JPH0212286Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an intake throttle device for a diesel engine that reduces vibration and noise even when the diesel engine is idling.

Diesel engines have a problem in that their vibrations and noise are greater when idle than gasoline engines.

One of the causes of this is the high rate of pressure rise in the cylinder, and by restricting the amount of intake air flowing into the intake manifold from the intake pipe,
It is known that mitigating the pressure increase within the cylinder is effective in reducing its vibration and noise.

On the other hand, when a diesel engine is idling, it does not require much output, so it is okay to throttle the intake air a little.
When the engine is operating at medium to high speeds, sufficient intake air must be delivered into the cylinders to provide the required air-fuel ratio.

In addition, there is Japanese Patent Application Laid-Open No. 142416/1989, which describes a bypass passage that bypasses the control valve of an air supply system equipped with an exhaust gas recirculation valve and is provided with a valve that opens when the engine is at low temperature. , which supplies extra air at low temperatures to relatively reduce the amount of exhaust gas recirculation, and has not been able to solve the above problem.

In addition, there is a method for controlling the negative pressure downstream of the intake throttle valve to a constant level using a bypass valve installed in the bypass passage, as disclosed in Japanese Utility Model Application Publication No. 55-35373, which uses water temperature control and constant negative pressure downstream of the throttle valve. There is Japanese Utility Model Application Publication No. 55-165933 that combines this with control.
The structure of these publications could not solve the above problem.

The present invention was developed with the above points in mind. When a diesel engine is idling, the intake throttle valve is closed and only the minimum amount of intake air necessary is sent into the cylinder, thereby reducing engine vibration and noise. On the other hand, during medium/high-speed loads after the engine has been warmed up to stabilize combustion, the throttle valve is opened in conjunction with the accelerator, and the bypass valve is opened and closed as necessary to ensure sufficient intake air. The purpose is to provide a diaphragm device.

That is, the intake throttle device of the present invention provides the intake pipe of a diesel engine with an intake throttle valve that opens and closes in conjunction with the accelerator device, and also provides a bypass passage with a bypass valve that allows the intake throttle valve to be bypassed. When the bypass valve is idling at a temperature below a predetermined temperature with the intake throttle valve closed, the vacuum pump and diaphragm chamber are electrically connected and the bypass valve is fully open, supplying air for stable combustion, but when idling at a temperature above a predetermined temperature. At times, the bypass valve opens and closes so that the negative pressure downstream of the intake throttle valve remains constant, and when the load is low, the bypass valve opens and closes in conjunction with the opening of the intake throttle valve so that the negative pressure downstream of the intake throttle valve remains constant. It is connected to a control device that opens and closes.

The details of the present invention will be explained below with reference to the drawings. FIG. 1 shows an intake throttle valve device provided in the intake pipe 13 of a diesel engine in Embodiment 1 of the present invention, and the arrow on the intake pipe 13 The air cleaner side indicated by A and the intake manifold indicated by arrow B are connected via a wire 8 by an accelerator pedal 15, which is an accelerator device of this diesel engine, and are opened and closed in conjunction with the accelerator pedal 15. An intake throttle valve 9 is provided.

Next, this intake pipe 13 is provided with the intake throttle valve 9.
Bypass path 1 with bypass valve 4 that can bypass
2 along the side wall of the intake pipe 13, and a control device 14 that can control the bypass valve 4 in accordance with the temperature of the circulating fluid of the diesel engine, for example, the cooling water W as in the first embodiment. It is set up.

This control device 14 includes a water temperature sensing valve 7 that moves up and down depending on the temperature of the cooling water W, and a bypass valve 4.
The valve opening/closing device 6 includes a diaphragm 11 and a valve spring 10 to control opening and closing of the valve, and a vacuum pump 2 and the like.

The diaphragm port 1 of the valve opening/closing device 6 and the vacuum pump 2 are communicated via the water temperature sensing valve 7 so as to be openable and closable, and the diaphragm port 1 and the intake pipe 13 are opened on the intake manifold B side. It also communicates with the vacuum port 3 via a water temperature sensing valve 7 so as to be openable and closable.

Therefore, when a diesel engine having the intake air throttling device of the present invention having the above-mentioned configuration is started in cold weather, such as when the cooling water temperature is below 60°C, the water temperature sensing valve 7
is in the downward position in the figure, so the diaphragm port 1 and the vacuum pump 2 work together, the diaphragm 11 moves to the right in the figure, the bypass valve 4 lifts and opens, and the bypass valve 4 is opened. Sufficient intake air necessary for combustion is supplied via the passage 12.

Further, even when the intake throttle valve 9 is closed when the diesel engine is idling, if the temperature of the cooling water W is low, the bypass valve 4 opens and necessary intake air is sent into the cylinder.

Furthermore, the combustion of the engine becomes stable and the temperature of the cooling water W decreases.
When the water temperature reaches 60°C or higher, the water temperature sensing valve 7 is lifted to the state shown in Fig. 1, the diaphragm port 1 communicates with the vacuum port 3, and the bypass valve 4 is opened so that the pressure in the vacuum port 3 is constant. The amount of air passing through is controlled.

Therefore, when the accelerator pedal 15 is depressed, the intake throttle valve 9 is opened.

Note that the valve opening/closing device 6 is not limited to the configuration in the first embodiment, and the bypass valve 4 can be adjusted depending on the temperature of the circulating fluid of the diesel engine, such as the cooling water W or lubricating oil. Any configuration may be used as long as it can be controlled.

Further, the type of the intake throttle valve 9 provided in the intake pipe 13 is not restricted to the above-described first embodiment, but is similar to that of the intake pipe 1 in the second embodiment shown in FIG.
3 is divided by a partition plate 5 and an intake throttle valve 9 is provided on one side of the two-barrel type, the other side of the partition plate 5 is used as a bypass path, and a bypass valve is installed in the middle of this bypass path. The intake throttle device of the present invention can be applied by providing a bypass valve and opening and closing the bypass valve using the valve opening/closing device 6 and the control device 14 shown in the previous example.

Therefore, in a diesel engine to which the intake air throttling device of the present invention is applied, the amount of intake air is throttled even when the engine is idling, thereby reducing engine vibration and noise. When the machine is under medium or high speed load after completion of the machine, the intake throttle valve opens in conjunction with the accelerator, allowing sufficient intake air to be delivered as before.

Note that the present invention can be effectively applied mainly to diesel engines provided with an intake throttle valve.

[Brief explanation of the drawing]

Fig. 1 is a schematic vertical sectional view of the main parts of an intake throttle device for a diesel engine according to Embodiment 1 of the present invention, and Fig. 2 is a main part showing an intake throttle valve to which the intake throttle device according to Embodiment 2 of the present invention can be applied. It is a schematic longitudinal cross-sectional view. 4... Bypass valve, 6... Valve opening/closing device, 7...
Water temperature sensing valve, 8...Wire, 9...Intake throttle valve,
12... Bypass path, 13... Intake pipe, 14...
Control device, 15... accelerator pedal.

Claims (1)

[Scope of utility model registration request] The intake pipe of the diesel engine is provided with an intake throttle valve that opens and closes in conjunction with the accelerator device, and a bypass passage with a bypass valve that allows the intake throttle valve to be bypassed is provided, and the bypass valve is connected to the intake throttle valve when the intake throttle valve is closed. Only the bypass valve opens when the engine is idling at a temperature below a predetermined temperature, and when the load exceeds a predetermined temperature in medium or high loads, the bypass valve opens and closes in conjunction with the opening of the intake throttle valve so that the negative pressure downstream of the intake throttle valve remains at a constant pressure. A diesel engine intake throttle device that is connected to a control device.