JPH059488Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an engine intake temperature control device that guides hot air around the exhaust manifold (including around the exhaust pipe) of an engine to the engine intake system.

[Conventional technology]

Many engine intake temperature control devices are known that introduce hot air around the exhaust manifold into the engine intake system when starting the engine in cold weather in order to prevent icing on the carburetor or the like.
For example, Utility Model Publication No. 4632, Showa 61-4632, Utility Model Publication No. 47-
Publication No. 6225, Special Publication No. 17493, Publication No. 17493, Publication No. 17493, Utility Model Publication No. 1983
Publication No.-42155 discloses this type of intake temperature control device.

The second representative example of a conventional engine intake temperature control device is
To explain with reference to the figure, the upstream passage 2 of the air cleaner 1 of the engine intake system and the hot air shroud 4 provided around the exhaust manifold 3 are communicated with each other through the hot air pipe 5. A hot air switching valve 6 is installed at the introduction site to the intake system, so that the introduction of hot air can be switched. The hot air switching valve 6 is driven by a vacuum motor 7, the vacuum motor 7 has a negative pressure chamber 8, and the negative pressure chamber 8 has a passage 10 downstream from a throttle valve 9 of the engine intake system and a first passage 1.
1. The first passage 11 is provided with an intake temperature sensing valve 12 that senses the engine intake temperature, and when the engine intake temperature is lower than the set temperature, the valve body 13 closes and engine intake negative pressure is transmitted to the negative pressure chamber 8. When the temperature is higher than the set temperature, the atmospheric pressure of the air cleaner 1 is communicated with the first passage 11 to weaken the negative pressure in the negative pressure chamber 8. When the temperature is lower than the set temperature, negative pressure is applied to the negative pressure chamber 8, the hot air switching valve 6 is opened, and hot air is introduced into the engine intake system, preventing icing of the carburetor etc., and the temperature becomes higher than the set temperature. At this time, the negative pressure in the negative pressure chamber 8 is weakened, the hot air switching valve 6 is closed, and the introduction of hot air into the engine intake system is stopped.

[Problem that the invention attempts to solve]

However, with conventional devices, the diaphragm of the diaphragm motor is hardened during cryogenic starting when the engine temperature is low and the outside temperature is extremely low. Introducing negative pressure may cause the diaphragm to break.

This invention is designed to prevent the diaphragm of the diaphragm motor from breaking when negative pressure is applied to an engine equipped with an intake air temperature compensator that utilizes exhaust manifold heating. The present invention aims to solve the above-mentioned problems by installing a device that temporarily stops the introduction of the throttle downstream negative pressure into the diaphragm motor negative pressure chamber.

[Means for solving problems]

The engine intake temperature control device according to the present invention for achieving the above object includes the following devices. That is, a hot air switching valve that switches the introduction of hot air is installed in the hot air pipe that introduces air around the exhaust manifold into the engine intake system, so that the hot air switching valve opens when negative pressure is introduced into the negative pressure chamber of the vacuum motor. In addition, the hot air switching valve is connected to the vacuum motor so that the hot air switching valve is closed when negative pressure is not introduced into the negative pressure chamber of the vacuum motor, and the negative pressure chamber of the vacuum motor and the downstream side of the throttle valve of the engine intake system are connected to the first valve. In the intake temperature control device, the intake temperature control device includes an intake temperature sensing valve that communicates with the first passage through a passage, senses the engine intake temperature in the first passage, and puts the first passage into communication when the intake temperature is lower than the set temperature. The second negative pressure chamber
The second passage is connected to the atmospheric pressure part through the second passage, and when the engine cooling water temperature is sensed and the engine is not warmed up, the second passage is placed in a communication state even when the intake air temperature is lower than the set temperature. An engine intake temperature control device characterized in that a coolant temperature sensing valve having a set temperature is provided in the second passage.

