JPS592775B2 - Fuel injection timing adjustment device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fuel injection timing adjustment device for a fuel injection device for an internal combustion engine.

In a diesel engine, such as an automobile diesel engine, which normally has a wide rotation range, it is necessary to change the fuel injection timing depending on the operating state in order to obtain optimal engine performance.

The device for this purpose is an autotimer.

Conventionally, in the above-mentioned autotimer, the rotation of the drive shaft that transmits power from the engine is transmitted to the pump shaft for driving the injection pump via a flyweight disposed on the drive shaft, and the rotation of the drive shaft is transmitted to the pump shaft for driving the injection pump. The flyweight was configured to move in response to an increase in rotational speed to advance the pump shaft with respect to the drive shaft.

Generally, in order to obtain optimal engine performance in a diesel engine, it is sufficient to advance the fuel injection timing as the engine rotates at high speed.

Therefore, in this respect, the conventional auto-timer described above fully fulfills its function.

However, when the engine is started, when the engine temperature is low and the fuel combustion speed is slow, and the fuel injection timing needs to be advanced, and when it is necessary to reduce nitrogen oxides contained in exhaust gas and reduce noise. In addition, during idling, etc., when it is necessary to retard the fuel injection timing, the fuel injection timing is neither advanced nor retarded.In other words, the fuel injection timing is set at a time that allows for a compromise between low-temperature startability and engine performance. As a result, there was a problem in that sufficient satisfaction could not be obtained in terms of low-temperature startability and engine performance.

Furthermore, since the conventional autotimer described above takes a direct means of directly advancing the pump shaft by moving the fly weight of the rotational speed, it has the disadvantage that minute adjustments are difficult.

In view of this, the present invention detects the operating state of the engine using various sensor devices and operates a hydraulic piston to control the fuel injection timing. It is an object of the present invention to provide a fuel injection timing adjustment device that can always obtain the optimum fuel injection timing depending on conditions.

Hereinafter, embodiments shown in the accompanying drawings will be described.

In FIGS. 1 and 2, a rotating flange 10 that rotates synchronously with the drive side (engine) is integrated with a device cover 14 by a fixing bolt 15, and together with the cover 14 forms a casing of the device.

The cover 14 has a fixed flange 1 connected to the driven side (fuel injection device 50) or an external fixed part by bolts 11.
It rotates while contacting the outer circumferential surface 13a of the cylindrical sleeve 13 formed at 2.

The driven rotary body 16 is incorporated into the rotary flange 10 and is connected by a nut 18 to the camshaft 17 of the injection device.

The bubble 16 is provided with two sets of large and small eccentric cams 33a and 33b.

The pair of sliders 19 have eccentric shaft pins 20 that support each set of large eccentric cams 33a, and the inclined surfaces 19a thereof are
The boss portion 16a of the sleeve 16 and the inner surface 13b of the sleeve 13 serve as guide surfaces, and are always in contact with the corresponding inclined surface 21a of the ring-shaped piston 21 that slides in the axial direction.

The small eccentric cam 33b and the rotation 7 flange 10 are the eccentric shaft pin 3
8.

The slider 19 and the piston 21 are each provided with at least one through hole 22, 23 for assisting the flow of lubricating oil and regulating oil within the device.

In other words, the presence of these through holes 22 and 230 not only makes the flow of oil in the device smooth and reduces wear on each part, but also reduces the sliding of the piston 21 and slider 19 (described later).
It also becomes smoother.

Furthermore, the piston 21 has at least one hole 24.
is formed, and a pin 27 having a corresponding cross-sectional shape is inserted into this hole 24 to form a pressure chamber 28.

The pin 27 is integrated with the fixed flange 12 and has an oil passage 26b led to the external gear pump 25.

The oil passage 26b is the oil passage 26a formed in the fixed 7 flange 12.
It is connected to the gear pump 25 via.

As will be described later, the provision of these oil passages 26a and 26b facilitates the supply of hydraulic pressure for operating the piston 21.

Further, an oil sump 29 is formed between the fixed flange 12 and the piston 21, and the oil sump 29 is connected to the fixed flange 1.
Excess oil is led to an external oil tank 34 through an oil passage 30 formed in 2.

A return spring 32 is fitted between both sliders 19 to prevent the sliders 19 from expanding in the circumferential direction.

For example, an electromagnetic pressure control valve 37 is provided on the discharge side of the gear pump 25 to control the discharge pressure of oil.

The microcomputer 31 controls the control valve 3T based on signals from various sensors.

Examples of this signal include engine exhaust gas temperature T1, rotational speed N, device advance value α, outside air temperature T2, outside air pressure P, outside air humidity, etc., but various other factors related to engine combustion may be used. It is detected by various sensors and the detection signal is input to the microcomputer 31.

The microcomputer 31 outputs instructions as appropriate electrical signals based on preprogrammed instructions to control the operation of the pressure control valve 37.

The constant pressure oil pumped by the gear pump 25 is adjusted to an appropriate pressure by the pressure control valve 37, and then the fixed flange 1
From the oil passage 26a provided in 2 to the oil passage 26b of the pin 27
and is sent to the pressure chamber 28.

In this way, the pressure in the pressure chamber is changed arbitrarily, and the piston 21
can be moved in the axial direction.

When the piston 21 moves in the axial direction, the inclined surface 2 of the piston
1a and the inclined surface 19a of the slider 19, the slider 19 is pushed up in the radial direction.

On the other hand, the slider 19 is rotated by the bub 16 via the pin 20 (the bub 16 itself is rotated by the rotating flange 10 via the pin 38), so the slider 19 is always in contact with the piston 21 while rotating. It will move in the radial direction.

As the slider 190 moves in the radial direction, the eccentric cam 33a supported by the pin 20 and the eccentric cam 33b supported by the pin 38 rotate, and the drive side is maintained in a balanced state by the action of the return spring 32 provided on the slider 19. The rotating flange and the bub on the driven side create an appropriate relative rotational phase to adjust the injection timing.

In addition, in FIG. 1, 35a, 35b, and 35c.

35d shows the oil run rule.

3 and 4 show other embodiments of the present invention, in which a medium 36 in the form of a rotating body having a sphere or a curved surface is disposed between the inclined surface 19a of the slider 19 and the inclined surface 21a of the piston 21.
This is the same as in FIG. 1, except that .

According to this modified embodiment, the axial movement of the piston 21 can be converted into the radial movement of the slider 190 more smoothly than in the case of FIGS. 1 and 2.

3 shows the state of the piston 21 and the slider 19 before they move, and FIG. 4 shows the state after they move.

As described above, according to the present invention, the rotation of the eccentric cam is controlled by the cooperative action of the slider that supports the eccentric cam and is movable in the radial direction and the hydraulic piston that is in contact with the slider and is movable in the axial direction. Since it can be adjusted by the axial movement of the piston, it is possible to finely adjust the fuel injection timing more easily and reliably than with the conventional fly weight method.

Further, since the piston is operated based on factors representative of various operating conditions, the fuel injection timing can be controlled to best suit the rotational conditions.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view showing a first embodiment of the present invention, FIG. 2 is a sectional view taken along the line ■-■ in FIG. 1, and FIGS. FIG. 3 is a longitudinal sectional view showing the main parts, and FIG. 3 shows the state before operation, and FIG. 4 shows the state after operation. 10... Rotating flange, 12... Fixed flange, 1
6...Rotating body hub, 17...Pump camshaft,
19...Slider, 21...Ring-shaped piston, 3
3a. 33b...Eccentric cam.

Claims (1)

[Claims] 1. It has a rotating knob connected to the camshaft of a fuel injection device of an internal combustion engine and a casing supported around the knob so as to be relatively rotatable, and the relative rotational position of these rotating knobs and the casing can be determined. It is a device that adjusts the fuel injection timing by adjusting an eccentric cam with an eccentric shaft pin inserted between the two, and a hydraulic piston that is operated according to predetermined operating conditions on the above-mentioned piston. A radially slidable slider having a slope formed at the tip of the piston and a corresponding slope in opposing contact with the slope is locked to the piston, so that the slopes the axial movement of the piston can be converted into a radial movement of a slider by means of action, and the slider is coupled to an eccentric shaft pier of the eccentric cam, so that the radial movement of the slider rotates the eccentric cam. A fuel injection timing adjustment device characterized in that it is movable.