JPH0619819Y2 - Hot idle compensator for supercharged internal combustion engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a hot idle compensator (HIC) for stabilizing idling operation at high temperature in a supercharged internal combustion engine.

[Problems to be solved by conventional techniques and devices]

In an internal combustion engine equipped with a carburetor in the intake system, when the ambient temperature or intake air temperature around the internal combustion engine becomes high,
Since the fuel supply amount from the carburetor becomes larger than that when these temperatures are low, idling operation becomes unstable.

Therefore, in Japanese Utility Model Laid-Open No. 61-33952 as a prior art, an air passage from an air cleaner is connected to a downstream side of the carburetor by bypassing the carburetor, and the air passage is opened when the temperature becomes high. It is proposed to stabilize the idling operation by providing the temperature sensing valve described above and introducing the air from the air passage to the downstream side of the carburetor when the ambient temperature or the temperature of the intake air is high.

Then, when the hot idle compensator proposed in this prior art is applied to a supercharged internal combustion engine having a supercharger such as an exhaust turbocharger in the intake system, the following problems occur. There is.

That is, in the intake system of this supercharged internal combustion engine,
Since a turbocharger such as an exhaust turbocharger and a surge tank for eliminating intake pulsation are installed in series, and the distance from the carburetor to the air cleaner is long, the air cleaner and the downstream side of the carburetor are connected. Connecting by an air passage makes the length of the air passage extremely long, and in addition, the intake air-fuel mixture on the downstream side of the carburetor is introduced into the air cleaner through the air passage in the air passage. Since a check valve gas is required to prevent reverse flow to the side, in addition to causing a considerable cost increase, a long air passage and a space for installing the check valve must be secured separately. It had to be.

The present invention thus solves the above-mentioned problems in the case of applying the hot idle compensator to the supercharged internal combustion engine by positively applying to the intake system of the fuel vapor generated in the float chamber of vaporized gas at high temperature. The purpose is to solve the problem under the condition that the purging has been achieved.

[Means for Solving the Problems]

In order to achieve this object, the present invention provides a supercharged internal combustion engine in which an intake system from an air cleaner to an internal combustion engine is provided with a supercharger, a surge tank and a carburetor in that order from the upstream side thereof. The tank is provided with a compartment that communicates with the surge tank through a small hole, and the compartment is provided with an air passage that communicates with the downstream side of the carburetor.
A temperature sensing valve is provided at the opening of the air passage into the compartment to open the opening of the air passage into the surge tank when the temperature rises, while purging from the float chamber in the vaporizer. The passage is connected to the compartment.

[Function and effect of device]

In this configuration, when the temperature rises, the temperature sensing valve provided in the surge tank opens, so that the air in the surge tank flows into the compartment through the small holes, then passes through the air passage and bypasses the carburetor. Since it is sucked into the downstream side of the vaporizer, the idling operation at high temperature can be stabilized.

In this case, the surge tank is located upstream of the carburetor,
The pressure in the surge tank is always higher than the downstream of the carburetor, and the intake air-fuel mixture on the downstream side of the carburetor does not flow back to the surge tank side through the atmosphere passage.
Since it is not necessary to provide a check valve in the air passage, and the surge tank is located closer to the carburetor than the air cleaner, the length of the air passage can be extremely shortened. Of.

On the other hand, when the air introduced into the downstream side of the carburetor through the air passage flows from the surge tank through the small holes into the compartment, the small holes serve as throttles to reduce the pressure in the compartment. Since the pressure becomes lower than the pressure in the surge tank, the fuel vapor generated in the float chamber of the carburetor at high temperature can be actively purged through the purge passage.

Therefore, according to the present invention, it is possible to prevent an increase in cost when the hot idle compensator is applied to the supercharged internal combustion engine, and further, the length of the air passage is shortened as described above, and the air passage is reduced. In addition to the fact that the check valve is not necessary, the temperature sensing valve is provided in the surge tank, which has the effect of eliminating an increase in mounting space.

