JPH0479848B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a heating device for a vehicle equipped with a water-cooled engine.

BACKGROUND ART In vehicles, especially automobiles, heating the interior of the vehicle is essential to improve comfort during winter operation. Currently, as this heating device, if the vehicle is equipped with a water-cooled engine, a hot water type device that utilizes the heat of engine cooling water is used. However, with conventional hot water heating systems,
Especially when the engine is cold, the cooling water temperature does not rise sufficiently, and therefore the heating does not work well.

Therefore, in Utility Model Application No. 55-155608, the cooling water that has been heated to some extent by the engine (cylinder) is further heated using the heat of the exhaust gas, and this further heated cooling water is used for heating. A heating device for an automobile has been proposed.

The heating device described in this published utility model publication further heats the cooling water heated by the engine (cylinder) with exhaust gas, and uses this further heated cooling water for heating, so there is sufficient heat. It has the advantage of being able to obtain heating temperatures. The present invention provides a vehicle equipped with a water-cooled engine in which the heat exchanger is provided in the exhaust passage, and the heat exchanger can be effectively used for purposes other than heating, such as controlling exhaust gas temperature and engine cooling water temperature. The purpose is to provide a heating device for

The heating device for a vehicle equipped with a water-cooled engine according to the present invention takes out cooling water from a cooling water mantle of the engine body, and includes a heat exchanger installed in an exhaust passage and heated in the vehicle interior by heat exchange with exhaust gas. a heater cooling water circulation path that passes through the heating heater core and returns the cooling water and the cooling water mantle; a bypass path that is provided in the exhaust passage and bypasses the heat exchanger;
a specific condition detection device that detects a condition in which the temperature of the catalyst is higher than its reference temperature or a condition in which the temperature of the cooling water is lower than its reference temperature and sends a signal indicating the occurrence of such a specific condition; an exhaust passage and a bypass; A switching valve is provided at a branch point of the passage and freely opens and closes the bypass passage, a water temperature detection means detects the temperature of the cooling water, and when the water temperature detected by the water temperature detection means is lower than the reference temperature during heating operation. The switching valve is controlled to close the bypass passage when the water temperature is higher than the reference temperature, and to open the bypass passage when the water temperature is higher than the reference temperature. The present invention is characterized by comprising a control means for controlling a switching valve to open a bypass passage and close the bypass passage when a signal is not received.

The heating system for a vehicle equipped with a water-cooled engine of the present invention having the above structure detects, for example, that the temperature of the catalytic converter is abnormally high by the specific state detection device when the heating system is OFF, and the switching valve is activated. is set to open the exhaust passage in order to guide the exhaust gas to the heat exchanger, whereby the exhaust gas is cooled by heat exchange with cooling water in the heat exchanger, and thus the exhaust gas is It is possible to prevent damage to the heat exchanger that may occur when the temperature becomes abnormally high. Furthermore, during warm-up operation when the cooling water temperature is lower than a specific temperature, that is, during low-temperature warm-up operation,
If this condition is detected by the specific condition detection device as described above and the switching valve is set in the same manner as described above, the cooling water will be heated by the exhaust gas, thus efficiently promoting warm-up of the engine. .

DESCRIPTION OF THE PREFERRED EMBODIMENTS A heating device for a vehicle equipped with a water-cooled engine according to the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a schematic diagram of a heating system for a vehicle equipped with a water-cooled engine according to a first embodiment of the present invention.

In FIG. 1, reference numeral E indicates a water-cooled engine mounted on an automobile (not shown), and a cooling water cannula 1 is provided outside the combustion chamber of this engine E. This cooling water cannula 1 is divided into upper and lower parts by a partition wall P, and a cylinder head part water cannula 1a,
The cylinder block portion constitutes a water jacket 1b.

A cooling water inlet 2 and an outlet 3 are formed in the cylinder head water cannula 1a. The inflow port 2 and the outflow port 3 are communicated by a heating cooling water circulation path 4, and a heater core 5, which is a heat exchanger for heating the vehicle interior, is interposed in the circulation path 4. This heater core 5 is connected to the blower 6
The air sent by the heater core 5 is heated by heat exchange with the heated cooling water passing through the heater core 5. This heated air is introduced into the vehicle interior for heating purposes. The blower 6 is operated by a manual blower switch 7 having ranges of OFF, LOW, and Hi, for example.

In the figure, numeral 8 indicates an exhaust manifold,
An exhaust passage 9 is connected to the exhaust manifold 8. A heat exchanger 10 is provided in the middle of this exhaust passage 9 and between the outlet 3 of the circulation route 4 and the heater core 5, and the cooling water sent to the heater core 5 through the circulation route 4 is transferred to this heat exchanger 10. heat exchanger 10
heated by exhaust gas at the A bypass passage 11 is formed in the exhaust passage 9 to bypass a portion where the heat exchanger 10 is provided. This bypass passage 11 allows exhaust gas to flow when the temperature of the cooling water flowing into the circulation path 4 from the outlet 3 is sufficiently high and there is no need to heat the cooling water by the heat exchanger 10. It is for. For this reason, a switching valve 12 is provided at the branching part of the bypass passage 11 from the exhaust passage 9 to adjust and flow the exhaust gas between the exhaust passage 9 where the heat exchanger 10 is provided and the bypass passage 11. It's becoming like that.

An on-off valve 13 is provided on the upstream side of the heater core 5 in the circulation path 4, and this on-off valve 13 can obtain heating temperature.

The engine E is provided with a water temperature sensor 27 as water temperature detection means for detecting the temperature of engine cooling water.

When the engine E has warmed up and the water temperature sensor 27 detects that the temperature of the cooling water in the cylinder head water jacket 1a has exceeded a predetermined temperature, the control circuit 2
4 sets the changeover switch 12 to open the bypass passage 11 and close the heat exchanger 10 side of the exhaust passage 9. Thus, heating of the cooling water by the exhaust gas in the heat exchanger 10 is stopped, and overheating of the cooling water and the engine is prevented. At this time, since the cooling water temperature is high as described above, the switching valve 16 is also set by the control circuit 24 so that the cooling water gradually passes through the bypass passage 14 side. The cooling water flowing to the bypass passage 14 side is transferred to the radiator 15
The cooling water is cooled in the cooling water, and joins with the cooling water passing through the circulation path 4 to lower the temperature of the entire cooling water. Thus, from this point as well, the cooling water and the cylinder head outlet 18 of the engine E are communicated through the radiator cooling water circulation path 20.
0 is provided with a radiator 21. The heating circulation path 4 and the radiator circulation path 20 are independent from each other.
Therefore, the first water pump 2 is connected to the circulation path 4.
2, a second water pump 2 is installed in the circulation path 20.
3 are provided separately. The first water pump 22 is driven and controlled by a control circuit 24 consisting of a microcomputer, while the second
The water pump 23 is driven by the engine E.

A bypass passage 25 that bypasses the radiator 21 is provided in the circulation path 20 . This bypass passage 25 is provided to help warm up the engine by circulating the cooling water without passing through the radiator 21 when the engine is in a cold state.
For this reason, a thermostatic valve 26 is provided at the branching portion of the circulation passage 20 and the bypass passage 25 to allow cooling water to flow into the bypass passage 25 until the engine is sufficiently warmed up.

The exhaust passage 9 is provided with a catalytic converter C _A for purifying the exhaust gas flowing through the exhaust passage 9. This catalytic converter C _A purifies exhaust gas through the action of a catalyst, and in order to perform this purification action sufficiently efficiently, the temperature of the catalyst or the temperature of the exhaust gas must be above a predetermined temperature. is important. Furthermore, this catalytic converter may be damaged if its temperature exceeds the dangerous temperature, so care must be taken to ensure that the temperature does not exceed the dangerous temperature.

The cylinder head water jacket 1a is provided with a water temperature sensor 27 for detecting the temperature of cooling water in this portion, and the catalytic converter C _A is provided with a temperature sensor 28 for detecting the internal temperature thereof. The water temperature sensor 27 detects that the temperature of the engine cooling water has become lower than a predetermined temperature, and the temperature sensor 28 detects that the temperature of the catalytic converter C _A has become higher than the dangerous temperature. That is, the water temperature sensor 27 and the temperature sensor 28 act as a specific state detection device. Output ends of the water temperature sensor 27 and temperature sensor 28 are connected to input ends of the control circuit 24, respectively. The blower switch 7 is connected to the other input terminal of the control circuit 24, and the control circuit 24 receives a signal S ₁ from the blower switch 7 indicating ON/OFF of the heater,
Upon receiving a signal S ₂ indicating the cooling water temperature from the water temperature sensor 27 and a signal S ₃ indicating the temperature of the catalytic converter C _A from the temperature sensor 28, the switching valve 1
2, 16 and the opening/closing valve 13.

