JPH0541261Y2 - - Google Patents

Description

[Detailed description of the invention] <<Industrial application>> The present invention uses a fuel injection cam to drive the plunger of an in-line fuel injection pump toward the top dead center via a tappet, and a return spring to drive the plunger toward the bottom dead center. The present invention relates to an in-row fuel injection pump for a diesel engine configured to push back into the engine.

<Prior Art> In a conventional inline fuel injection pump for a diesel engine of this type, the injection timing during operation is adjusted using a centrifugal mechanical timer attached to the camshaft driving side of the fuel injection cam. is rotated in the direction of rotation, and the injection timing is adjusted according to this rotation speed.
For example, the injection timing is changed such that the higher the rotational speed, the earlier the injection timing, and the lower the rotational speed, the slower the injection timing.

<<Problems to be Solved by the Invention>> However, in the above-mentioned conventional technology, there is a problem in that the centrifugal timer delays the fuel injection timing when the engine is started at a low temperature, making it difficult to start the engine.

This invention is not restricted by the injection timing retardation effect of the centrifugal timer when starting the engine at low temperature.
The purpose is to make it easier to start the engine by advancing the injection timing, and to enable it to be implemented easily and inexpensively without major changes to the current structure.

<Means for Solving the Problems> In order to achieve the above object, the present invention drives the plunger of an in-line fuel injection pump toward top dead center via a tappet with a fuel injection cam, and uses a return spring to In a diesel engine in-line fuel injection pump configured to push back toward the bottom dead center, a temperature-sensitive actuator is interposed between the tappet and the plunger, and the temperature-sensitive actuator is in a high-temperature detection operation state when a low temperature detection operation is performed. The plunger is configured to advance toward the top dead center side.

<<Operation>> According to the above structure, when the temperature is low at the time of starting, the temperature-sensitive actuator interposed between the tappet and the plunger detects the low temperature and operates, and in this low-temperature detection operating state, when the engine is running, The plunger is advanced toward the top dead center in the high temperature detection operating state, and the injection timing of the injection pump is advanced, thereby making it easier to start the engine.

<<Example>> Hereinafter, an in-line fuel injection pump for a diesel engine according to the present invention will be explained by referring to an example shown in the drawings.

The column type fuel injection pump shown in FIG. 1 has a substantially cylindrical pump body 1, an inner cylinder member 3 into which a plunger 2 is fitted so as to be able to slide vertically, and an outer cylinder member 4 into which the inner cylinder member 3 is fitted. is inlaid.

Furthermore, an outlet cylinder 5 that communicates with an injection nozzle (not shown) is screwed into the upper end of the outer cylinder member 4 that is fitted into the pump body 1.

Further, a tappet 6 that pushes the plunger 2 toward the injection side is fitted into the lower end of the pump body 1 so as to be able to move vertically. A fuel injection cam 7 that pushes the fuel to the side is disposed, and the cam shaft 7a of the cam 7 is connected to a centrifugal mechanical timer (not shown), and the timer causes the cam shaft 7 to
The injection timing is changed according to the rotation of a.

Further, a return spring 9 is interposed between the tappet 6 and a cylindrical spring stopper 8 fitted on the outside of the lower end of the inner cylinder member 3.

Further, a protruding shaft 8a is attached to the cylindrical spring stopper 8 fitted into the inner cylinder member 3, and a control pin 11 is inserted into the pump body 1 into the angle adjustment hole 10 bored in the pump body 1. A protruding portion 11a protruding from the portion is arranged so as to be lockable.

Also, a delivery valve 1 is provided in the outlet cylinder 5.
A valve-closing spring 13 is provided between the delivery valve 12 and the injection-side inner surface 5a on the outlet 5b side of the outlet cylinder 5.

In the figure, reference numeral 14 denotes a fuel supply pipe screwed into a fuel intake hole 1b formed in the upper side of the pump body 1.

Further, 6b is a roller provided on the tappet 6 and brought into contact with the cam surface of the cam 7.

The feature of the present invention is that in the in-line fuel injection pump configured as described above, the tappet 6
On the upper surface of the middle wall 6a, the tapepet 6
A temperature-sensitive actuator 15 made of bimetal, shape memory alloy, or the like is interposed between the plunger 2 and the plunger 2.

With the above configuration, the injection timing of the fuel injected from the injection nozzle (not shown) directed into the cylinder chamber of the engine is set at a certain angle earlier than the top dead center of the piston (not shown). The tappet 6 is then rotated by the rotation of the cam 7.
is moved up and down within the pump body 1, and the plunger 2 is moved up and down via the temperature-sensitive actuator 15 to open and close the delivery valve 12, thereby opening and closing the fuel intake hole 1.
Fuel is supplied from inside b into the outlet cylinder 5, and the fuel is injected into the cylinder chamber from the outlet cylinder 5 through the injection nozzle at a predetermined time.

Further, after fuel is injected, the delivery valve 12 is returned to the lower side in the figure by the valve closing spring 13, and the plunger 2 is returned to the lower position.

When the temperature is low at the time of starting, the temperature-sensitive actuator 15 detects this low temperature and activates the low temperature detection operation, that is, it is curved so that its central portion is lifted by a predetermined distance L toward the plunger 2, as shown in FIG. The plunger 2 is lifted in advance by an amount corresponding to its curved shape, the tappet 6 is lifted by the cam 7, the plunger 2 is moved further upwards from the lifted point, and the delivery valve 12 is opened early to supply fuel. is injected into the cylinder chamber from the outlet cylinder 5 through the injection nozzle at an early advance.

By doing so, the temperature-sensitive actuator 15 operates to detect low temperature at the time of starting, especially when the temperature is low, and the fuel injection timing can be advanced, so that the engine can be started easily.

In addition, when the temperature of the engine is high, as shown in FIG.
detects a high temperature and enters a high temperature detection operating state, that is, a flat plate state, and operates normally.

<<Effects of the invention>> Since the present invention has the above-mentioned configuration and is in an operating state,
The injection timing is automatically advanced by the low temperature detection operation of the temperature-sensitive actuator, making it easier to start the engine and improving starting performance. Since it has a structure in which the components are arranged, it has a simple structure, can be easily implemented, and can be easily applied to existing products.

[Brief explanation of the drawing]

Fig. 1 is a vertical cross-sectional view of one embodiment of the in-line fuel injection pump for a diesel engine according to the present invention;
The figure is an enlarged vertical cross-sectional view of the main part of the temperature-sensitive actuator in a low-temperature detection operating state, and FIG. 3 is an enlarged longitudinal cross-sectional view of the temperature-sensitive actuator in a high-temperature detection operating state. 2... Plunger, 6... Tappet, 7... Fuel injection cam, 9... Return spring, 15... Temperature sensitive actuator.

Claims (1)

[Claims for Utility Model Registration] The plunger 2 of the in-line fuel injection pump is configured to be driven toward the top dead center by the fuel injection cam 7 via the tappet 6, and pushed back toward the bottom dead center by the return spring 9. In the inline fuel injection pump for a diesel engine, a temperature-sensitive actuator 15 is interposed between the tappet 6 and the plunger 2, and the temperature-sensitive actuator 15 moves the plunger 2 higher in the low-temperature detection operating state than in the high-temperature detection operating state. An in-line fuel injection pump for a diesel engine characterized by being configured to advance toward the dead center side.