JPS61207832A - Control of fuel jet amount - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention provides at least one pump piston for generating and controlling the injection pressure and for delimiting the pump working chamber and for controlling the relief passage of the pump working chamber t2 and thus the discharge. It has an electromagnetically operated control device that defines the start and end of discharge,
The amount of fuel injected via the fuel injection pump of the internal combustion engine, which control device completely opens the relief passage in the de-energized state and can be energized by the electric control machine in dependence on the operating 'iu value of the internal combustion engine. Concerning how to control.

As is well known in the prior art, in many diesel engines an undesirably strong combustion noise occurs in the no-load operating range or in the low part-load range, which can be reduced by extending the injection period in the above-mentioned speed range. Can be reduced. In the case of the above-mentioned known fuel injection pump, the extension of the injection period in the above-mentioned rotational speed range is achieved by causing a portion of the discharged fuel to flow out without pressure through a bypass operated by a solenoid valve to maintain the engine rotational speed. In order to achieve this, fuel is discharged from the pump working chamber towards the injection nozzle for a suitable length of time during the discharge stroke of the pump piston, based on the required fuel quantity usage. In addition to additional innovations, this requires a solenoid valve which is controlled by an electrical signal.

The invention provides a method of the type mentioned at the outset, in which a control device which is actuated in a suitable manner during the delivery stroke of the pump piston in order to control the fuel injection amount in a predetermined lower rotational speed range of the internal combustion engine is used to extend the injection period. Therefore, in order to prevent the control device from completely blocking the relief passage, the control device uses electric current to control the fuel injection amount in the internal combustion engine rotation speed range above the predetermined lower rotation speed range. Therefore, the control device is operated with a higher current to completely block the passage.

The advantage of the method according to the invention is that, with the same control device that defines the fuel injection quantity, the injection period can be extended in no-load operation and in the low load range for noise reduction, without adversely affecting the injection start control. That's what it means.

Advantageous embodiments of the method according to the invention are described in claim 2.

Embodiment In the fuel injection pump shown in FIG. 1, a bushing 2 is disposed within a casing 1, within which a pump piston 3 reciprocates and simultaneously rotates. The pump piston 3 is driven by a cam drive 4 via a shaft 5, which rotates synchronously with the rotational speed of the internal combustion engine, which is supplied with fuel by the injection pump. A pump working chamber 6 is formed by the end face of the pump piston 3 and the bushing 2,
This pump working chamber 6 is connected via a supply channel 7 to a suction chamber 8 in the housing 1 of the fuel injection pump. For example, a fuel tank 1 is connected to the suction chamber 8 via a transfer pump 9.
Fuel is supplied from 0. From the pump working chamber 6, fuel is distributed via the longitudinal groove of the pump piston and the distribution groove 11 at the appropriate rotational position of the pump piston into a pressure line 12, which is connected via the bushing 2 and the housing 1. It is led to the injection nozzle 13 of the internal combustion engine. In the region of the end of the pump piston facing the pump working chamber 6, the pump piston 3 is provided with a longitudinal groove 14 which is open towards the end face and thus towards the pump working chamber 6, and through which the suction of the pump piston is provided. In-stroke supply passage 7 and pump work chamber 6
are connected.

A relief duct 16 branches off from the pump working chamber 6 at a point unaffected by the pump piston and is guided to the suction side of the pump piston and communicates with, for example, a supply duct 7.

A valve seat 17 is provided in the relief channel and cooperates with a valve closing member 18 . The valve closing member is used as part of an electromagnetically operated control device 20, for example a solenoid valve, and thus opens or closes a cross section of the relief passage. The control device 20 controls the type of internal combustion engine by means of an electrical control machine 2).
Customized values for each operation, such as load 22, rotation speed 23, temperature 2
It is controlled in relation to 4th grade. The control device 20 defines the injection start and the injection path of the fuel injection port during the discharge process of the pump piston in a known manner. Control bag [20
In the de-energized state, for example, the valve closing member 18 is lifted off the valve seat 17 and the relief passage 16 is thus opened, so that no sufficient pressure is generated in the pump working chamber 6 to open the injection nozzle. Valve closing member 1 is activated by energization of control device 20.
8 moves towards the valve seat 17 , which defines the start of the discharge and creates a pressure in the pump working chamber 6 , and the fuel reaches the injection nozzle 13 via the distribution groove 11 .

Demagnetization of the control device 20 defines the end of discharge.

This is because the valve seat 17 is completely opened and the pressure in the pump working chamber 6 is reduced. Fuel is injected via one of the injection nozzles 13 during the period between the start of the discharge, that is, the excitation of the control device 20, and the end of the discharge, that is, the destruction of the control device. This amount of fuel injected is a part of the maximum amount of fuel that can be delivered during the delivery stroke of the pump piston 3.

