JPH0244045Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] The present invention relates to a starting fluid supply device for a supercharged engine, and more specifically, to a pressurized chamber for closing a pressure-responsive valve that is opened by starting fluid pressure. , relates to a starting fluid supply device that applies supercharging pressure. This is used in the field of cold starting fluid supply technology for engines with superchargers.

[Prior art]

Generally, in extremely cold regions where the temperature can drop as low as -30°C to -50°C, if a vehicle is left with the engine stopped, the moisture in the combustion gas remaining in the combustion chamber often freezes. A similar phenomenon occurs when the engine is started and the initial detonation does not result in a complete detonation. In such cases, if ice that has formed in the combustion chamber or working chamber adheres to the sliding surfaces of the piston, etc., it will reduce the tracking ability of the piston rings, etc.
The pressure sealing properties are significantly impaired, and sufficient compression pressure cannot be obtained during cracking, resulting in extremely poor engine startability.

To solve this problem, antifreeze containing ethylene glycol as a main component, which is injected into radiators, etc.
At the time of starting, the starting liquid is supplied to the combustion chamber or the like directly or through the intake passage to prevent residual water or moisture generated by combustion from freezing or to promote the melting of frozen water. For example, Utsukai Showa 56-74854
In the publication, a starting fluid supply device that effectively realizes this is proposed, and the starting performance thereof is improved.

By the way, there is a starting fluid supply device that supplies starting fluid pressurized by a starting fluid pump to an intake passage downstream of a throttle valve via a pressure-responsive valve that opens at the pressure. According to this, at the time of starting, a predetermined amount of starting fluid is delivered by a liquid pump, and when it flows into the valve chamber of a pressure-responsive valve, that valve is opened, and the starting fluid supplied to the intake passage is accompanied by the air-fuel mixture. It is now introduced into the combustion chamber. Note that the starting fluid is supplied only at the time of starting, and after that, the liquid feeding pump is stopped, the valve body of the pressure-responsive valve is restored by the spring, and the starting fluid supply path is closed.

When an engine with such a starting fluid supply device is equipped with a supercharger that compresses intake air to increase output, supercharging pressure acts in the direction of opening the valve body of the pressure-responsive valve, causing the starting fluid to flow. The starting fluid remaining in the supply path flows back and is returned to the starting fluid tank through the gap between the stopped fluid pumps. the result,
Even if the liquid feed pump is activated at the next start, there is a problem in that the supply of the starting liquid is delayed and the starting liquid is not supplied at the desired time immediately after starting. In addition, even if a check valve is used instead of a pressure-responsive valve to prevent such backflow, the starting fluid supply path communicates with the intake passage downstream of the throttle valve, so the backflow may occur during idling. The valve opens due to large intake negative pressure,
After the start is complete, starting fluid that is not needed will leak out, inhibiting combustion. Furthermore, if a solenoid valve is used to open and close the starting fluid supply path, the desired starting fluid supply operation can be achieved, but this is not only expensive but also requires a control system to operate it, making it undesirable and complicated. There's a problem.

[Effect of idea]

The present invention was developed in view of the above-mentioned problems, and its purpose is to prevent the backflow of starting fluid that occurs when a supercharger is installed in an engine that supplies starting fluid. To provide a starting fluid supply device for a supercharged engine that can avoid delays and leakage of starting fluid outside the desired timing, and can be realized with a simple structure, low cost, and a configuration that does not require complicated control. That's true.

[Structure of the idea]

A feature of the starting fluid supply device for a supercharged engine of the present invention is that a pressure-responsive valve that opens with pressurized starting fluid is interposed in the starting fluid supply path that communicates with the intake passage downstream of the throttle valve. A pressurized chamber equipped with a spring that biases a valve element in a direction to close the response valve is connected to a communication passage that applies supercharging pressure from a supercharger provided in an intake passage.

[Effect]

When the liquid feed pump is driven during startup, the starting fluid is pressurized and sent to the pressure-responsive valve, and the starting fluid pressure moves the valve body of the pressure-responsive valve against the spring to open the valve. Liquid is supplied from the starting fluid supply path to the intake passage.

On the other hand, when the liquid feed pump stops, the starting liquid pressure decreases and the pressure-responsive valve is closed by the elastic force of the spring. Even if negative pressure occurs downstream of the throttle valve during idling, the valve body of the pressure-responsive valve receives force in the direction of closing, so starting fluid will not leak into the intake passage. In operating conditions where the intake air is pressurized by the turbocharger and the pressure downstream of the throttle valve increases, that pressure acts on the valve body of the pressure-responsive valve.
The boost pressure also acts on the pressurized chamber via the communication path. As a result, supercharging pressure is applied to the diaphragm to which the valve body is fixed from both sides, and the two pressures cancel each other out. Therefore, only the urging force of the spring acts on the valve body, and the closed state of the pressure-responsive valve is maintained. Since the starting fluid does not leak into the intake passage through the pressure-responsive valve, the starting fluid is prevented from entering the mixer unnecessarily, and combustion in the engine is not inhibited.

〔Example〕

Hereinafter, the present invention will be described in detail based on examples thereof. Figure 1 is a schematic overall view of the intake system including the starting fluid supply device for the supercharged engine of the present invention.
is a combustion chamber defined by a cylinder 2 and a piston 3, into which air-fuel mixture supplied from an intake passage 4 is taken in via an intake valve 5.
A throttle valve 6 is provided in the intake passage 4, and a carburetor 7 is provided downstream of the throttle valve 6 in the intake passage 4, and a carburetor 7 is provided downstream of the throttle valve 6 in the intake passage 4, and a fuel injection nozzle (not shown) is provided in the case of a fuel injection type. ing. The intake passage 4a downstream of the throttle valve 6 is connected to a starting fluid supply path 8 that supplies starting fluid during cold starting. In this supply path 8,
A pressure-responsive valve 9 that opens with pressurized starting fluid is interposed, and a liquid feed pump 10 and a starting fluid tank 11 for storing starting fluid are installed upstream thereof. The liquid feed pump 10 sends out a predetermined small amount of starting liquid in a short period of time, and although its type is not specified, it is designed to be driven immediately upon receiving an engine starting command. . Pressure responsive valve 9
As shown in the figure, the inside of the valve is 2 with a diaphragm 12.
One chamber is a valve chamber 14 that has a valve body 13 fixed to a diaphragm 12, and the other chamber has a spring 16 that biases the valve body 13 from behind in order to seat the valve body 13 on a valve seat 15. A pressurized chamber 17 is provided.

A supercharger 18 that compresses intake air to increase output is added to an engine equipped with such a starting fluid supply device.
is provided. Most of the supercharged intake air flows through the intake passage 4, but a portion of it flows into the pressurized chamber 17, which biases the valve body 13 in the direction of closing it. A communication passage 19 is connected between the chamber 17 and the intake passage 4 so that pressure acts thereon.

According to such an embodiment, as will be described below, it is possible to prevent delays in supplying the starting fluid and leakage of the starting fluid at undesired times.

When the engine is started, the engine temperature is detected by a temperature sensor (not shown) in response to the signal. If the detected temperature is, for example, -30°C or lower, the liquid feed pump 1 is turned on to prevent residual water in the combustion chamber or from freezing if a complete explosion does not occur after the first explosion.
0 is driven. The antifreeze liquid in the starting liquid tank 11 is pressurized as a starting liquid by the liquid feeding pump 10, and is sent to the pressure-responsive valve 9. When the starting hydraulic pressure acts on the valve chamber 14 of the pressure-responsive valve, the diaphragm 12 moves against the spring 16, and the valve body 13 moves against the valve seat 1.
The starting fluid in the starting fluid supply path 8 is supplied to the intake passage 4a through a pressure-responsive valve 9 that is open and apart from the starting fluid supply path 8. Since the starting fluid flows into the combustion chamber 1 along with the air-fuel mixture flowing through the intake passage 4, icing is prevented, and the followability of the piston ring 20 is not impaired, and there is no leakage between the piston 3 and the cylinder 2. The pressure seal is maintained, and the engine starts smoothly.

