JP2616154B2 - Gear ratio control device for continuously variable transmission - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a speed ratio control device for a continuously variable transmission.

(Conventional technology and problems to be solved) The DBW (Driver By Wire) system controls the opening and closing of the throttle valve of the engine, and the CVT (Continuos)
In a vehicle equipped with a DBW and a CVT system in which the gear ratio is steplessly controlled by a ly Variable Transmisson (Variable Transmisson) system, an abnormality in the DBW system, for example, an actuator (DC motor or the like) for controlling opening and closing of the throttle valve may cause some trouble. If a failure occurs and the throttle valve is fully open and cannot be controlled, the CVT system is activated to shift down as the vehicle speed decreases even if the driver steps on the brake to stop the vehicle. There is a problem that the force may increase and it may be difficult to stop the vehicle.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and in a gear ratio control device of a continuously variable transmission, when a throttle valve control means (DBW system) for electrically controlling a throttle valve of an engine fails, an accelerator is released. A continuously variable transmission (CVT system) that controls the speed ratio of the continuously variable transmission (CVT system) based on the amount of pedal depression, and further controls the speed ratio of the continuously variable transmission to the minimum speed ratio when the brake pedal is depressed. An object of the present invention is to provide a transmission ratio control device for a transmission.

(Means for Solving the Problems) To achieve the above object, according to the present invention, claim 1 is provided.
An electric throttle valve control means for setting a throttle valve opening disposed in the intake system according to an operation state of the engine, and electrically controlling the throttle valve based on the set valve opening, An accelerator pedal depression amount detecting means for detecting an accelerator pedal depression amount operated by a driver; and Failure detection means for detecting a failure of the throttle valve control means; and, when no failure of the electric throttle valve control means is detected, the speed ratio of the continuously variable transmission so that the speed ratio increases when the vehicle speed decreases. When the failure of the first transmission control means for controlling the operation of the electric throttle valve control means is detected, the speed of the continuously variable transmission is changed based on only the depression amount of the accelerator pedal. Is obtained by a structure in which a second shift control means for controlling.

According to claim 2, a brake operation detecting means for detecting an operation state of a brake pedal operated by a driver, and when it is detected that the brake pedal is depressed, the presence or absence of the failure or the amount of depression of an accelerator pedal Irrespective of the above, a third transmission control means for setting the transmission ratio of the continuously variable transmission to a minimum transmission ratio is further provided.

(Operation) When the failure detection unit does not detect a failure in the electric throttle valve control unit, the transmission ratio control unit changes the speed of the continuously variable transmission so that the transmission ratio increases when the vehicle speed decreases by the first transmission control unit. Control the ratio. Further, when the failure detection means detects the failure of the electric throttle valve control means, the gear ratio control device changes the gear ratio of the continuously variable transmission based on only the depression amount of the accelerator pedal by the second gear change control means. Control.

Further, when the brake operation detecting means detects that the brake pedal is depressed, the speed ratio control device supplies the hydraulic pressure to the hydraulic chamber of the pulley of the continuously variable transmission by the third speed changing means, thereby changing the speed. Control the ratio to the minimum gear ratio. When the brake pedal is depressed and the accelerator pedal is depressed, even if the speed ratio is on the minimum speed ratio side when the brake pedal is depressed and the vehicle is stopped, the third shift control means The gear ratio is shifted to the gear ratio based on the stepping amount, that is, the maximum gear ratio side.

Embodiment An embodiment of the present invention will be described below in detail with reference to the accompanying drawings.

FIG. 1 shows a control system of an engine and a power transmission device of a vehicle to which the present invention is applied.
A fluid coupling of the automatic transmission 3 of the system, for example, connected to an input shaft of the torque converter 4,
Is connected to a drive pulley 7 of a V-belt driven continuously variable transmission (hereinafter referred to as “CVT”) 6 via a planetary gear 5, and the drive pulley 7 is connected to a driven pulley 8 via a V-belt 9. , Output shaft 10 of driven pulley 8
Are axles 13 on the left and right via a gear train 11 and a differential mechanism 12,
Connected to 14.

The drive pulley 7 and the driven pulley 8
These hydraulic chambers 15 and 16 are connected to a hydraulic control valve system 17. The hydraulic control valve system 17 includes a CVT computer 41 described later.
The pulley diameters of the drive pulley 7 and the driven pulley 8 are continuously varied by controlling the hydraulic pressure in the hydraulic chambers 15 and 16 based on the control signal from the controller.

The intake manifold 20 of the engine 1 is a surge tank 21
Is connected to the air cleaner 22 via the Engine 1
The ignition valve 23 disposed on the cylinder head is connected to the ignition coil 24, and the intake manifold 20
An injector 25 and a throttle valve 26 are provided between the surge tank 21 and the air cleaner 22, respectively. The throttle valve 26 is connected to an actuator, for example, a DC motor 28.

Hydraulic chamber of drive pulley 7 and driven pulley 8 of CVT6
Oil pressure sensors 30 and 31 are provided in 15 and 16, and an air flow sensor is provided in the air cleaner 22 to detect the intake air amount of the engine 1.
32 are arranged. The accelerator pedal 27 is provided with an accelerator opening sensor 34. Further, a dashboard (not shown) is provided with a DBW shutdown switch 35 for operating when a driver detects an abnormality of the DBW system and shutting down the DBW system.

Then, the hydraulic sensors 30, 31 and the air flow sensor 32
Is connected to an engine control computer 40, and the accelerator opening sensor 34 and the DBW shutdown switch 35 are connected to a DBW computer 42 for controlling the DBW system and a CVT computer 41 for controlling the CVT system. Furthermore,
The engine control computer 40 receives an engine speed signal from an engine speed sensor (not shown),
A brake signal is input to the computer 41 from a brake sensor (not shown). The DC motor 28 that controls opening and closing of the throttle valve 26 is connected to the DBW computer 42.

The DBW computer 42 outputs a throttle control signal to the motor 28 and outputs a failure signal to the CVT computer 41 when the DBW system fails. Further, the DBW computer 42 receives signals from the engine control computer 40, such as the number of engine revolutions and the amount of intake air. The CVT computer 41 receives a signal input from the accelerator opening sensor 34,
Based on various signals input from the DBW computer 42 and each signal input from the DBW shutdown switch 35, a hydraulic control signal is output and supplied to the hydraulic control valve system 17.

The operation will be described below with reference to the flowchart shown in FIG.

The engine control computer 40 detects the operating state of the engine 1 based on the engine speed signal and the signals input from the sensors 30 to 23, and determines the optimal fuel injection amount, injection timing, ignition timing, etc. according to the operating state. And determine
The injector 25 is driven to inject fuel, and the ignition plug 23 is ignited.

The DBW computer 42 is an engine control computer 40
A throttle opening corresponding to the operating state of the engine 1 is determined based on a signal such as an engine speed and an intake air amount supplied from the engine and a signal from an accelerator opening sensor 34, and a throttle control signal is output to output a motor. 28 to control opening and closing of the throttle valve 26.

As described above, various signals are input to the CVT computer 41. Based on these signals, hydraulic control signals are output and supplied to the hydraulic control valve system 17, and the hydraulic pressure chambers of the drive pulley 7 and the driven pulley 8 are controlled. 15, 16
The pulley diameters are adjusted by controlling the hydraulic pressure supplied to the gears to control the gear ratio.

First, the CVT computer 41 determines whether or not the brake is depressed (off) while the vehicle is running (step 1). If the answer is affirmative (YES), the DBW shutdown switch 35 is turned on. It is determined whether or not it is off (step 2), and if not (NO), the CVT
Is set to the minimum speed ratio (step 3).
Then, the CVT computer 41 determines whether or not the DBW system is operating normally (step 4) when the determination result in step 2 is affirmative (YES), and determines the failure control (step 4) described later when the determination is negative (NO). Go to 5).

The CVT computer 41 determines that the answer to the question in step 4 is affirmative (Y
ES) ie C when the DBW system is working properly
VT6 is controlled normally, and if not (NO), the process shifts to failure control (step 7). The failure control is performed as follows.

For example, it is assumed that the motor 28 that controls the throttle valve 26 for some reason breaks down and the opening / closing control of the throttle valve 26 cannot be performed. DBW Computer 42
Equipped with self-diagnosis function, CVT when DBW system failure
Output that information to the system. That is, the DBW computer 42 outputs a failure signal when the motor 28 fails,
Add to CVT computer 41. Also, throttle valve 2
The same applies when a serious failure occurs, such as when 6 is stuck for some reason and remains fully open.

When the failure signal is input from the DBW computer 42, the CVT computer 41 sets the speed ratio of the CVT to the target speed ratio. For example, as shown in the characteristic diagram of FIG. 4, this target gear ratio is a maximum gear ratio (LOW side) when the accelerator opening is 100% (fully open), and a target gear ratio when the accelerator opening is 0% (fully closed). Is set to a minimum gear ratio (HIGH side), and a gear ratio according to the accelerator opening is set between them. That is, this target gear ratio is written in the map of the CVT computer 41 using the accelerator opening as a parameter.

The CVT computer 41 determines that the answer to step 2 is negative (N
O) In other words, when the driver detects a DBW system error,
When the DBW shutdown switch 35 is turned on, it is determined that there is an abnormality in the DBW system, and the target gear ratio is set from the map based on the accelerator opening signal input from the accelerator opening sensor 34 (FIG. 3). Then, the control at the time of failure (step 5) is performed. Also, CVT computer 41
Performs failure control (step 7) in the same manner as described above even when the answer to the question in step 4 is negative (NO).

This caused the DBW system to fail and throttle valve 2
Even when the vehicle 6 is fully opened, the vehicle can be driven under the minimum conditions without runaway, and the vehicle can travel to the nearest repair shop or home.

Further, if the answer to the question in step 1 is negative (NO), that is, if the brake is depressed while the vehicle is running, the CVT computer 41 controls the target gear ratio of the CVT 6 to the minimum gear ratio (step 3). Moreover, while the brake is being depressed, the CVT computer 41 detects the signal from the accelerator opening sensor 34 even if it detects that the accelerator pedal 27 is being depressed (when the accelerator opening is not 0%). Control CVT6 to gear ratio.

(Effects of the Invention) As described above, according to the present invention, the throttle valve opening provided in the intake system is set in accordance with the operating state of the engine, and the throttle valve is electrically set based on the set valve opening. Depressing an accelerator pedal operated by a driver in a system including an electric throttle valve control means for controlling the throttle valve, and a continuously variable transmission connected to the engine and capable of continuously changing a gear ratio. Accelerator pedal depression amount detecting means for detecting the amount, failure detecting means for detecting a failure of the electric throttle valve control means, and when no failure of the electric throttle valve control means is detected, when the vehicle speed decreases, the gear ratio The first transmission control means for controlling the speed ratio of the continuously variable transmission so that the speed of the continuously variable transmission becomes large, and when the failure of the electric throttle valve control means is detected, the accelerator pedal A second speed change control means for controlling the speed ratio of the continuously variable transmission based only on the stepping amount of the dull, so that it is impossible to control the throttle valve, which is the worst failure for the electric throttle valve control means. In such a case, there is an excellent effect that runaway of the vehicle can be avoided and the limp home function can be maintained.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a speed ratio control device for a continuously variable transmission according to the present invention, and FIGS. 2 and 3 are flowcharts showing a control method of the speed ratio control device for a continuously variable transmission of the present invention. The figure shows the throttle opening of the transmission ratio control device for the continuously variable transmission of FIG.
FIG. 5 is a characteristic diagram showing a relationship between a CVT and a target speed ratio. 1 ... Engine, 3 ... Automatic transmission, 6 ... CVT, 15, 1
6… Hydraulic chamber, 17… Hydraulic control valve system, 26 …… Throttle valve, 27 …… Accelerator pedal,
28 …… Motor, 30, 31 …… Hydraulic sensor, 32 …… Air flow sensor, 34 …… Accelerator opening sensor, 35 …… DBW shutdown switch, 40 …… Engine control computer, 41 …… CVT computer, 42 …… DBW computer.

Continued on the front page (72) Inventor Kazuhide Tsugai 5-33-8 Shiba, Minato-ku, Tokyo Inside Mitsubishi Motors Corporation (72) Inventor Keishi Takatsuka 5-33-8 Shiba, Minato-ku, Tokyo Mitsubishi (56) References JP-A-62-53248 (JP, A) JP-A-2-253046 (JP, A) JP-A-2-112937 (JP, U)

Claims (2)

(57) [Claims] An electric throttle valve control for setting a throttle valve opening disposed in an intake system in accordance with an operation state of an engine and electrically controlling the throttle valve based on the set valve opening. And a stepless transmission that is connected to the engine and that can change a gear ratio in a stepless manner. An accelerator pedal depression amount detection unit that detects an accelerator pedal depression amount operated by a driver, and A failure detecting means for detecting a failure of the electric throttle valve control means; and a failure detecting means for detecting the failure of the electric throttle valve control means. First speed change control means for controlling the speed change ratio of the electric throttle valve control means, and when a failure of the electric throttle valve control means is detected, the stepless change is performed based only on the accelerator pedal depression amount. Gear ratio control device for a continuously variable transmission, characterized in that a second shift control means for controlling the transmission ratio of the machine. 2. A gear ratio control device for a continuously variable transmission according to claim 1, wherein a brake operation detecting means for detecting an operation state of a brake pedal operated by a driver, and wherein the brake pedal is depressed. And a third shift control means for setting the speed ratio of the continuously variable transmission to a minimum speed ratio regardless of the presence or absence of the failure or the depression amount of an accelerator pedal when detected. Transmission gear ratio control device.