JPS6014130A - Firing time sensor of internal-combustion engine - Google Patents

Abstract

PURPOSE:To detect precisely a firing time and to control appropriately the firing time by detecting directly the light of a flame in a combustion chamber by using an optical guide. CONSTITUTION:A firing time sensor 10 consists of a flame sensor part 11 and a photodetecting part 21. The part 11 has a structure in which a rod-shaped optical guide member 13 is inserted and fixed to a core part of a cylindrical case body 12, and is mounted on a cylinder head 1. The part 21 has a photodetecting part 22 and an optical fiber cord 23 for connecting the detector 22 to the part 11. When the engine is operated, the flame light due to self-firing is detected by the part 11 and is detected by the detector 22. In this way, the firing time is detected. The firing time is controlled appropriately by adjusting next fuel jetting time basing on the detected result.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field of the Invention The present invention relates to an ignition timing sensor for detecting the ignition timing of an internal combustion engine, and particularly to an ignition timing sensor that detects the ignition timing by detecting flame light in a combustion chamber using a light guide. Related to ignition timing sensor.

Background of the Technology In recent years, improvements in output and fuel efficiency have become important issues, particularly in diesel engines and gasoline engines for automobiles. One effective means to achieve this is to appropriately control the ignition timing.

However, in order to properly control the ignition timing, it is first necessary to accurately detect the ignition timing. However, in the past, there was no simple sensor that could accurately detect the ignition timing, so appropriate control of the ignition timing was practically impossible.

OBJECTS OF THE INVENTION In view of the current situation, an object of the present invention is to provide a simple ignition timing sensor that can accurately detect the ignition timing in the engine as described above.

Structure of the Invention The ignition timing sensor according to the present invention is, in principle, designed to detect the light of the flame in the combustion chamber of the engine using a light guide to detect the ignition time M'f. The structure is generally constructed by inserting and fixing a rod-shaped heat-resistant light guide member having a refractive index distribution into the core of a cylindrical heat-resistant housing, and the tip thereof is inserted into a combustion chamber. The flame sensor includes a flame sensor section, and a light detection section that detects output light from the rear end of the flame sensor section.

Embodiments of the Invention Below, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 shows an implementation of the ignition timing sensor according to the present invention.
t f An example applied to an easel engine will be shown. In the figure,
Reference numeral 1 indicates a cylinder head of a diesel engine, 2 indicates a main combustion chamber, 3 indicates an auxiliary combustion chamber, 4 indicates a fuel injection nozzle, 5 indicates an injection twist P+, and 1o indicates an ignition timing sensor according to the present invention.

First, the overall configuration and operation of the ignition timing sensor 10 will be explained. The ignition timing sensor IO basically includes a flame sensor section 11 and a light detection section 21. The flame sensor section 11 basically has a structure in which a rod-shaped light guide member 13 is inserted and fixed into the core of a cylindrical casing 12, as shown in FIG. 2 (detailed configuration will be described later). It is configured such that light entering the member 13 from its tip (right end in Figure 2) propagates through it and outputs from its rear end (left end in Figure 2).As shown in Figure 1, The flame sensor section 11 is attached to the cylinder head 1 with its tip end inserted into the vicinity of the injection path of the fuel 5 in the auxiliary combustion chamber 3.On the other hand, the light detection section 21 is connected to a light detector 22. , has an optical fiber coat 23 (!:) that connects this photodetector 22 to the flame sensor section 11.
3 is detachably connected to the rear end of the flame sensor section 11 by an optical connector 24. Now, when the fuel 5 is injected from the nozzle 4 during engine operation and a flame is generated due to self-ignition, the light is detected by the flame sensor section 11, further propagated through the optical connector 24 and the original fiber cord, and the light is It is detected by the detector 22. This allows the ignition timing to be detected.

By adjusting the next fuel injection timing based on this detection result, the ignition timing can be appropriately controlled. This control method will be described later.

Next, the flame sensor section 11 will be explained in detail.

During engine operation, the temperature of the flame sensor section 11 reaches approximately 900° C. at the tip inserted into the combustion chamber, and reaches a maximum temperature of about 150° C. even at the rear end protruding to the outside of the cylinder head. For this reason, the casing 12 of the flame sensor section 11 is made of heat-resistant material, such as SU.
S 310 S, an alloy with the trade name "Hains Alloy" (51% Co, 21% Cr).

It is formed from a metal material such as W15% and other 9, or a ceramic material. There is a male screw 1 on the outer peripheral surface of the housing 12.
4 and a tool hooking portion 15 having a rectangular cross section are formed, whereby the flame sensor portion 11 can be screwed onto the cylinder rod 1 as described above. On the other hand, the light guide member 13
is made of quartz glass with a heat-resistant temperature, and as shown in FIG. 3, it is composed of 1713a and cladding 13b, and their refractive index noynl has a step-shaped distribution as shown in the figure. The diameter of the core 13a is about 1 inch, and the outer diameter of the cladding 13b is about 2 degrees.

Furthermore, the combustion chamber of the engine is required to be highly airtight. Therefore, the flame sensor section 11 includes the housing 12 and the light guide member 13.
It is necessary to have an airtight structure with an airtight seal between the In this case, it is ideal to closely bond the housing 12 and the light guide member 13 over their entire length. However, case 1
There is a very large difference in the coefficient of thermal expansion between the light guide member 13 and the light guide member 13, and the difference in thermal expansion between the two becomes extremely large at the above-mentioned high temperatures, so that various problems occur in a closely joined structure over the entire length. FIG. 4 shows a specific example of the structure of the flame sensor section that solves this problem. In this example, a substantially spherical expanded diameter portion 16 is provided at the rear end of the light guide member 13.
The enlarged diameter portion ↓6 and its front and rear portions are fixedly sealed to the housing 12 via a heat-resistant resin 17. The center portion and the tip portion of the light guide member 13 are not joined to the housing 12 and are in a mutually expandable and retractable state. In addition to this, the housing 12
Both the problems associated with the expansion and contraction of the light guide member 13 and the problems of hermetic sealing are solved. In addition, as a heat-resistant resin, for example, a heat-resistant resin with a heat-resistant temperature of 280 to 360°C is used. Liimide resin or the like can be used. Further, the enlarged diameter portion 16 of the light guide member 13 shown in FIG. 4 may be formed by forming a part of the light guide member itself into a spherical shape, or, for example, as partially schematically shown in FIG. The enlarged diameter portion can also be formed by fitting and fusing another motherboard member 18 onto the light guide member 13.

Next, FIG. 6 shows an example of the results of detecting the ignition timing using the above-mentioned ignition timing sensor 10. In the figure, the horizontal axis indicates the crank angle, and the symbol TDC indicates the top dead center. And curve A is the ignition timing sensor 10
Curve B represents the needle valve lift of the fuel injection nozzle, that is, the fuel injection timing, detected using another suitable sensor (not shown). Based on these detection results, the ignition timing is advanced or retarded,
By adjusting the next lift timing of the nozzle needle valve according to this detection result, it is possible to appropriately control the sweetfish injection timing.

Effects of the Invention As described above, the ignition timing sensor according to the present invention detects the ignition timing by directly detecting the flame light in the combustion chamber using a light guide, and in terms of performance, it is possible to accurately detect the ignition timing. It has excellent features such as easy detection, small size, simple structure, and high reliability.

Although an example in which the ignition timing sensor of the present invention is applied to a diesel engine has been described above, it is also applicable to a gasoline engine.

[Brief explanation of drawings]

Fig. 1 is a schematic partial cross-sectional view showing an embodiment of the ignition timing sensor according to the present invention together with the main parts of the engine, Fig. 2 is a longitudinal sectional view of the flame sensor portion of the ignition timing sensor, and Fig. 3 is a schematic partial cross-sectional view of the flame sensor portion of the ignition timing sensor. FIG. 4 is a longitudinal sectional view of another embodiment of the flame sensor section; FIG.
The figure is a diagram showing another embodiment of the enlarged diameter part of the light guide member.
The figure is a graph showing an example of the detection results of the ignition timing sensor. l...engine cylinder head, 2...main combustion chamber,
3... Sub-combustion chamber ζ 4... Fuel injection nozzle, 5...
- Injected fuel, 10... Ignition auxiliary phase sensor, 11... Flame sensor section, 12... Housing, 13... Light guide section, 13a... Core, 13b... Clad, 14・・・
・Male thread, 15... Tool hanging part, 16... Expanded diameter part, 1
7...Resin, 18...Lee? Eve-shaped member (inflated diameter part),
21... Photodetector, 22... Photodetector, 23...
Optical fiber cable, 24...optical connector. Patent Applicant Toyota Motor Corporation Take♂1 Patent Attorney Patent Attorney Ro Aomizu Patent Attorney Shisha I Patent Attorney Yukio Uchida Patent Attorney Akira Yamaguchi 1 Figure 2 Figure 3 + 3b Figure 4 1 Figure 6 figure

Claims (1)

[Scope of Claims] 1. A rod-shaped heat-resistant light guide member that defines a refractive index distribution is inserted and fixed into the core of a cylindrical heat-resistant housing, and the tip end is inserted into the combustion chamber of an internal combustion engine. and a light detection section that detects output light from the rear end of the flame sensor section, and is configured to detect the ignition timing by detecting the light of the flame within the combustion chamber. An ignition timing sensor for an internal combustion engine, characterized by: 2. In the ignition timing sensor according to claim 1, a swollen diameter portion is formed in a part of the light guide member of the flame sensor, and the light guide member is formed in the swollen diameter portion and a portion near the swelled diameter portion. A flame sensor characterized by being fixedly sealed to a housing via a heat-resistant resin.