The starting fluid is no longer needed once the engine maintains a complete explosion, so after the fluid feed pump 10 has delivered a predetermined amount, it is automatically stopped and the starting fluid pressure is reduced, causing the valve body 13 to release the spring 16. It seats under force and prevents the flow of starting fluid.

Incidentally, in an idling state, etc., a large negative pressure is generated downstream of the throttle valve 6, and this exerts a force that draws the valve body 13 toward the intake passage 4a, and also acts on the pressurized chamber 17 via the communication passage 19.
The supercharging pressure from the supercharger 18 acts on the diaphragm 12 behind the valve body 13. Since all of these forces act to seat the valve body 13 on the valve seat 15, the pressure-responsive valve 9 does not open, and leakage of starting fluid that inhibits combustion is prevented.

As the engine speed increases, the negative pressure in the intake passage 4a downstream of the throttle valve 6 becomes smaller.
Moreover, the pressure in the intake passage 4 increases due to the boost pressure generated by the supercharger 18. As a result, the pressure is applied to the valve body 13 of the pressure-responsive valve 9, but the supercharging pressure also acts on the pressurized chamber 17 via the communication passage 19 as described above. As a result, supercharging pressure is applied to the valve body 13 from both sides, and the force that moves the valve body 13 is canceled out. Therefore, only the biasing force of the spring 16 acts on the valve body 13, keeping the pressure-responsive valve 9 closed, and the starting fluid does not leak into the intake passage 4a.

By the way, when the engine is stopped, the supercharger is also stopped, and the spring of the pressure-responsive valve keeps the valve body in a seated state, preventing starting fluid from leaking. It goes without saying that if the temperature detected at startup is higher than the predetermined temperature, the above-mentioned starting fluid supply device does not operate.

[Effect of idea]

As can be seen from the description of the embodiments above, the present invention has the following features:
A pressure-responsive valve is interposed in the starting fluid supply passage that communicates with the intake passage downstream of the throttle valve, and a communication passage that applies boost pressure to the pressurized chamber that urges the valve body in the seating direction is connected to the fluid supply passage. Starting fluid is supplied to the intake passage only when the pump is operating, and even if large negative pressure acts on the intake passage or supercharging pressure from the turbocharger acts when the pump is stopped, the starting fluid will not be supplied to the intake passage. Leakage from the pressure-responsive valve or backflow into the starting fluid tank is prevented. As a result, it is avoided that the starting fluid that inhibits combustion is mixed into the air-fuel mixture at an undesired time, or that the supply is delayed at a desired time. Moreover, the configuration for realizing this is simple and inexpensive, and the operation control is not complicated, making it possible to provide a practical starting fluid supply device.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of an intake system of an engine to which the starting fluid supply device for a supercharged engine of the present invention is applied. 4, 4a...Intake passage, 6...Throttle valve,
8... Starting fluid supply path, 9... Pressure-responsive valve, 13...
... Valve body, 16 ... Spring, 17 ... Pressurized chamber,
18...Supercharger, 19...Communication path.

Claims (1)

[Scope of Claim for Utility Model Registration] In an engine in which starting fluid is supplied to the intake passage during cold starting, a pressure-responsive valve opened by pressurized starting fluid communicates with the intake passage downstream of the throttle valve. A communication passage for applying supercharging pressure of a supercharger provided in an intake passage is connected to a pressurized chamber interposed in the fluid supply passage and equipped with a spring that biases a valve body in a direction to close the pressure-responsive valve. A starting fluid supply device for a supercharged engine, characterized in that: