JPS5842592Y2 - Internal combustion engine intake preheating device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an intake air preheating device for preventing icing in the carburetor brake of an internal combustion engine when used in a cold region.

In cold regions, the carburetor brake also gets cold, so especially when there is little fuel being supplied, such as when idling or under low load, icing occurs and fuel atomization becomes poor, making it difficult to operate stably and smoothly. There is a problem.

Especially when idling when starting the engine,
Since the harmful effects of icing are significant, it is necessary to quickly increase the preheating effect by using a preheating medium with high thermal energy, and in this respect, none of the previously proposed methods has been satisfactory.

The present invention was developed in view of the above circumstances.Exhaust gas has high thermal energy, and in order to purify exhaust gas,
We focused on the fact that even when the exhaust gas is recirculated to the intake system, there is almost no recirculation during idling or low load, and by using this exhaust gas as a preheating medium to quickly and effectively preheat the carburetor brake, we have developed a system to prevent icing. The present invention provides an intake air preheating device for an internal combustion engine that is devised in this way.

For this purpose, the present invention provides a preheating passage on the outer periphery of the throttle chamber portion of the carburetor brake, communicates this preheating passage with the exhaust pipe via the first exhaust gas passage, and connects the preheating passage with the exhaust pipe through the first exhaust gas passage.
The exhaust gas is connected to the inlet side of the control valve through the passageway, and one of the outlet sides of the control valve is connected to the exhaust pipe through the third passageway for exhaust gas return, thereby converting the exhaust gas into a preheating medium. The other outlet side of the control valve is connected to the EGR valve side through a fourth passage, and this control valve is connected to the outlet side during idling and low load. One force is opened and the other is closed, and when the load is high, the other force is opened and one side is closed.When idling or under low load, the exhaust gas introduced into the preheating passage is exhausted through the third passage. It is characterized in that it is configured to be returned to the pipe and flowed to the EGR valve side via a fourth passage when the load is high.

Incidentally, as a prior art example of an intake air preheating device designed to heat the carburetor portion, there is known one described in Japanese Utility Model Application Publication No. 50-1441.22.

Hereinafter, one embodiment of the present invention will be specifically described with reference to the drawings.

In FIG. 1, reference numeral 1 denotes an engine body, 2 a carburetor brake, 3 an intake pipe, and 4 an exhaust pipe. The carburetor brake 2 is provided with a preheating passage 5 through which a preheating medium for exhaust gas passes.

This preheating passage 5 communicates with the exhaust pipe 4 via a first passage 6 for exhaust gas, and also with a control valve 8 via another second passage 7, and one of the outlet sides of the control valve 8 is connected to the exhaust pipe 4 through a first passage 6 for exhaust gas. A third passage 9 for exhaust gas return is connected to the exhaust pipe 4, and a fourth passage 10 is connected to the EGR valve 25.

The control valve 8 has a third valve chamber 11 communicating with the second passage 7.
and a port t- which communicates with the fourth passages 9 and 10, respectively.
12 and 13 are arranged facing each other, and their ports 12 and 13
A valve body 14 is provided in between to open one force and close the other force.

The valve body 14 is connected to a diaphragm 16 of a negative pressure chamber 15 on the operating side, and the negative pressure chamber 15 is connected to the intake pipe 3 through a negative pressure passage 17.
When the negative pressure in the intake pipe 3 is high, such as when idling or under low load, the diaphragm 16 is deflected and the valve body 14 moves upward, opening the port 12 and opening the port 1.
3 closes, the second passage 7 communicates with the third passage 9, and when the negative pressure in the intake pipe 3 decreases due to an increase in throttle valve opening as at high load, the valve body 14
When the lower blade moves, the port 12 closes and the second port passage 7 communicates with the fourth passage 10.

Further, reference numeral 26 in the figure is an electromagnetic valve provided in the first passage 6 for exhaust gas, and this electromagnetic valve 26 is communicated with the second passage 7 via a bypass passage 27, and controls the carburetor temperature. It is electrically connected to the battery 30 via a temperature switch 28 for detection and a main switch 29, and the bypass passage 27 is opened only when the power is applied.

Although not shown in the drawings, a check valve mechanism is provided in the passage structure leading from the exhaust pipe 4 to the exhaust pipe 4 via the first passage 6, second passage 7, return third passage 9, etc. For example, by interposing a check valve that only allows flow from the control valve 8 side toward the exhaust pipe 4 side in the third return passage 9, the exhaust gas as a preheating medium can be gas,
By utilizing the exhaust pulsation in the exhaust pipe 4, it is possible to reliably circulate from the first passage 6 side to the third return passage 9 side.

Next, referring to FIG. 2, the preheating passage 5 provided in the carburetor brake 2 will be described in detail.The carburetor brake 2 is divided into a slot chamber portion 18, a venturi portion 19, etc. from the intake pipe 3 side, and a throttle valve 2 is connected to the throttle chamber portion 18.
0, a slow port 21 for a slow system, an idle port 22 for an idle system, and the like are provided.

Therefore, in consideration of the fact that icing is particularly likely to occur when fuel is sucked out from the idle port 22 of such a slow ball l-2L, a preheating passage 5 is bored in the slot chamber portion 13 where each of these ports 21 and 22 is located. It is formed by

In addition, in FIG. 2, the reference numeral 23 is a cooling water channel;
This waterway 23 is connected to a waterway 24 for preheating the slow system, which is similarly provided in the throttle chamber section 18.

Since the present invention is constructed as described above, during idling and low load, the second passage 7 and the third passage 9 are communicated with each other by the action of the control valve 8 due to the intake pipe negative pressure, and the second passage 7 and the third passage 9 are An exhaust gas circulation passage is formed that connects to the first passage 6, the preheating passage 5, the second passage 7, and the third return passage 9.

As a result, the exhaust gas as a preheating medium receives exhaust pulsations in the exhaust pipe 4 and circulates in the circulation passage, and the thermal energy of this exhaust gas is used to generate the carburetor brake 2.
This rapid preheating effect prevents slow and idle icing immediately after the engine is started.

On the other hand, when the control valve 8 switches the passage in this way, the fourth passage 10 to the EGR valve 25 is blocked, so no exhaust gas is recirculated at all, and therefore during idling and low load. Stable driving performance can be obtained.

Then, under high load, the second passage 7 and the fourth passage 10 are communicated by the action of the control valve 8 due to the intake pipe negative pressure, and the third passage 9 on the return side is closed, so that the exhaust gas is 2 passage 7
After passing through, it begins to flow to the EGR valve 25 side.

Therefore, from now on, exhaust gas recirculation control is performed according to the load by the action of the EGR valve 25, and the exhaust gas continues to pass through the preheating passage 5, so that the carburetor brake 2
Heating continues, and in this way the entire carburetor brake, including the venturi portion 19 from the slot chamber portion 18, is heated and icing of the main system is also prevented.

Note that under temperature conditions where there is no risk of icing occurring, the temperature switch 2 is closed when the main switch 29 is closed.
8 is closed by an appropriate means, the electromagnetic valve 26 is energized, and the bypass passage 27 is opened by the passage switching operation.

By doing this, the exhaust gas flows through the bypass passage 27 side and does not circulate to the preheating passage 5 side, which prevents the harmful effects of unnecessary heating of the carburetor brake 2, such as percolation of fuel in the float chamber and evaporation. Occurrence can be avoided.

In addition, although intake pipe negative pressure is used to operate the control valve 8,
The switching operation may be performed in conjunction with the EGR valve 25.

In this way, according to the present invention, while the exhaust gas is recirculated as before, the exhaust gas is used to generate the carburetor brake 2.
Since the fuel is preheated, icing in the fuel system is reliably prevented, fuel atomization is promoted, and driving performance is stabilized.

Further, since the temperature of the exhaust gas is lowered by the heat exchange action in the preheating passage, effects such as a reduction in the heat load on the EGR valve can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram showing an embodiment of the device according to the present invention, and FIG. 2 is a sectional view of the main parts. 1... Engine body, 2... Cab brake, 3... Intake pipe, 4... Exhaust pipe,
5... Preheating passage, 6... First passage,
7... Second passage, 8... Control valve, 9
...Third passage, 10...Fourth passage, 11...Valve chamber, 12.13...Port, 14...・Valve body, 15...Negative pressure chamber,
16...Diaphragm, 17...Negative pressure passage, 18...Throttle chamber section, 19...
...Venturi part, 20...Throttle valve, 21...Slow port, 22...
・Idle port, 23.24... Waterway, 25
...EGR valve 26...Solenoid valve, 27...Bypass passage, 28...
Temperature switch, 29... Main switch, 30
······battery

Claims (1)

[Scope of utility model registration request] A preheating passage is provided on the outer periphery of the throttle chamber portion of the carburetor brake, the preheating passage is communicated with the exhaust pipe via a first passage for exhaust gas, and communicated with the inlet side of the control valve via a second passage, One of the outlet sides of the control valve is connected to the exhaust pipe through a third passage for exhaust gas return, and the other side is connected to the ECR valve side through a fourth passage, and During idling and low load, the exhaust gas introduced into the preheating passage through the passage No. 1 is returned to the exhaust pipe through the third passage by the switching action of the control valve No. 2 to one force when the load is high. An intake preheating device for an internal combustion engine, characterized in that the intake preheating device for an internal combustion engine is configured to sometimes cause the air to flow through the fourth passage to the EGR valve side by switching the control valve to the other side.