JP2788508B2 - Automotive heating system - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heating device for an automobile, and more particularly, to a heating device for an automobile in which a good heating effect can be obtained even at the initial stage of engine start or at low speed operation. It relates to a heating device.

[Conventional technology]

2. Description of the Related Art Conventionally, a heating device installed in a vehicle such as an automobile widely employs a hot water heating system, and supplies and circulates hot air generated by heat exchange using hot water after cooling an engine into a vehicle interior. In other words, a part of the cooling water, which is heated when the engine is cooled and becomes hot water, is introduced into a heat exchanger arranged in a hot air discharge passage for air conditioning in the passenger compartment to generate hot air. Was. However, in a severe winter, the temperature of the cooling water was low immediately after the start of the engine, so that sufficient warm air could not be generated, and the person sometimes felt cold. In addition, the defroster did not function sufficiently, and the fogging of the window glass could not be removed. In particular, such a tendency was remarkable in a diesel engine vehicle and a small displacement vehicle.
This is because in a diesel engine vehicle, the engine combustion efficiency is good, and in a vehicle with a small displacement, the engine work itself is small, so that the water temperature does not easily rise.

For this reason, for example, Japanese Patent Application Laid-Open No. 61-218416 discloses that in order to solve the above-mentioned difficulties, a heat receiving end of a heat pipe is arranged in a part of a branch passage provided in an exhaust gas passage of an engine. In addition, there has been proposed a heating device for a vehicle in which a heat radiation end is disposed in a hot air discharge passage for air conditioning in a vehicle compartment. This is to take advantage of the fact that the exhaust gas of the engine becomes relatively hot from the beginning of startup, and to heat the air in the hot air discharge passage early through the heat pipe to obtain a rapid heating effect. It is what it was.

[Problems to be solved by the invention]

However, even in the heating device using the heat pipe as an auxiliary as described above, for example, when the engine speed is low during low-speed operation or idling, the pressure of the exhaust gas in the branch passage is low. In some cases, heat exchange is not sufficiently performed, and a heating auxiliary effect by a heat pipe cannot be expected.

The present invention has been made in view of such circumstances, and it is an object of the present invention to provide a heating device that uses a heat pipe as an auxiliary so that a sufficient heating effect can be obtained even during low-speed operation.

[Means for solving the problem]

The present invention is directed to a vehicle heating apparatus capable of performing auxiliary heating by using exhaust heat from an engine. In order to solve the above-described problem, a branch formed in an exhaust gas passage of the engine is provided. A heat pipe in which a heat receiving end is disposed in the branch passage; and a heat pipe in which a heat radiation end is disposed in a warm air discharge passage for cabin air conditioning; and an exhaust gas passage provided at least in parallel with the branch passage. Flow rate adjusting means provided in the portion for variably adjusting the cross-sectional area of the exhaust gas passage portion, and reducing the cross-sectional area of the exhaust gas passage portion when the engine speed is low as compared with when the engine speed is high. And control means for controlling the flow rate adjusting means.

[Action]

Accordingly, in the present invention, when the engine speed is low, such as during low-speed operation, the pressure of the exhaust gas is lower than when the engine speed is high. By reducing the cross-sectional area of the provided exhaust gas passage portion, the exhaust gas is introduced into the branch passage through a throttle. As a result, the exhaust pressure rises, a load is applied to the engine, and the temperature of the exhaust gas also rises, so that the heat receiving end of the heat pipe is efficiently heated, and the air in the hot air discharge passage is effectively heated at the heat radiation end. In this way, the shortage of heat exchange due to warm water can be effectively compensated, and the heating assist effect can be improved.

〔The invention's effect〕

In a heating device for an automobile according to the present invention, a branch passage formed in an exhaust gas passage of an engine, a heat receiving end in the branch passage, and a heat radiating end in a hot air discharge passage for vehicle interior air conditioning are arranged. A heat pipe, at least an exhaust gas passage portion provided in parallel with the branch passage, a flow control means for variably adjusting the cross-sectional area of the exhaust gas passage portion, and an engine when the engine speed is low. Control means for controlling the flow rate adjusting means so as to reduce the cross-sectional area of the exhaust gas passage portion as compared with when the rotation speed is high, so that during low-speed operation such as low-speed operation, during high-speed operation On the other hand, by controlling the flow rate adjusting means to adjust the cross-sectional area of the exhaust gas passage portion to be small and increase the pressure of the exhaust gas, the temperature of the exhaust gas is increased and introduced into the branch passage. It is possible to improve the heating auxiliary effect piped.

