JPS5844862B2 - Internal combustion engine intake path device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in an air intake path device that uses exhaust heat to warm air taken into an internal combustion engine.

The purpose is to moderately heat the air taken into the internal combustion engine, atomize the fuel, improve the mixture of fuel and air, promote startability and warm-up, especially when starting the engine at low temperatures, and at the same time improve exhaust performance. There is a known device in which an air heating chamber is provided around the exhaust manifold, and the heated air is introduced into the engine intake passage via an air cleaner using the heat radiation of the exhaust gas.

By the way, in order to reduce unburned harmful exhaust components (Co, HC) emitted from internal combustion engines, these are re-burned (
When installing a thermal reactor that causes oxidation) in the exhaust system,
In order to increase the reaction efficiency of the reactor, it is necessary to install it in the high temperature part of the exhaust gas and to reduce the amount of heat dissipated from the reactor.
Therefore, in an engine equipped with such an exhaust purification device, the air heating chamber for warming intake air is provided around the exhaust pipe downstream of the reactor.

Problems are particularly likely to occur when such an engine is installed in a car, but the closer the intake heating chamber is to the road surface, the more likely mud from the road surface will get clogged or water will enter the air intake or passageway of the heating chamber. As a result, the intake air flow deteriorates, negative pressure increases in the intake passage upstream of the fuel supply system, mud and water are absorbed into the engine combustion chamber, and the required amount of air cannot be obtained, causing the engine to This impairs drivability and, in severe cases, may even cause engine damage.

In order to solve this problem, the present invention introduces outside air from another intake hole when the intake passage (warm air passage) upstream of the fuel supply device becomes blocked and the negative pressure inside the passage increases. The present invention provides an air intake path device that ensures engine operation.

Examples will be described below based on the drawings.

The embodiment shown in FIG. 1 is an air intake path device for a torch ignition engine that has a main chamber and a sub-chamber.
is a carburetor, 3 is an intake manifold, 4 is a cylinder head, 5 is a thermal reactor, and 6 is an exhaust pipe.

The outside air introduction duct 7 of the air cleaner 1 has a warm air introduction passage 8.
is connected in an open manner, and a temperature control valve 9 is provided at this connection,
Controls the inflow ratio of cold air (outside air) and warm air.

The temperature control valve 9 includes a valve body 1 in a diaphragm device 10.
1 are connected and driven, engine suction negative pressure is applied to a negative pressure chamber 13 partitioned by a diaphragm 12 via a negative pressure passage 14, and a temperature-sensitive valve 15 is interposed in the negative pressure passage 14 to control intake air. The operating negative pressure is controlled by sensing the temperature of the valve body 11, and the opening degree of the valve body 11 is continuously controlled.

An intake air heating chamber 17 is formed by a cover 16 on the circumferential surface of the exhaust pipe 60, and an air intake port 18 communicates with this intake air heating chamber 17, and the other end of the warm air introduction passage 8 is connected in communication with the intake air heating chamber 17 to transfer exhaust heat. The heated air is sucked into the air cleaner 1.

A control valve 20 is provided downstream of the temperature control valve 9 of the air cleaner 1 to introduce outside air when the passage self-negative pressure rises.

In this embodiment, the valve body 21 is made of an elastic material, and normally closes the valve port 22 communicating with the outside air, but when the negative pressure increases, the valve body 21 opens the valve port 22.

As the control valve 20, it is also possible to employ other means as long as it responds to the internal pressure of the passage.

Further, the control valve 20 may be provided in the warm air introduction passage 8.

With the above configuration, normally by applying negative suction pressure to the temperature control bulk 9, the outside air introduction duct T is closed and the warmed air from the warm air introduction passage 8 flows into the air cleaner 1.
It flows into the vaporizer 2 through the interior of the .

In other words, air heated in the intake heating chamber 17 provided around the exhaust pipe 60 is taken in, which promotes atomization of the fuel and improves stable and good combustion in the engine.

The temperature-sensitive valve 15 interposed in the negative pressure passage 14 is fully closed when the intake air temperature exceeds a certain level, and the diaphragm device 10
At this time, the temperature control valve 9 closes the warm air introduction passage 8 while opening the outside air introduction duct 7 to prevent the intake air from being heated more than necessary. prevent.

In addition, since the temperature control valve 9 responds to the suction negative pressure when the negative pressure is applied, the proportion of warm air intake increases during low loads such as idling, and the proportion of cold air intake increases during high loads.

Therefore, when warm air is taken in, the air intake port 1 of the intake heating chamber 1T
If mud or water from the road surface is sucked into the carburetor 8 and temporarily blocks the passage, the negative pressure in the passage upstream of the carburetor 2 will increase, but as a result, the negative pressure control valve 20 will open. Since outside air is sucked in through the valve port 22, the negative pressure upstream of the carburetor 2 does not become so large, and the amount of intake air necessary for engine operation is secured.

In this way, if a predetermined amount of air is secured and the negative pressure is kept below a certain level, there is no risk that mud or water accumulated on the warm air introduction passage 8 side will be sucked into the intake manifold 3 via the air cleaner 1. It is possible to avoid inconveniences such as damage to the engine.

Next, another embodiment is shown in FIG.

In this example, the negative pressure generated in the upstream passage of the carburetor 2 is applied in opposition to the suction negative pressure acting on the diaphragm device 10 of the temperature control valve 9. This working chamber 30 is communicated with the downstream passage of the temperature control valve 9 (the downstream side when the temperature control valve 9 closes the outside air introduction duct 7) through the opening 31. , when the intake air from the warm air introduction passage 8 is being supplied to the carburetor 2 side, when clogging occurs as described above, the passage internal mass pressure correspondingly increased is applied to the working chamber 30, The pressure difference between the suction negative pressure in the negative pressure chamber 13 and the spring 3 is reduced.
With an elastic force of 20, the valve body 11 is returned from the chain line state to the solid line state to suck in cold air.

That is, by having the temperature control valve 9 also have the function of the control valve 200, when the warm air introduction passage 8 is blocked, cool air is sucked in from the outside air introduction duct 7 to ensure a predetermined amount of air.

Note that in the normal state, the downstream pressure of the temperature control valve 9 is approximately equal to atmospheric pressure, so the pressure in the working chamber 30 is also atmospheric pressure.
The diaphragm device 10 responds only to the suction negative pressure, and the function of the temperature control valve 90 is maintained.

Although this embodiment has been described using an engine with a carburetor as an example, the present invention can also be applied to an engine equipped with an electronically controlled fuel injection device as a fuel supply device.

In addition, the capacity and mounting position of the control valve 20 can be appropriately designed based on the engine displacement, model, etc. Also, the intake heating chamber 17 is difficult to get mud and water into, and the cover 16 is divided so as to prevent clogging. It would be even more advantageous to be able to easily remove them.

As described above, according to the present invention, the relatively downstream part of the exhaust system,
Moreover, by installing the intake air heating chamber close to the road surface, it is possible to prevent dirt, water, etc. from being sucked into the engine combustion while ensuring engine operation, and outside air is introduced only when the warm air introduction passage is blocked. Therefore, it has no effect on warm air intake under normal conditions.

Furthermore, when the warm air introduction passage is no longer clogged and the pressure within the passage returns to a steady state, the introduction of outside air by the pressure control valve is automatically canceled and normal intake air temperature control is started.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of the first embodiment, and FIG. 2 is a cross-sectional view of essential parts of the second embodiment. 1... air cleaner, 2... carburetor,
3...Intake manifold, 6...Exhaust pipe, I...Outside air introduction duct, 8...Warm air introduction passage, 9...Temperature Control valve, 10...
... Diaphragm device, 12 ... Diaphragm, 13 ... Negative pressure chamber, 14 ... Negative pressure passage, 15 ... Temperature-sensitive valve, 16 ... ... Cover, 17 ... Intake heating chamber, 18 ... Air intake port, 20 ... Control valve, 21 ...
Valve body, 22... Valve port, 30... Working chamber, 31... Vent, 32... Spring.

Claims (1)

[Claims] 1. In an internal combustion engine in which warm air and cold air are selectively introduced by a valve upstream of a fuel supply device, while warm air is being sucked in through the valve, negative pressure increases in the intake passage upstream of the fuel supply device and downstream of the valve. An intake path device for an internal combustion engine that is provided with a means for sucking cold air into the intake path when