JPS6093172A - Fuel injection valve for diesel-engine - Google Patents

Abstract

PURPOSE:To enable the injection rate of fuel to be changed, by providing such an arrangement that a spring guide on a pressure spring urging a nozzle needle in a Bosch type fuel injection valve is moved up and down under electronic control during running of the engine so that the valve opening pressure is suitably changed during running of the engine. CONSTITUTION:A microcomputer 4 receives a signal from a rotational phase sensor positioned in the vicinity of a flywheel, and computes and delivers a signal for energing a solenoid so that the valve opening pressure may be adjusted during running of the engine. That is, for example, in a rotational speed range in which the concentration of exhaust fume is high, the solenoid coil is energized to slide a spindle 20 so that a control rack 16 rotates a control pinion 13. As a result an adjusting screw 11 lowers while being screwed to press a pressure spring 7 by means of a spring guide 8 so that the valve opening pressure of a nozzle needle 3 becomes high to reduce the injection amount of fuel. Further a control for increasing the injection amount of fuel may be made to increase the torque in the intermediate speed range.

Description

[Detailed description of the invention] The present invention relates to a fuel injection valve for a diesel engine.

In general, this type of fuel injection valve is divided into automatic valves and mechanical valves, and the former automatically opens and injects when the pressure in the injection pipe reaches a certain value, and the injection amount and timing are controlled. All controls are performed by the fuel injection pump, and the fuel injection valve is
It is operated only by hydraulic pressure. On the other hand, in the latter case, a constant hydraulic pressure is always acting on the nozzle needle.
When injecting, the nozzle needle is mechanically opened using a cam or lever, and the injection amount and timing are controlled by the tsubara fuel injection valve itself. The former valve opening pressure is generally adjusted using an adjusting washer or an adjusting screw, and the adjustment is performed to achieve the best matching at maximum practical output, which is the engine's high-speed, high-load range. Therefore, it was inevitable that the performance would deteriorate in the partial load range. In other words, in this partial load range, the oil delivery rate of the fuel injection pump is small, and the nozzle needle of the fuel injection valve cannot be kept fully open during the injection period. Moreover, the injection rate can be changed by appropriately changing the valve opening pressure during operation. I can't. For this reason, many proposals have been made over the years, such as a so-called variable injection valve and a Vintalks nozzle that has improved the nozzle itself, but all of them have complex mechanisms and restrictions on usage conditions. , it is not satisfactory as a practical device.

Therefore, the present invention attempts to solve the disadvantages of the prior art by applying electronic injection device technology to the nozzle itself, which has a well-used structure.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The 4'+'7i configuration of the present invention will be described in detail below based on embodiments shown in the accompanying drawings. Figure 1 is a longitudinal sectional view, Figure 2
The figure shows a sectional view taken along lines A and A in FIG.

In the figure, 1Cj fuel unit, 2 a fuel valve nozzle, 3 a nozzle needle, 4 a nozzle cap nut, 5 a distance piece, 6 a pressure pin, 7 a pressure spring, 8 a spring guide, and 9 a The structure of the fuel inlet and the leakage outlet 101 is a well-known structure.

In this embodiment, a cylindrical part 12 that maintains oil tightness is installed on the head of the adjusting screw 11 that contacts the spring guide 8.
The cylindrical part 12 rotates and moves up and down (-) by the screwing of the adjusting screw 11 to prevent oil from leaking.
It is formed with a shaped clamp and is fastened with bolts 14. Furthermore, a rotary tool engaging groove 15 is provided at the upper end. A control rack 16 meshes with the control pinion 13, and the control rack 16 is connected to an extension 17 of the fuel valve body 1.
It is slidably supported. 18 is a rack guide pin, and 19 is a pin sliding groove.

As shown in FIG. 2, the control rack 16 is fitted onto a spindle 20 and has both ends attached to circlips 21.
2] is fixed to the spindle 20. An iron core 22 is fitted into the spindle 20, and the iron core 22 is slidably fitted into a solenoid housing 23 extending from the fuel valve body 1. A solenoid coil 24 is built into the solenoid housing 23. A contact piece 25 is fixed to the end of the solenoid housing 23, and a bearing portion 26 is fitted into the corresponding contact piece 25. A return spring 27 is built in between the bearing portion 26 and the iron core 22 in a compressed state. Reference numeral 28 denotes a power supply line, which is electrically connected to a microcomputer (not shown), and 29 is a sensor, which is also electrically connected to the microcomputer.

This embodiment has the following configuration. For example, a signal from a rotational phase sensor installed close to the flywheel is calculated by a microcomputer, and this signal is used to energize the solenoid coil 24 to start the engine. ”]1! This allows the valve opening pressure to be adjusted even during operation. That is, for example, in a rotation range (partial load range) where the exhaust smoke concentration is high, the solenoid coil 24 is energized, the spindle 20 slides, and the control pinion 13 is rotated by the control rack 16. As a result, the adjusting screw 11 descends while spiraling, and the spring guide 8 presses the pressure spring 7, so that the valve opening pressure of the nozzle needle 3 increases and the amount of fuel injected is reduced. In addition, for medium-speed torque direction -1-, control such as increase, F, and E can be performed.

In this embodiment, the reciprocating motion of the control 1 call rack 16 that meshes with the control pinion 13 is controlled by the solenoid coil 24, but it may be controlled by a normal Stella Pink motor.

In summary, the present invention provides an adjustment screw that is brought into contact with the spring guide of a pressure spring that presses the nozzle needle of a Bosch type fuel injection valve, and the adjustment screw is connected to a rack.
Since this is a fuel injection valve for a diesel engine that is screwed by a pinion mechanism and the rack-pinion mechanism is electronically controlled, it has the following effects.

■The adjustment screw is in contact with the spring guide on the pressure spring, and the adjustment screw is screwed by a rack-pinion mechanism, so the opening pressure of the nozzle needle can be adjusted even when the engine is running, so at low and medium speeds. It is also possible to obtain an appropriate injection rate.

■It is possible to control the injection rate over the entire range without requiring an Angleich mechanism or torque control cam for fuel injection.

■Since it is a well-seasoned Bosch type fuel injection valve, injection is performed accurately and can be well adapted to existing fuel injection systems and combustion chambers.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of an embodiment of the present invention, and FIG. 2 is a sectional view taken along line A and A in FIG. 3... Nozzle needle, 7... Pressure spring, 8... Spring guide, 11... Adjustment screw, 1
3...Control rack, 16...Control binion, 24...Solenoid coil Attorney Yoshihiko Okabe

Claims (1)

[Claims] A fuel injection valve for a diesel engine in which the spring guide on the pressure spring that presses the nozzle needle of the Horash type fuel injection valve is lowered by electronic control during engine operation.