JPH02169333A - Engine controller for vehicle provided with continuously variable transmission - Google Patents

Abstract

PURPOSE:To make improvements in shift speed by discriminating the changed state of a request gear ratio in a continuously variable transmission, while regulating an engine output at a time when this request gear ratio is suddenly changed, and making the torque variation larger as long as the specified time. CONSTITUTION:A gear ratio transmitting output of an engine 1 to driving wheels is changed in stepless by gear ratio control means 3 via a continuously variable transmission 4 according to a driving state of the engine 1. The output of the engine 1 is controlled by an engine output control means 5. In this case, a gear ratio changed state in the continuously variable transmission 4 by means of the gear ratio control means 3 is discriminated by a request gear ratio discriminating means 6. Then, a compensation signal is outputted to the engine output control means 5 from an engine output compensating means 7 according to a discriminating signal of the request gear ratio discriminating means 6. In brief, when a request gear ratio to the transmission 4 is suddenly changed, the output of the engine 1 is regulated, and the torque variation is made larger as long as the specified time.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to an engine control device for a vehicle equipped with a continuously variable transmission that continuously changes the gear ratio for transmitting engine output to drive wheels. .

(Prior Art) Continuously variable transmissions that change the gear ratio steplessly have been used as vehicle transmissions, for example, as disclosed in Japanese Patent Laid-Open No. 62-12.
This is known as seen in Japanese Patent No. 7554.

In this continuously variable transmission, for example, the main pulley and the sub-boot that are engaged with the drive belt are configured with variable pulleys, and the operation of the variable pulley is hydraulically controlled, and the gear ratio is adjusted between the vehicle speed and the throttle opening. Various techniques have been proposed that change the speed according to the operating conditions.

(Problem to be Solved by the Invention) However, in the speed change control of the continuously variable transmission as described above, when changing gears in the downshift direction for acceleration, for example, it is necessary to quickly change the gear ratio. However, when there is a sudden change in the required gear ratio, the shifting speed is insufficient and the driving performance required by the driver cannot be obtained.

In other words, in a general continuously variable transmission, in order to reduce slippage in the engagement between the drive belt and the variable pulley, the variable pulley's belt pressing force (scissor force) is adjusted relative to the input torque by hydraulic control of the variable pulley. It is adjusted to a relatively high value so that there is no excess or deficiency. However, for this reason, when changing the gear ratio, the drive belt slips, changing the engagement radius position with the boob and changing the gear ratio, but as mentioned above, the drive belt is set to reduce slippage. As a result, the speed of shifting is restricted, resulting in a delay in shifting.

In addition, if the belt pressing force in engagement with the variable pulley is reduced to increase belt slip and shift speed, this continuous belt slip will cause wear on the belt and the pulley, reducing reliability. A problem arises.

SUMMARY OF THE INVENTION In view of the above-mentioned circumstances, it is an object of the present invention to provide an engine control device for a vehicle equipped with a continuously variable transmission that improves the speed change without causing the problem of wear due to increased slip. It is.

(Means for Solving the Problems) In order to achieve the above object, an engine control device for a vehicle equipped with a continuously variable transmission according to the present invention drives the output of an engine 1, as the basic configuration is shown in FIG. It is equipped with a continuously variable transmission 4 that continuously changes the gear ratio transmitted to the wheels 2 by controlling the gear ratio control means 3 according to the driving condition, and also includes an engine 1.
Engine output control means 5 is provided to control the output of the engine.

Furthermore, a required gear ratio determination means 6 is provided for determining a gear ratio change state by the gear ratio control means 3 of the continuously variable transmission 4,
The signal of the required gear ratio determining means 6 is output to the engine output correcting means 7, and the engine output correcting means 7 controls the engine output controlling means 5 when the required gear ratio for the continuously variable transmission 4 suddenly changes. The engine is configured to output a correction signal to adjust the engine output and increase the torque fluctuation for a predetermined period of time.

(Function) In the engine control device of a vehicle equipped with a continuously variable transmission as described above, when the required gear ratio suddenly changes, the engine output control means increases the torque fluctuation of the engine output for a predetermined period of time, and the continuously variable transmission Vibration due to engine torque fluctuations acts on the contact between the drive belt and pulley of the machine, and even when the belt is under high pressure, the contact point of the drive belt against the boob can be moved quickly, and the gear shifting speed can be increased. The transmission ratio is increased to quickly change the gear ratio to obtain driving performance that meets the driver's needs.

(Example) The present invention will be described in detail below with reference to the drawings.

FIG. 2 shows a schematic configuration of an engine control device that controls fluctuations in engine torque through air-fuel ratio control.

The output of the engine 1 is transmitted through a continuously variable transmission 4 to drive the vehicle forward and backward, converted into a predetermined gear ratio, and transmitted to drive wheels 2, thereby driving the vehicle.

The output of the engine 1 is controlled by the air-fuel ratio, that is, the amount of fuel supplied, and an injector 12 is disposed downstream of the throttle valve 11 in an intake passage 10 that supplies intake air to the engine 1, and injects fuel to each cylinder. The injection control is performed by the engine control unit 13.

On the other hand, the operation of the continuously variable transmission 4 is performed by a speed change control unit 14, and its forward and backward movement and gear ratio are controlled by control signals from a transmission control means 3 that receives various signals. is controlled by belt pressing force control means 16 which receives a signal from engine output detecting means 15 so that the pressing force increases in accordance with an increase in engine output.

The output of the engine 1 is achieved by controlling the fuel injection amount and fuel injection timing for the injector 12, and a fuel injection pulse is output to the injector 12 from a fuel injection timing determining means 17 at a predetermined time. In addition, the fuel injection amount is the intake air amount from the intake air amount sensor 18,
Intake air temperature from intake air temperature sensor 19, atmospheric pressure sensor 2
Intake air mass measuring means 2 into which the atmospheric pressure signal from 0 and the engine rotation speed signal from the rotation sensor 21 are respectively input.
The basic fuel injection amount is calculated by the fuel injection amount determining means 23 which receives the signal from the correction means 2.
4, and the corrected signal is output to the fuel injection timing determining means 17.

Then, the correction means 24 calculates, based on the change in throttle opening,
When the required gear ratio of the continuously variable transmission 4 changes suddenly,
This control is performed by varying the amount of fuel supplied to cause slight fluctuations in engine torque for a predetermined period of time.

The configuration of the unit of the continuously variable transmission 4 is shown in FIG. The continuously variable transmission 4 includes a mechanical clutch 30 operated by hydraulic pressure, a forward/reverse switching device 31 for switching between forward and reverse, and a gear ratio converting device 32. The clutch 30 includes an input shaft 33 to which engine output is input, a disk 35 attached to the output shaft 34, and a suppression plate 36 that presses the disk 35 to the input side.
are connected and disconnected by the operation of the clutch cylinder 38 via the link 37.

The forward/reverse switching device 31 is provided between the clutch output shaft 34 and the main shaft 40, and has a driven gear 42, which is loosely engaged with the main shaft 40 and always meshes with a forward fixed gear 41 formed on the clutch output shaft 34. In addition, an idler gear 44 is always engaged with a fixed gear 43 for reverse movement formed on the clutch output shaft 34.
is installed parallel to the main shaft 40. Furthermore, the main shaft 40
A sleeve 45 that is slidably spline-fitted to the switch cylinder 46 moves in response to the operation of the switching cylinder 46, and the movement of the sleeve 45 connects the forward driven gear 42 and the main shaft 40 to the forward drive shown in the figure. state and movement of the sleeve 45 to the opposite side, the idler gear 44 and the sleeve 4
5 is switched to a reverse drive state in which it is in a connected state.

On the other hand, in the gear ratio changing device 32, a sub-shaft 50 is arranged parallel to the main shaft 40, a main pulley 51 and a sub-pulley 52 are provided as variable pulleys on both shafts 40, 50, respectively, and both pulleys 51. An endless drive belt 53 is engaged between the belts 52 and 52 . The main pulley 51 and the sub pulley 52 are fixed pulleys 51a and 52a and a movable pulley 51b, respectively.

