JPS6314059Y2 - - Google Patents

Description

[Detailed description of the invention] This invention is an intake manifold preheating system that improves the atomization of the air-fuel mixture when the engine is at low temperatures and the charging efficiency when the engine is at high temperatures, thereby improving engine combustion stability, output performance, etc. Regarding structure.

In order to improve the combustion stability and output performance of the engine, when starting the engine, especially when the outside temperature is low, the intake manifold is used to promote atomization of gasoline and distribute the mixture evenly to each cylinder. It is preferable to preheat the

However, when the temperature rises, it is necessary to prevent the carburetor, especially slow system fuel, from overheating and prevent heat damage such as vapor lock and percolation. In order to maintain charging efficiency and keep air/fuel efficiency constant, it is necessary to prevent the intake manifold from becoming hot.

However, in the conventional intake manifold preheating structure, for example, as disclosed in Japanese Utility Model Application Publication No. 53-81719, a bypass flow path passing through the preheating part of the intake manifold is used as a cooling water flow path for engine cooling, and this cooling water flow at low temperatures is used. It is connected via a thermostatic valve that closes the water flow path.

However, with conventional devices like this, although they promote warm-up at the initial stage of engine startup, the cooling water flows through the bypass flow path even when the temperature rises, and the high-temperature cooling water excessively heats the preheating section. Therefore, there was a problem in that heat damage such as vapor lock was more likely to occur.

This invention uses a thermostatic valve that opens and closes the bypass flow path, which operates both when the coolant is at low and high temperatures, to create a preheating structure for the intake manifold that can help improve the performance of the engine at both low and high temperatures. For the purpose of providing this information, one embodiment thereof will be described below based on the drawings.

FIG. 1 schematically shows the entire system of an engine that employs the intake manifold preheating structure of the present invention, in which the cooling water flowing through the water jacket in the engine 2 flows through the outlet housing 3 at both ends of the engine 2. The outlet hole 9 of the radiator 6 is connected to the inlet hole 7 of the radiator 6 through the connection hose 5 connected to the discharge hole 4 of the thermostat housing 11, and the outlet hole 9 of the radiator 6 is connected to the inlet port 12 of the thermostat housing 11 through the connection hose 10. There is. A connection hose 14, one end of which is connected to a water pump 15 of the engine 2, is attached to a discharge port 13 provided in the thermostat housing 11. A bypass outlet 16 is provided on the side of the outlet housing 3, and the bypass outlet 16 connects via a bypass pipe 17 to a preheating section for preheating an intake manifold provided in an intake manifold 19 installed on the side of the engine 2. It is connected to the inlet 21 of 20. The preheating section 20 is provided with a flow path that is separated from other cooling water flow paths flowing through the water jacket and extends from the inflow port 21 to the discharge port 22. A bypass pipe 23 for circulation is connected to the discharge port 22 of the preheating section 20, and the bypass pipe 23 is connected to the bypass inlet 24 of the thermostat housing 11. Therefore,
The connection hoses 5, 10, 14, together with the outlet housing 3, form a cooling water flow path that connects the engine 2 and the radiator 6 and circulates cooling water, and the bypass pipe 23 connects the outlet housing 3 and the thermos A bypass flow path is formed with the tact housing 11 as a branching part, bypassing the radiator 6, and having the preheating part 20 interposed therebetween.
In addition, in FIG. 1, 25 is a chiyoke sensor;
6 is a water temperature sensor, and 27 is an electric fan thermoswitch, each of which can detect the temperature of the cooling water flowing through the outlet housing 3. In this embodiment, the thermostat housing 11 is formed integrally with the outlet housing 3, and as shown in FIG. The discharge port 13 is provided on the side, and the bypass inlet 24 is opened in the recess 32 below the thermostat 29, which is composed of an upper thermostat valve 42 and a lower bottom bypass valve 47. is being delivered. The temperature-sensitive part 34 of the thermostat 29 has a valve stem 35 and a wax case 48, and expands the temperature-sensitive wax filled in the wax case 48.
Can be expanded or contracted by contraction. The upper end of the valve shaft 35 is stationary at the upper end of the support member 36, and the wax case 4
8 is inserted through the guide portion of the spring receiver 37, and a valve plate 40 is attached to the wax case 48, which inserts the spring 39 between the spring receiver 37 and the valve plate 40. The valve plate 40 cooperates with a valve seat plate 41 fixed around its periphery to form a thermostatic valve 42. Further, the lower end of the wax case 48 is provided with a valve plate 45 which is biased downward by a cone spring 43, and the valve plate 45 constitutes a bottom bypass valve 47 together with the valve seat 46 on the upper surface of the recess 32. Note that the support member 36 and the spring receiver 37 are each provided with a side hole for cooling water circulation.
Further, the wax case 48 is lowered due to a rise in temperature, and the thermostat valve 42 is opened and the bottom bypass valve 47 is closed, thereby forming a bottom bypass type cooling water system.

However, in the intake manifold preheating structure of the present invention, when the engine 2 is started when the outside temperature is low, such as in winter, the temperature sensing portion 34 in the thermostat housing 11 is reduced, and therefore the thermostat is By closing the valve 42 and opening the bottom bypass valve 47, the cooling water from the outlet housing 3 passes through the bypass discharge port 16 and the bypass pipe 17, passes through the preheating section 20, and returns to the bypass pipe 23, forming a bypass flow. Entrance 2
4. It flows into the water pump 15 of the engine 2 via the discharge port 13 and the connection hose 14. Therefore, the cooling water prevents overcooling of the engine 2 without circulating through the radiator 6, and at the same time warms the preheating section 20 and the intake manifold 19, thereby preheating the air-fuel mixture and improving the atomization of gasoline. It is possible to uniformly distribute the air-fuel mixture to each cylinder, improve combustion instability during startup, shorten warm-up time, improve warm-up performance, and improve fuel consumption. In the bottom bypass system, the diameters of the bypass pipes 17 and 23 are relatively large, so that the preheating section 20 can be heated efficiently.

On the other hand, when the cooling water temperature is high, the temperature sensing section 3
4 extends, the valve plates 40, 45 are lowered, the thermostatic valve 42 is opened, and the bottom bypass valve 47 is closed when the water temperature reaches a predetermined temperature, for example, about 95°C. Therefore, the cooling water flows through the bypass pipe 17.
It flows into the engine 2 through the connection hose 5, radiator 6, connection hose 10, thermostat housing 11, and connection hose 14, cooling the engine, and the preheating part 20 is not preheated and flows into the intake manifold 19. This prevents an increase in intake air temperature due to heating of the engine, prevents deterioration of engine filling efficiency and improves high-temperature performance, and prevents overheating of the carburetor and prevents heat damage to the carburetor such as vapor lock and percolation.

As mentioned above, the preheating structure of the intake manifold of the present invention is such that the preheating part of the intake manifold is interposed in the bypass passage, and the cooling water passes through the radiator and a bottom bypass valve that opens the bypass passage when the temperature is low and closes it when the temperature is high. A thermostat with a thermostat valve that closes the cooling water passage when the temperature is low and opens it when the temperature is high is installed, and is configured to preheat as appropriate by controlling the circulation of the cooling water flowing through the bypass passage. At high temperatures, the intake manifold is heated to promote gasoline atomization, improve combustion stability, improve warm-up performance, shorten warm-up time, and improve output performance. It is possible to significantly improve various engine performances, such as improving charging efficiency and preventing heat damage to the carburetor.

[Brief explanation of the drawing]

FIG. 1 is an overall layout diagram showing an embodiment of the present invention;
FIG. 2 is a cross-sectional view of the thermostat housing with its bypass inlet rotated 90 degrees. 2... Engine, 17, 23... Bypass pipe,
19...Intake manifold, 20...Preheating section, 42...Thermostat valve, 47...Bottom bypass valve.

Claims (1)

[Scope of utility model registration request] A bypass flow path that bypasses the radiator is branched into a coolant flow path that circulates the coolant from the engine through the radiator, and a preheating section provided in the intake manifold of the engine is interposed in the bypass flow path. a bottom bypass valve that opens a bypass passage when the cooling water is at a low temperature and closes as the temperature of the cooling water rises; and a bottom bypass valve that closes the cooling water passage between the branch portions of the cooling water passage when the cooling water is at a low temperature and closes the bypass passage when the cooling water is at a high temperature; A preheating structure for an intake manifold, wherein a thermostat having a thermostat valve that opens is provided at the branch portion of the bypass flow path.