JPH0350101B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to an engine control device, and particularly to an engine control device that controls the drive of a water pump in accordance with the engine temperature to control the amount of circulating water in accordance with the engine temperature. The present invention relates to an engine in which various combustion control devices of the engine are controlled according to engine temperature.

(Prior Art) Conventionally, a water pump for circulating cooling water inside an engine has been driven directly by the engine at a constant speed ratio with respect to engine rotation. However, recently, in order to reduce driving loss and improve fuel efficiency, as well as precisely control engine temperature, water pumps have been
By using its own motor or by connecting it to the engine via a variable pulley or clutch, the speed ratio can be varied with respect to the engine rotation, that is, it can be driven independently of the engine rotation. (Utility Model Application Publication No. 138630, Utility Model Application Publication No. 1973)
-Refer to Publication No. 138631) has been proposed.

(Problem to be solved by the invention) By the way, the water pump, which can be driven independently of the engine rotation, is controlled in accordance with the engine temperature, and the amount of circulating water is controlled in accordance with the engine temperature. In an engine, when controlling various engine combustion control devices such as an exhaust recirculation control device and an air-fuel ratio control device according to the engine temperature, the amount of circulating water changes depending on the engine temperature, especially when the engine is cold. As a result, the detected engine temperature value tends to fluctuate depending on factors such as the engine type and the concentration of antifreeze in the cooling water, making it impossible to accurately detect the temperature of the entire engine. There is a problem in that it lacks precision as a warm-up signal for various combustion control devices and cannot control the various combustion control devices with high precision. In particular, inside the engine, there are high-temperature regions and low-temperature regions even when the vehicle is running, and when the circulation speed of cooling water is slow, this tendency becomes more pronounced, and the above-mentioned problem becomes more pronounced.

In view of this, the present invention provides an engine in which the water pump, which can be driven independently of engine rotation, is controlled in accordance with the engine temperature, as described above, in which the temperature of the low-temperature part of the engine inside the engine and The temperature of each high-temperature part of the engine is detected, and the calculated value is calculated using both the two-point temperature measurement signals of the temperature of the low-temperature part of the engine and the temperature of the high-temperature part of the engine (in other words, the temperature of one detected temperature is By controlling various combustion control devices such as the exhaust recirculation control device based on the correction value corrected based on the other detected temperature, the engine temperature can be controlled even when the engine is cold, with a small amount of circulating water and a slow circulation speed. It is an object of the present invention to provide an engine control device that can accurately detect a warm-up signal and control various combustion control devices with high precision using this accurate warm-up signal.

In this case, instead of detecting, for example, the average temperature as a calculated value (corrected value) using the two-point temperature measurement method, one sensor measures the temperature at an intermediate position between the low-temperature part of the engine and the high-temperature part inside the engine. It is possible to detect the average temperature, but the location where the average temperature is detected changes depending on the operating conditions, so
This one-point temperature measurement method is difficult to adopt because the temperature detection position cannot be specified.

(Means for Solving the Problems) In order to achieve the above object, the solving means of the present invention includes a water pump for circulating cooling water inside the engine, and a drive control of the water pump according to the engine temperature. The present invention is based on an engine that is equipped with a drive device and that controls the amount of circulating water in accordance with the engine temperature. A first temperature sensor provided inside the engine detects the temperature of a low temperature section inside the engine, a second temperature sensor provided inside the engine and detects the temperature of a high temperature section inside the engine, and a second temperature sensor provided inside the engine that detects the temperature of a high temperature section inside the engine. Output signal and second
A control circuit is provided that receives the output signal of the temperature sensor and compares a correction value obtained by correcting one detected temperature with the other detected temperature with a preset setting value to control various combustion control devices of the engine. shall be

(Function) Accordingly, in the present invention, the temperature of the low temperature part inside the engine is detected by the first temperature sensor, and the temperature of the high temperature part inside the engine is detected by the second temperature sensor, and these detection signals are are respectively input to the control circuit. The control circuit calculates a correction value by correcting one detected temperature by the other detected temperature using both the detection signal from the first temperature sensor and the second temperature sensor, and calculates this correction value. Various combustion control devices of the engine are controlled by comparing the value with a preset value.