[Effect]

In the above device, the warm-up state of the engine is also detected by the engine cooling water temperature, and when the engine is in an extremely cold state that is not warmed up, a second cooling water temperature-sensitive valve is installed in the negative pressure chamber of the diaphragm motor. Since the atmosphere is introduced by communicating the passages, the hardened diaphragm does not break. When the engine has warmed up to a certain extent, the cooling water temperature-sensitive valve closes the second passage, so the negative pressure downstream of the throttle is introduced into the negative pressure chamber of the diaphragm motor.
This allows the engine to be warmed up.

〔Example〕

Hereinafter, preferred embodiments of the engine intake temperature control device according to the present invention will be described with reference to the drawings.

FIG. 1 shows an embodiment of the invention. In the figure,
Reference numeral 20 denotes an engine body, from which an exhaust manifold 21 and an intake manifold 22 extend from the cylinder head. Intake manifold 2
An air cleaner 23 is connected to the air cleaner 2, and a carburetor 24 and a throttle valve 25 are provided therebetween.
Intake negative pressure is generated downstream of the throttle valve 25.

There is a hot air shroud 26 around the exhaust manifold 21 (including when it is an exhaust pipe).
The hot air warmed between the hot air shroud 26 and the exhaust manifold 22 is guided upstream of the air cleaner 23 in the engine intake system via the hot air pipe 27.

The hot air pipe 27 has a hot air switching valve 28 that can be opened and closed at the connection with the engine intake system.
is provided, and when it is open, hot air is sucked into the intake system. The hot air switching valve 28 is driven to open and close by a vacuum motor 29. The driving source of the vacuum motor 29 is intake negative pressure,
Engine intake negative pressure downstream of the throttle valve is introduced into the negative pressure chamber 30 via a first passage 31 . When negative pressure is introduced into the negative pressure chamber 30, the vacuum motor 29 drives the hot air switching valve 28 to the open side, and when the pressure is atmospheric, the diaphragm 33 is pushed by the spring 32 installed in the negative pressure chamber 30. The hot air switching valve 28 is driven to the closed side. An intake temperature-sensitive valve 34 is provided in the first passage 31 . The intake air temperature sensing valve 34 senses when the intake air temperature is below the set temperature and closes the passage leading to the air cleaner 23 to guide intake negative pressure to the negative pressure chamber 30, and when the intake air temperature is above the set temperature, it closes the passage leading to the air cleaner 23. Upon sensing this, the passage leading to the air cleaner 23 is opened and the negative pressure in the negative pressure chamber 30 is weakened to atmospheric pressure or near atmospheric pressure. 42
is a jet.

The negative pressure chamber 30 of the vacuum motor 29 is connected to an atmospheric pressure section (in the illustrated example, the air cleaner 23
downstream of the filter and upstream of the vaporizer 24)
A second passage 35 is provided which communicates with the. A coolant temperature-sensitive valve 37 is provided in the middle of the second passage 35 to sense the temperature of the engine coolant 36 and open and close the second passage 35 accordingly. The cooling water temperature-sensitive valve 37 includes a bimetal 41 that causes the valve 38 to approach the valve seat 39 and closes the port 40 when the cooling water temperature rises, and a spring 40 that biases the valve 38 away from the valve seat 39. Becomes,
The bimetal 41 senses the cooling water temperature and deforms.

Therefore, compared to the conventional structure, the second passage 3
5 and a cooling water temperature-sensitive valve 37 are added.

To explain the operation of the device having the above configuration, when the engine 20 is cold, the valve 38 of the coolant temperature-sensitive valve 37 provided in the coolant passage of the intake manifold 22 is open, and the clean side of the air cleaner 23 is opened. Atmospheric air is introduced into the negative pressure chamber 30 of the vacuum motor 29 in the air cleaner nose. The intake air temperature-sensitive valve 34 attached to the air cleaner 23 closes the passage leading from the first passage 31 to the air cleaner clean side because the temperature is low. As a result, the negative pressure in the intake manifold 22 is connected to the vacuum motor 29 via the jet 42, but since the atmosphere from the cooling water temperature-sensitive valve 37 is leaking to the vacuum motor 29, the negative pressure acting on the vacuum motor 29 decreases. Then, the hot air switching valve 28 is closed. Therefore, at extremely low temperatures, the vacuum motor 2
Even if the diaphragm 33 of No. 9 is hardened, the negative pressure will not become too strong and damage the diaphragm 33. As a result, cool air is introduced into the air cleaner 23.

The engine 20 is warmed up, the cooling water rises,
When the temperature of the cooling water temperature-sensitive valve 37 is exceeded, the valve 3
7 closes. Therefore, air does not leak into the vacuum motor 29. The intake temperature-sensitive valve 34 in the air cleaner 23 is closed because the temperature is low due to the cool air. As a result, the negative pressure in the intake manifold 22 acts on the vacuum motor 29, and the hot air switching valve 28 opens. Therefore, since the temperature of the exhaust manifold 21 is already sufficiently high, warm hot air between the exhaust manifold 21 and the hot air shroud 26 is drawn in through the hot air pipe 27. Hot air is sucked in, the intake air temperature rises, and when it reaches the set temperature, the intake temperature sensing valve 34 opens.
Since the atmosphere on the clean side of the air cleaner 23 leaks into the vacuum motor 29, the hot air switching valve 28 is closed. When cool air is taken in, the temperature of the intake temperature sensitive valve 34 decreases, the valve 34 closes, air no longer leaks to the vacuum motor 29, the negative pressure of the vacuum motor 29 increases, and the hot air switching valve 28 opens. In this way,
The temperature of the intake air is controlled to the set temperature of the intake temperature sensitive valve 34.

[Effect of idea]

As explained above, the engine intake temperature control device of the present invention provides a passage (second passage) communicating with the atmospheric pressure section in the negative pressure chamber of the vacuum motor that drives the hot air switching valve, and provides cooling water sensing in this passage. Since a hot valve is installed, even when the intake temperature is below the set temperature in extremely cold weather, the second passage is kept in communication until the engine cooling water rises and warms up, so that the atmospheric pressure remains at the diaphragm motor. Negative pressure is not applied to the diaphragm, which is introduced into the negative pressure chamber and hardened, thereby preventing damage to the diaphragm.

In addition, since hot air is not inhaled until the engine has warmed up to a certain extent, in cars with a catalyst, the exhaust gas temperature can be prevented from decreasing due to the hot air, and as a result, the catalyst warms up more quickly. , exhaust gas can be reduced accordingly.

[Brief explanation of the drawing]

FIG. 1 is a system diagram of an engine intake temperature control device according to an embodiment of the present invention, and FIG. 2 is a system diagram of a conventional engine intake temperature control device. 21... Exhaust manifold, 26... Hot air shroud, 27... Hot air pipe, 28... Hot air switching valve, 29... Vacuum motor, 30... Negative pressure chamber, 31... First
passage, 34...intake temperature sensitive valve, 35...second passage, 37...cooling water temperature sensitive valve.

Claims (1)

[Scope of utility model registration request] A hot air switching valve that switches the introduction of hot air is installed on the hot air pipe that introduces air around the exhaust manifold into the engine intake system. The hot air switching valve is connected to the vacuum motor so that the hot air switching valve is closed when negative pressure is not introduced into the negative pressure chamber of the vacuum motor, and a first passage is connected between the vacuum motor's negative pressure chamber and the throttle valve downstream of the engine intake system. In an intake temperature control device, an intake temperature sensing valve is provided in a first passage, which senses the engine intake temperature and puts the first passage into communication when the intake temperature is lower than a set temperature. Pressure chamber second
The second passage is connected to the atmospheric pressure part through the second passage, and when the engine cooling water temperature is sensed and the engine is not warmed up, the second passage is placed in a communication state even when the intake air temperature is lower than the set temperature. An engine intake temperature control device characterized in that a coolant temperature sensing valve having a set temperature is provided in the second passage.