No-load operating range and low part-load range, i.e. approximately 4
According to the invention, the control current supplied to the control device 20 via the control machine 21 in order to extend the injection period in a predetermined lower rotational speed range of 00 to 1000/man is:
The electrical power generated by the control current is applied to the valve closing member 1.
8 toward the valve seat 17 only partially,
In other words, it is just so thick that it does not completely block the valve seat 17. Therefore, the fuel throttled through the valve seat 17 can flow toward the suction chamber 8 through the relief passage 16. Due to this control of the control device in the predetermined lower speed range of the internal combustion engine, a pressure profile of the fuel in the pump working chamber 6 as shown in FIG. In this case, the fuel pressure is Pk and the time is designated t. The fact that a portion of the fuel delivered by the pump piston in the predetermined lower speed range of the internal combustion engine can always be throttled out of the pump working chamber 6 and flow out via the relief channel 16 causes the control device 20 to be activated at time t. After energization, a pressure curve occurs that corresponds to the solid line a, and the maximum value of this pressure curve is reached when the control device 20 completely blocks off the relief channel 16 (in this case, a high value corresponding to the dashed line bK is generated). pressure curve (occurring). During the delivery stroke of the pump piston, the injection period is lengthened in order to obtain the required amount of injected fuel in the lower rotational speed range due to the small fuel pressure that occurs in the control device 200 according to the invention. Therefore, the demagnetization of the control device 20 only takes place at a time t2 later than the time t'2 at which the control device 20 completely closes the relief passage 16.

In FIG. 3, the excitation current I of the control device 20 over time t is marked, which makes it clear that it corresponds to the solid customized curve between the excitation time t and the demagnetization time t2. In the case of the control type of the control device according to the invention in the predetermined lower rotational speed range, the holding current required to control the control device in such a way as to completely block the relief passage 16 is determined by the custom curve shown in dotted lines. This is slightly less than the holding current indicated by .

In a further embodiment, the control of the control device 20 from time t to time t2 in a predetermined lower rotational speed range during the delivery stroke of the pump piston is carried out by means of a number of individual pulses, for example as illustrated in FIG. so that three individual nols ξ2
6, 27, 28, thereby increasing the fuel pressure P in the pump working chamber, as shown in FIG.
k is produced.

The necessary extension of the injection period in a given lower speed range is determined by the control device 2 on the basis of the determined operating values of the internal combustion engine.
1 or called from a stored value.

In the upper rotational speed range of the lower predetermined rotational speed range, in both the exemplary embodiments shown in FIGS. 2 and 3 and in FIGS. This must be carried out with the following current, that is, with a current such that the relief passage 16 can be completely shut off in order to control the fuel injection amount by means of an electromagnetically generated force.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, in which Fig. 1 is a schematic diagram of a fuel injection pump, Fig. 2 is a diagram showing the time course of fuel pressure in the pump working chamber, and Fig. 3 4 is a diagram showing the control current for the control device over time; FIG. 4 is a diagram showing the time course of the fuel pressure in the pump working chamber for another type of control of the control device; The figure is a diagram showing the complete curve of the control device control. DESCRIPTION OF SYMBOLS 1...Casing, 2...Bushing, 3...Pump histone, 4...Cam drive device, 5...Shaft, 6...
・Pump work chamber, 7... Supply passage, 8... Suction chamber, 9... Transfer pump, lO... Fuel tank, 11.
...Distribution groove, 12...Pressure conduit, 13...Injection nozzle, 14...Vertical groove, 16...Relief passage, 17...
Valve seat, 18... Valve closing member, 20... Control device, 2
1...Control machine, 22...Load, 23...Rotation speed, 24...Temperature, 26°27.28...S ξ Lus, P
k...Fuel pressure, t...Time. ♀ DL Koichi

Claims (1)

[Claims] 1. At least one pump piston (3) for generating the injection pressure and delimiting the pump working chamber (6) and an electromagnetic type for controlling the relief passage (16) of the pump working chamber and thus for defining the start and end of the pumping. a control device (20) to be operated;
the control device completely opens the relief passage in the de-energized state and can be energized by an electric control machine (21) in dependence on the operating characteristic values (22, 23, 24) of the internal combustion engine;
A method for controlling the fuel injection amount via a fuel injection pump of an internal combustion engine, in which the pump piston (3) is electromagnetically operated during the discharge stroke to control the fuel injection amount in a predetermined lower rotational speed range of the internal combustion engine. The control device (20) is connected to the relief passage (16) to extend the injection period.
The control device (21) controls the fuel injection amount in the internal combustion engine rotational speed range above the predetermined lower rotational speed range. 20) is controlled with a higher current so as to completely block the escape passage (16). 2. During the discharge stroke of the pump piston (3), the control device (20) generates a large number of pulses (26, 27, 28) in order to control the fuel injection amount in a predetermined lower rotational speed range of the internal combustion engine.
A method according to claim 1, wherein the method is controlled by: