JPH01249537A - Speed change control device - Google Patents

Abstract

PURPOSE:To reduce the load of an engine by increasing the rotational speed of the engine when the temperature of lubrication oil for transmitting a power within a torque converter disposed in a transmission is below a predetermined value. CONSTITUTION:A torque converter 21 for transmitting a power through lubrication oil 23 is disposed in a transmission 2 coupled to an engine 1, and is controlled by a shift control section 3 which is in turn controlled by a speed shift control computer 4 in accordance with a vehicle speed and a throttle opening degree. In this arrangement, there is provided an oil temperature sensor 6 for detecting the temperature of the lubrication oil 23 in the torque converter 21 so that a detection signal from the sensor 6 is delivered to the speed shift control computer 4. Further, when the temperature of the lubrication oil 23 is below a predetermined value, the speed shift point of the transmission 2 is changed to increase the rotational speed of the engine.

Description

[Detailed description of the invention] [Summary] Auto-7 tick (A/T) that automatically determines the gear stage
In a car, when the temperature of the lubricating oil in the transmission is low, the shift control computer software raises the shift point and increases the engine speed to avoid placing a high load on the engine.

[Industrial application field]

The present invention relates to a transmission control device that increases engine speed when lubricating oil in a transmission is at a low temperature.

[Conventional technology]

In A/T vehicles that use a torque converter, if the temperature of the lubricating oil in the transmission (hereinafter referred to as oil temperature) rises too much, the performance of the torque converter and gear train will deteriorate, so an oil temperature sensor is used to warn the user. The system may be configured to turn on the lamp.

[Problem to be solved by the invention]

However, if the oil temperature is too low, another problem occurs.

At low temperatures, the viscosity of the transmission lubricating oil is high, so the engine load is high. Furthermore, since the engine is at a low temperature, low engine speeds will result in poor response to the accelerator, which can also cause knocking.

In such a case, the present invention automatically increases the engine speed to reduce the engine load.

[Means to solve the problem]

FIG. 1 is a basic configuration diagram of the present invention, in which 1 is an engine, 2 is a transmission, 3 is a shift control section, 4 is a speed change control computer, and 5 is a drive shaft. The transmission 2 includes a torque converter 21 and a gear train 22, and is filled with lubricating oil 23.

Reference numeral 6 denotes an oil temperature sensor that detects the temperature of the well-oiled oil 23.

[Effect]

As shown in FIG. 3, the shift control computer 4 has a shift map that determines the gear position (shift) of the transmission 2 based on the relationship between the vehicle speed and the throttle opening. This speed change map is for shift door/tp (1→2, 2 in case of 4 speed).
-3.3-4) and shifter.

There are two gears for running (4→3, 3→2.2→l), but in the illustrated example, only one for downshifting from third gear to second gear (3-2) is shown. However, in the present invention, two types of the same shift map are prepared, and while the oil temperature is below a certain value, shift map 2, which facilitates downshifting, is selected instead of normal shift map 1 (shift map 2 for shift amplifier). Map 2 has the characteristic that it is more difficult to shift up than the normal one).

When shift map 2 is selected, assuming that the current driving state is, for example, at point P, the engine speed becomes higher than normal because the speed change is 3rd speed in shift map I but 2nd speed in shift map 2.

FIG. 2 is a flowchart of the speed change control for performing this map switching. In step S1, it is determined whether the oil temperature is high or low, and if it is lower than a certain value, the shift map is switched to shift map 2 in step S2. If the value is higher than a certain value, the shift map is switched to shift map 1 in step S3.

Step S4 is the original shift control process that outputs a shift signal to the shift control section 3 according to the selected shift map.

〔Example〕

FIG. 4 is a configuration diagram showing an embodiment of the present invention.

Since the oil temperature sensor signal is an analog value, the processing circuit 7
It converts into D and inputs it to the computer 4.

This transmission 2 is equipped with an overdrive mechanism 24 that locks up the fourth gear.

The gear train 22 in FIG. 1 is called an auxiliary transmission, and the shift control section 3 is called a hydraulic control mechanism.

FIG. 5 is a coupling performance curve diagram of the torque converter 21. Of these, the output shaft torque decreases as the output shaft rotational speed increases, so naturally it can be seen that the load becomes lighter in the region of high engine rotational speed.

〔Effect of the invention〕

As described above, according to the present invention, in an A/T vehicle using a torque converter, when the temperature of the lubricating oil in the transmission is below a certain value, the shift point is automatically changed to increase the engine speed. This has the advantage that the engine does not have to drive a high load when the temperature is low.

[Brief explanation of the drawing]

Fig. 1 is a basic configuration diagram of the present invention, Fig. 2 is a flowchart of shift control, Fig. 3 is a shift characteristic diagram of a transmission, Fig. 4 is a block diagram of an embodiment of the present invention, and Fig. 5 is a diagram of a torque converter. It is a binding performance curve diagram. Applicant: Minoru Aoyagi, Patent Attorney, Fujitsu Ten Ltd. Figure 5

Claims (1)

[Claims] 1. In a shift control device for an automatic vehicle, which includes a torque converter in the transmission that transmits power through lubricating oil, and automatically changes the gear position of the transmission by determining the relationship between vehicle speed and throttle opening using a computer. A transmission control device, characterized in that, when it is detected that the temperature of the lubricating oil is below a certain value, the transmission is controlled to change a shift point of the transmission to increase the engine speed.