52b, each of the movable pulleys 51b and 52b is provided with a hydraulic servo device 54, 55 so that the engagement radius position of the drive belt 53 can be adjusted in coordination with each other by controlling the feed oil pressure. The rotation of the subshaft 50 adjusted to the rotational speed is output to the driving wheels.

On the other hand, in the hydraulic system, the hydraulic pressure discharged by the oil pump 57 is regulated by the relief valve 58, and this line pressure is sent to the clutch cylinder 38 via the clutch switching valve 59. This clutch switching valve 59 is operated by a solenoid and is switched between a connected position and a disconnected position in response to a signal from the speed change control unit 14. Further, the line pressure is supplied to the switching cylinder 46 via the forward/reverse switching valve 60. This forward/reverse switching valve 60 is switched between a forward position and a backward position by operating a switching lever 61. Furthermore, the line pressure is sent to each hydraulic servo device 54, 55 of the main pulley 51 and the sub pulley 52 via the speed change switching valve 62. This shift changeover valve 62 is operated by a solenoid and is switched between a speed increase position and a deceleration position in response to a signal from the speed change control unit 14.

In order to control the continuously variable transmission 4, the speed change control unit 14 includes a throttle opening signal, a vehicle speed signal, an accelerator opening signal, and a main boost rotation speed signal for determining the operating state of the engine 1 and the vehicle. , a control lever position signal, and various other signals are input. This speed change control unit 14 basically controls the fourth
The target rotation speed N of the main pulley 51 is determined from a speed change map as shown in the figure, and the speed change ratio is changed so that the target rotation speed N is achieved. In the above shift map, the vehicle speed ■
Between the deceleration limit line LD where the engine speed is a large value relative to the vehicle speed V and the speed increase limit line OD where the engine speed is a small value relative to the vehicle speed V, the engine speed is changed depending on the throttle opening. A target rotation speed N of the main boolean 951 is set. Furthermore, in a high load region with a large throttle opening, the constant throttle line is set so that the target rotational speed N increases as the vehicle speed V increases, thereby improving the sense of acceleration. On the other hand, in the region of low throttle opening, the map is set densely to lower the engine speed and improve fuel efficiency.

A state in which the gear ratio changes greatly, that is, a large change in the target rotational speed N with a small change in vehicle speed occurs when the throttle opening changes rapidly, and at this time, a rapid change in the gear ratio is required. Ru.

Furthermore, the actual rotation speed of the main pulley 51 is compared with the target rotation speed N set by the shift map as described above, and if the actual rotation speed exceeds a predetermined value (dead band), the shift is shifted in the upshift direction. The gear ratio is changed, and conversely, if the actual rotation speed is smaller than a predetermined value (dead band), the gear ratio is changed in the downshift direction, and the gear ratio is adjusted so that the actual rotation speed matches the target rotation speed N. This is feedback control.

The engine control unit 13 detects a sudden change in the required gear ratio in the gear change control unit 14 from a sudden change in the throttle opening, and when such a quick change in the gear ratio is required, fuel injection is performed. The engine torque is varied by slightly changing the amount, and vibration is applied to the engagement portion between the main pulley 51 and the drive belt 53, especially in the deceleration downshift direction where the drive belt 53 slips and moves toward the outer circumference. It promotes change.

The processing of the engine control unit 14 will be explained based on the flowchart shown in FIG. After the control starts, various sensor signals are read in step S1, and based on these detection signals, the basic amount determined from the intake air amount and engine rotation speed is corrected by atmospheric pressure and intake air temperature, and the intake air mass is calculated in step S2. . Further, in step S3, a fuel injection amount that provides an optimal air-fuel ratio for the intake air mass is calculated.

Subsequently, in step S4, it is determined whether or not there has been a sudden change in the required gear ratio based on whether or not the change in throttle opening is greater than or equal to a predetermined value. This judgment is N.

If the change in the required gear ratio is small, step SI
At G, the fuel injection timing is calculated from the engine speed, and at step Sll, an injector operation signal is output to execute fuel injection.

On the other hand, if the determination in step S4 is YES and there is a sudden change in the required gear ratio, then flag F is flagged in step S5.
Determine whether or not has been reset to 0. Initially, the flag F is O, and the process proceeds to step S7 where the fuel injection amount is increased by a predetermined value α, and then the flag F is set to 1 in step S9.

When the flag F is set to 1, the process proceeds to step S6 due to a No determination in step S5, where the fuel injection amount is corrected by a predetermined value α, and then the flag F is reset to 0 in step S8. By repeatedly setting and resetting the flag F, the fuel supply amount is increased and decreased to change the air-fuel ratio, thereby slightly varying the engine output for a predetermined period of time, thereby promoting the shifting speed.

Note that a timer may be used to provide torque fluctuations without using the flag F, or a constant periodic torque fluctuation may always be obtained even when the engine speed changes.

According to the embodiment described above, when the required gear ratio of the continuously variable transmission 4 changes rapidly and the throttle opening changes, the air-fuel ratio is repeatedly changed and vibrations caused by engine output fluctuations cause the drive belt 53 to By changing the engagement position with the pulleys 51 and 52, the speed change can be promoted and the speed change speed can be improved.

In the above embodiment, the engine torque is varied by changing the fuel supply amount, but the engine torque may be varied by controlling the ignition timing. Furthermore, a sudden change in the required gear ratio in the continuously variable transmission 4 is detected by a change in throttle opening, but the shift control unit detects a sudden change in the required gear ratio according to the target rotation speed N and the actual rotation speed determined from the shift map. It may also be detected.

(Effects of the Invention) According to the present invention as described above, when the required gear ratio changes suddenly, the torque fluctuation of the engine output is increased for a predetermined period of time to prevent contact between the drive belt and the boot of the continuously variable transmission. By applying vibration, the speed of shifting can be increased by quickly moving the contact point of the drive belt against the boob even when the belt is under high pressing force, especially during acceleration operations to obtain sudden acceleration. Good acceleration performance can be obtained when shifting in the downshift direction, and driving performance that meets the driver's demands can be ensured.

In addition, the engine torque fluctuations as described above are performed in a transient state such as during acceleration, and good running stability can be obtained during steady running without being affected by torque fluctuations.

[Brief explanation of the drawing]

FIG. 1 is a functional block diagram for clearly showing the configuration of the present invention. FIG. 2 is a schematic configuration diagram of an engine control device for a vehicle equipped with a continuously variable transmission according to an embodiment. FIG. FIG. 4 is a schematic diagram showing an example of the mechanism of the engine, FIG. 4 is a characteristic diagram showing a speed change map, and FIG. 5 is a flowchart for explaining the processing of the engine control unit. 1... Engine, 2... Drive wheel, 3.
... Speed ratio control means, 4 ... Continuously variable transmission, 5 ... Engine output control means, 6 ...
・Required gear ratio determination means, 7...Engine output correction means, 11...Throttle valve, 12...
... Injector, 13 ... Engine control unit, 14 ... Speed change control unit, 24 ... Correction means, 30 ... Clutch, 31 ... ... Forward/forward switching device, 32...
... Gear ratio changing device, 51 ... Main pulley, 5
2... Sub-pulley, 53. Old... Drive belt, 5
4.55... Servo device. Figure 4 Voice 1Xv

Claims (1)

[Claims] (1) Equipped with a continuously variable transmission that continuously changes the gear ratio for transmitting the engine output to the driving wheels by controlling the gear ratio control means according to the driving condition, and an engine output control means that controls the engine output. In the vehicle, a required speed ratio determining means for determining a speed ratio change state by the speed ratio controlling means of the continuously variable transmission, and receiving a signal from the required speed ratio determining means;
A continuously variable transmission characterized by comprising: engine output correction means for adjusting engine output and increasing torque fluctuation for a predetermined period of time when a required gear ratio for the continuously variable transmission suddenly changes. Vehicle engine control device.