Next, the operation of the heating device having the structure explained above will be explained.

First, the operation of the heating system when the engine E is in a cold operating state will be explained. The blower switch 7 of the heating device is moved from the OFF state to the ON state, LOW or Hi range, and a signal S ₁ indicating this,
and the signal S ₂ from the water temperature sensor 27 is sent to the control device 2.
4, this control circuit 24 sets the switching valve 12 to a position that closes the bypass passage 11 and opens the on-off valve 13. The switching valve 16 is
Since the blower switch 7 is turned on and the temperature of the cooling water is low, it is opened so that the cooling water flows to the circulation path 4 side. On the other hand, thermostatic valve 26
Since the temperature of the cooling water is low, it is opened so that the cooling water flows into the bypass passage 25.

Further, the control circuit 24 drives the first water pump 22 based on the signal S ₁ from the blower switch 7 to circulate the cooling water in the circulation path 4 . The cooling water circulated in the circulation path 4 is heated by the cylinder head of the engine E in the cylinder head water cannula 1a. The cooling water heated by the cylinder head flows into the circulation path 4 from the outlet 3 and passes through the heat exchanger 10 into the exhaust path 9.
It is further heated by the exhaust gas flowing through it. This further heated cooling water is sent to the heater core 5. The heater core 5 heats the air sent from the blower 6 and sends it into the vehicle interior to heat the vehicle interior. The cooling water that has passed through the heater core 5 is returned to the cylinder head water cannula 1a from the inlet 2 by the water pump 22. In this way, the cooling water
Since it is sufficiently heated by the relatively high temperature cylinder head and the heat exchanger 10, a sufficient heating temperature can be obtained even when the engine E is at a low temperature.

When the rotational speed of the engine E gradually increases and the water temperature sensor 27 detects that the temperature of the cooling water in the cylinder head water cannula 1a has exceeded a predetermined temperature, the control circuit 24 switches the changeover switch 12 to the bypass passage 11. is set to open, and the heat exchanger 10 side of the exhaust passage 9 is closed. Thus, heating of the cooling water by the exhaust gas in the heat exchanger 10 is stopped, and overheating of the cooling water and the engine is prevented. At this time, since the cooling water temperature is high as described above, the switching valve 16 is also set by the control circuit 24 so that the cooling water gradually passes through the bypass passage 14 side.
The cooling water flowing toward the bypass passage 14 is cooled in the radiator 15 and joins with the cooling water passing through the circulation path 4 to lower the temperature of the entire cooling water. Thus, also from this point of view, overheating of the cooling water and the cylinder head of the engine E is prevented.

On the other hand, the second water pump 23 is driven by the engine E to circulate the cooling water to the circulation path 20, but as mentioned above, when the engine E is cold, the thermostatic valve 26 moves the cooling water to the bypass path. Since the cooling water is set to flow through the radiator 25, the cooling water does not flow through the radiator 21.
Therefore, no heat is radiated, thus promoting warm-up of the engine E. When the engine E warms up and the temperature of the coolant circulating in the circulation path 20 reaches a predetermined temperature or higher, the thermostatic valve 26 gradually opens to allow the coolant to flow to the radiator 21, and thus the coolant flows to the radiator. cooled at 21;
Prevents overheating of the cooling water and the cylinder block of the engine E.

Further, when the control circuit 24 detects, based on the signal _S3 from the temperature sensor 28, that the temperature of the catalytic converter C _A has become lower than the minimum temperature at which the converter C _A can efficiently purify exhaust gas. , the switching valve 12 is set to flow exhaust gas to the bypass passage 11 side with priority over other control systems.
In this way, the exhaust gas is supplied to the catalytic converter C _A at a high temperature without losing heat through heat exchange with the cooling water, and therefore the purification performance of the catalytic converter C _A is maintained.

