JPS585449A - Control device of engine - Google Patents

Abstract

PURPOSE:To accurately perform control without causing the surging phenomenon, in the control of various controllers in accordance with temperature of an engine, by performing the control on the basis of a maximum value of wall surface temperature of the engine for a prescribed period. CONSTITUTION:For instance, in a water pump driving controller, wall surface temperature of an engine 1 is detected by a sensor 14 and input to a control circuit 13. This input is converted into a voltage signal by a temperature detector circuit 23 and synchronized with a sampling period signal of an oscillator circuit 24 to hold a maximum value in its period by a circuit 25, then the maximum value is sampled by a circuit 26 to control speed of a motor 12 through an output control circuit 27 and amplifier circuit 28. Accordingly, a pump is controlled by direct engine wall temperature further by the maximum value in a prescribed period, and the pump can be controlled in a good response further in good accuracy to adequate temperature without being affected by change of a thermal cycle of the engine and without causing the surging phenomenon.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an engine control device, and particularly to one in which various control devices are controlled in accordance with engine temperature.

Generally, various control devices such as an engine air-fuel ratio control device, ignition timing control device, exhaust recirculation control device, etc. are controlled according to the engine temperature in order to perform optimal control according to the engine operating state. . (Unexamined Japanese Patent Publication No. 54-47
(Refer to Publication No. 014) Recently, the speed of the water pump for circulating cooling water inside the engine has been increased by using its own motor or by connecting the engine via a variable pulley or clutch. A water pump drive control device (Utility Model Application No. 51-138630) in which the ratio is variable, that is, the drive is controlled independently to reduce drive loss and improve fuel efficiency, as well as to precisely control engine temperature. No. Publication, Utility Model No. 51
138631) has been proposed.

By the way, when controlling such various control devices according to the engine temperature, detecting the temperature of the engine wall near the combustion chamber of the engine is a direct and accurate way to detect the engine temperature. Directly affected by temperature, engine thermal cycle fluctuations, i.e. intake, compression,
There is a problem in that surging phenomena occur in various control devices due to various thermal fluctuations during the explosion and exhaust strokes.

Therefore, in view of the above, the present invention provides a temperature sensor whose temperature-sensing section contacts the engine wall surface near the combustion chamber and detects the engine wall surface temperature when controlling various control devices according to the engine temperature as described above. is provided, and the output of the temperature sensor (
Engine wall temperature signal) within a predetermined period (within cycle)
By sampling and detecting the maximum value of It is an object of the present invention to provide an engine control device that detects temperature at different times and thereby controls various control devices with high accuracy without causing a surging phenomenon.

Hereinafter, the present invention will be described in detail based on embodiments shown in the drawings.

FIG. 1 shows an example in which various control devices of the present invention are applied to a water pump drive control device, where 1 is an engine, 2 is a water pump for circulating cooling water inside the engine 1, and 3 is a radiator. The engine 1 and the radiator 3 are connected by a first circulation path 4a and a first circulation return path 4b to form a first circulation path 4, and the first circulation path 4 is connected to the first circulation path 4a. A bypass passage 5 that branches off from the middle of the radiator 3 and bypasses the radiator 3 is arranged in parallel, and a thermostat 6 is disposed at the branch part of the bypass passage 5 with the first circulation passage 4a, so that the cooling water temperature is lower than the set value. When the engine is cold, the thermostat 6 is closed to close the first circulation path 4a and open the bypass passage 5, thereby bypassing the cooling water without circulating it to the radiator 3, promoting warm-up of the engine 1, and cooling. After engine warm-up is completed when the water temperature is higher than the set value, the thermostat 6 is opened to close the bypass passage 5 and open the first circulation passage 4a, thereby circulating the cooling water to the radiator 3 and cooling the engine 1 normally. It is designed to be efficient. Further, 7 is a second circulation passage for circulating the cooling water of the engine 1 to the heater core 8, and the downstream end of the second circulation passage 7 is connected to the middle of the bypass passage 5, and the downstream end of the second circulation passage 7 is connected to the middle of the bypass passage 5. A part of the return circulation path 4b is also used as a part of the second circulation passage 7.

A switching valve 9 is interposed in the middle of the second circulation passage 7, and when the switching valve 9 is opened, the cooling water is circulated to the heater core 8.
(not shown) to generate warm air.

Reference numeral 10 denotes a drive device comprising a motor 12 that independently drives and controls the water pump 2 via a belt transmission mechanism 11 so that the speed ratio is variable with respect to the rotation of the engine 1; A control circuit 13 for controlling the motor 12 is connected to the motor 12 of the device 10 .

Further, 14 is a temperature sensor for detecting the engine wall surface temperature, and as shown in FIGS. 2 and 3, the temperature sensor 14 has grooves 15a and 15b extending in the shape of wings on both sides in the engine wall 1a. A cylindrical sensor insertion hole 15 is formed, and the bottom surface of the insertion hole 15 is connected to the combustion chamber 1 of the engine 1.
One groove portion 15 of the charging hole 15 faces the side b.
A faces the cooling water passage 16 at a substantially intermediate position between the combustion chamber 1b and the cooling water passage 16 formed in the engine wall 1a. In the charging hole 15, one of the grooves 15a is provided.
A cylindrical temperature sensing portion 17 having a protrusion 17a fitted into the
The protrusion of the temperature sensing portion 17 17a
is pressed against the bottom surface of one groove 15a of the sensor insertion hole 15 by a spring 20 inserted into the other groove 15bK with a constant pressure. Further, the terminal 21 of the temperature sensing section 17 is connected to a lead-out hole 22 formed in the plug body 18.
It is led out to the outside via and connected to the control circuit 13, and is therefore configured to detect the engine wall surface temperature on the side surface of the temperature sensing section 17 and input the detection signal to the control circuit 13. .

The control circuit 13 includes, as shown in FIG. 4, a temperature detection circuit 23 that outputs a voltage signal corresponding to the engine wall surface temperature in accordance with the detection signal (resistance value signal) of the temperature sensor 14;
An oscillation circuit 24 that outputs a sampling period signal with a predetermined period (for example, a period equivalent to 2 rotations in the case of a 4-cycle engine) that is variable depending on the engine rotation speed, and receives the output of the temperature detection circuit 23 and the oscillation circuit 24. - a maximum value holding circuit 25 that holds the maximum value (peak value) of the output signal of the temperature detection circuit 23 within the sampling period;
, a sampling circuit 26 that samples the maximum value signal of the maximum value holding circuit 25 in synchronization with the sampling period signal of the oscillation circuit 24;
The output current control circuit 27 controls the output current to the motor 12 according to the output signal of the output current control circuit 27, and the amplifier circuit 28 amplifies the output current signal of the output current control circuit 27. Then, the field current to the excitation coil 12a of the motor 12, which is supplied with power from the power supply B, is controlled via the transistor Tr, and the relay wind is turned ON by the output current signal, so that the field current is supplied to the excitation coil 12b of the motor 12 from the power supply B. By energizing motor 1
2 (drive device 10) according to the maximum value of the engine wall surface temperature within a predetermined sampling period.

In addition, in FIG. 4, S is a key switch.

Next, the operation of the above embodiment will be described. The temperature sensor 14 detects the wall surface temperature of the engine 1, and this detection signal is input to the control circuit 13. In the control circuit 13, the detection signal from the temperature sensor 14 is converted into a voltage signal corresponding to the engine wall temperature by a temperature detection circuit 23, and then a maximum value within a predetermined sampling period is set by a maximum value holding circuit 25. is held,
This maximum value signal is sampled by the sampling circuit 26. Subsequently, in response to the output signal from the sampling circuit 26, the output current control circuit 27 outputs an output current signal corresponding to the output current to the motor 12, which is preset based on the engine wall surface temperature, and the output current signal is output from the amplifier circuit 28.
After being amplified, the signal is input to the motor 12. As a result, the field current of the motor 12 is controlled according to the output current signal, and the rotation speed of the motor 12, that is, the rotation speed of the water pump 2, is controlled according to the maximum value of the engine wall surface temperature within a predetermined sampling period. , temperature control of the engine 1 is performed.

In that case, the drive control of the water pump 2 is performed based on the direct engine wall temperature and the maximum value of the engine wall temperature that begins within a predetermined period, so it is not affected by the thermal cycle fluctuations of the engine 1 and can be monitored. Since the wall surface temperature is detected at a certain period of high demand, no surging phenomenon occurs in the water pump 2, and the temperature of the engine 1 can be controlled to an appropriate temperature with good responsiveness and accuracy. In particular, in this embodiment, the temperature sensing portion 17 of the temperature sensor 14 detects approximately the average temperature of the wall surface temperature on the combustion chamber 1b side and the wall surface temperature on the cooling water passage 16 side at its side surface (protrusion 17a). Therefore, the temperature of the engine 1 can be detected more accurately once without being affected by thermal cycle fluctuations in the combustion chamber 1b, and the temperature control of the engine 1 can be further made more accurate.

Note that the present invention is not limited to the above-mentioned embodiment, and includes various other modifications. For example, in the above-mentioned embodiment, the water pump 2 has a speed ratio relative to the rotation of the engine 1. As a drive device 10 that performs variable drive control, a motor 12 that is driven independently of the engine 1 is provided,
Although the motor 12'◆ drives and controls the water pump 2 via the belt transmission mechanism 11, it is also possible to connect the engine 1 and the water pump 2 via a variable pulley or a clutch to control the water pump 2. Of course, the drive may be controlled, but the motor as in the above embodiment is preferable in terms of ease of control.

Further, in the above embodiment, the case of controlling a water pump drive control device was described, but the present invention C also applies to control of various control devices such as an air-fuel ratio control device, an ignition timing control device, an exhaust gas recirculation control device, etc. Needless to say, it can be applied in the same way.

As explained above, according to the present invention, in controlling various engine control devices according to engine temperature, control is performed based on the maximum value of engine wall surface temperature within a predetermined period. It is possible to accurately control various control devices without causing a surging phenomenon.

[Brief explanation of the drawing]

The drawings illustrate embodiments of the present invention, and FIG. 1 is a diagram showing the engine cooling water circulation system, FIG. 2 is a cross-sectional view showing the installed state of the temperature sensor, and FIG. II[-
1 [line sectional view, FIG. 4 is a block diagram of the control circuit. DESCRIPTION OF SYMBOLS 1... Engine, 1b... Combustion chamber, 2... Water pump, 10... Drive device, 12... Motor, 1
3... Control circuit, 14... Temperature sensor, 23...
To the temperature detection circuit 24...Oscillation circuit, 25...Maximum value holding circuit, 26...Sampling circuit, 27...Output current control circuit.

Claims (1)

[Claims] (1) A temperature sensor whose temperature sensing part contacts the engine wall near the combustion chamber to detect the engine wall temperature, and receives the output of the temperature sensor and performs various controls according to the maximum value within a predetermined period of time. An engine control device comprising a control circuit for controlling the device.