JPS6225866B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an intake air heating device that can rapidly heat an intake pipe without heat loss when starting an engine at a low temperature.

Some internal combustion engines employ intake air heating in order to prevent deterioration in fuel efficiency or increase in the content of harmful components in exhaust gas due to poor atomization of fuel from a carburetor during low-temperature startup. Conventionally, this intake air heating is performed using exhaust gas, an electric heater, or the like. However, the former method, which relies on exhaust gas temperature, has the disadvantage that it takes time for the exhaust gas temperature to rise, so that intake air heating cannot be performed quickly after startup. Also, those that use electric heaters have good response, but the amount of heat generated is small.
Another disadvantage is that the power consumed by the heater cannot be ignored.

Therefore, it is an object of the present invention to overcome the drawbacks of such conventional intake air heating devices. The gist of this is that a heat storage tank is installed in the engine's cooling water circulation system, the temperature of the water in the tank is maintained at a certain level while the engine is stopped, and when the engine is restarted, the heated water in the tank is used to pipe the intake pipe. It's where you heat it.

An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, 10 is an engine body, 12
14 shows a carburetor, and 14 shows an intake manifold. The intake manifold 14 has a so-called riser section 14A located directly below the carburetor 12, and the mixture is distributed to intake ports 16 to each combustion chamber.

A radiator 18 is arranged in front of the engine body 10. A bottom tank 18A of the radiator 18 communicates with a cooling water jacket 22 in the engine body 10 via a cooling water passage 20A, while an upper tank 18B communicates with the cooling water jacket 22 via a cooling water passage 20B. In this way, a cooling water circulation system connecting the radiator 18 and the engine body is configured. A water pump 24 is provided at the connection point between the cooling water passage 20A and the cooling water jacket 22. This water pump 24 shares a common shaft with a cooling fan 26 located between the radiator 18 and the engine body 10, and is connected to a crankshaft (not shown). Connected by a belt. Thus, the pump 24 moves in the direction of arrow P between the jacket 22 and the radiator 18 due to the rotational driving force from the engine.
A circulating flow of cooling water is formed as shown in FIG. A well-known thermostatic valve 28 is provided at the connection point between the cooling water passage 20B and the cooling water jacket 22, and this functions to close the passage 20B when the cooling water is at a low temperature. Reference numeral 19 designates a relief passage through which cooling water discharged from the pump 24 is circulated into the cooling water jacket 22 when the thermostat valve 28 is closed.

The present invention contemplates keeping cooling water, which is heated to a considerable temperature during engine operation, while the engine is stopped and using this warm cooling water for rapid heating of the riser section 14A when the engine is restarted. This is achieved with the following configuration. That is, the heat storage tank 30 is provided in a passage 20B that constitutes a cooling water circulation system that connects the radiator 18 and the engine body 10. On the other hand, a cooling water space 31 is formed within the wall constituting the riser portion 14A of the intake manifold 14, and one end thereof is connected to the heat storage tank 3 through a cooling water passage 32A.
0 near the inlet 30A of the heat storage tank 30, and the other end is connected to the outlet 30B of the heat storage tank 30 via the cooling water passage 32B.
connected nearby. Thus, radiator 18
A second circulation system is configured that bypasses the main circulation system connecting the engine body 10 and the engine body 10 and passes through the intake pipe. A second pump 34 is disposed in the passage 32A. This pump is driven when the engine is started, but since it only needs to cool the intake pipe, it has a smaller capacity than the pump 24.

The specific structure of the heat storage tank 30 is that it has a built-in heat exchanger that confines a heat storage body. In other words, in FIGS. 2 and 3, the heat storage tank 30 has an outer case 301 and an inner case 302. The space 303 between these is made into a vacuum to improve heat retention. A heat exchanger 304 is installed inside the inner case 302.
is installed, which has the capacity to store the required amount of cooling water. Heat exchanger 304 and inner case 3
02 is filled with a heat storage body 305. Since the temperature of the cooling water while the engine is running is 70-80℃,
It is preferable to use a heat storage body that has good heat retention properties at temperatures around this range. For example, if a substance that has a transformation point at this temperature is used, a large amount of heat is generated due to the transformation, and this can be effectively used for heat retention. Such a substance includes naphthalene.

To describe the operation of the device of the present invention described above, when the engine is at a low temperature, the water pump 2
4 is activated, but since the bimetallic valve 28 is closed, there is no circulation of cooling water through the passages 20A, 20B, so that the cooling water from the pump 24 returns to the relief passage 19. On the other hand, the second pump 34 is also driven at the same time as the engine is started. Therefore, the flow of the heated water in the tank 30 flows through the passage 32A,
It is pumped up by the pump 34 through the space 31 and the passage 32B as shown by the arrow Q. Therefore, the riser portion 14A is heated by the water kept warm in the heat storage tank 30. As a result, a rapid intake air heating effect is created and atomization of the fuel from the carburetor 12 is promoted.

When the engine is warmed up, the bimetallic valve 28 is opened. Therefore, a flow of cooling water as indicated by arrow P is formed through the passages 20A and 20B. pump 3
4 maintains the flow as shown by arrow Q through the passages 32A and 32B. As a result, the engine body 10 and the intake manifold 14 are maintained at appropriate temperatures. During this time, heat is accumulated in the heat storage tank 30 for the next cold start.

[Brief explanation of the drawing]

FIG. 1 is an overall view of the intake air heating device according to the present invention;
2 is a vertical sectional view of the heat storage tank in FIG. 1, and FIG. 3 is a sectional view taken along the line - in FIG. 2. 10...Engine body, 18...Radiator, 30
...heat storage tank, 32A, 32B...bypass passage,
34...Pump.

Claims (1)

[Claims] 1. A heat storage tank is placed in the main cooling water circulation passage that connects the main body of the internal combustion engine and the radiator, and a bypass cooling water circulation passage passing through the intake pipe is connected to the main cooling water circulation passage on the inlet side of the heat storage tank at one end and connected to the heat storage tank at the other end. An intake air heating device for an internal combustion engine, which is connected to the main cooling water circulation passages on the outlet side of the engine, and is provided with a pump in the bypass passage that is driven by engine startup.