JPS593160Y2 - Injection amount correction device for fuel injection pump - Google Patents

Description

[Detailed description of the invention] The present invention is an injection amount correction device for a fuel injection pump for an internal combustion engine;
In particular, the present invention relates to an improvement of an atmospheric pressure correction device that controls the injection amount based on changes in atmospheric pressure, and relates to a correction device that has a simple configuration and increases control force in response to changes in atmospheric pressure.

An embodiment of the present invention will be described below with reference to the drawings.

In the figure, a negative pressure inlet 2 is formed at one end of the main body 1, and a first diaphragm 3 is attached to a position facing the negative pressure inlet 2 in the main body 1, and atmospheric air is introduced into the first diaphragm 3. A valve seat body 5 forming an opening 4 is attached, and a control negative pressure generating chamber 6 is formed by the first diaphragm 3 and the main body 1.

A valve 7 is disposed between the atmospheric air inlet 4 and the negative pressure inlet 2 to control the opening and closing of each inlet 2 and 4, and the valve 7 releases the negative pressure when the first diaphragm 3 is displaced upward in the figure. It is configured such that when the inlet 2 is opened and the air inlet 4 is moved downward, the atmosphere inlet 4 is opened.

A second diaphragm 8 is attached to one end of the valve seat body 5, and the diaphragms 3 and 8 form a pressure chamber 9 within the main body, and the pressure chamber 9 and the control negative pressure generation chamber 6 are formed next to each other. ing.

The control negative pressure generation chamber 6 communicates with a governor of a fuel injection pump (not shown) via a control negative pressure transmission port 10.

Because of the above structure, when the pressure in the pressure chamber 9 is equal to the atmospheric pressure, no force is generated to change the valve 7 (force to move it upward), and the control negative pressure in the control negative pressure generation chamber 6 is constant. Keep value.

In this state, when the atmospheric pressure decreases (as the altitude increases), the force with which the atmosphere presses the second diaphragm 8 decreases, and the valve seat body 5
The valve 7 moves upward, opens the negative pressure inlet 2, increases the controlled negative pressure in the controlled negative pressure generation chamber 6, pulls down the first diaphragm 3, closes the negative pressure inlet 2, and responds to the drop in atmospheric pressure. Generates increased control negative pressure.

This increased control negative pressure displaces the maximum injection amount setting member of a governor (not shown) in the direction of fuel reduction, reducing the maximum injection amount as the atmospheric pressure decreases and preventing the generation of black smoke.

Next, changes in the controlled negative pressure in the above configuration will be explained below.

In the above configuration, atmospheric pressure: PA, pressure chamber pressure crab PN
, control negative pressure: PO, area of diaphragm 8: SA, area of diaphragm 3: SO, the change in PO is (PN-
PA) SA= (PN-PO)SOlSA 5A PO=PN (1---) Ten PA, δ, and two DaS.

By selecting the area ratio of the earphragms 3 and 8, it is possible to freely and easily change the change in the control negative pressure with respect to the change in atmospheric pressure.

As described above, the injection amount correction device of the present invention has a simple configuration and can generate a controlled negative pressure having an arbitrary rate of change in response to changes in atmospheric pressure, thereby providing an injection amount correction device with sufficient control power. This is a practically effective idea.

[Brief explanation of drawings]

The figure is a sectional view showing an embodiment of the present invention. 2: Negative pressure inlet, 3: First diaphragm, 4: Atmospheric inlet, 5: Valve seat body, 6: Control negative pressure generation chamber, 7: Valve, 8:
Second diaphragm, 9: pressure chamber.

Claims (1)

[Scope of utility model registration request] It has a controlled negative pressure generating chamber whose one end is closed by a first diaphragm, a negative pressure inlet is formed on a surface of the controlled negative pressure generating chamber opposite to the first diaphragm, and the first diaphragm is connected to the atmosphere. A valve seat body forming an inlet is fixed, an integral valve for controlling the opening and closing of each of the atmosphere inlet and the negative pressure inlet is provided on the valve seat body, a second diaphragm is attached to the valve seat body, and a second diaphragm is attached to the valve seat body. An injection amount correction device for a fuel injection pump comprising a pressure adjusting member configured to form a pressure chamber with two diaphragms and receive atmospheric pressure through a second diaphragm.