JPS5891337A - Fuel injection device for internal-combustion engine - Google Patents

Abstract

PURPOSE:To improve the finish of the injection as well as the consumption of the fuel and reduce the poisonous composition of exhaust gas a well as the noise of operation by a method wherein an electromagnetic device variably controlling the set closing force of a fuel injection valve in accordance with the operating condition of an engine is provided in the system. CONSTITUTION:The fuel injecton device is provided with the injection valve 5, sensors 25-27, detecting the operating condition, the electromagnetic device 14 and a control unit 20. The outputs of the revolution sensor 25, the acceleration sensor 26 and the crank angle sensor 27 are inputted into the control unit 20 to control variably the set closing force of the injection valve 5 through the electromagnetic device 14. According to this method, the finish of the injection may be improved for over whole operation range of the engine. Thus, combustion may be stabilized, a combustion efficiency may be increased and the fuel consumption, the poisonous composition of the exhaust gas as well as the noise may be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fuel injection device that corrects injection cut-off at the end of injection in an internal combustion engine.

Conventionally, a fuel injection system has a fuel injection system, for example, as shown in FIG. 1, in which fuel 1. The fuel is supplied to a distributor 2, and from this distributor 2, fuel is supplied to an injection valve 5 via a delivery pulp 3 and a high pressure pipe 4t. Here, the injection valve 5 is configured as shown in FIG. When this happens, the needle 10 lifts and fuel is injected from the injection port 12 provided in the nozzle case 11. and,
At the same time as the discharge from the injection pump 1 ends, the delivery pulp 3 performs the conventionally known suction (S return action) to rapidly reduce the fuel pressure in the injection chamber 8, so the needle 10 is pushed down by the valve closing force of the spring 9. The nozzle 12 is closed, and the injection ends.

By the way, in the conventional delivery valve, Fig. 3 (5),
As shown in (B), the pressure of the fuel pumped by the plunger of the injection pump 1 increases (then the pulp V overcomes the valve opening force of the spring S and lifts, so the fuel is directed toward the injection valve 5. Spit out.

Next, at the end of injection, the pulp (■) comes into close contact with the pulp sea (CK) due to the valve closing force of the spring S to prevent the reverse VLv of the fuel, but a piston part P is provided in the middle of this pulp (■).
C, the suction action of the piston part P is performed before the pulp V is seated, and the oil pressure in the high-pressure nozzle valve 4 is lowered to improve the sharpness of injection and prevent fuel from dripping from the injection valve. It is. Therefore, since the fuel refund amount determined by the stroke of the piston portion P is constant, for example,
A sufficient suction effect can only be obtained within a specific area such as a low load area. Therefore, in other areas such as medium to high load ranges, the suction back by the delivery valve becomes a non-luminous component, which may cause the needle to bounce as shown by the broken line in Figure 5d, worsening the sharpness of the injection. Alternatively, there is a possibility that drips may occur and cause various problems. (Technical manual [Diesel Engine JP65, published by NHK Motors Co., Ltd., June 1978]) In view of the above, the present invention has been developed to vary the set valve closing force of the injection valve according to the operating condition of the engine represented by the load, etc. By providing a control means, the purpose is to improve the injection path over the entire operating range of one engine, improve engine output, improve fuel efficiency by improving combustion efficiency, and reduce harmful exhaust components and noise.

The present invention will be explained in detail below based on one embodiment shown in FIGS. 4 to 7. Also, in Figure 9.

Parts having the same functions as those of the conventional example described above are given the same reference numerals, and detailed explanation thereof will be omitted.

In FIG. 4, a jet 90 formed in the nozzle case 11 is shown.
A rod 13 inserted between the needle 10 that opens and closes the needle 12 and the sub IJ ring 9 is inserted into the main magnetic pole 15 of the electromagnetic device 14, and the armature 11 is attached and fixed to the upper end of this rod 13 with a nut 16 ( Sru.

Then, the coil 18 for energizing the armature 17 is fixed in the case 1B, and the coil 18 is connected to the control device 20. 22 is an insulator interposed between the lead wire 23 of the coil 1B and the case 19, and 24 is a linkage pipe.

In the above configuration, high-pressure fuel discharged from the fuel injection pump 1 driven by an engine (not shown) is distributed to each cylinder by the distributor 2, passes through the Delino (Loop 3) and the high-pressure vibrator 4, and then passes through the injection valve 5. The high-pressure fuel supplied to the fuel population 6 is sent to the injection chamber 8 through the fuel passage 7, and the pressure in the injection chamber 8 increases.The pushing force due to this increase in pressure is When the pushing force becomes larger than the force exerted by the spring 9, the needle 10 resists the spring 9.
is pushed up and the nozzle 12 opens. Then, the fuel in the injection chamber 8 is injected from the injection port 12 into the combustion chamber.

The pressure at which the needle 10 is pushed up and the nozzle 12 opens, that is, the valve closing force set by the spring 90, which determines the valve opening pressure, is set to a predetermined value (for example, 100 mm) depending on the thickness of the shim 21.
~150Kf/cIt).

When the discharge from the injection pump 1 ends and the discharge pressure becomes lower than the valve-opening pressure of the delivery valve 3.

Since the pulp 3 closes and performs a suction action, the pressure of the injection amount 8 decreases rapidly. Then, the valve closing force of the spring 9 pushes down the needle 10 and closes the nozzle 12, thus ending the injection. The pressure in the injection chamber 8 is as shown in Figure 5C.
The needle lifts with the characteristics shown in d of the same figure.

Here, as shown in FIG. 6, the control device 20 includes a rotation sensor 25 for detecting the engine rotational speed NY, an accelerator sensor 26 for detecting the engine load from the accelerator opening α, and a crank angle position sensor 25 for detecting the engine rotation speed NY. Each output is supplied to the crank angle sensor 27 for detection.

Then, the timing θ and period t1 for energizing the coil 18 of the electromagnetic device 14 are calculated based on the engine rotation speed N (the pump rotation speed for the father) and the accelerator opening α.

The coil 18ft is energized for a predetermined period immediately before the internal pressure of the injection chamber 8 drops to the valve closing pressure of the needle 10. Furthermore, when the coil 18 is energized, the armature 1T is attracted downward and tries to push down the needle 10 via the rod 13, so the injection path is controlled by the pushing down force of the spring 9 and the biasing force of the electric A1 device 14. With the composite set valve closing force and the needle 10 force (the valve is about to close), historically, the valve closing force applied to the needle 10 varies depending on the engine load, so the suction back by the delivery valve 3 The action is not sufficient. For example, the needle 1θ can be closed quickly and reliably even in medium and high load operating ranges.
It is possible to improve the injection path over the entire operating range of the engine. In addition, Fig. 5 a1 is a waveform diagram of the signal output from the crank angle sensor 27 each time the crankshaft reaches a specific phase, and the same figure shows the waveform diagram of the signal output from the rotation sensor 26 each time the crankshaft rotates by a unit angle. FIG. 5e is a waveform diagram of the operating signal of the electromagnetic device 14, and FIG. 7 is a flowchart of the control device 20.

In addition to the above-mentioned embodiments, the means for detecting the operating state of the engine include the fuel injection period and the fuel injection amount.

It goes without saying that the detection may be performed by known means such as fuel pressure (in-cylinder pressure).

As explained above, according to the present invention, an electromagnetic device is provided that variably controls the set valve closing force of the injection valve according to the operating state of one engine. However, it is possible to close the injection valve accurately and improve the injection path. For this reason, it is possible to eliminate the bound dust phenomenon of the needle that is seen when the injection path is turned, improve the injection cut-off, and prevent the fuel from dripping, thereby making it possible to stabilize the combustion.

By improving combustion efficiency, fuel consumption, significant exhaust components, noise, etc. can be reduced.

[Brief explanation of the drawing]

In the figure, (6) indicates when the valve is open, and (6) indicates when the valve is closed. Fig. 4 is a sectional view of an example of an injection valve equipped with an electromagnetic device according to the present invention, Fig. 5 is a waveform diagram of an injection pattern and various signals, Fig. 6 is a system diagram of a control system, and Fig. 7 is a control device. This is a flowchart. 1...Fuel injection pump 3...Delivery pulp 5
... Injection valve 9 ... Spring 10 ... Needle 13 ... Rod 14 ... Electromagnetic device 1
T...Amateur 18...Coil 20...
・Control device 25...Rotation sensor 26...Accelerator sensor 27...Crank angle sensor Patent applicant Nissan Motor Co., Ltd. Representative Patent attorney Fujio SasashimaFigure 4Figure 5Figure 6Figure 09S7

Claims (1)

[Claims] an injector that opens and closes in response to the pressure of fuel delivered from the fuel injection pump; a means for detecting the operating state of the engine; an electromagnetic device that controls the set valve closing force of the injector; A control device that controls an electromagnetic device and a fuel injection device for an internal combustion engine.