JPH03367A - How to control the power unit - Google Patents

Abstract

PURPOSE:To suppress the generation of shift shock by temporarily switching to low torque valve operating characteristic to start shifting when power-on and shift-up are conducted during operation with high torque valve operating characteristic. CONSTITUTION:When power-on and shift-up of an automatic transmission AT is conducted during operation of an engine E by using high torque valve characteristic by a variable timing lift mechanism, a control unit CU first switches the valve operating characteristic of intake and exhaust valves to low torque valve operating characteristic and, after delay of a determined time, operates the shift solenoids 251-253 of a hydraulic control valve CV to start the power-on and shift-up speed change. When the shift is completed, the valve operating characteristic is returned to high torque valve operating characteristic. Hence, the change quantity of the transmission output is reduced even if the changing rate at the time of shifting is unchanged, and the generation of shift shock can be suppressed by this extent.

Description

DETAILED DESCRIPTION OF THE INVENTION A.Objective of the invention (industrial application field) The present invention comprises an engine whose valve operating characteristics can be freely changed, and a transmission connected to the output shaft of the engine. Regarding the power unit.

Note that switching the valve operating characteristics refers to switching the opening/closing timing and opening period of the intake valve or exhaust valve, and/or the valve lift amount, and it means switching the opening/closing timing and opening period of the intake valve or exhaust valve, and/or the valve lift amount. 1
It also includes switching the open period of two valves to substantially zero and switching them to a closed state.

(Prior Art) Conventionally, according to Japanese Patent Publication No. 49-33289, the valve operating characteristics of at least one of the intake valve and the exhaust valve are set to have a low-speed valve operating characteristic suitable for a low-speed region and a high-speed valve operating characteristic suitable for a high-speed region. Engines that can freely switch valve operating characteristics are known. In this engine, the engine speed is below a predetermined value and the intake negative pressure is below a predetermined pressure (
The valve operating characteristics are switched to low-speed valve operating characteristics in the area (vacuum side), and switched to high-speed valve operating characteristics in other areas.

FIG. 6 shows an example of the output characteristics of such an engine. When the low-speed valve operation characteristic is used, the characteristic is shown as a line, and when the high-speed valve operation characteristic is used, the characteristic is shown as a line H. Both characteristics intersect at the point of engine rotation speed N, and in the region of engine rotation speed Ne<N1, the torque of the low-speed valve operation characteristic (line At) is higher than the torque of the high-speed valve operation characteristic (line Bt). In the region where N e >Nl, the torque of the high-speed valve operation characteristic (line A2) is larger than the torque of the low-speed valve operation characteristic (line B2). A1 and A2
The characteristics shown by lines B1 and B2 are referred to as high-torque valve operating characteristics, and the characteristics with smaller torque (characteristics shown by lines B1 and B2) are referred to as low-torque valve operating characteristics.

On the other hand, an automatic transmission is configured to automatically change gears depending on the driving condition to obtain desired driving characteristics.

For this reason, for example, it is possible to have a shift map in which upshift lines and downshift lines are set for each shift based on the relationship between vehicle speed and engine output, and to perform shift control by comparing the driving condition with this shift map. Well done. Examples of such speed change control include, for example, Japanese Unexamined Patent Application Publication No. 1986-61-
There is one disclosed in Japanese Patent No. 189354.

When performing such shift control, it is required to reduce shock during shift as much as possible.

Such a shock during a shift includes shift shock during power-on shift-up (shift-up with the accelerator pedal depressed).

This will be explained using an example of a power shift up from 2nd speed to 3rd speed as shown in FIG.

At time t1, a shift command from 2nd speed to 3rd speed is output, and based on this, the shift solenoid output is changed from 2nd speed to 3rd speed. Correspondingly, the second speed clutch pressure P2 decreases and the third speed clutch pressure P3 increases.

For this reason, the engine torque that was previously transmitted only to the 2nd speed clutch is also divided to the 3rd speed clutch and gradually transfers to the 3rd speed clutch. This transition is completed at time t2, and the transition from time tz to time t2 is referred to as a torque phase. Due to this transition, the gear ratio (reduction ratio) in the transmission changes to become smaller, so the engine torque is pulled into the transmission side and decreases, and the acceleration G on the transmission output side is shown in graph (e). to decrease.

After this, torque is transmitted by the second-speed clutch, and the engine rotation decreases as shown in the figure.At this time, due to the inertia of the input side of the engine and transmission, the acceleration G of the transmission output decreases as shown in the figure. Rise. Then, at time t3 when the gear shift is completed, the acceleration G returns to the original level. The period from time t2 to t3 is referred to as an inertial phase.

(Problems to be Solved by the Invention) As described above, when a power-on shift-up is performed, a change ΔG1 in acceleration G in the torque phase and changes ΔG2 and ΔG3 in acceleration G in the inertia phase occur, and these acceleration changes There is a problem in that shift shifting occurs due to this.

Nao, this power-on shift-up is performed automatically when the accelerator pedal is pressed and the vehicle speed increases while driving, and it is a shift that is performed regardless of the driver's intention, so there is no possibility of a shift shock occurring. It is desirable to keep it as small as possible.

The present invention has been made in view of the above circumstances, and when the power-on shift-up of the transmission is performed, the shift control and the switching control of the valve operating characteristics of the engine are controlled in conjunction with each other, and the above-described control is performed. It is an object of the present invention to provide a control method that can reduce such acceleration changes and suppress shift shocks.

1. Structure of the Invention (Means for Solving the Problems) To achieve such an object, in the first control method of the present invention, when the engine is operating using high torque valve operating characteristics,・When an upshift is performed, the valve operating characteristics are first switched to low torque valve operating characteristics, and after a predetermined time delay, the shift solenoid is activated to start the power-on shift-up shift, and the power-on shift is performed. When the upgrade is completed, the valve operating characteristics are returned to the high torque valve operating characteristics.

On the other hand, in the second control method according to the present invention, when a power-on Φ shift up is performed while the engine is operating using the low-torque valve operating characteristic, the valve operating characteristic is switched to the high-torque pulp operating characteristic. At the same time, this power-on shift-up is started by activating the shift solenoid, etc., and after that, when it is detected that the power-on shift-up has shifted from the torque phase to the inertia phase, the valve operation characteristics are changed. Return to low torque valve operating characteristics. From the point of transition to the inertia phase, the speed change clutch actually starts to engage, and the engine rotation, clutch input/output rotation speed ratio, etc. begin to change, as indicated by time t2 in FIG. 12.

(Operation) In the case of the first control method, the low torque valve operating characteristic is switched from a predetermined time before the start of the shift until the end of the shift, and the engine output is reduced during this period. Therefore, the amount of change in the transmission output upon shifting is reduced, and the shift shock is also reduced accordingly.

Furthermore, in the case of the second method, since the high torque valve operating characteristic is switched only during the torque phase during gear shifting, it is possible to reduce the amount of decrease in torque due to torque pull during this torque phase.

Therefore, the change in acceleration on the output side of the transmission during the torque phase is reduced, and the shift shock is also reduced in this case.

(Embodiments) Hereinafter, preferred embodiments of the present invention will be described based on the drawings.

FIG. 1 shows a power unit controlled by the method according to the invention, which comprises an engine E having a variable valve timing/lift mechanism VT and an automatic transmission AT controlled by a hydraulic control valve Cv. configured. Here, the variable valve timing/lift mechanism VT adjusts the opening/closing timing, opening period, and lift amount of the intake valves of the engine E into low-speed valve operating characteristics suitable for the low-speed region and high-speed valve operating characteristics suitable for the high-speed region. As will be described later, this switching is performed by supplying and discharging a predetermined hydraulic pressure by turning the solenoid valve 91 ON@OFF. Further, the hydraulic control valve CV is a valve that performs engagement control of the lock-up clutch in the automatic transmission AT, operation control of the speed change clutch, etc., and this operation control is performed by the solenoid valves 251, 25
2.253,255.

The above solenoid valve 91, 251, 252° 253.
The operation of 255 is controlled by an operation signal from the control unit CU. Therefore, the control unit CU includes an engine cooling water temperature signal from the water temperature sensor 92, a throttle opening signal from the throttle sensor 93,
Various signals such as an engine rotation signal from the engine rotation sensor 94 and a transmission output rotation signal from the transmission rotation sensor 85 are input, and based on these various signals, an activation signal is sent from the control unit CU to each of the solenoid valves. is output.

First, the variable valve timing/lift mechanism VT will be explained with reference to FIGS. 2 and 3. A pair of intake valves 1atlb is arranged for each mechanism of the engine E, and these pair of intake valves 1a, lb are integrally connected to a camshaft 2 that is driven at a rotation ratio of 1/2 in synchronization with the rotation of the engine. The first low speed cam provided in 3. Second
Low-speed cam 3', high-speed cam 5, and camshaft 2
The first. It is opened and closed by the action of the second and thirtieth claw 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 la and 1b. Moreover, the first
The second low speed cam 3.3' has a high portion 3a+3a' 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 1a, 1b.

Further, a cam slipper 10 that slides on the low-speed cam 3 is provided at the top of the tenth claw arm 7, and a cam slipper 11 that can come into contact with the second low-speed cam 4 is provided on the top of the 20th claw arm 8. The intake valves la and lb are biased toward the valve closing direction, that is, upward, by valve springs 1B and 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 1a from the rocker shaft 8.
, is slightly extended to the ib side, and a high-speed cam 5 is mounted on the upper part.
A cam slipper is provided that slides into contact with 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 connects each rocker arm 7 to 9 integrally is connected to the first to second rocker arms 7 to 9.
It is installed at the 0-tsuka 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 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 caused by the movement of the oil passage 31.32.3 in accordance with the operation of the solenoid valve 91.
This is done by the hydraulic pressure supplied into the hydraulic chamber 29 through 0.

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

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

When the engine E is operating at low speed, the solenoid valve 91 is OFF, and the oil passage 31 and the oil pressure source (
(not shown), and the connection switching means 2
Hydraulic pressure is not supplied to the first hydraulic chamber 29, and the stopper 24 is pressed toward the 30th lever arm 9 by the spring 25. 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 and 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 intake valves la 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.
The opening time and amount of the intake valve 1b may be made extremely 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. You can also do it.

When operating engine E at high speed, solenoid valve 9
1 is ON, and as shown in FIG. 4, the hydraulic pressure source (not shown) and the oil passage 31 are communicated by the solenoid 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 move until the stopper 24 comes into contact with the restriction step 36, and the first piston 22 causes the first and 30th lever arms 7.9 to move. are connected, and the third and twentieth hook arms 9, 8 are connected by the second piston 23.

In this manner, when the first to thirtieth lever arms 7°8.9 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 valves 1a+1b are connected 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 1a+1b based on the first and second low-speed cams 3, 3' are referred to as low-speed valve operating characteristics, and the opening/closing timing of the intake valves 1a+1b based on the high-speed cam 5 is referred to as low-speed valve operating characteristics. and the amount of lift 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. As mentioned above, in this figure, the line shows the characteristic in low-speed valve operation characteristic operation, the line H shows the characteristic in high-speed valve operation characteristic operation, and the characteristic shown by lines AI and A2 is high torque valve operation. The characteristic shown by the line Bt+B2 is the low torque valve operating characteristic.

Next, the automatic transmission AT will be explained based on 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. 2, 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 4Etb and the turbine 4Etb.

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 83.
has. Between the input shaft 61 and the counter shaft 62, there are five sets of gear trains that mesh with each other, namely, 1st speed gear train 51a, 51b12th speed gear train 52a, 52b13th speed gear train 53a+53bN 4th speed gear train 54a,
54b and reverse gear train 55a + 55b
+55c is installed. Hydraulically actuated clutches 64 to 68 for selecting each gear train are disposed in the driving gear or driven gear of each gear train, and by selectively operating these hydraulically actuated clutches 64 to 68, the driving gear or the driven gear of each gear train is arranged. The power transmission path 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 one-way clutches 58.57 are attached to the first-speed driven gear 51b and the second-speed driven gear 52b, and an engine clutch 89 for locking and holding these one-way clutches 58.57 is also provided.

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 69 to 69 is performed by a control valve Cv shown in FIG.

In the power unit configured as described above, when a power-on shift is performed, switching control of valve operating characteristics by the variable valve timing/lift mechanism VT of the engine E and control of switching of the transmission mechanism 50 by the hydraulic control valve CV are performed. The operation control will be explained with reference to the control flow shown in FIG.

In this control, first, whether the gear change command is an upshift or not (
Step 81) and whether or not the power is on (step 82) are determined. Note that the power-on state refers to a state in which the throttle opening is opened, such as by pressing the accelerator pedal. If it is not a power-on shift-up, it will not be controlled by this flow, and the process will proceed to the return step.

If it is a power-on shift up, step S
3, it is determined whether the engine valve operating characteristic is a high torque valve operating characteristic, that is, whether it is the characteristic indicated by line A1 or A2 in FIG.

When the high-torque valve operating characteristic is present, the control shown in steps S4 to S9 is performed, and this will be explained with reference to the graph of FIG. 9 as well.

First, at time t□ when a shift command is issued, the delay time TD is calculated from the shift pattern of this shift, the engine output at that time, etc. (step S4), and the valve operating characteristic is switched to a low torque valve operating characteristic. And the delay time T. (step S6), and then in step S7, the shift solenoids (solenoid valves 251 and 252 in FIG. 10) are operated to start shifting based on the shift command (time ta). Note that here, a case of power-on upshift from 2nd speed to 3rd speed is shown.

When the gear shift starts at time t2, the engine torque that had been transmitted only to the 2nd gear clutch side is also divided to the 3rd gear clutch side and gradually transfers to the 3rd gear clutch side, and this transition is completed at time t3. . That is, time t2
The period from t3 to time t3 is the torque phase. Due to this transition, the gear ratio (reduction ratio) in the transmission changes to become smaller, so the engine torque is pulled into the transmission side and decreases, and the acceleration G on the transmission output side decreases as shown in the graph. do.

However, in the case of this control, the engine output is reduced by switching the valve operating characteristic to the low torque valve operating characteristic at time t1, so even if the torque reduction rate due to engine torque pull is the same, the engine output is reduced. The amount of torque reduction will be reduced accordingly. For this reason,
As shown by the solid line in the graph, the acceleration G decreases a little at time t1 when the valve operating characteristic is switched, but the decrease in acceleration G during the torque phase (from time t2 to ta) becomes smaller.

From time t3, the engine shifts to the inertia phase, the third speed clutch starts to engage, and the engine speed decreases as shown. In this inertia phase, the transmission output side acceleration G increases as shown in the figure due to the inertia of the engine and the input side of the transmission, and then returns to the original state at the shift completion time t4.

When the completion of the shift is detected based on a change in engine rotation, the input/output rotation speed ratio of the speed change clutch, etc., the process proceeds to step S9, where the valve operating characteristic is returned to the high torque valve operating characteristic and the main control is completed.

In the graph of Figure 9, the change in acceleration G on the transmission output side in the case of this control is shown by a solid line, and the change in acceleration G in the case of conventional transmission without switching the valve operating characteristics is shown in a broken line. It shows. As can be clearly seen by comparing the two, the change in acceleration in the case of this control is smaller than in the conventional case, and the shift lock is smaller.

On the other hand, control when it is determined in step S3 that the low torque valve operating characteristic is being used will be described below with reference to FIG. 10 as well.

First, at time t when a shift command is issued, the valve operating characteristic is switched to a low torque valve operating characteristic (step 510). At the same time, in step 811, the speed change solenoids (solenoid valves 251 and 2 in FIG.
52) to start shifting based on the shifting command.

When the gear shift starts, the engine torque that was previously transmitted only to the 2nd gear clutch side is also divided to the 3rd gear clutch side and gradually transfers to the 3rd gear clutch side, and this transition is completed at time t2 (torque phase ). Due to this transition, the gear ratio (reduction ratio) in the transmission changes to become smaller, so the engine torque is pulled toward the transmission and decreases.
The acceleration G on the transmission output side decreases as shown in the graph.

However, in the case of this control, the valve operating characteristic is switched to the high-torque valve operating characteristic at time t1 and the engine output is increased, so a torque decrease due to engine torque pulling is suppressed by this increase in engine output. Therefore, as shown by the solid line in the graph, the decrease in the acceleration G during the torque phase (from time t to tz) becomes small. For comparison, the change in acceleration G without switching to the high torque valve operating characteristic is shown in the 10th column.
This is indicated by a broken line in the figure, and as can be seen from this figure, the acceleration G decreases more greatly when the valve operating characteristics are not switched.

When a transition from the torque phase to the inertia phase is detected (step 8
12), the valve operating characteristic is returned to the low torque valve operating characteristic (step 513), and gear shifting is continued. Note that the transition to the inertial phase is detected based on changes in the engine rotation speed, changes in the input/output rotation speed ratio of the speed change clutch, and the like.

When the engine shifts to the inertia phase and the third gear clutch starts engaging, the engine rotation decreases as shown. In this inertia phase, the transmission output side acceleration G increases as shown in the figure due to the inertia of the input side of the engine and the transmission, and then returns to the original state at the shift completion time t3 to complete the main control.

The embodiments of the present invention have been described above, but instead of setting only two types of valve operating characteristics, high-speed valve operating characteristics and low-speed valve operating characteristics, as shown in FIG. 6, as shown in FIG. 11. Thus, three types of characteristics may be set: low-speed valve operation characteristics, medium-speed valve operation characteristics, and high-speed valve operation characteristics.

In this case, line A1. A2. The characteristic indicated by A3 is the high torque valve operating characteristic, and the characteristic indicated by the line B1+B2tBa-B4 is the low torque valve operating characteristic. Furthermore, 4
It is a hot theory that it is okay to set characteristics that are higher than species.

C1 As described in detail, according to the present invention, when a power-on shift-up is performed while the engine is operating using the high-torque valve operating characteristic, the valve operating characteristic is first changed to the low-torque valve operating characteristic. After a predetermined time delay, a power-on shift-up shift is started by activating the shift solenoid, etc., and when the power-on shift-up is completed, the valve operating characteristic is returned to the high-torque valve operating characteristic. Therefore, from a predetermined period of time before the start of the shift until the end of the shift, the operating characteristics of the torque valve are switched to low torque, and the engine output is reduced during this period.

Therefore, even if the rate of change in the transmission output during a shift is the same, the amount of change is reduced, and the shift shock can be reduced accordingly.

In addition, when a power-on shift is performed while the engine is operating using the low-torque valve operating characteristic, the valve operating characteristic is switched to the high-torque valve operating characteristic, and at the same time, the shift solenoid is operated, etc., to increase the power. When it is detected that the power-on shift-up has actually started, the valve operating characteristics are returned to the low-torque valve operating characteristics, so only during the torque phase of the gear shift. Switched to high torque valve operating characteristics. Therefore, the amount of decrease in torque due to torque pull in this torque phase can be reduced, and shift shock can be suppressed.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing a power unit controlled by the method according to the present invention; FIG. 2 is a sectional view of a variable valve timing/lift mechanism used in an engine constituting the power unit; FIGS. 3 and 4. The figure is a cross-sectional view of this mechanism, Figures 5A and 5B are graphs showing the opening/closing operation characteristics of the intake valve, Figure 6 is a graph showing the relationship between the output torque and rotational speed of the engine, and Figure 7 is the graph shown above. A schematic diagram showing the power transmission system of the automatic transmission that constitutes the drive unit, FIG. 8 is a flowchart showing the control according to the present invention, and FIGS. Figure 11 is a graph showing the characteristics of an engine with three types of valve operating characteristics. Figure 12 is a graph showing changes over time in various signals during power-on shift up under conventional control. be. 3.3'...Low speed cam 5...High speed cam 6...
・Rocker shaft 2 construction...Connection means 22.23・
...Piston 29...Hydraulic chamber 47...Lock-up clutch 50...Transmission mechanism 63...Transmission input shaft 9
2...Water temperature sensor 93...Throttle sensor 94...Engine rotation sensor 95...Transmission rotation sensor CU...Control unit VT...Variable valve timing/lift mechanism Fig. 1

Claims (1)

[Scope of Claims] 1) A method for controlling a power unit comprising an engine capable of freely changing the valve operating characteristics of at least one of an intake valve and an exhaust valve, and an automatic transmission connected to the output shaft of this engine. When power-on and upshifting of the automatic transmission is performed while the engine is operating using a high-torque valve operating characteristic, first, the valve operating characteristic is switched to a low-torque valve operating characteristic, and the operation is performed for a predetermined period of time. After a delay, the power-on shift-up is started, and when the power-on shift-up is completed, the valve operating characteristic is returned to the high-torque valve operating characteristic. Method. 2) A method for controlling a power unit comprising an engine capable of freely changing valve operating characteristics of at least one of an intake valve and an exhaust valve, and an automatic transmission connected to an output shaft of the engine, the method comprising: When a power-on shift-up of the automatic transmission is performed during driving using a torque valve operating characteristic, the power-on shift-up is started at the same time as the valve operating characteristic is switched to a high-torque valve operating characteristic. and when it is detected that the power-on shift-up shifts from a torque phase to an inertia phase, the valve operating characteristic is returned to a low torque valve operating characteristic. .