JPS6220672Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fuel injection amount control device for a diesel engine equipped with a boost compensator.

Diesel engines employing a supercharging system are equipped with a boost compensator, and the amount of fuel injection at full load is controlled by the boost pressure and the characteristics of the spring used in the boost compensator.

However, since conventional boost compensators use one linear spring (a coil spring with a constant spring thickness and winding diameter),
There is a drawback that the control characteristics are stepped and the desired characteristics cannot be obtained. In addition, attempts have been made to combine two linear springs to obtain the desired control characteristics, but this also results in a breaking point, and it is difficult to incorporate two springs into a narrow casing. There are disadvantages such as oxidation.

By using a single non-linear spring, the present invention eliminates the break point and easily obtains the desired fuel injection amount characteristics, while also being structurally superior to the conventional single linear spring. It is designed to be the same as the one using .

Various methods can be considered to obtain a nonlinear spring with a single spring, but it is possible to obtain a nonlinear spring with a single spring by using a coil spring and changing its winding diameter, or by changing the thickness of the spring material. can be obtained.

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

A control rack 5 is connected via a link 4 to the other end of a floating lever 3, to which an accelerator pedal (control lever) 1 is connected in the middle and a centrifugal governor, generally indicated by 2, is connected to one end. This control rack 5
controls a fuel injection pump (not shown).

The boost compensator, generally designated by 6, comprises a chamber 9 and a chamber 10 separated by a diaphragm 8. Boost pressure is supplied to the chamber 9 from an inlet 9a, and the chamber 10 communicates with the atmosphere through an opening 10a. Coil spring 11 that counters boost pressure
is provided. Rod 1 for diaphragm 8
The rod 12 protrudes through the intermediate wall 7b of the casing 7, and a lever 13 is connected to the tip of the rod 12.
is rotatable at a support point 13a. An adjustable stopper 14 is provided on the outer wall 7a of the casing 7.

By depressing the accelerator pedal 1, the control rack 5 moves in the direction of arrow A to increase the fuel injection amount via the floating lever 3 and the link 4, and as the engine speed increases, the control rack 5 moves due to the action of the centrifugal governor 2. It is moved in the direction of arrow B to decrease the fuel injection amount.

At full load (when the accelerator pedal is depressed 4/4 of the way) when the tip of the control rack 5 contacts the lever 13 of the boost compensator 6, the control rack 5 and therefore the fuel injection amount depend on the boost pressure and the spring characteristics of the coil spring 11. controlled. When the boost pressure increases, the coil spring 11 is compressed from the state shown in FIG. 1 to the state shown in FIG. Move in the direction of arrow A to increase quantity.

In the present invention, one nonlinear spring is used as the coil spring 11, and the spring has spring characteristics that match the target torque characteristics of the engine.

In order to obtain such a spring, the winding diameter of the coil spring may be changed as shown in FIG. 3, or the diameter of the spring material may be changed as shown in FIG. 4.

Figure 5 shows the relationship between the position L of the control rack and the rotational speed n of the fuel injection pump. In Figure 5, A is the characteristic for one linear spring, and B is the characteristic for a combination of two linear springs. The characteristic obtained by this, C, indicates the position of the control rack required from the target torque characteristic, and the curve C indicates the position of the control rack required from the target torque characteristic.
can be obtained by using one nonlinear spring as described above and giving that spring a spring characteristic matching the target torque characteristic of the engine.

As can be seen from the figure, the broken line A is far away from the curve C, and the broken line B is closer to the curve C than the broken line A, but a breaking point still occurs.

FIG. 6 shows the relationship between engine torque T and engine speed N when each spring shown in FIG. 5 is used, where A' indicates the torque characteristic obtained with one linear spring, B' indicates the torque characteristic obtained by combining two linear springs, and C' indicates the target torque characteristic, i.e., the torque characteristic obtained with the spring of the present invention.

As explained above, according to the present invention, the conventional one
The fuel injection amount characteristics are smoother without the break point that occurs when using a real linear spring, and the fuel injection amount characteristics are also smoother compared to a combination of two linear springs. Desired injection quantity characteristics can be obtained, and it can be manufactured at low cost and can be made compact.

[Brief explanation of the drawing]

Figures 1 and 2 are side views showing a part of the fuel injection amount control device for a diesel engine equipped with a boost compensator. The case of large is shown. 3 and 4 are longitudinal sectional views showing an example of a nonlinear spring used in the boost compensator of the present invention. FIG. 5 is a graph showing the relationship between the control rack and the rotational speed of the fuel injection pump, and FIG. 6 is a graph showing the relationship between the engine torque and the engine rotational speed. 1...Accelerator pedal, 2...Centrifugal governor, 3
...Floating lever, 4...Link, 5...
...Control rack, 6...Boost compensator, 7...Casing, 8...Diaphragm, 9...Chamber to which boost pressure is guided, 10...
Chamber communicating with atmosphere, 11...Nonlinear coil spring, 1
2...rod, 13...lever, 14...stopper.

Claims (1)

[Scope of utility model registration request] Boost pressure is guided into one chamber separated by a diaphragm, and the other chamber is open to the atmosphere, and a spring is provided to counteract the boost pressure.The characteristics of the boost pressure and spring allow the fuel injection pump to inject at full load. Fuel injection for a diesel engine, characterized in that, in a boost compensator that performs quantity control, one nonlinear spring is used as the spring of the boost compensator, and the spring has spring characteristics that match the target torque characteristics of the engine. Volume control device.