JP2555694B2 - Internal combustion engine intake system - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an intake device for an internal combustion engine, and more particularly to an intake device for an internal combustion engine that uses engine cooling water to vaporize fuel.

[Conventional technology]

In an internal combustion engine, in order to make combustion smoothly,
A mixture of fuel and air must be supplied to the combustion chamber. Therefore, in order to further promote the vaporization of fuel,
A hot water heating unit (riser) is provided in the intake manifold, and the hot water heating unit is heated by exhaust gas and engine cooling water.

Further, as such an intake device, for example, Japanese Patent Laid-Open No.
-113860 publication. In this publication, the intake heating control means stops the operation of the intake heating means when the load of the engine detected by the load detection means is a full load or a high load state close to the full load. Since the heating means is activated to perform strong intake air heating, fuel vaporization is sufficiently high during partial load operation where strong intake air heating is performed, resulting in excellent mixing with air and distribution among cylinders. Therefore, the fuel consumption can be improved by improving the lean burnability, and the intake throttle can be made as small as possible, so that the pressure loss due to the throttle can be reduced as much as possible and the fuel consumption can be improved also in this aspect. .

Further, as shown in FIG. 6, the intake device has a hot water passage 62 for guiding the engine cooling water when the cooling water temperature becomes equal to or higher than a set temperature in order to improve the engine output (improve the volumetric efficiency). With a hot water cut valve 64 for closing the intake pipe, or as shown in FIG. 7, the bypass passage 66 and the intake pipe heating passage 68 are arranged in series (see FIG. 7) so that the intake pipe is heated only when the heater is used. Some have been configured to be exposed. The sixth and seventh
In the figure, 2 is an internal combustion engine, 4 is an intake manifold, 6 is a carburetor, 8 is a water pump, 12 is a radiator, 24 is a hot water heating unit, and 58 is a heater valve.

[Problems to be solved by the invention]

However, in the case of controlling by the cooling water temperature, when the cooling water temperature exceeds the set temperature, the intake pipe heating is always closed, so that there is a disadvantage that distribution in the low load / low rotation range deteriorates.

Further, it is necessary to provide a passage in addition to the bypass passage for the cooling water, which disadvantageously increases the number of parts.

Further, in the case of using the heater circuit, there is a disadvantage that the output of the engine cannot be improved when the heater is used.

Furthermore, if a heater is not used, heating of the intake pipe is not performed, and there is the inconvenience that distribution performance and vaporization cannot be promoted.

[Object of the Invention]

Therefore, an object of the present invention is to eliminate the above-mentioned inconvenience and to circulate hot water to the hot water heating unit at a differential pressure between the upstream side and the downstream side of the flow rate control means in accordance with the increase or decrease in the pressure of the engine cooling water caused by the machine speed. By adjusting the amount, the vaporization state of the fuel is adjusted to improve the distribution performance between the cylinders, the number of parts is reduced, and an intake device of an internal combustion engine capable of improving the engine output is realized.

[Means for solving problems]

In order to achieve this object, the present invention relates to an intake system for an internal combustion engine that heats a hot water heating section provided in an intake manifold with engine cooling water to vaporize fuel, and increases or decreases the pressure of the engine cooling water caused by the engine speed. According to the above, flow rate control means having a moving valve body that moves to expand or contract the passage opening area and adjusts the circulating amount of cooling water to the warm water heating section is provided.

[Action]

According to the configuration of the present invention, when the differential pressure between the upstream side and the downstream side of the flow rate control means is small, such as when the engine speed is low,
The moving valve body moves so as to increase the passage opening area and increases the circulating amount of warm water to the warm water heating unit. On the other hand, when the differential pressure between the upstream side and the downstream side of the flow rate control means increases as the engine speed increases, the moving valve body moves to reduce the passage opening area, and Reduce hot water circulation. As a result, the vaporization state of the fuel can be adjusted according to the engine speed, the distribution performance between the cylinders can be improved, and the engine output can be improved.

〔Example〕

Embodiments of the present invention will be described in detail and specifically below with reference to the drawings.

1 to 5 show an embodiment of the present invention.
In the figure, 2 is an internal combustion engine, 4 is an intake manifold, and 6 is a carburetor. The internal combustion engine 2 includes a water pump 8
Is attached. The water pump 8 is driven by rotation of a crank shaft (not shown) of the internal combustion engine 2,
The cooling water for the internal combustion engine 2 is supplied to the cooling water passage 1 for the first radiator.
4, radiator 12 and second radiator side cooling water passage 10
After that, the internal combustion engine 2 is circulated again.

Further, the cooling water is sent to the heating heat exchanger 18 of the hot water heating device through the first hot water passage 20, and then returns to the water pump 8 through the heating cooling water passage 16. Meanwhile, the second
The cooling water sent to the warm water heating unit (riser) 24 attached to the intake manifold 4 through the warm water passage 22 merges with the cooling water in the heating cooling water passage 26 through the riser cooling water passage 26, Return to the water pump 8.

Further, the second hot water passage 22 is moved to the hot water heating unit 24 so as to enlarge or reduce the passage opening area according to the increase or decrease in the pressure of the cooling water generated by the rotation speed of the internal combustion engine 2, that is, the rotation speed of the water pump 8. Moving valve body 28 for adjusting the circulating amount of hot water of
A flow rate control valve 30 as a flow rate control means having the above is provided.

This flow control valve 30 is constructed as shown in FIGS. That is, the flow control valve 30 moves in the flow chamber 38, a valve case 36 having an inflow port 32 and an outflow port 34, a distribution chamber 38 formed between the inflow port 32 and the outflow port 34. The movable valve body 28 that can be installed and the movable valve body 28
The valve spring 40 presses the inlet 32 side in the inside 38. That is, in the flow chamber 38, the moving valve element 28 reciprocates due to the difference between the pressure of the cooling water on the inlet 32 side which is the upstream side and the pressure of the cooling water on the outlet 34 side which is the downstream side. It is arranged.

Further, the valve spring 40 flows through the pressure receiving portion 42 of the moving valve body 28 when the pressure difference between the upstream side and the downstream side of the flow control valve 30 is small when the internal combustion engine 2 is stopped or the engine speed is low. When there is an urging force for contacting the first locking portion 44 formed by the stepped portion on the outer surface of the chamber 38, and the engine speed becomes high and the differential pressure between the upstream side and the downstream side of the flow control valve 30 becomes large. In addition, the pressure receiving portion 42 of the moving valve body 28 is allowed to come into contact with the second locking portion 46 formed on the outer surface of the flow chamber 38. Further, one end of the valve spring 40 is engaged with the pressure receiving portion 42, and the other end thereof is fixed to a spring engaging portion 48 formed in the valve case 36.

Further, the movable valve body 28 includes the pressure receiving portion 42 and the pressure receiving portion 42.
The shaft portion 50 is fixed at one end side thereof and the taper portion 52 protruding toward the outflow port 34. Further, the pressure receiving portion 42 is provided separately from the inner surface of the valve case 36 forming the flow chamber 38.

The tapered portion 52 is formed to be tapered on the outlet 34 side,
Adjusting the circulation amount of hot water flowing out to the outlet 34 side by projecting and retracting in the flow control hole 56 formed in the throttle portion 54 of the valve case 36 to expand and contract the opening area of this flow control hole 56, the so-called passage opening area. To do. Therefore, the flow rate of cooling water, which is the circulating amount of hot water flowing into the hot water heating unit 24, is adjusted according to the engine speed, and the vaporized state of the fuel at the branch portion of the intake manifold 4 is adjusted. Reference numeral 52a is a tapered surface.

 Next, the operation of this embodiment will be described.

Flow control valve when the internal combustion engine 2 is stopped or at low speed
When the differential pressure of the cooling water between the upstream side and the downstream side of 30 is small (see FIG. 4), as shown in FIG.
The moving valve body 28 is pressed toward the inflow port 32 by the biasing force of 40, and the pressure receiving portion 42 contacts the first locking portion 44. At this time, the tip portion of the taper portion 52 of the moving valve body 28 is substantially pulled out from the flow rate control hole 56 to increase the passage opening area. Therefore, the inlet
The cooling water from the 32 side flows into the flow chamber 38 through a gap between the outer surface of the pressure receiving portion 42 and the inner surface of the valve case 36, and then flows from the flow control hole 56 having a large passage opening area to the outlet 34 side. Leave. As a result, the cooling water flow rate increases (see FIG. 5), and the hot water heating unit 24 rapidly heats the intake manifold 4 to accelerate the vaporization of the fuel, so that the distribution performance to each cylinder is improved and the engine performance is improved. It is possible to maintain good drivability.

In addition, as the engine speed increases, the flow control valve
When the differential pressure of the cooling water between the upstream side and the downstream side of 30 becomes large (see FIG. 4), as shown in FIG.
Moves toward the outlet 34 side against the biasing force of the valve spring 40. Therefore, when the taper portion 52 of the moving valve body 28 is gradually inserted into the flow rate control hole 56, the passage opening area of the flow rate control hole 56 is gradually reduced by the taper portion 52. Then, finally, the pressure receiving portion 42 contacts the second locking portion 46, and the movement of the moving valve body 28 is stopped. As a result, when the internal combustion engine 2 is at a high temperature and is rotating at a high speed, the circulation amount of hot water to the hot water heating unit 24 is reduced (see FIG. 5) to prevent excessive heating of the air-fuel mixture to improve the engine output. It can be planned.

〔The invention's effect〕

As is clear from the above detailed description, according to the configuration of the present invention, the differential pressure between the upstream side and the downstream side of the flow rate control means is applied to the hot water heating unit in accordance with the increase or decrease in the engine cooling water pressure caused by the engine speed. By adjusting the hot water circulation amount, the vaporization state of the fuel can be adjusted to improve the distribution performance between the cylinders, the number of parts can be reduced, and the engine output can be improved.

[Brief description of drawings]

1 to 5 show an embodiment of the present invention, FIG. 1 is a schematic view of an intake system of an internal combustion engine, FIG. 2 is a sectional view of a flow control valve when the differential pressure is small, and FIG. FIG. 4 is a cross-sectional view of the flow rate control valve when the pressure is large, FIG. 4 is a diagram showing the relationship between the differential pressure and the engine speed, and FIG. 5 is a diagram showing the relationship between the cooling water flow rate and the differential pressure. 6 and 7 are schematic views of a conventional intake device. In the figure, 2 is an internal combustion engine, 4 is an intake manifold, 8 is a water pump, 20 is a first hot water passage, 22 is a second hot water passage, 24 is a hot water heating section, 26 is a riser cooling water passage, and 28 is a moving valve. Body, 30 is a flow control valve, 32 is an inlet, 34 is an outlet, 36
Is a valve case, 40 is a valve spring, 42 is a pressure receiving portion,
52 is a taper part, and 56 is a flow control hole.

Claims (1)

(57) [Claims] 1. In an intake system of an internal combustion engine for heating a hot water heating section provided in an intake manifold with engine cooling water to vaporize a fuel, a passage opening area according to an increase / decrease in a pressure of the engine cooling water caused by an engine speed. The intake device for an internal combustion engine is provided with a flow rate control means having a moving valve body that moves to expand and contract and adjusts the circulating amount of cooling water to the hot water heating unit.