JPS5919804Y2 - 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 an internal heat engine, and more particularly to an intake air preheating device with an improved control means for preheating air.

Conventionally, as an intake air preheating device for an internal combustion engine, a preheating air passage is connected to an air passage in an air cleaner having a fresh air intake port, and a negative pressure operating body is connected to a control valve that controls the opening degree of the preheating air passage. The negative pressure chamber of this negative pressure actuator is communicated with the suction pipe through a negative pressure passage, and a temperature control valve that senses the temperature of the mixed intake air of fresh air and preheated air and increases its opening on the high temperature side of the sensed temperature. The negative pressure passage is communicated with the atmosphere to control the intake amount of preheated air so that the temperature of the mixed intake air of fresh air and preheated air reaches a predetermined temperature.

As this type of prior art, for example, Japanese Patent Application Laid-Open No. 48-332
16 and JP-A-50-43312 are known.

However, in this intake air preheating device, since the intake amount of preheated air is controlled only by the temperature control valve, it is difficult to control the intake air temperature to be appropriate depending on the operating conditions of the engine.

The present invention was developed in view of the above-mentioned circumstances, and it enables engine operation by ensuring a reliable response to outside air temperature and by keeping the intake air temperature relatively high during idling operation such as during warm-up of the engine. It is an object of the present invention to provide an intake air preheating device for an internal combustion engine that can appropriately control intake air temperature according to conditions and thereby provide stable and excellent fuel efficiency and engine operating characteristics.

In order to achieve this objective, the present invention provides an air intake preheating device for an internal combustion engine as described above, in which the negative pressure passage of the negative pressure actuator is connected to the suction pipe side from the communication part with the atmosphere side when the outside air temperature is low. In addition to providing an outside temperature sensing valve that opens only when the negative pressure passage is open, the part between the communication part of the negative pressure passage with the atmosphere side and the outside temperature sensing valve is made to communicate with the part immediately downstream of the throttle valve idling opening of the intake passage of the carburetor. It is something.

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

In the figure, reference numeral 1 is an internal combustion engine main body, 2 is an intake system, and 3 is an exhaust pipe, and the intake system 2 includes an air cleaner 4, a carburetor 5, and an intake manifold 6.

A heat exchanger 7 is provided by covering the outer circumferential side of the upstream end of the exhaust pipe 3 with a pipe body, and a preheating air passage 8 communicating with the heat exchanger 7 is connected to a filter element 9 in the air cleaner 4 and intake of fresh air. A control valve 12 is provided in the air passage 11, which opens into the air passage 11 formed between the preheating air passage 8 and the opening 10, and controls the degree of opening of the opening of the preheating air passage 8.

The control valve 12 is connected to an operating rod 14 of a negative pressure actuating body 13, and the operating rod 14 of the negative pressure actuating body 13 is connected to a diaphragm 16 which has a back pressure of a spring 15. It is configured to operate by the negative pressure in the negative pressure chamber 17 against the pressure.

The negative pressure chamber 17 is communicated with the suction manifold 6 through a negative pressure passage 18, and the negative pressure passage 18 is communicated with the downstream side of the filter element 9 in the air cleaner 4 through a leak passage 19. A temperature control valve 20 is provided at the opening to.

This temperature control valve 20 has a temperature sensing body 22 equipped with thermowax, bimetal, etc. facing upstream of the suction passage 21 of the vaporizer 5 near the air cleaner 4.
2 is configured to sense the temperature of the intake air passing through the intake passage 21 and increase the opening degree of the leak passage 19 on the high temperature side.

A second negative pressure passage 23 is connected to the suction manifold 6 side from the leak passage 19 of the negative pressure passage 18, and this passage 23
is provided with a throttle 24, and a second negative pressure passage 23 opens into the suction passage 21 of the carburetor 5 at a position immediately downstream of the throttle valve 25 at the idling opening.

An outside temperature sensing valve 26 that senses the outside air temperature and opens only when this temperature is low is provided on the side of the suction manifold 6 from the communication portion of the negative pressure passage 18 with the second negative pressure passage 23.

The outside temperature sensing valve 26 is opened and closed by a temperature sensing body 27 made of thermowax, bimetal, or the like.

Further, reference numeral 28 in the figure is a preheated air intake port.

Next, the operation of the intake air preheating device configured as above will be explained.

If the outside air temperature is the set temperature of the outside temperature sensing valve 26 (for example, 10°
C or 20°C), the outside temperature sensing valve 26 opens the negative pressure passage 18, and when the temperature of the intake air passing through the intake passage 21 is lower than the set temperature of the temperature control valve 20, this temperature control valve opens. 20 closes the leak passage 19, the suction negative pressure of the suction manifold 6 acts on the negative pressure chamber 17 of the negative pressure actuator 13 via the negative pressure passage 18, and the control valve is closed by the operation of the negative pressure actuator 13. 12 opens the preheating air passage 8.

Therefore, the outside air or the air in the engine room sucked in from the preheated air intake port 28 is heated by the heat exchanger 7 and becomes warm air, and this warm air passes through the preheated air passage 8 and enters the air cleaner 4.
The air is sucked into the air passage 11 inside the engine and mixed with fresh air, which is outside air or air inside the engine room, which is directly sucked in through the intake port 10.

The intake air, which is a mixture of warm air, that is, preheated air, and fresh air at a lower temperature, passes through filter membranes 1 to 9 to the vaporizer 5.
Fuel is supplied to the carburetor 5 through the intake passage 21 to form an air-fuel mixture, which is sucked into the internal combustion engine main body 1 and combusted.

The exhaust gas after combustion is discharged into the exhaust pipe 3, heats the air passing through the heat exchanger 6, and then is discharged into the atmosphere.

When the temperature of the mixed intake air of fresh air and preheated air passing through the intake passage 21 of the carburetor 5 exceeds the set temperature of the temperature control valve 20, the temperature sensor 22 senses this temperature and the temperature control valve 20 is activated. The opening degree increases as the intake air temperature increases.

Therefore, air is introduced from the nok passage 19 into the negative pressure passage 18, and the negative pressure in the negative pressure chamber 17 becomes smaller.

Therefore, the negative pressure actuator 13 controls the opening degree of the control valve 12 in the closing direction to reduce the warm air sucked from the preheating air passage 8,
Or eliminate the intake to prevent the intake air temperature from becoming excessively high.

Furthermore, when the outside air temperature becomes higher than the set temperature of the outside temperature sensing valve 26, the sensing valve 26 cuts off communication between the negative pressure passage 18 and the suction manifold 6.

Therefore, the negative pressure chamber 17 of the negative pressure operating body 13 is communicated only with the suction passage 21 of the carburetor 5 through the second negative pressure passage 23.

In this case, if the set temperature of the temperature control valve 20 is set higher than the set temperature of the outside temperature sensing valve 26, the negative pressure in the suction passage 21 will become
Since the negative pressure passage 23 acts on the negative pressure chamber 17, the control valve 12 opens the preheated air passage 8 to the required opening degree by the negative pressure operating body 13, and a certain amount of preheated air is mixed with fresh air and sucked. I can do it.

Then, when the engine is operated with the opening degree of the throttle valve 25 increased, the opening of the second negative pressure passage 23 is opened to the throttle valve 25.
5, the negative pressure chamber 17 becomes almost atmospheric pressure, and the preheating air passage 8 is heated by the control valve 12 via the negative pressure actuator 13.
is closed and only fresh air is used as intake air without mixing preheated air.

Note that when the outside air temperature is higher than the set temperature of the temperature control valve 20, this valve 20 opens the leak passage 19, and air is introduced from this passage 19 into the negative pressure chamber 17, so that the control valve 12 is preheated. The air passage 8 is closed and only fresh air is used as intake air.

As explained above, the intake preheating device for an internal combustion engine according to the present invention detects the temperature of the mixed intake air of fresh air and preheated air, and controls the intake amount of preheated air using the control valve provided in the preheated air passage. In addition, when the outside air temperature is detected and the outside air temperature is higher than a predetermined temperature other than during idling operation, preheated air is not sucked, and when the outside air temperature is above the predetermined temperature during idling operation, the preheated air is not sucked. but,
If the intake air temperature is lower than the set temperature of the temperature control valve, the preheated air can be mixed with fresh air to keep the intake air temperature relatively high, making it possible to control the preheated air according to the outside air temperature, improving warm-up characteristics. can be done.

Therefore, the intake air preheating device of the present invention can use intake air at an appropriate temperature depending on the operating conditions of the engine, and has the effect of providing stable and excellent fuel economy characteristics and engine operability.

In addition, in this invention, the temperature sensor of the temperature control valve, which operates by sensing the mixed intake air temperature of fresh air and preheated air, faces the upstream part of the intake passage of the carburetor, so that the intake air temperature distribution inside the air cleaner is improved. Since the temperature is non-uniform, the detected temperature varies depending on the mounting position of the temperature sensor, and compared to the temperature difference in the intake air passing through the carburetor, the temperature control valve can be operated by sensing the intake air temperature stably and accurately. It is possible to control the negative pressure of the negative pressure operating body appropriately, and the above-mentioned effects can be further improved.

[Brief explanation of drawings]

The figure is a configuration explanatory diagram showing an embodiment of the present invention. 1...Internal combustion engine main body, 2...Intake system,
3...exhaust pipe, 4...air cleaner,
5... Carburizer, 6... Suction manifold, 7... Heat exchanger, 8... Preheating air passage, 9... Filter Element, 10...
...Intake port, 11...Air passage, 12...
...Control valve, 13...Negative pressure actuating body, 14...
...Operating rod, 15...Spring, 16.
...Diaphragm, 17...Negative pressure chamber, 1
8...Negative pressure passage, 19...Leak passage, 20...Temperature control valve, 21...Suction passage, 22...Temperature Sensing body, 23...
Second negative pressure passage, 24... Throttle, 25...
...Throttle valve, 26...Outside temperature sensing valve, 2
7...Temperature sensor, 28...Preheated air intake port.

Claims (2)

[Scope of utility model registration request] (1) A preheated air passage is communicated with an air passage in an air cleaner having a fresh air intake port, and a negative pressure operating body is connected to a control valve that controls the opening degree of this preheated air passage. The negative pressure chamber is communicated with the suction pipe through a negative pressure passage, and the negative pressure passage is connected to the atmosphere through a temperature control valve that senses the temperature of the mixed intake air of fresh air and preheated air and increases its opening on the high temperature side of the sensed temperature. In an intake air preheating device for an internal combustion engine that communicates with the atmosphere side of the negative pressure passage, an outside temperature sensing valve that opens only when the outside air temperature is low is provided on the intake pipe side from the communication part with the atmosphere side of the negative pressure passage; The part between the communication part and the outside temperature sensing valve,
An intake air preheating device for an internal combustion engine, characterized in that the intake air preheating device for an internal combustion engine is connected to a portion immediately downstream of an idling opening of a throttle valve of an intake passage of a carburetor. (2) The intake air preheating device for an internal combustion engine as set forth in claim 1, wherein the temperature sensor for operating the temperature control valve faces the upstream side of the intake passage of the carburetor.