JP2999285B2 - Engine control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for an engine combined with an automatic transmission.

[0002]

2. Description of the Related Art In an automatic transmission having a lock-up clutch capable of connecting a pump impeller of a hydraulic power transmission and a turbine runner, the engine stops when the vehicle stops while the lock-up clutch is engaged. become. Therefore, the control device is configured to release the lock-up clutch in a low vehicle speed range. However, when the vehicle is suddenly braked and stopped, there is a possibility that the lock-up clutch is not released in time. For this reason, Japanese Unexamined Patent Publication
Japanese Patent Application Laid-Open No. 9-103064 discloses a configuration in which when the engine rotation speed decreases at a speed higher than a predetermined speed during a brake operation, the lock-up clutch is released even before the vehicle speed decreases to a predetermined value. Have been. This prevents the engine from stopping.

[0003]

In the above prior art,
Only when the foot brake is actuated and the vehicle is suddenly decelerated, the lock-up clutch is released earlier. In other cases, the effect of preventing the engine from stopping due to the lock-up clutch is obtained. It is not possible. That is, even if the valve of the hydraulic control device releases the lock-up clutch and enters a hydraulic operation state in which the lock-up clutch piston is actually released, the frictional force of the lock-up clutch piston that rotates relatively to a small clearance causes the valve to relatively release. The state where small torque is transmitted may be continued. If the vehicle decelerates and stops in such a state, the engine may stop due to engine conditions or the like. An object of the present invention is to solve such a problem.

[0004]

SUMMARY OF THE INVENTION According to the present invention, a friction state of a lock-up device is detected from a ratio of rotation speeds of a pump impeller and a turbine runner, and when the friction is large, the idling rotation speed of the engine is increased. By
Solution to the Problems That is, the engine control device according to the present invention includes a pump rotation speed sensor that detects a rotation speed on the pump impeller side, a turbine rotation speed sensor that detects a rotation speed on the turbine runner side, a rotation speed of the pump impeller and a rotation speed of the turbine runner. Calculating means for calculating the ratio of the rotation speed to the rotation speed of the pump impeller; and the idling control device when the rotation speed of the pump impeller and the rotation speed of the turbine runner are equal to or less than the predetermined value. And idling rotation speed increasing means for outputting a signal for instructing an increase in idling rotation speed.

[0005]

When the ratio of the rotation speed of the pump impeller to the rotation speed of the turbine runner is smaller than a predetermined value, that is, when a certain amount of torque is transmitted from the pump impeller to the turbine runner, the idling of the engine is stopped. A signal is output to the control device, and the idling rotation speed increases. That is, in a state where the torque of the engine is transmitted to the turbine runner to some extent, the engine rotation speed increases, and the engine is prevented from stopping when the vehicle stops.

[0006]

FIG. 2 shows an embodiment of the present invention. Engine 1
0, the automatic transmission 12 is combined. The engine 10 includes a fuel injection device 14 (idling control device). The fuel injection device 14 can adjust the amount of fuel to be supplied to the cylinder of the engine 10 in accordance with an applied electric signal, and controls the supplied fuel so as to have a predetermined idling rotational speed particularly during idling.
The operation of the fuel injection device 14 is controlled by the control unit 18.
Controlled by a signal from The automatic transmission 12 has a torque converter 20 (fluid transmission) with a lock-up clutch 40 (lock-up device). The lock-up clutch 40 can connect the pump impeller 42 and the turbine runner 44. Signals from the pump rotation speed sensor 24 and the turbine rotation speed sensor 26 are input to the control unit 18. The pump rotation speed sensor 24 can detect the rotation speed of the pump impeller 42 (this is the same as the rotation speed of the engine 10, so the pump rotation speed sensor 24 is actually an engine rotation speed sensor). Turbine rotation speed sensor 26
Can detect the rotation speed of the turbine runner 44.

The control of the engine speed in the idling state is performed according to a control flow shown in FIG. First, the rotational speed NP (engine rotational speed) of the pump impeller 42 is read from the pump rotational speed sensor 24 (step 5).
0), the rotational speed NT of the turbine runner 44 is read from the turbine rotational speed sensor 26 (52). Then, R
= NP ÷ NT (54), it is determined whether the calculated R is smaller than a predetermined value R1 (56), and if the condition is not satisfied, the processing is terminated without performing any special operation. On the other hand, if R is smaller than R1, it is determined whether or not the pump impeller rotation speed NP is smaller than a predetermined value N1 (No. 58). If the condition is not satisfied, the process is terminated, while NP is smaller than N1. In this case, the amount of increase in the engine rotation speed is calculated (60). The amount of increase in the engine speed is determined in inverse proportion to the value of R described above. In other words, the smaller the value of R, the larger the increase in the calculated engine rotational speed. Next, a command signal is output to the fuel injection device 14 so as to actually increase the engine rotation speed by the calculated increase amount of the engine rotation speed (No. 62). Step 54 constitutes the calculating means, and steps 56, 58 and 62 constitute the idling rotation speed increasing means. As a result, due to the above control, when the ratio R between NP and NT is smaller than R1, that is, the rotation speed NT of the turbine runner 44 is relatively close to the rotation speed NP of the pump impeller 42, and the slip of the lock-up clutch 40 decreases. When it is determined that the pump impeller rotation speed NP is low, that is, the engine rotation speed is low and the engine is in an idling state, control for increasing the idling rotation speed of the engine 10 is performed. As a result, the lock-up clutch 40
However, when a certain amount of torque is transmitted by this friction, the engine rotation speed increases, and the engine can continue rotating without stopping.

[0008]

As described above, according to the present invention, the friction state of the lock-up device is detected from the ratio of the rotation speed of the pump impeller to the rotation speed of the turbine runner.
Since the engine speed is increased in a state in which a certain amount of frictional force is transmitted, it is possible to reliably prevent the engine from stopping when the vehicle stops.

[Brief description of the drawings]

FIG. 1 is a diagram showing a relationship between components of the present invention.

FIG. 2 is a diagram showing an embodiment of the present invention.

FIG. 3 is a diagram showing a control flow.

[Explanation of symbols]

 Reference Signs List 10 engine 12 automatic transmission 14 fuel injection device (idling control device) 18 control unit 20 torque converter (fluid transmission device) 24 pump rotation speed sensor 26 turbine rotation speed sensor 40 lock-up clutch (lock-up device) 42 pump impeller 44 turbine Runner

Continuation of the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) F02D 41/16 B60K 41/04 F02D 29/00 F02D 29/02 331 F02D 41/08 330 F16H 61/14

Claims (2)

(57) [Claims] An engine used in combination with an automatic transmission having a fluid transmission with a lock-up device capable of fastening a pump impeller and a turbine runner,
In an engine control device having an idling control device capable of adjusting an idling rotational speed, a pump rotational speed sensor for detecting a rotational speed on a pump impeller side, a turbine rotational speed sensor for detecting a rotational speed on a turbine runner side, and a pump impeller Calculating means for calculating the ratio of the rotation speed of the turbine runner to the rotation speed of the turbine runner; and the ratio of the rotation speed of the pump impeller to the rotation speed of the turbine runner is equal to or less than a predetermined value. In the case of (1), an idling rotation speed increasing means for outputting a signal for instructing the idling control device to increase the idling rotation speed. 2. The idling rotational speed increasing means is configured to increase the amount of increase in the idling rotational speed as the value of the ratio between the rotational speed of the pump impeller and the rotational speed of the turbine runner decreases. Engine control device.