In the heating device described above, the first water pump 22 basically rotates at a constant high speed when the heating device is in operation to achieve early heating, and when the heating device is not in use, the water pump 22 is cooled by detecting water temperature sensor 27. The rotation may be set depending on the water temperature, engine load, rotational speed, etc., or the water pump 22 may be stopped during cranking.
For example, when the water pump 22 is controlled according to the temperature of the cooling water when the heating device is not used, the temperature of the cooling water detected by the water temperature sensor 27 is set to the first predetermined temperature T ₁ as shown in FIG. Until it becomes
The water pump 22 is operated at a constant low speed so that the circulating cooling water is sufficiently heated by the engine E, or the engine E
The engine is prevented from being locally overheated, and then the rotational speed of the water pump 22 is increased in accordance with the rise in the temperature of the cooling water until the temperature of the cooling water reaches a sufficient temperature _T2 , thereby preventing the engine from overheating. After that, the engine is operated at a constant rotation speed. The case where the operation of the water pump 22 is controlled according to the cooling water temperature has been described above, but since local overheating of the engine E may occur even when the load increases, the load can be controlled in almost the same way as above. It is desirable to control the rotation speed of the water pump 22 according to the increase. Further, when starting the engine, that is, during cranking, it is desirable to temporarily stop the operation of the water pump 22 as described above in order to prevent deterioration of startability due to voltage drop due to the operation of the water pump 22. In order to perform the above control, it is necessary to provide an engine load sensor, an engine rotation speed sensor, and a cranking sensor in addition to the water temperature sensor 27, and input the output signals of these sensors to the control circuit. It is.

In the above embodiment, the water pump 22
Although the control of the operation is performed by the control circuit 24 using a microcomputer has been described, this control may also be performed by an electric circuit as shown in FIG.

The electric circuit 30 shown in FIG. 3 is a drive control circuit for the water pump 22, and includes a differential amplifier 31 and a drive transistor 32 whose base is connected to the output terminal of the differential amplifier 31. The water temperature sensor 2 is connected to one input terminal of the differential amplifier 31.
7 is connected, and the other input terminal has a constant voltage
A constant voltage generator 33 that generates V _r is connected. The differential amplifier 31 compares the constant voltage V _r with a signal S ₂ output by the water temperature sensor 27 which detects the temperature of the cooling water in the cylinder head water cannula 1 a and outputs a difference signal S _d . When the cooling water temperature is _T1 or higher, the transistor 32 controls the operation of the water pump 51 with a current according to the difference signal _Sd2 as shown in FIG. As described above, it is desirable that the pump 22 rotates at a constant low speed until the cooling water reaches the first predetermined temperature _T1 .
2 is also connected to a power supply 34 which generates a constant low voltage. Further, a contact 7' that interlocks with the blower switch 7 is interposed at the base of the transistor 32, and when this contact 7' is turned on, that is, when the heating system is activated, the pump 22 is connected to the output of the water temperature sensor 27. It can be rotated at a constant high rotation speed. As described above, the pump 22 is driven as a whole as shown in FIG. 2 when the heating device is not used, but when cranking, that is, when starting the engine, the pump 22 is driven as a whole to supply a large amount of current to the starter S _t . As shown in FIG. 3, it is desirable to provide a relay 35 in front of the pump 22 that cuts off the operating circuit of the pump 22 when the starter S _t is turned on.
Note that the differential amplifier 31 is
The pump is configured to rotate at a constant low speed without outputting the difference signal S _d until T ₁ is reached.

The functions of the control circuit 24, heat exchanger 10, etc. when the heating device is ON have been explained above, but the control circuit 24, heat exchanger 10, etc.
It can be used even when it is OFF. In addition,
Since the water pump 22 cools the engine with cooling water, it is operated at a constant rotation speed when the cooling water temperature is T2 _or higher even when the heating device is off.

For example, when the heating device is turned off, the temperature sensor 2
Based on the signal _S3 from 8, when the control circuit 24 detects that the temperature of the catalytic converter C _A has reached a dangerously high temperature with a risk of damage, the control circuit 24
The switching valve 12 is closed by closing the portion of the exhaust passage 9 where the heat exchanger 10 is provided, and the bypass passage 1 is closed.
From the normal position where 1 is opened, the exhaust passage 9 is reversed.
section is opened, the bypass passage 11 is switched to the closed position, the exhaust gas is cooled by heat exchange with cooling water in the heat exchanger 10, and the cooled exhaust gas is supplied to the catalytic converter C _A. By lowering the temperature of the catalytic converter, the above dangerous situation can be avoided.

