JPH04166428A - Power control device for vehicle with automatic transmission - Google Patents

Abstract

PURPOSE:To improve durability of a drive train system by setting an automatic transmission to the high speed side when the trouble of an engine torque reducing means is detected. CONSTITUTION:An EFI computer 32 for controlling combustion of an engine computes whether engine torque is reduced and decides the trouble of the reduction control system of engine torque through detection of whether a corresponding current is fed to a motor 30 based on a computing result. When it is decided that the trouble occurs, the trouble is communicated through a communication wire 39 to an ECT computer 36 to perform hydraulic control of the shift of an automatic transmission 22. The ECT computer 36 shifts the speed of the automatic transmission 22 to a high speed based on a signal therefrom.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a power control system for a vehicle with an automatic transmission that prevents an input torque exceeding an allowable torque from being applied to a drive drain system by reducing engine torque using an engine torque reduction means.

[Conventional technology]

It is known that when the engine stalls under high load, such as when the brake and accelerator are depressed at the same time, the load applied to the drive drain system is considerably greater than the load applied during normal acceleration. Conventionally, when a load is applied that exceeds the load required during normal start-up acceleration, the engine torque is automatically reduced and the drive drain system such as the automatic transmission, such as the propeller shaft, differential gear, etc. Alternatively, technologies have been proposed that reduce the load on input shafts such as drive shafts, protect these devices, and reduce weight accordingly (for example, SAE paper 8).
70081).

[Problem to be solved by the invention]

However, in a vehicle configured to reduce engine torque when a load exceeding the allowable input torque is applied to any part of the drive drain system, if there is any means for reducing engine torque, If the drive drain system does not operate properly for any reason, an unreduced load will be applied to the drive drain system, which may reduce the durability of the drive drain system. The present invention has been made in view of such conventional problems, and even if a situation occurs in which the engine torque reduction means does not operate normally for some reason, the drive drain system will not be overloaded. It is an object of the present invention to provide a power braking aIJ device that can prevent heavy loads from being applied, thereby maintaining good durability of the drive drain system.

[Means to solve the problem]

As summarized in FIG. 1, the present invention has an automatic transmission equipped with an engine torque reducing means that prevents an input torque exceeding an allowable torque from being applied to a drive drain system by reducing engine torque. In a power control device for a vehicle, means for detecting whether or not the engine torque reduction means has failed; and when it is determined that the engine torque reduction means has failed, the gear position of the automatic transmission is changed to a higher gear position. The above object has been achieved by providing means for setting.

[Effect]

The present invention first includes means for detecting whether or not the engine torque reducing means has failed. Furthermore, when it is determined that the engine torque reduction means has failed, the gear position of the automatic transmission is set to a high speed side. Causes of failure of the engine torque reduction means include, for example, failure of the motor for rotating the sub-throttle valve,
Possible causes include a failure of the throttle sensor for detecting the opening of the throttle valve, or a poor connection between these devices and the computer. Further, as a means for determining whether or not the engine torque reduction means has failed, for example, a flag indicating whether or not the torque reduction means is normal is sent from the computer controlling the engine to the computer controlling the automatic transmission. It is possible to adopt a system in which the computer controlling the transmission determines the failure state by checking the value of this flag. For example, when the computer that controls the engine determines that the engine torque should be reduced in order to respond to the cause of the failure as described above, the computer that controls the engine adjusts the current to the subthrottle valve motor accordingly. The failure state can be determined by checking whether the In this way, when it is determined that the engine torque reduction means has failed, the gear position of the automatic transmission is set to the high speed side. For example, in the case of the forward range, the first gear is omitted and the gear shift is executed using only the second gear or higher. or,
When the vehicle is in the reverse range, only the high-speed reverse range among the reverse ranges is used to perform reverse travel. By doing this, the input torque to the drive drain system is reduced by the amount corresponding to the reduced gear ratio, and as a result, it is possible to prevent input torque exceeding the allowable torque from being applied.

