JPS5987249A - Optimum combustion controller of internal-combustion engine - Google Patents

Abstract

PURPOSE:To provide result which is useful to the output of an engine, improvement of fuel consumption, and a measure to counter exhaust gas through proper control of an engine, by directly collecting combustion information through a light permeable window formed in a part of a combustion chamber. CONSTITUTION:A light permeable window 5 is formed in a part of a combustion chamber 1, and flame light is detected by a light collecting element 6. A signal from the light collecting element 6 and a signal from a crank angle sensor 8 are inputted to a control circuit 9 incorporating a microcomputer. The control circuit 9 is adapted to allow discrimination of the output of the light collecting element 6, varying according to a crank angle, by patterning it, and further, it previously stores a signal patterned under an optimum combustion condition and can compare it with a signal under a general operating condition. Namely, from a combustion flame light, the control circuit 9 decides whether a combustion condition is optimum or not, and maintains an optimum operating condition through driving of a fuel feed system actuator 10.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a control device for controlling air and fuel supplied to an internal combustion engine.
In particular, the combustion state in the combustion chamber is detected, and the maximum J[4 air-fuel ratio +! The present invention relates to an optimal combustion control device that provides feedback to II control and injection timing.

[Prior art]

Conventionally, the air-fuel ratio 1b () control device for internal combustion engines has widely used a zirconia l!&p sensor as an air-fuel ratio sensor, and the output signal from this sensor is fed back to the carburetor or fuel 1 child (shooting device <r: , +l
lt is supplied to the ring of the internal combustion engine and used for YA 7
1i to get close to the total theoretical value of 1L air ratio (air fuel ratio)
lJ ll1ll. However, this zirconia T
The 112A 7-sensor was installed at the exhaust pipe base of the four internal combustion flames or downstream thereof, and detected the total oxygen concentration in the exhaust gas after the combustion arm to judge the suitability of the air-fuel mixture. ,
Because of the flow path from the cylinder to the exhaust pipe, the response time for nitrous fuel ratio control is long, and it is extremely difficult to accurately control the air fuel ratio at t:i, especially when there is a sudden change in load.

Furthermore, this zirconia oxygen sensor does not operate sufficiently at low temperatures, and has the disadvantage that it cannot be used to control the air-fuel ratio at startup, etc. Furthermore, this zirconia oxygen sensor has the problem that although the output changes greatly with respect to a specific air-fuel ratio (for example, the stoichiometric air-fuel ratio J), it cannot be detected linearly over a wide range.

[Purpose of the invention]

An object of the present invention is to provide an air-fuel ratio control device for an internal combustion engine that eliminates the drawbacks of the prior art described above, and is capable of optimally controlling the injection timing or ignition timing to the engine compartment. An object of the present invention is to provide an air-fuel ratio control N111 device.

[Requires 111°C of the invention J The present invention converts the flame during combustion into an electric signal by a light receiving element through a light-transmitting window provided in a part of the combustion chamber, and also converts the flame of the light receiving element in the normal operating state of an internal combustion engine. 1. Write down the output signal as a pattern signal in response to the crank angle change. Ha, the optimal J/r that I have already memorized:? If the output 4i of the light-receiving element deviates by more than the allowable value when compared with the pattern signal of the firing state, the air-fuel ratio should be adjusted to 1 (full automatic adjustment such as the ignition timing etc.) so that the output 4i of the light receiving element deviates by more than the allowable value. It is something that is managed.

Thu: I^ Ming internal combustion engine most suitable combustion 'd+lJ i'+l
Implementation of tl device side noise 1 Before explaining, the principle of the present invention will be briefly explained below. In an internal combustion engine, fuel is usually injected into the air passing through an air cleaner, for example, by a fuel injector or a carburetor. Mixed at a predetermined ratio, this air-fuel mixture is introduced into the combustion chamber of the engine, compressed by the piston, and ignited.At this time, the combustion state in the combustion chamber changes depending on the air-fuel ratio inhaled. .

In particular, the flame light within the combustion chamber changes depending on the air-fuel ratio, fuel injection timing, ignition timing, etc. Therefore, the output level of the light receiving element changes in the light emission pattern in response to changes in the crank angle.

The present invention takes advantage of this phenomenon, and will be described in detail below with reference to Examples.

FIG. 1 shows an example in which the present invention is applied to a diesel engine equipped with an auxiliary combustion chamber.

The combustion chamber 1 is composed of 414 pistons 2 and cylinders 3,
A fuel injection nozzle 4 is attached.

A part of the combustion chamber 1 is provided with a translucent window 5 that allows the entire state of the flame inside the combustion chamber to be observed from the outside, and is further provided with a light receiving element 6 that detects flame light and converts it into an electrical signal. . The signal from the light receiving element 6 and the signal from the crank angle sensor 8 attached to the crankshaft 7 are input to each control circuit 11 9 containing a microcomputer.

11tlJ↑In the wholesale circuit 9, the output of the light-receiving element 6, which changes in accordance with the crank angle, can be patterned and discriminated.Furthermore, the patterned signal in the optimal combustion state is stored in advance, and the general operating state can be determined. The signal in rilA can be compared. In other words, 'l1il
The J control circuit 9 has the function of determining whether combustion conditions are optimal from the combustion flame light and driving the fuel supply system actuator 10 to maintain optimal operation.

FIG. 2 shows an example in which the present invention is fully applied to a gasoline engine, and its operation is similar to that of the diesel engine shown in FIG. 1
The signals from the lilJ control circuit 9 drive the fuel flow regulator 11 and the air flow regulator 12, and also control the fuel injection timing of the injector 13 and the firing timing of the spark plug 15 connected to the ignition system circuit 14. can be controlled.

FIG. 3 is a block diagram of a signal processing circuit according to the present invention, in which an analog signal from the light receiving element 6 is converted into a digital signal by an A/D converter 16, and similarly input to the center processor unit 19 via an interface circuit 17.

Center Processor Unit) 19Ki, J: A random access memory 20 and a read-only memory 21 are attached to temporarily store input information. Then, if the optimal combustion information signal stored in yet another read-only memory 22 and the center processor unit 19 are in relative symmetry and the signal is within the allowable error, no output signal is output. If the difference is large, the first flow i, t'N, "a" is output through the output interface circuit 23 and the output D/A converter 24. A signal for adjusting 14 is issued 2, and the light-receiving element output signal obtained corresponding to the crank angle is automatically adjusted so as to fall within the falsified value.

Figure 4 shows the air and fuel ratio of the mixture in the combustion chamber, and shows the IP! 4 property 25 shows that air and fuel are in an inversely proportional relationship. Therefore, the automatic adjustment signal processing circuit shown in FIG. 3 is also controlled based on the correlation characteristics between air and fuel.

FIG. 5 is a graph showing the analog signal of the light receiving element 6 and the signal of the crank angle sensor 8.

The vertical line in the center of the graph is the top dead center 26, and the top dead center is υ
There is fuel injection timing 27 a little before.

Also, the flame light inside the combustion chamber exhibits very complicated characteristics, which differs somewhat from iI between diesel engines and gasoline engines.

Here, typical characteristics of the waveform 28 in which the maximum value of the output signal distribution characteristic of the light receiving element 6 is close to the top dead center side, the waveform 29 in the medium heat state, and the waveform 30 in which the maximum value is away from the top dead center side will be explained as examples.

Generally, the timing of combustion is just past top dead center.
The closer it is to the top dead center, the more desirable it is, and in the example of FIG. 5, the waveform 28 in which the maximum output value is closer to the top dead center is most preferable.

However, maintaining this state during normal operation is 1)i
l[: L<, the waveform is often represented by waveform 29 where the highest value is in the center or waveform 30 which is far from the top dead center.

Therefore, by comprehensively adjusting the air-fuel ratio, fuel injection timing, and ignition timing, the top dead center 261 as shown in FIG.
After determining the ideal Ichikawa cover turn 31 of the crank angle vs. light receiving element output characteristic after measurement, data with upper and lower allowable ranges is stored in the read-only memory 22 shown in FIG.
I'll leave it alone. ! The actual input data at each crank angle obtained in the UB operating state is compared to the center processor unit 19-'C', and if it is not within the range of the ideal Ichikawa cover turn 31 at each crank angle, the output data is Interface time h! +5232 and output D/
automatically adjusting the fuel control system circuit through the A converter 24;
The operation is performed while maintaining the condition with the button L11 set to allow.