Moreover, by utilizing the above, there is an effect that the purge of the fuel vapor generated in the float chamber of the carburetor can be positively achieved at high temperature.

〔Example〕

An embodiment of the present invention will now be described with reference to the drawings. In the drawings, reference numeral 1 is an internal combustion engine, reference numeral 2 is an exhaust turbocharger in which an exhaust turbine 3 and a blower compressor 4 are directly connected, and reference numeral 5 is the blower compression. Air cleaners connected to the suction side of the machine 4 are shown, and a horizontal carburetor 7 is connected to the intake manifold 6 for the internal combustion engine 1, and a surge tank 8 for pulsation elimination is provided on the upstream side of the carburetor 7. Further, an intake passage 9 is connected to the surge tank 8 from the discharge side of the blower compressor 4.

A compartment 11 is formed inside the surge tank 8 and communicates with the surge tank 8 through a small hole 10. The compartment 11 is provided in the compartment 11 and in the intake manifold 6 and the like downstream of the carburetor 7. Port 12 and the air passage 13
When the temperature of the opening 13a of the air passage 13 into the compartment 11 increases, the opening 1a
A temperature sensing valve 14 that opens 3a is provided.

Further, the inside of the compartment 11 and the upper portion of the float chamber 7a in the carburetor 7 are connected via a purge passage 15 for barging the vapor of the fuel generated in the float chamber 7a.

In this configuration, when the temperature is low, the temperature sensing valve 1
Since 4 closes the opening 13a of the air passage 13, no air is introduced to the downstream side of the carburetor 7 through the air passage 13, but when the temperature rises, the temperature sensing valve 14 causes the air passage 13 to move. The opening 13a is opened. In this case, the pressure in the surge tank 8 on the upstream side of the carburetor 7 is
Since the pressure in the downstream side of the carburetor 7 is always higher, the air in the surge tank 8 flows into the compartment 11 through the small holes 10 and then from the compartment 11 through the air passage 13 to the carburetor. 7 is introduced downstream of the carburetor 7 to stabilize the idling operation and the intake air-fuel mixture downstream of the carburetor 7 flows back to the surge tank 7 side through the air passage 13. There is nothing to do.

On the other hand, when the air introduced to the downstream side of the carburetor 7 through the air passage 13 flows from the surge tank 8 into the compartment 11 through the small hole 10, the small hole 10 serves as a throttle. As a result, the pressure in the compartment 11 becomes lower than the pressure in the surge tank 8. Therefore, the fuel vapor generated in the float chamber 7a of the carburetor 7 at a high temperature is positively charged through the purge passage 15. It can be purged.

The present invention is not limited to an internal combustion engine with an exhaust turbocharger, but can be applied to a supercharged internal combustion engine including another type of supercharger such as a mechanical supercharger that is rotationally driven by the internal combustion engine. Needless to say, it is also applicable.

[Brief description of drawings]

The drawings show the embodiments of the present invention. 1 ... Internal combustion engine, 2 ... Exhaust turbocharger, 5 ... Air cleaner, 6 ... Intake manifold, 7 ... Vaporizer, 8
... Surge tank, 9 ... intake passage, 10 ... small hole, 1
1 ... compartment, 12 ... port, 13 ... air passage, 1
3a ... Air passage opening, 14 ... Temperature sensing valve, 7a
... Float chamber of vaporizer, 15 ... Purge passage.

Claims (1)

[Scope of utility model registration request] 1. A supercharged internal combustion engine in which an intake system from an air cleaner to an internal combustion engine is provided with a supercharger, a surge tank and a carburetor in that order from the upstream side of the intake system. A compartment that communicates with each other through a small hole is provided therein, and an air passage that communicates this compartment with the downstream side of the carburetor is provided. When the temperature rises, a temperature sensing valve that opens the opening of the air passage into the surge tank is provided, while the purge passage from the float chamber in the carburetor is connected to the compartment. Hot idle compensator for feed type internal combustion engine.