【Example】

Embodiments of the present invention will be described in detail below based on the drawings. In this embodiment, a conventionally known traction control system is used as a hardware configuration for changing engine torque when a load exceeding an allowable input is applied to the drive drain system. A traction control system is a traction control system that adjusts the engine output and improves control when the engine output is too large for the friction coefficient between the road surface and the tires and slip occurs when the vehicle starts or accelerates. This allows for effective starting or acceleration. The outline of this system will be explained using FIG. Air is drawn into the engine 20 via a main throttle valve 24 and a sub-throttle valve 26. The intake air amount of the engine 20, that is, the engine output, is adjusted by the opening degree of the main throttle valve 24 and the opening degree of the bus throttle valve 26. The main throttle valve 24 is connected to an accelerator pedal 28, and the opening degree of the main throttle valve 24 is adjusted according to the amount of depression of the accelerator pedal 28. Further, the sub-throttle valve 26 is connected to the motor 30.
By electrically operating this motor 30, the amount of intake air can be changed independently of the accelerator pedal 28. The EFI computer 32 is mainly used to control combustion of the engine, the TRC computer 34 is mainly used to control the motor 30 described above, that is, traction control and excessive input prevention control, and the ECT computer 36 is mainly used to control the automatic transmission 22. Used for hydraulic control for gear shifting. The EFI computer 32 calculates whether or not the engine torque should be reduced within its own computer, and detects whether a corresponding current is being supplied to the motor 30 based on the result of this calculation. Based on this detection result, a failure of the engine torque reduction control system is determined, and if it is determined that there is a failure, the ECT computer 36 is notified of this via the communication line 39. When the ECT computer 36 receives this signal, it performs an operation to change the gear position of the automatic transmission 22, as will be described later. As shown in FIG. 3, the automatic transmission 22 includes a torque converter 120, a second transmission section 140, and a first transmission section 160 with three forward speeds and one reverse speed. The torque converter 120 includes a pump 121, a turbine 122, a stator 123, and a lock-up clutch 124. The pump 121 is connected to the crankshaft 20a of the engine 20, and the turbine 122 is connected to a carrier 141 of a planetary gear set in the second transmission section 140. In the second transmission section 140, this carrier 14
a planetary binion 1 rotatably supported by 1;
42 meshes with sun gear 143 and ring gear 144. Further, a clutch CO and a one-way clutch FO are provided between the sun gear 143 and the carrier 141, and a brake BO is provided between the sun gear 143 and the housing Hu. The first transmission section 160 is provided with two rows of planetary gears, one on the front side and the other on the rear side. This planetary gear device includes a common sun gear 161, ring gear 162, 163, planetary pinion 164, 165,
and carriers 166 and 167. The ring gear 144 of the second transmission section 140 includes a clutch C
1 to the ring gear 162. Moreover, between the ring gear 144 and the sun gear 161,
A clutch C2 is provided. Furthermore, the carrier 1
66 is connected to the ring gear 163, and these carrier 166 and ring gear 163 are connected to the output shaft 170.
is connected to. On the other hand, a brake B3 and a one-way clutch F2 are provided between the carrier 167 and the housing Hu, and a brake B2 is provided between the sun gear 161 and the housing Hu via the one-way clutch F1. A brake B1 is also provided between the sun gear 161 and the housing Hu. This automatic transmission includes a transmission section as described above, and includes a throttle sensor 100 that detects the opening degree of the main throttle valve 24, and a vehicle speed sensor 10 that detects the vehicle speed.
An electromagnetic solenoid valve in a hydraulic control circuit (not shown) is driven and controlled according to a preset shift pattern by the ECT computer 36 to which the second signal is input.
As shown in FIG. 4, the combination of engagement of latches, brakes, etc. is performed to control the speed change. In FIG. 4, the O mark indicates the engaged state, and the X mark indicates the engaged state only when the engine brake is applied. Next, FIG. 5 shows a control flow executed by the apparatus of the above embodiment. Here, as an example, it is assumed that the engine output is reduced during stall and reverse. First, in step 201, the EFI computer 3
Check the status of the communication flag from 2. In step 202, it is determined whether the engine torque reducing means is normal or not based on the value of this flag. If normal, exit from this control flow. As a result of the determination, if it is determined that the engine torque reducing means is not normal, the process proceeds to step 203 and the current first
It is determined whether the gear is in gear or not. If it is the first gear, the process proceeds to step 204 to execute a 1→2 upshift, then in step 207 the 1→2.2→1 shift line is deleted, and in step 208, the current engine torque reduction means is generates a warning that it is not working properly and resets it. Therefore, from now on, running in the first gear will be prohibited, and only running in the second to overdrive gears will be allowed. As a result, torque greatly amplified by the large gear ratio is prevented from being applied to the drive drain system. On the other hand, in step 203, the current running state is the first one.
When it is determined that the vehicle is not in gear, the process proceeds to step 205, where it is determined whether the current running state is in reverse gear. If it is not the reverse stage, the process directly advances to step 207. On the other hand, when it is determined that the gear is in reverse gear, the process proceeds to step 206, where the brake BO is engaged and the clutch C is engaged.
O is released, and the process then proceeds to step 207. As a result, when it is determined that the torque reduction means is operating normally and that the gear is in reverse gear, the second transmission section 140 is placed in the high gear gear state. Therefore, a reverse stage with a correspondingly smaller gear ratio can be achieved. Therefore, in this case as well, it is possible to prevent the torque greatly amplified by the large gear ratio from being applied to the drive drain system. Note that the warning in step 207 is the same as that in step 202.
and 203.

【Effect of the invention】

As explained above, according to the present invention, even if the engine torque reduction means does not operate normally for some reason, it is possible to prevent input torque exceeding the allowable input from being applied to the drive drain system. An excellent effect can be obtained in that the drive drain system can be protected or durability can be improved.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the gist of the present invention, and FIG. 2 is a block diagram showing the gist of the present invention.
A control system diagram of an automatic transmission for a vehicle and an engine showing an embodiment of the present invention, FIG. 3 is a skeleton diagram showing an outline of the automatic transmission, and FIG. 4 shows each friction engagement device of the automatic transmission. FIG. 5 is a flowchart showing the control flow executed by the ECT computer. 20...Engine, 22...Automatic transmission, 24...Main throttle valve, 26...Sub throttle valve, 32...EFI computer, 34...TRC computer, 36...ECT Computer.

Claims (1)

[Claims] (1) In a power control device for a vehicle with an automatic transmission, the power control device for a vehicle with an automatic transmission is configured to prevent an input torque exceeding an allowable torque from being applied to a drive drain system by reducing engine torque using an engine torque reduction means. Means for detecting whether or not the engine torque reduction means has failed; and means for setting the gear of the automatic transmission to a high speed side when it is determined that the engine torque reduction means has failed. A power control device for a vehicle with an automatic transmission, characterized by: