US3720192A

US3720192A - Controlling device for fuel injection of an internal combustion engine

Info

Publication number: US3720192A
Application number: US00070805A
Authority: US
Inventors: S Aono
Original assignee: Nissan Motor Co Ltd
Current assignee: Nissan Motor Co Ltd
Priority date: 1969-10-22
Filing date: 1970-09-09
Publication date: 1973-03-13
Anticipated expiration: 1990-03-13
Also published as: DE2052860A1; GB1331946A; FR2064849A5; JPS4945651B1; DE2052860C3; DE2052860B2

Abstract

A controlling device for controlling an operation of fuel injection system of an internal combustion engine, comprising an optical means having light absorbing characteristics and a photodetecting means arranged to move relative to said optical means, the optical means has prerecorded optical variation of the light absorbing characteristics corresponding to requested twodimensional characteristics of the operation of the internal combustion engine, the optical variation is detected by the photodetecting means to produce an electric output voltage to control the injection period of fuel injector to obtain desired output characteristics of the internal combustion engine.

Description

United States Patent 1 Aono l 51March 13, 1973 1 CONTROLLING DEVICE FOR FUEL INJECTION OF AN INTERNAL COMBUSTION ENGINE [75] Inventor: Shigeo Aono, Yokosuka, Japan [73] Assignee: Nissan Jidosha Kabushiki Kaisha,

Yokohama City, Japan [22] Filed: Sept. 9, I970 [21] App1.No.: 70,805

[30] Foreign Application Priority Data Oct. 22, 1969 Japan ..44/83976 [52] US. Cl ..l23/32 EA, 123/32 AE, 123/119 R, 123/139 E [51] Int. Cl. ..F02b 3/00, F02m 51/00 [58] Field of Search...l23/32 EA, 32 AE; 250/219 DD, 250/219 QA, 219 Q [56] References Cited UNITED STATES PATENTS 2,856,910 10/1958 Goodridge ..123/32 EA 2,635,195

4/1953 Hancock ..250/2l9 DD 3,051,152 8/1962 Paule et a1 ..l23/32 EA 2,398,238 4/1946 McNatt ..250/2l9 DD 3,408,634 10/1968 Lee et a1. ..250/219 DD 3,543,739 12/1970 Mennesson ..123/32 EA 3,548,791 12/1970 Long ..123/32 EA 2,859,738 11/1958 2,950,706 8/1960 Senckel ..123/32 EA Primary Examiner-Laurence M. Goodridge Assistant Examiner-Cort R. Flint Att0rney-Sughrue, Rothwell, Mion, Zinn & Macpeak [57] ABSTRACT A controlling device for controlling an operation of fuel injection system of an internal combustion engine, comprising an optical means having light absorbing characteristics and a photodetecting means arranged to move relative to said optical means, the optical means has prerecorded optical variation of the light absorbing characteristics corresponding to requested two-dimensional characteristics 01 the operation of the internal combustion engine, the optical variation is detected by the photodetecting means to produce an electric output voltage to control the injection period of fuel injector to obtain desired output characteristics of the internal combustion engine.

6 Claims, 5 Drawing Figures PATENTEDHARI 3197a sum ear 3 I HyZ. 1m

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SHEET 3 0F 3 Y w WAT/617F145 a a X 1:111: iiiiifur r a 5 5mm 5 L94 i/d/VAA W V L) Acumen/A14 CONTROLLING DEVICE FOR FUEL INJECTION OF AN INTERNAL COMBUSTION ENGINE BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a controlling device for the operation of a fuel injecting system of an internal combustion engine such as used in automobiles or the like. The present invention particularly relates to an improvement of an electronic type fuel injection controlling device.

2. Description of the Prior Art Various attempts have been made for effecting the control of fuel injection system for an internal combustion engine, particularly such as used in automobiles, in order to obtain ideal working conditions. As one of such controlling systems, there have been proposed an electromagnetic fuel injector. In such system, an intermittently operating electromagnetic injector is used. The opening period of the electromagnetic injector may correspond to the amount of fuel supply to the engine. This amount should meet with the working condition and with the characteristics of the engine. Usually, this amount depends upon the intake manifold pressure and also the engine speed. In other words, this amount should be controlled under two parameters, and may not be decided by either the intake manifold pressure or the engine speed alone.

Electric or electronic controlling apparatus for such fuel injection system of an internal combustion engine had been proposed. However, since the amount of the fuel supply or the opening period of an electromagnetic injector depends upon said two functions, the controlling circuit or the computing circuit used to control the injector may become rather complicated. Therefore, a practical and economical computing circuit may hardly be realized, which can be used in an automobile.

The present invention has for its object to obviate such complications for designing a memory element of the. controlling device for controlling the electronic controlled fuel injection system.

SUMMARY OF THE INVENTION The present invention had been obtained by an idea of using an optical device, such as photographic film, on which the two dimensional operational characteristics are recorded in a form of variation of darkness or variation of light absorbing characteristics as a memory element for the feed forward controller to the engine. The above optical variation is detected by a photoelectronic detector to produce an electric output voltage to be supplied to the fuel injector as the controlling signal.

According to the present invention, the computing circuit or the memory portion thereof may uniformly be manufactured with a very low cost so that the system is quite suitable for mass-production.

DESCRIPTION OF THE DRAWINGS FIG. 1 shows working characteristics curves of an internal combustion engine expressed by the relation between the duration of fuel injection and engine speed while making load conditions as the parameter;

FIG. 2 shows relations between intake manifold pressure and engine speed making the duration of fuel injection as the parameter;

FIG. 3 is a perspective view illustrating the device according to the present invention schematically;

FIG. 4 is an explanatory view of the essential part of the device of the invention; and

FIG. 5 is an electronic circuit used in one embodiment of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT FIG. 1 shows relations between the opening duration of the injector controlled by operational pulses and engine speed for various intake manifold pressures or various load conditions as the parameter. FIG. 2 shows relations between the intake manifold pressure and the engine speed for the duration of fuel injections as the parameter.

In order to realize an ideal working condition of an engine for various engine speed under varying load conditions, the relation between the three variables as shown in FIG. 2 should be satisfied. In the present invention, in order to realize such condition the characteristics variation as shown in FIG. 2 is represented on two dimensional plane or two dimensional curved surface by using an optical film as the memory element, of which the gradient of the darkness represents the given characteristics. By illuminating thus recorded memory film and by detecting the light output which penetrates the film an electric voltage representing the recorded darkness on the film is obtained. Accordingly, if the desired operational characteristics of an engine are recorded on a film as the variation of the darkness, the operational condition may be memorized by the film. By selecting an operational condition by the position of the film, an electric output corresponding to the darkness of the film may be obtained, which represents the given amount of fuel supply to the engine, namely the opening duration of the injector. Therefore, an ideal predetermined working condition is realized for any operational condition.

FIGS. 3 and 4 represent an embodiment of the present invention. In FIG. 3, reference numeral 1 represents a rotating cylinder having the memory film la wound thereon. This film has darkness gradient previously recorded to represent predetermined working condition of the engine such as shown in FIG. 2 schematically.

As shown in the figures, the rotational angle 0 of the cylinder 1 is controlled by a Bourdon's tube 2, connected to an axis of the cylinder 1, so that the rotational angle deviation 0 is proportional to the intake manifold pressure of the engine. By this means, the intake manifold pressure for any desired operational condition of the engine is given by the rotational deviation 0 of the cylinder 1.

A light source 3 is provided to illuminate the memory film from inside the cylinder.

A photodetecting device 6 is arranged to move along the axial direction of the cylinder 1 over the surface of the memory film 10 by means of pulleys 4a, 4b, 4c and a driving string 5 wound therethrough. The position of the photodetecting element 6 along the 0-]: axis is so arranged to correspond a certain engine speed. If the engine speed is given, the photodetecting element 6 takes a certain predetermined position along o-x axis over the memory film la. For instance if the engine speed is increased, the photodetecting element 6 is moved in the right hand direction towards the pulley 40. Accordingly, if both the intake manifold pressure and the engine speed are given, the photodetecting element 6 chooses one definite point over the memory film 1a at which the element 6 receives a light output corresponding to predetermined duration of the injection. As explained above, the memory film la is recorded darkness gradient as schematically illustrated in FIG. 2. If considering the intake manifold pressure of 500 mmI-Ig abs and the engine speed of 2,000 rpm. The relative position of the cylinder 1 and the photodetecting element 6 may be expressed by point A on FIG. 2. This means that, by the stored information on the memory film, the duration of the injection pulse should be about 5 ms (milli-second). Then if considering about 600 mmI-Ig abs intake manifold pressure and 3,000 r.p.m. engine speed. The relative position is represented by point B on FIG. 2. This means that the duration of injection of the injector should be controlled to be about 6.4 ms. By this means, an exact duration of opening the injector is given by the memory film la. FIG. 2 shows very simple characteristic relation for the sake of illustration, but any type of complicated information for the control of opening duration of the injector is given by a suitable preparation of the memory film 1a.

The detected electric output from the photodetecting element 6 is supplied to a voltage to pulse width converting circuit 7. Thus the desired output pulse representing the necessary injection duration meeting with the two dimensional operational condition of the engine is obtained. This pulse is supplied to a fuel injector 8 to control the operation of the same.

Since the detail of the voltage to pulse width converting circuit 7 'per se is known, no detailed explanation of the circuit might be required.

FIG. 5 shows practical embodiment of a current feeding circuit for the light source 3. In the foregoing explanation of the invention, the light source 3 has been explained to emanate a constant light output. However, it is also possible to modify the current feeding circuit to the light source 3 so as to meet practical requirement of an engine. The circuit diagram shown in FIG. 5 includes three additional functions.

In FIG. 5, Ba represents a dc supply voltage, such as a battery. in order to simplify the drawing, the ordinary elements such as a source switch and a fuse are not shown in the drawing. The light source 3 is included in collector emitter circuit of a transistor Tr, and is energized by the current originated from the battery and passing through the collector emitter circuit. The rating of the transistor Tr, and of the light source 3 are so chosen to emanate a necessary amount of light for illuminating the memory film la under ordinary condition.

, The base of the transistor Tr, is connected to collector of second transistor Tr, via a resistor r,, which is also connected to the source Ba via a resistor r,. The emitter of the transistor Tr is connected to ground via a resistor r,,. The base of the transistor Tr, is on the one hand connected to the source Ba via a resistor r, and on the other hand connected to a ground via a thermistor 9. The thermistor 9 is arranged to respond to the engine temperature.

The thermistor 9 has a negative temperature coefficient of the resistance. In other words it has a higher resistance in the cold condition and will have a lower resistance in a warm condition. During the warming up time of the engine, according to the fact that the thermistor 9 is in a high resistance condition owing to the temperature. The transistor Tr, is applied a smaller collector base voltage and passing relatively low-electric current in the collector emitter circuit r, and r,,.

The base of the first transistor Tr, is supplied a potential nearly comparative to the collector voltage of the transistor Tr,.

During the warming up period of an engine, the resistance value of thermistor 9 decreases according to the increase of the temperature. By this variation the second transistor Tr, increases its current and the first transistor Tr, decreases its current to make the light output of the light source 3 to be dimmer owing to the fact of decreasing the collector base voltage.

By the inclusion of the'thermistor element or a temperature depending element in the controlling circuit of the light source 3, the feature of the warming up condition of an engine is conveniently improved.

It is also possible to supply a starting signal and an accelerating signal to increase amount of injection in such occasions. The above signals may be supplied by positive signals.

FIG. 5 isjust an embodiment of such circuit. This circuit is designed to decrease the light output of the light source 3, which may preferably be a Xenon lamp, by increasing the resistance of the thermistor 9, but it may be designed to increase the light output of the light source 3. Such choice is just optional and may easily be realized together with suitable choice of the film polarity, i.e., negative or positive.

According to the present invention, the construction of the controlling circuit, especially, for the memory part is much simplified and easily be manufactured uniformly. Accordingly, the present invention is suitable for use in automobiles, and the present invention has a remarkable effect for simplifying the production of the controlling system and improving the operational property of automobiles.

What is claimed is:

l. A device for controlling a fuel injector in an internal combustion engine, said device comprising:

a. photographic film means having a darkness gradient in accordance with desired engine operating conditions which is a continuous function of two independent variable engine characteristics;

. first means, operatively connected to said engine for detecting a first of said two independent characteristics and for moving said photographic film means in accordance with the detected first characteristic;

. light source means for illuminating said photographic film means;

. photodetecting means for moving relative to said photographic film means in response to the second of said independent characteristics for detecting light passing through said photographic film means whereby the output of said photodetecting means is a continuous function of said first and second independent characteristics; and

. circuit means for developing a control signal in accordance with the output of said photodetecting means, wherein said control signal is applied to said fuel injector for controlling the output of said fuel injector whereby said fuel injector is controlled as a function of said two independent characteristics.

2. A controlling device as claimed in claim 1 wherein said photographic film means is wound around a cylinder arranged in rotatable manner about an axis, and the rotating angle deviation is proportional to intake manifold pressure of the engine.

3. A controlling device as claimed in claim 1, wherein the photodetecting means is a photoelectronic converter.

4. A controlling device as claimed in claim 2, wherein photodetecting means is arranged to move along the axial direction of the cylinder.

5. A controlling device as claimed in claim 3, wherein the cylinder carrying the photographic film means rotates in proportion to the intake manifold pressure of the engine and the photodetecting means moves along the axial direction of the cylinder and in proportion to number of revolutions per minute of the internal combustion engine.

6. A controlling device as claimed in claim 1, further including a thermistor means for detecting the temperature of the engine and for controlling the light out put of the light source according to the engine temperature to increase the amount of fuel supply at starting, warming up and acceleration of the engine.

Claims

1. A device for controlling a fuel injector in an internal combustion engine, said device comprising: a. photographic film means having a darkness gradient in accordance with desired engine operating conditions which is a continuous function of two independent variable engine characteristics; b. first means, operatively connected to said engine for detecting a first of said two independent characteristics and for moving said photographic film means in accordance with the detected first characteristic; c. light source means for illuminating said photographic film means; d. photodetecting means for moving relative to said photographic film means in response to the second of said independent characteristics for detecting light passing through said photographic film means whereby the output of said photodetecting means is a continuous function of said first and second independent characteristics; and e. circuit means for developing a control signal in accordance with the output of said photodetecting means, wherein said control signal is applied to said fuel injector for controlling the output of said fuel injector whereby said fuel injector is controlled as a function of said two independent characteristics.