〔Example〕

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

The heating apparatus for a vehicle according to the present embodiment utilizes exhaust heat from the engine as an auxiliary, so that a quick heating effect can be obtained, and a sufficient heating effect can be obtained even during low-speed operation. It is configured as follows.

As shown in FIGS. 1 and 4, a branch passage 4 is formed in an exhaust gas passage 3 derived from the engine 2 of the automobile 1, and a heat receiving end 6 of a heat pipe 5 is formed in the branch passage 4. The heat radiating end 7 of the heat pipe 5 is disposed in a warm air discharge passage 8 for air conditioning in a vehicle compartment. Hot air discharge path 8
Is provided with a heater core 9 for main heating, and heat is exchanged by introducing hot water after cooling the engine 2 so as to return to a radiator (not shown).
The heat radiating end 7 of the heat pipe 5 is arranged adjacent to the heater core 9 to constitute a heater unit 10 (see FIG. 3). The heater unit 10 is provided with a hot air outlet 8a for a defroster at an upper portion thereof and a hot air outlet 8b for a vehicle interior heating at a lower portion thereof, and pipes (not shown) are connected to the respective portions. Hot air can be supplied to

The upstream side of the heat receiving end 6 in the branch passage 4 of the exhaust gas passage 3 and the exhaust gas passage 3 provided in parallel with the branch passage 4.
And the opening / closing door 12
A and 12b are provided. The opening of each of the opening and closing doors 12A and 12B is individually adjusted via each of the actuators 16A and 16B by a control signal sent from the control means 13 according to the rotation speed of the engine 2. That is, when the engine speed is low during low-speed operation or idling, the open / close door 12B on the exhaust gas passage 3 side is closed and the open / close door 12A on the branch passage 4 side is opened to a half-open state, as shown by the solid line. , The exhaust gas is throttled. As a result, an appropriate load is applied to the engine 2 to raise the temperature of the exhaust gas, thereby efficiently heating the heat receiving end 6 of the heat pipe 5, effectively warming the air in the hot air discharge passage 8, and as an auxiliary The heating effect can be improved. In addition, the fogging of the window glass 22 can be removed cleanly by the warm air for the defroster.

On the other hand, when the throttle opening increases and the engine speed increases, as indicated by the two-dot chain line, both the open / close doors 12A, 12A
B is opened to a neutral state, exhaust resistance is minimized, exhaust gas escape is improved, and power characteristics are improved. In FIG. 1, 11 is a blower and 19 is a mix door.

More specifically, the heat pipe 5 is a so-called fin-tube heat exchanger that exchanges heat between a liquid flowing in the tube or a phase-change fluid and a gas flowing on the fin side. Branch passage 4
As shown in FIG. 4, the exhaust gas is disposed in a heat receiving portion 15 formed so as to swell to a position immediately downstream of the catalytic converter 14 provided on the upstream side of the exhaust gas passage 3 and has no temperature drop. Can be introduced. And the first
As shown in the figure, an opening / closing door 12A provided in the branch passage 4
And an opening / closing door 12B provided in a portion of the exhaust gas passage 3 corresponding to the branch passage 4, respectively, are integrally incorporated into an actuator 16A including a motor and a link mechanism.
By 16B, each can be individually operated in a half-open state, a full-open state, a closed state, and the like.

The control means 13 for controlling and driving these actuators 16A and 16B is provided in an engine control unit 21 composed of a microcomputer for adjusting the operation of the engine. An engine speed sensor 17 for detecting the engine speed or a throttle sensor 18 for detecting the throttle opening is connected to the input side, and actuators 16A and 16B of the doors 12A and 12B are connected to the output side. Have been. A preset program is stored in the control means 13, and based on a detection signal from the engine speed sensor 17 or the throttle sensor 18, when the engine speed or the throttle opening is smaller than a predetermined value, for example, In the case of a diesel engine vehicle, when the engine speed is 1500 rpm or less, an operation command is sent to the actuators 16A and 16B to close the opening / closing door 12B on the exhaust gas passage 3 side and open / close the branch passage 4 side as described above. Door 12A
The opening degree is set to a half-open state, exhaust gas is narrowed down, and an appropriate load is applied to the engine 2. Thereby, the temperature of the exhaust gas is increased, the heat receiving end 6 of the heat pipe 5 is efficiently heated, and the auxiliary heating effect can be improved. That is, as described above, during low-speed operation and idling, the engine speed is low, so the temperature of the cooling water after cooling the engine is low, and the main heat exchange with hot water alone cannot sufficiently warm the passenger compartment. Therefore, by increasing the temperature of the exhaust gas used as the auxiliary heat source, a sufficient heating effect can be obtained. In addition, even when the temperature of the engine cooling water is low immediately after the engine is started, it is needless to say that a good start-up is obtained by such an auxiliary heating effect, and a quick effect is exhibited.

On the other hand, when the engine speed exceeds 1500 rpm, 40K / h
When traveling at a speed of about m / h or more, a sufficient heating effect can be exhibited only by heat exchange with the main hot water, without requiring such auxiliary heating by exhaust gas. This is because the temperature of the cooling water is raised to approximately 80 ° C. or higher, sufficient heat exchange is performed in the heater core 9, and the temperature of the hot air blown out of the hot air discharge passage 8 is rising. Therefore, the opening and closing doors 12A and 12B are opened to the neutral state, the exhaust pressure is minimized, and the power characteristics are improved.

When the control operation of the control means 13 is represented by a flowchart, first, as shown in FIG. 2, when a heating switch (not shown) is turned on (step 1, hereinafter referred to as S1, etc.), the control means 13 An actuation signal is sent to the actuators 16A and 16B, the door 12A is opened halfway (shown by a solid line in FIG. 1), and the door 12B is turned to the closed position (S2). Exhaust gas whose pressure has been raised to a high temperature is introduced, and efficient auxiliary heating by the heat pipe 5 is performed. Next, the engine speed sensor 17 asks whether the engine speed is 1500 rpm or more (S3).
12B is released to the fully open state (indicated by a two-dot line in FIG. 1) (S4). If the engine speed is not higher than 1500 rpm, the opening and closing door 12A is maintained in the half-open state, and the opening and closing door 12B is maintained in the closed position (S5). If the heating switch is not turned off, the process returns to step 3;
A is closed (indicated by the dashed line in FIG. 1), and the door 12B is opened.
Is opened to the fully opened state (S7).

As described above, according to the present invention, even in severe winter, by performing the auxiliary heating by the heat pipe, it is possible to significantly improve the heating effect quickly and efficiently,
Even during idling or low-speed operation, the auxiliary heating effect of the exhaust gas is improved, and the comfort level is improved.

FIG. 5 shows a different embodiment, in which a spike-shaped flow control valve is provided at the upstream end of the branch passage as flow control means for variably adjusting the cross-sectional area of a branch passage and an exhaust gas passage portion provided in parallel with the branch passage. 31 is arranged. In this example, when the engine speed is low, the flow control valve 31 is set to the position indicated by the solid line to close the exhaust gas passage portion, and when the engine speed is increased, the flow path is set to the position indicated by the two-dot chain line to close the branch passage 4. ing. As described above, even with the single flow control valve 31, the same effect as in the previous embodiment can be obtained. In this case, the flow control valve 31 can be operated by the single actuator 16.

[Brief description of the drawings]

BRIEF DESCRIPTION OF THE DRAWINGS The drawings show an embodiment of the present invention, FIG. 1 is an overall configuration diagram of the apparatus, FIG. 2 is a flowchart diagram showing a control operation, FIG. 3 is a configuration diagram of a heater unit, and FIG. FIG. 5 is an overall layout diagram of the apparatus, and FIG. 5 is a main configuration diagram of the apparatus in a different embodiment. 2 ... Engine 3 ... Exhaust gas passage 4 ... Branch passage 5 ... Heat pipe 6 ... Heat receiving end 7 ... Heat dissipation end 8 ... Hot air discharge passage 12A, 12B ... Flow rate Adjusting means (opening / closing door), 31 ... Flow adjusting means (Flow adjusting valve), 13 ...
Control means.

Claims (1)

(57) [Claims] An automobile heating device capable of performing auxiliary heating using exhaust heat from an engine, wherein a branch passage formed in an exhaust gas passage of the engine, and a heat receiving passage in the branch passage. A heat pipe having a heat radiation end disposed in a hot air discharge passage for vehicle interior air conditioning; and an exhaust gas passage provided at least in an exhaust gas passage portion provided in parallel with the branch passage. Flow rate adjusting means for variably adjusting the cross-sectional area of the portion, and control means for controlling the flow rate adjusting means so as to reduce the cross-sectional area of the exhaust gas passage portion when the engine speed is low as compared with when the engine speed is high. A heating device for a vehicle, comprising: