a connected to P, a turbine 48b connected to an output shaft (transmission mechanism input shaft) 61, and a fixedly held stator 46c.
It has a lock-up clutch 47 that can freely engage and disengage the turbine 48b and the turbine 48b.

The transmission mechanism 50 includes an input shaft 61 integrated with the torque converter output shaft, a counter shaft 62 parallel to this, and an output shaft 63.
has. Between the input shaft 61 and the counter shaft 62, there are five sets of gear trains meshing with each other, namely, 1st speed gear trains 51a, 51b, 2nd speed gear trains 52a, 52b, 3rd speed gear trains 53a, 53b, 14th speed gear train 54a. , 54b and reverse gear trains 55a, 55b, 55c
is installed. Hydraulically operated clutch 64 for selecting each gear train as the driving gear or driven gear of each gear train
68 are arranged, and these hydraulically operated clutches 64 to
By selectively operating 68, the power transmission path by one of the gear trains is selectively switched, and the speed is changed.

Output gear trains 59a and 59b are disposed between the counter shaft 62 and the output shaft 63, and the power shifted as described above is transmitted to the output shaft via the output gear trains 59a and 59b. .

Note that power transmission from the engine in the driving direction is permitted to the first speed driven gear 51b and the second speed driven gear 52b.
One-way clutches 56 and 57 are installed to prevent power transmission in the opposite direction (engine braking direction) by idling. The input side of the 1st speed one-way clutch 56 attached to the 1st speed driven gear 51b is connected to the 1st speed driven gear 51b, and the output side is connected to the input side of the 2nd speed one-way clutch 57 attached to the 2nd speed driven gear 52b. ing. The input side of the second speed one-way clutch 57 is further connected to the second speed driven gear 52b, and the output side is connected to the counter shaft 62.

Furthermore, an engine clutch 69 is provided to lock and hold these one-way clutches 5 (3, 57). It is a clutch that engages and disengages, and when it is ON (engaged), the 1st gear train and 2nd gear train constitute a power transmission path where engine braking is effective, and when it is OFF (disengaged), , constitutes a power transmission path in which engine braking is not effective.

Operation control of the lock-up clutch 47 in the automatic transmission AT configured as described above and each clutch 64 of the transmission mechanism 50
The operation control of ~θ9 is performed by a control valve CV shown in FIG. A regulator valve RV shown in FIG. 9 is used.

This regulator valve RV has a first valve body 70
a and a second valve body 70b, which are fixed together with a diaphragm 71 in between. The first valve body 70a is provided with an inflow port 72 through which oil discharged from an oil pump (not shown) flows in, an outflow port 73 through which pressure-regulated oil flows out, and a drain port 74. Each port is opened and closed. A hydraulic chamber 75b is configured by the right end of the spool 75 and a part of the inner wall of the first valve body 70a, and the inflow port 72 and the oil chamber 75b communicate with each other via a communication hole 75a bored inside the spool 75. ing.

Further, the left end portion of the spool 75 is in contact with the diaphragm 71. On the other hand, the second valve body 70b is connected to the communication oil passage 108 shown in FIG. 1 for variable valve timing ◆A working pressure boat 78 on which the working oil pressure of the lift mechanism VT acts, and a communicating pipe 107 are connected to the turbo unit TU. A supercharging pressure boat 80 on which supercharging pressure acts, and this supercharging pressure boat 8
A supercharging pressure chamber 80a that is connected from 0 and has the diaphragm 71 as one side is provided. A piston 79 is inserted into the operating pressure boat 78 with a portion thereof protruding into the supercharging pressure chamber 80a, and the right end of the piston 79 is in contact with the center portion of the diaphragm 71. Working pressure boat 78 and supercharging pressure chamber 80
a is blocked by this piston 79, and the second valve body 70b is in contact with the side surface of the piston 79 to prevent oil in the operating pressure boat 78 from leaking into the boost pressure chamber 80a. A drain port 81 is provided.

Next, the operation of this regulator valve RV will be explained.

When the low-speed valve operation characteristic is used in the low rotation range, the aforementioned connection switching means is in the disconnected state as shown in FIG. The force pushing 75 to the right is only the force due to the supercharging pressure supplied into the supercharging pressure chamber 74 (hereinafter referred to as supercharging pressure chamber force F7). As the engine speed increases, the discharge pressure of the oil pump of the transmission also increases, so the oil pressure in the hydraulic chamber 75b communicating with the inflow boat 72 via the communication passage 75a increases, causing the spool 75 to move to the left. (hereinafter referred to as hydraulic chamber force F)
It is called L. ) works. The spool 75 has Ft>Ft
When , it moves to the right to close the drain port 74, and when FT≦FL, it moves to the left to open the drain port 74. When the drain port 74 opens, the oil pump discharge pressure, that is, the transmission control oil pressure, does not increase any further.

On the other hand, since the boost pressure also increases as the engine speed increases, the boost pressure chamber force Ft also increases. Then, spool 7
5 moves to the left to close the drain port 74, and the oil pump discharge pressure increases until the hydraulic chamber force FL becomes equal to this increased supercharging pressure chamber force Ft. In this way, the transmission control oil pressure corresponding to the boost pressure is set.

The graph in FIG. 8 shows the relationship between the control oil pressure set in this way and the engine rotational speed. In the low rotation range, the transmission control oil pressure increases in response to boost pressure,
At the rotational speed Nep at which the boost pressure reaches its maximum value, the first shelf pressure PLL corresponds to the engine output torque with the low-speed valve operating characteristics. In a rotation range higher than the rotation speed Nep, the supercharging pressure is maintained at a constant value by the action of a wastegate valve (not shown), and the control oil pressure is maintained at the first shelf pressure PLL. Next, at the rotational speed Ne, when the operation is switched to the high-speed valve operation characteristic in the high rotation region, the connection switching means 21 becomes connected as shown in FIG. acts. The force due to this working hydraulic pressure (hereinafter referred to as working pressure boat force F) pushes the piston 79 to the right and moves the diaphragm 71 and spool 75 to the right, so the drain port 74 closes. In this way, the control oil pressure increases until FT+FI=FL, and the second shelf pressure P'Ln corresponds to the engine output torque with high-speed valve operation characteristics.

In this way, when this control device is used, the transmission control oil pressure is set to Ptt corresponding to the boost pressure in the low rotation range where the low speed valve operating characteristic is used, and the transmission control oil pressure is set to Ptt corresponding to the boost pressure. In the rotation range, the control oil pressure is set to PLL, which corresponds to the sum of the boost pressure and the working oil pressure of the variable valve timing/lift mechanism, and these control oil pressures are set according to the engine output torque for each valve operating characteristic. Since the hydraulic pressure is the minimum required for transmission control, it is possible to prevent lock-up clutches and hydraulically operated clutches from slipping, and it is also possible to keep engine loss low.

C1 Effects of the invention As described above, when the control device of the invention is used, for example,
In the low-speed range where low-speed valve operating characteristics are used, the transmission control oil pressure is set in accordance with boost pressure, and in the high-speed range where high-speed valve actuation characteristics are used, the control oil pressure is set depending on the boost pressure and valve pressure. These control oil pressures are the minimum oil pressure required to control the transmission according to the engine output torque for each valve operation characteristic, so the friction element In addition to reliably preventing slippage, engine loss can be kept as low as possible.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing the configuration of an engine and transmission for using the control method according to the present invention, and FIGS. 2, 3, and 4 show the variable valve timing/lift mechanism of the engine. 5A and 5B are graphs showing the relationship between the valve timing and lift amount of the variable valve timing/lift mechanism, and FIG. 6 is a graph showing the relationship between the engine output torque and the engine lift amount due to the variable valve timing/lift mechanism. FIG. 7 is a schematic diagram showing the configuration of the automatic transmission, FIG. 8 is a sectional view of the regulator valve, and FIG. 9 is a graph showing the relationship between the rotation speeds. It is a graph showing the control oil pressure of the transmission. 1a, 1b...Intake valve 3.3'...Low speed valve 5...High speed valve 2
1...Connection switching means 91...Switching valve 10
2...Turbine 104...Compressor

Claims (1)

[Scope of Claims] 1) The engine is comprised of an engine in which the valve operating characteristics of at least one of an intake valve and an exhaust valve can be freely changed, and a transmission connected to the output shaft of this engine, and the engine is equipped with a supercharger. A power unit having a valve operating characteristic switching mechanism that switches the valve operating characteristics, and a hydraulic control means that sets a control hydraulic pressure of the transmission, and the hydraulic control means that controls the control hydraulic pressure of the supercharger. A control device for a power unit, characterized in that the control oil pressure is set in accordance with boost pressure, and the control oil pressure is corrected in response to switching of the valve operation characteristic by the valve operation characteristic switching mechanism.