Other methods of recognizing first-to-burn Kabataan - C is the 7th
As shown in the figure, the light emission time is divided into 4 parts, and the output of each section (C-integrated) is integrated value data of ideal pattern 3.
2, if it is above the allowable range, the fuel control system circuit can be automatically adjusted until the input data falls within the allowable i1iα range.

This ideal Ichikawa Kabataan differs slightly depending on engine type and structure, but it is generally the same and can be commonly used depending on the engine.

〔Effect of the invention〕

According to the present invention, it is possible to achieve accurate engine control by directly capturing the combustion information in the combustion chamber.In comparison with the 111j method, which has been used indirectly to control signals, the engine output and fuel efficiency are improved. Results can be obtained that are useful for improving environmental conditions, exhaust gas countermeasures, etc.

That is, by associating the crank angle with the combustion state, information on the combustion chamber inside the combustion chamber can be grasped and controlled accurately and timelessly, and more accurate control 11 becomes Fq function.

In addition, the device of the present invention adds a part for detecting combustion flame light to the engine IT' control method using a microphone computer, which is currently available, and by adding +1ilJ according to this method to the filJ +1i11 circuit, the entire system can be greatly improved. It is relatively easy to compare DA and DA because they can be adapted without modification.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional explanatory diagram of a diesel engine to which the present invention is applied, and FIG. ! 3 is a block diagram of the signal processing circuit of the present invention. Figure g4 is a diagram showing the relationship between air and fuel, Figure 5 is a diagram showing an example of a combustion flame signal, and Figures 6 and 7 are diagrams showing an ideal cover pattern of the light receiving element output with respect to the crank angle. be. 1... Combustion chamber, 2... Piston, 3... Cylinder, 5... Translucent window, 6... Light receiving element, 8... Crank angle sensor, 9...'+ijJ# Circuit, 11...
・Fuel miscarriage regulator, 12... Air flow rate regulator, 13.
... Injector, 14... Ignition system circuit, 15...
Spark plug, 16...A/D converter, 17...Interface circuit, 19...Center pre-sensor unit, 20...Random access memo 17.21.
22... Read-only memory, 23... Output interface circuit, 24... Output D/A converter, 26
...Top dead center, 28...Waveform closer to top dead center, 29
... waveform around the center, 30 ... waveform away from top dead center, 31 ... ideal cover turn, 32 ... integral value data of ideal pattern. Flute trZJ Flute l, -t7 figure

Claims (1)

[Claims] 1. Means for supplying air and fuel to the combustion chamber of an internal combustion engine;
means for detecting flow rates of air and fuel; means for detecting operating parameters of the internal combustion engine; and means for determining a mixture ratio of air and fuel, fuel injection timing, and ignition timing based on control signals from each of the above-mentioned means. A light-transmitting window is provided in a part of the combustion chamber, and the combustion chamber is placed close to the outside of the window, and the combustion flame in the combustion chamber is
The output signal of the light receiving element under normal operating conditions is stored as an optimum combustion state pattern signal corresponding to the crank angle, and the output signal a appearing on the light receiving element when the engine is operating is provided. An optimal combustion control device for an internal combustion engine, characterized in that the mixture ratio of air and fuel, fuel injection timing, and ignition timing are controlled by comparing the signal with the optimal combustion state pattern signal. 2. In claim 1, the optimal combustion state pattern signal has a predetermined tolerance value of two lights, and if the output signal from the light receiving element exceeds this tolerance value, the optimal combustion state pattern signal is always used. An optimal combustion control device for an internal combustion engine, characterized in that it controls the mixture ratio of air and fuel, fuel injection timing, and ignition timing. 3. In claim 1, the output signal of the light-receiving element is made into a pattern signal corresponding to the change in crank angle, the pattern signal is divided and integrated with respect to the crank angle, and the value is always set to the optimum combustion condition! An optimal combustion control device for an internal combustion engine, characterized in that it is configured so as to be able to be compared with No. 1 of the Act.