JPS5951159A - Fuel injection device of diesel engine - Google Patents

Abstract

PURPOSE:To obtain a real combustion signal, which is stable for a long period, by forming the nozzle part of a fuel injection valve with a transparent substance and by furnishing a means to sense the combustion flames in the cylinder. CONSTITUTION:Nozzle part 1 of a fuel injection part is formed by a transparent substance. A real combustion timing sensor 4 is mounted at the top of an optical passage 3b. The fuel pressed forward from a fuel injection pump 9 passes through fuel passages 3a, 2a and 12a and is injected from an opening 13. Because the combustion light L reaches a photo-electric transducer 43 through optical passages 2b, 3b, so an electric control circuit 10 can sense it as real combustion timing signal. This signal is used in feedback control etc. of the fuel injection timing. Thus the configuration can be simplified, and real combustion signals obtained for a long time stably.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fuel injection device for a diesel engine that includes a detection means for detecting actual combustion timing from flame during combustion.

In order to obtain the output of a diesel engine efficiently, it is necessary to change the fuel injection timing depending on the rotation speed, the magnitude of the load, etc. For this purpose, it is necessary to detect the actual injection timing. Conventionally, as a method for detecting the actual fuel injection timing, there is a method in which the occurrence of flame is used as a signal for the actual injection timing using a combustion detector installed in the cylinder. It is superior in that it eliminates the need to correct for delays, etc., and the accuracy of the actual injection timing is less than the required injection timing.However, a hole is made in the cylinder as a detector to detect the flame, and light passes through glass, etc. The structure is such that a photo-electrical converter such as a phototransistor is attached via a magnetic object, which poses the problem of changing the shape of the cylinder head and increasing machining.Furthermore, the surface of the glass exposed inside the cylinder is The problem is that when the sensor is operated for a long time, soot builds up and the light transmittance decreases, the detection sensitivity gradually decreases, and eventually detection becomes impossible.

Therefore, the present invention provides a fuel injection device in which the nozzle portion of the fuel injection valve is formed of a translucent material, and is equipped with a detection means for sensing the combustion flame in the cylinder through the nozzle portion and the nozzle opening during fuel injection. This eliminates the need for extra processing on the cylinder and allows the actual combustion timing to be detected using the combustion light that has passed through the nozzle.Furthermore, the nozzle surface that is exposed inside the combustion chamber due to long-term engine operation is Even if the light becomes difficult to pass through due to adhesion of J, the actual combustion timing can be detected by the combustion light that enters through the nozzle opening during fuel injection, making it possible to obtain an actual combustion signal that has been determined for a long time. The purpose is to

The present invention will be explained below with reference to embodiments shown in the drawings.

In FIG. 1, 1 is a nozzle part with a nozzle needle 11,
It consists of a nozzle body 12, which is made of translucent alumina ceramic (for example, 8ρ2o3°MgO, Y2
O3, ZrO2, etc.) or quartz glass is used. Here, the nozzle body 12 is provided with a fuel passage 12a. 13 is a nozzle part (this part opens only when fuel is injected). 2 is a distance piece having a fuel passage 2a and a light passage 1182b, similar to the nozzle body. Further, the rubber valve 1 and the distance piece 2 are positioned in the rotational direction by a knock pin 21 so that the respective fuel passages are aligned with each other. 3 is a nozzle boulder body with a fuel flow path 3a and a light path 3b, and at the upper end of the light path 3b is a photo-electric conversion element 43 such as a fumet transistor that converts the presence or absence of light into an electrical signal; A connector 44 for taking out the signal of the element 43, and an optical
An actual combustion timing detector 4 consisting of a housing 45 holding an electrical conversion element 43 and a connector 44 is attached.

Furthermore, the dowel pin 2 is placed so that the light path 2b of the distance piece 2 and the path 3b of the nozzle boulder body 3 are aligned.
2 for positioning in the rotational direction. Also 3c
A return passage for leaked fuel communicates with the fuel tank via a nipple 31.

32.33 is a Nando gasket 34. 5 is a nozzle holder pressure bottle, 6 is a nozzle boulder pressure spring, and 7 is a spug seat. A nozzle retaining nut 8 holds the nozzle 1 and the nozzle boulder 3, and is attached to the engine cylinder nod using a threaded portion 8a, with the nozzle portion 1 facing the cylinder chamber. 9 is a fuel injection pump such as a distribution type or sub-type that sends fuel to this injection device; 10 is an injection pump 9
An electric control circuit Il & (E
CU), into which signals representing engine operating conditions such as the signal of the actual combustion timing detector 4, the rotational speed signal N, and the accelerator amount signal α are input.

Next, the operation of the configuration described in "2" will be explained. The fuel pumped under pressure from the fuel injection pump 9, which is controlled by a signal from the electrical control circuit 10 determined by the operating conditions of the engine, passes through the fuel passages 3a, 2a, and 12a, and connects the nozzle needle 11 to the nozzle holder pre-nozzle spring 6. It is pushed up against the pressure and injected from the Sekiguchi part 13. At this time, the inside of the cylinder is under high pressure and high temperature, and the injected fuel ignites, creating a flame. At this time, the combustion light enters from the bottom surface 12b of the nozzle body exposed inside the combustion chamber or from the entrance part 13, and enters the nozzle body 12. Since the light reaches the light-to-electric conversion element 43 via the light path 2b of the distance piece 2 and the light path 3b of the nostalpolder 3, the electric control circuit 10 can detect it as an actual combustion timing signal. This signal is used for feedback control of fuel injection timing, etc.

In the above embodiment, the light-to-electric conversion element may be installed in the nozzle boulder, or the light may be guided into the electrical control circuit 10 through an optical fiber 46 as shown in FIG. . In Figure 2, 46
is an optical fiber made of a bundle of glass fibers of several tens of microns, and transmits the light entering from the end 46a to the light-to-electrical conversion element 43 in the electrical control circuit IO. Reference numeral 47 denotes an optical fiber housing that fits into a hole drilled in the nozzle holder 3 to hold the optical fiber. Reference numeral 48 denotes an outer covering of the optical fiber 46 made of flexible plastic or the like. The distance piece 2 is also made of transparent ceramic, and has circumferential fuel channels 2b and 2c on both end surfaces.
are formed, so the nozzle body 12., the distance piece 2. Positioning pins in the circumferential direction of the nozzle holder body 3 are no longer necessary. The operation is the same as in the previous embodiment.

As described above, in the fuel injection device according to the present invention, the nozzle portion of the fuel injection bulb f is formed of a translucent material, and the fuel injection device
Since the configuration is equipped with a detection means that detects the combustion flame in the cylinder by opening this nozzle part and the nozzle part [-1] m during injection, there is no need to perform extra processing on the cylinder, and the structure is simplified. The actual combustion timing can be detected by the combustion light transmitted through the nozzle. In addition, even if the nozzle surface becomes sticky and light cannot pass through, the actual combustion timing can be detected by the nozzle opening [1, A stable actual combustion signal (M all is C).

[Brief explanation of drawings]

1. F"l is a cross-sectional configuration diagram showing one embodiment of the present invention IJII, and FIG. 2 is a cross-sectional configuration diagram showing another embodiment of the present invention. 1... Nozzle part, 2... Distance Peace, 3.
... Nozzle boulder +1 day, 4... Actual combustion timing detector forming the main part of the detection means, 9... Fuel injection pump, 1°... Electrical control circuit, 13... Nozzle opening Section 43... Optical-electric conversion element, 46... Optical fiber. Representative Patent Attorney Takashi Okabe Figure 1 Figure 3 Figure 2

Claims (1)

[Claims] In a fuel injection device that injects fuel into a cylinder of a diesel engine using a fuel injection valve, the nozzle portion of the fuel injection valve is formed of a translucent material, and the nozzle portion and the opening of this nozzle portion are provided at the time of fuel injection. 1. A fuel injection device for a diesel engine, comprising a detection means for detecting a combustion flame in a cylinder through the cylinder.