Next, the electric circuit 36 for controlling the switching valve 12 in the above manner will be explained with reference to FIG.
7, the switching valve 12 is switched. This actuator 37 is adapted to be driven by a relay switch 39 which is energized by a temperature switch 38 which closes when the temperature of the catalytic converter C _A rises above the above-mentioned critical temperature. The temperature switch 38 is connected in series to the OFF terminal of the blower switch 7. With the electric circuit 36 configured as described above, the switching valve 12 closes the bypass passage 11 when the blower switch 7 is in the OFF state, that is, the heating device is in the OFF state, and the temperature of the catalytic converter C _A is lower than the above-mentioned dangerous temperature, and the switching valve 12 closes the bypass passage 11 to exchange heat. The exhaust passage 9 on the side of the container 10 is opened.

In addition, when the engine is operating at a low temperature, the switching valve 12 is controlled to open the exhaust passage 9 on the heat exchanger 10 side depending on the temperature of the cooling water when the heating device is turned off, and the heat exchanger 10 cools the air. The water can be heated by the exhaust gas, thereby facilitating warm-up of the engine.

In the above embodiment, the second water pump 23 has been described as being of the type driven by an engine, but it may be electrically controlled.

Further, in the above embodiment, the partition wall that divides the cooling water cannula 1 into the cylinder head portion and the cylinder block portion is of a complete partition type.
As shown in the figure, an incomplete partition wall P may be used to allow some cooling water to flow between the cylinder head and cylinder block of the cooling water cannula. In addition, in the above embodiment, the heating cooling water circulation path 4
Although a type in which the radiator cooling water circulation path 20 and the radiator cooling water circulation path 20 are completely independent has been described, it is also possible to use a type in which they share a part as shown in FIG. In this case, as shown in the figure, an outlet 18 is provided in the cylinder head 1a, a thermostatic valve 40 is provided at the outlet 18, which opens when the heating device is not in use, and a thermostatic valve 40 is installed at the branching part of the passages 4 and 20. Although it is necessary to provide a stud valve 41, the radiator 16 shown in Fig. 1 is not required, and only one water pump W _P is required.
The structure becomes simple. Note that the water pump W _P is of a type driven by the engine E.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of a heating device according to a first embodiment of the present invention, FIG. 2 is a graph showing an example of the operation of the first water pump, and FIG. 3 is a graph showing the operation of the first water pump. A circuit diagram showing an example of an electric circuit,
FIG. 4 is a circuit diagram showing an example of an electric circuit that operates a switching valve provided at a branch point between an exhaust passage and its bypass passage, and FIG. 5 is a schematic diagram of a heating device according to a second embodiment of the present invention. It is a diagram. E... Engine, 1... Cooling water mantle, 1a... Cylinder head water mantle, 1b... Cylinder block water mantle, 4...
Heating cooling water circulation path, 5... heater core, 9... exhaust passage, 10... heat exchanger, 11... bypass passage,
DESCRIPTION OF SYMBOLS 12...Switching valve, 20...Cooling water circulation path for radiators, 22...1st water pump, 23...2nd water pump.

Claims (1)

[Claims] 1. Cooling water is taken out from the cooling water canopy of the engine body and passed through a heat exchanger installed in the exhaust passage and heating the cooling water through heat exchange with exhaust gas and a heater core for heating the vehicle interior. , a heater cooling water circulation path that returns the cooling water and the cooling water cannula; a bypass passage provided in the exhaust passage and bypassing the heat exchanger; and a state in which the temperature of the catalyst is higher than its reference temperature or the cooling a specific state detection device that detects a state in which the temperature of water is lower than its reference temperature and sends a signal indicating the occurrence of such a specific state; a switching valve that freely opens and closes; a water temperature detection means that detects the temperature of the cooling water; and during heating operation, if the water temperature detected by the water temperature detection means is lower than a reference temperature, the bypass passage is closed and the water temperature is is higher than a reference temperature, the switching valve is controlled to open the bypass passage, and when the heating is not in operation, when the signal is received from the specific state detection device, the bypass passage is closed; A heating device for a vehicle equipped with a water-cooled engine, comprising: control means for controlling the switching valve to open the bypass passage when no signal is received.