At this time, the combustion control device is controlled based on a correction value that reflects both the temperature of the low-temperature part and the temperature of the high-temperature part inside the engine, so even when the engine is cold with a small amount of circulating water and a slow circulation speed. The engine temperature as a warm-up signal can be accurately detected without being influenced by the engine type, antifreeze temperature, etc., and therefore the combustion control device can be controlled with high precision.

(Example) Hereinafter, an example of the present invention will be described in detail based on the drawings.

In FIG. 1, 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. A bypass passage 5 that branches off from the middle of the first circulation passage 4a and bypasses the radiator 3 is provided in parallel to the first circulation passage 4, and a thermos A tattoo 6 is provided. Therefore, when the coolant temperature is lower than the set value and the engine is cold, the thermostat 6 is closed to close the first circulation path 4a and open the bypass passage 5, so that the coolant is not circulated to the radiator 3 but is bypassed and the engine is cooled. 1
On the other hand, after the engine warms up when the cooling 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. The engine 1 is cooled normally. 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, cooling water is circulated to the heater core 8, and the heater core 8 directs air from a blower (not shown). is configured to generate warm air.

Reference numeral 10 denotes a motor that independently drives 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 12 is connected to control the control circuit 1.
2, a third temperature sensor 13 that detects the engine temperature (temperature near the combustion chamber of the engine or cooling water temperature);
is connected.

As shown in FIG. 2, the control circuit 12 includes a third temperature detection circuit 14 that outputs a voltage signal corresponding to the engine temperature in accordance with the detection signal (resistance value signal) of the third temperature sensor 13; 3 Temperature detection circuit 1
4, and an amplifier circuit 16 that amplifies the output current signal of the output current control circuit 15. Become.
Then, according to the output current signal, the field current to the excitation coil 10a of the motor 10 that is supplied with power from the power source B is controlled via the transistor Tr, and the output current signal
By turning on MR and energizing the armature 10b of the motor 10 from the power source B, the motor 10
The drive is controlled according to the engine temperature. The motor 10, belt transmission mechanism 11, control circuit 12, and third temperature sensor 13 constitute a drive device 17 that drives and controls the water pump 2 according to the engine temperature. It is configured to control according to the In addition, in FIG. 2, S is a key switch.

On the other hand, reference numeral 18 denotes an exhaust gas recirculation passage that recirculates a part of the exhaust gas discharged from the engine 1 to the intake passage 19. A control valve 20 is provided. The reflux control valve 20 is
A valve body 21 that opens and closes the exhaust gas recirculation passage 18, a diaphragm 23 that supports the valve body 21 via a rod 22, a negative pressure chamber 24 defined by the diaphragm 23, and the negative pressure chamber 24. The spring 25 is compressed inside. The negative pressure chamber 24
communicates with the intake passage 19 immediately upstream of the fully closed position of the throttle valve 27 via the negative pressure introduction passage 26, and an atmospheric release port 28 is provided in the middle of the negative pressure introduction passage 26. A solenoid valve 29 for opening and closing the atmosphere opening port 28 is disposed at 28 . When the solenoid valve 29 is turned on, the atmosphere opening port 28 is closed and intake negative pressure is introduced into the negative pressure chamber 24 through the negative pressure introduction passage 26, thereby causing the diaphragm 23 to resist the spring force of the spring 25. When the solenoid valve 29 is turned OFF, the valve body 21 is opened and the exhaust gas recirculation passage 18 is opened to recirculate the exhaust gas to the intake passage 19. When the solenoid valve 29 is turned OFF, the atmosphere release port 28 is opened. By opening the negative pressure chamber 24 to the atmosphere, the diaphragm 23 is biased downward as shown in the figure by the spring force of the spring 25, and the valve body 21 is operated to close, thereby closing the exhaust gas recirculation passage 18 and preventing the recirculation of the exhaust gas. An exhaust gas recirculation control device 30, which is a type of combustion control device, is configured to control the combustion to stop.

Furthermore, a first temperature sensor 31 is disposed in a low-temperature part of the engine 1 such as a lower part of the cylinder block and detects the temperature of the low-temperature part of the engine 1;
Reference numeral 2 denotes a second temperature sensor that is disposed in a high-temperature part such as near the combustion chamber inside the engine 1 and detects the temperature of the high-temperature part of the engine 1, and each temperature sensor 3
1 and 32 are each connected to a control circuit 33, and the above-mentioned solenoid valve 29 is connected to the control circuit 33.

As shown in FIG. 3, the control circuit 33 is a first temperature detection circuit that outputs a voltage signal corresponding to the temperature of the low temperature part of the engine 1 in response to a detection signal (resistance value signal) of the first temperature sensor 31. 34, a second temperature detection circuit 35 that outputs a voltage signal corresponding to the temperature of the high temperature portion of the engine 1 according to the detection signal of the second temperature sensor 32, and from the first and second temperature detection circuits 34 and 35. An arithmetic circuit 36 that outputs an average value signal obtained by averaging both detected temperatures as an example of a correction value in which one detected temperature is corrected by the other detected temperature using both output signals, and an average value signal of the arithmetic circuit 36. The solenoid valve 29 is compared with a preset setting value.
Output current signal (ON−
an output current control circuit 37 that outputs an OFF signal);
and an amplifier circuit 38 for amplifying the output current signal from the output current control circuit 37. Then, the solenoid valve 29 is turned on and off according to the output current signal.
Therefore, the exhaust gas recirculation control device 30 is controlled in accordance with the average temperature as a correction value determined by reflecting both the temperature of the low temperature part and the temperature of the high temperature part inside the engine 1, and the average temperature is When the engine is cold, which is lower than the set value, the solenoid valve 29 is turned OFF to stop the recirculation of exhaust gas, while when the normal temperature is higher than the set value, the solenoid valve 29 is turned OFF after the engine is warmed up.
This is to control the exhaust gas to be recirculated by turning it on.

Next, the operation of the above embodiment will be explained.
The engine temperature is detected by the third temperature sensor 13, and this detection signal is input to the control circuit 12. Then, in the control circuit 12, the third
The detection signal from the temperature sensor 13 is converted by the third temperature detection circuit 14 into a voltage signal corresponding to the engine temperature, and then the output current control circuit 15 outputs a preset output current to the motor 10 based on the engine temperature. An output current signal corresponding to is output, amplified by an amplifier circuit 16, and input to the motor 10. As a result, the field current of the motor 10 is controlled according to the output current signal,
The rotation speed of the motor 10, that is, the water pump 2
The rotational speed of the engine is controlled appropriately according to the engine temperature. Therefore, the amount of circulating water circulating inside the engine 1 is appropriately controlled according to the engine temperature, the temperature of the engine 1 is accurately controlled to an appropriate temperature, and good engine cooling performance can be ensured.

On the other hand, the first temperature sensor 31 detects the temperature of the low temperature part inside the engine 1, and the second temperature sensor 32 detects the temperature of the high temperature part inside the engine 1, and these detection signals are sent to the control circuit. 33. In the control circuit 33, the detection signals from the first and second temperature sensors 31 and 32 are sent to the first and second temperature detection circuits 34 and 32, respectively.
35 converts it into a voltage signal corresponding to the temperature of the low temperature part inside the engine 1 and the temperature of the high temperature part inside the engine 1, and then the arithmetic circuit 36 converts both the temperature of the low temperature part and the temperature of the high temperature part of the engine 1 into a voltage signal corresponding to the temperature of the low temperature part and the temperature of the high temperature part inside the engine 1. An average value signal corresponding to the average value as a correction value obtained using An output current signal (ON-OFF signal) corresponding to the output current to the valve 29 is output, amplified by the amplifier circuit 38, and then input to the solenoid valve 29.

In that case, when the engine is cold and the average value signal is lower than the set level, the solenoid valve 29 is turned OFF by the OFF signal from the output current control circuit 37.
As a result, the atmosphere opening port 28 is opened, the valve body 21 of the exhaust gas recirculation control device 30 is closed, the exhaust gas recirculation passage 18 is closed, and the exhaust gas is not recirculated. On the other hand, after the engine warm-up is completed when the average value signal is higher than the set level, the solenoid valve 29 is turned ON by the ON signal from the output current control circuit 37, thereby blocking the atmosphere opening 28 and controlling the exhaust gas recirculation. The valve body 21 of the device 30 is opened, the exhaust gas recirculation passage 18 is opened, the exhaust gas is recirculated, and NO _x is reduced.

At that time, the solenoid valve 2 of the exhaust recirculation control device 30
9 is controlled according to the average temperature as a correction value obtained using both the temperature of the low temperature part and the temperature of the high temperature part inside the engine 1, so when the engine is cold with a small amount of circulating water and a slow circulation speed. Also, the engine temperature as a warm-up signal can be accurately detected without being influenced by the engine type, antifreeze concentration, etc., and therefore the exhaust gas recirculation control device 30 can be controlled with high precision.

It should be noted that the present invention is not limited to the above-mentioned embodiments, but also includes various other modifications. For example, in the above embodiment, the water pump 2 is driven by the unique motor 10 at a variable speed ratio relative to the engine rotation, but the engine 1 and the water pump 2 may be driven by a variable pulley or clutch, etc. Of course, the motors may be coupled together to drive the water pump 2, but in terms of ease of control, a motor like the one in the above embodiment is preferable.

Further, in the above embodiment, a case has been described in which the exhaust gas recirculation control device 30 is controlled based on the outputs of the first and second temperature sensors 31 and 32, but other than that,
Needless to say, the present invention can be similarly applied to various engine combustion control devices such as air-fuel ratio control devices.

Furthermore, in the above embodiment, the exhaust gas recirculation control device 30 is controlled according to the average temperature of the low temperature part of the engine 1 and the temperature of the high temperature part of the engine 1, but the point is that the detected temperature of the low temperature part inside the engine It is configured to calculate a correction value by correcting one detected temperature by the other detected temperature using the detected temperature of the high temperature section, and compare this correction value with a preset setting value to control various combustion control devices. do it.

(Effects of the Invention) As explained above, according to the present invention, in an engine in which the amount of circulating water by the water pump is controlled according to the engine temperature, various combustion control devices of the engine are controlled in the low-temperature section inside the engine. By using both the detected temperature and the detected temperature of the high-temperature section, a correction value is calculated by correcting one detected temperature by the other detected temperature, and this correction value is compared with the set value for control. Accurately detects the engine temperature as a control signal for the combustion control device even when the engine is cold, with a small amount of circulating water and a slow circulation speed, and accurately controls various combustion control devices according to operating conditions and operational demands. It is something that can be done.

[Brief explanation of drawings]

The drawings illustrate embodiments of the present invention.
FIG. 2 is a schematic diagram showing an engine cooling water circulation system, FIG. 2 is a block diagram of a control circuit for a water pump driving motor, and FIG. 3 is a block diagram of a control circuit for an exhaust gas recirculation control device. 1...Engine, 2...Water pump, 10
... Motor, 12 ... Control circuit, 13 ... Third temperature sensor, 17 ... Drive device, 18 ... Exhaust gas recirculation passage, 20 ... Reflux control valve, 26 ... Negative pressure introduction passage, 28 ... Atmospheric release port, 29...Solenoid valve,
30... Exhaust recirculation control device, 31... First temperature sensor, 32... Second temperature sensor, 33... Control circuit, 34... First temperature detection circuit, 35... Second temperature detection circuit, 36... ... Arithmetic circuit, 37... Output current control circuit.

Claims (1)

[Claims] 1. In an engine that is provided with a water pump for circulating cooling water inside the engine and a drive device that drives and controls the water pump according to the engine temperature, and the amount of circulating water is controlled according to the engine temperature, A first temperature sensor provided inside the engine to detect the temperature of the low temperature part inside the engine, a second temperature sensor provided inside the engine to detect the temperature of the high temperature part inside the engine, and an output signal of the first temperature sensor. A control circuit receives the output signal of the second temperature sensor and compares a correction value obtained by correcting one detected temperature with the other detected temperature with a preset setting value to control various combustion control devices of the engine. An engine control device characterized by comprising: