JPH0574715B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Technical field The present invention relates to a method and apparatus for controlling an internal combustion engine, and more particularly, to a heat generating section disposed in a combustion chamber of an internal combustion engine, and operating characteristics that characterize the driving state of the internal combustion engine. a sensor that detects the amount of heat, a device that adjusts the amount of heat supplied to the heat generating section, and a control section that controls the control device to drive the internal combustion engine according to the state, and controls the internal combustion engine using the heat generating section. The present invention relates to a method and apparatus for doing so.

(b) Prior Art German Patent Publication No. 2402586 describes an internal combustion engine driven using a heat generating part. According to a preferred embodiment of the publication, the energy supplied to the heat generating section from the outside is adjusted to the energy necessary for the heat generating section via a control device. In order to ignite the mixture at a given time, the actual temperature of the heating element and the temperature required to ignite the mixture must be taken into account. Both of these temperature characteristics will have variations due to, among other things, vortices in the mixture. This makes it impossible to accurately determine the ignition point of the air-fuel mixture in advance, resulting in a certain time range relative to the ignition point.

(C) Purpose Therefore, the present invention has been made to eliminate such conventional drawbacks, and provides a control method and device for an internal combustion engine that can minimize the time period in which air-fuel mixture ignites. The purpose is to provide

(d) Structure of the Invention In order to achieve the above object, the present invention supplies electric energy to the heat generating part so that the temperature of the heat generating part increases dramatically just before the target ignition time, and ignites the air-fuel mixture at the target ignition time. We have adopted a configuration that allows

(e) Examples The present invention will be described in detail below according to examples shown in the drawings.

FIG. 1a shows the variation range of the ignition point in fast-response constant temperature control. What is indicated by the reference numeral 10 is the temperature characteristic necessary for igniting the air-fuel mixture, that is, the ignition temperature characteristic. Reference numeral 11 indicates the range of ignition temperature characteristics, that is, the range of variation in ignition temperature. Further, reference numeral 13 indicates the actual temperature characteristics of the heat generating portion, while reference numeral 14 indicates the range of temperature variation of the heat generating portion.
Further, reference numeral 16 indicates the range of variation in the ignition timing of the air-fuel mixture. Figure 1a shows the temperature characteristics,
The temperature T is shown on the vertical axis, and the crankshaft angle Ψ is shown on the horizontal axis. Instead of using the crankshaft angle Ψ, time t can also be used on the horizontal axis. The top dead center of the piston is indicated by the symbol OTP in the figure, and the variation width of the ignition point of the air-fuel mixture is 1.
The boundary values of 6 are illustrated as Ψ11 and Ψ12.

In FIG. 1a, the temperature characteristic 13 of the heat generating portion is maintained at a substantially constant temperature with a small variation width 14 due to fast-response constant temperature control. A variation width 16 at the time of ignition is determined from the intersection of the actual temperature variation width 14 of the heat generating portion and the ignition temperature variation width 11.

FIG. 1b shows the variation in the ignition point using temperature control by current pulses. 1st
The numbers used in Figure b correspond to those used in Figure 1a. Unlike FIG. 1a, the boundary values of the variation width 16 at the time of ignition of the air-fuel mixture are illustrated by Ψ21 and Ψ22.

In FIG. 1b, the temperature of the heating element is controlled using current pulses. As a result, the temperature characteristics of the heat generating part 13
has a variation width 14 corresponding thereto. This temperature characteristic has the characteristic that the temperature of the heat generating part rises rapidly at the point where the air-fuel mixture ignites. A variation width 16 at the time of ignition of the air-fuel mixture is determined from the intersection of the actual temperature variation width 14 of the heat generating portion and the temperature variation width 11 necessary to ignite the air-fuel mixture.

Comparing FIG. 1a and FIG. 1b, it can be seen that the variation width 16 in FIG. 1a is considerably larger than the variation width 16 in FIG. 1b. The area of Ψ11-Ψ12 is much larger than the area of Ψ21-Ψ22.
That is, by rapidly increasing the actual temperature of the heat generating portion, it is possible to significantly reduce the variation in the ignition timing during the mixing period.

FIG. 2a shows a circuit for constant temperature control. Reference numeral 20 indicates a heat generating portion, specifically an ignition source. When used in controls associated with internal combustion engines, it is preferred that the time constant of the ignition source 20 be as small as possible so that it can quickly adapt to rapidly changing conditions in the combustion chamber. 21 indicates a resistance for measurement, and 22 indicates a drive circuit. Also code 25
26 is an amplification circuit; 27 is a target value forming circuit that forms a target value for the heat generating section; and 28 is a comparison between the target value and the actual value. Each comparison circuit is shown. Drive circuit 22, resistor 21 and ignition source 20 are connected in series. The voltage across resistor 21 is supplied to actual value forming circuit 25 . The signal generated by the actual value forming circuit 25 is amplified in an amplifier circuit 26 and is fed to the input terminal of a comparator circuit 28 . The target value forming circuit 27 is connected to the other input terminal of the comparison circuit 28, and the drive circuit 22 is driven by the output signal of the comparator 28.

The ignition source 20 is, for example, a device that generates heat in the surroundings according to the current flowing through it. The current flowing through the ignition source 20 also flows through the resistor 21, thereby causing a voltage drop. Actual value forming circuit 25 measures this voltage drop and generates a corresponding output signal. This output signal is therefore a signal relating to the actual temperature of the ignition source 20. The target value forming circuit 27 is configured as a variable resistor in its simplest configuration. The value of this resistance may be adjusted manually, for example, or controlled to a predetermined value by a target value generator (not shown) in accordance with the operating temperature, air-fuel ratio, etc. of the internal combustion engine. Comparison circuit 28 compares the signal formed by actual value forming circuit 25 and amplifier circuit 26 with the signal generated by target value forming circuit 27, and drives circuit 22 according to the comparison result. .
In this way, the circuit shown in FIG. 2a controls the temperature of the heat generating part to a predetermined value, thus making it possible to perform constant temperature control with quick reaction.

FIG. 2b shows a temperature control circuit using current pulses. The numbers in FIG. 2b correspond to those in FIG. 2a. In FIG. 2b, the measuring resistor 21
A power supply indicated by 30 and a control unit indicated by 31 are provided.

The ignition source 20 and the drive circuit 22 are connected in series,
The ignition source 20 and the power source 30 are connected in parallel. The voltage of the ignition source 20 is supplied to an actual value forming circuit 25 . The output signal is amplified by an amplifier circuit 26 and guided to a comparison circuit 28. The target value forming circuit 27 is connected to the other input terminal of the comparison circuit 28 . The output signal of the comparison circuit 28 is sent to the control unit 31.
The control unit 31 drives the drive circuit 22. The control unit 31 receives operating characteristic quantities characterizing the operating state of the internal combustion engine, such as signals relating to the angular position of the internal combustion engine, the engine speed, the position of the accelerator pedal, and the flow velocity in the combustion chamber.

When the drive circuit 22 is cut off, the power supply 3
A constant current obtained by 0 flows through the ignition source 20. The temperature of the ignition source 20 then depends on the current flowing through it. At the same time, the resistance of the ignition source 20 changes with temperature. A temperature-dependent voltage drop therefore occurs in the ignition source 20. This value is input to the actual value forming circuit 25, amplified by the amplifier circuit 26, and compared with the target value by the comparison circuit 28.
The output signal of the comparison circuit 28 is a signal representing the deviation between the actual temperature of the ignition source 20 and the target value. The control unit 31 processes this signal and the operating variables characterizing the operating state of the internal combustion engine and generates current pulses. The drive circuit 22 changes from a cut-off state to a conduction state only during that pulse period.

Under normal conditions, the drive circuit 22 is shut off and the ignition source 20 receives a constant current provided by the power supply 30. This temperature characteristic is shown in Figure 1b as the boundary value Ψ2
It is illustrated on the left side of 1. When the drive circuit 22 becomes conductive, a large current flows through the drive circuit 22 and the ignition source 20, thereby causing the temperature of the heat generating portion to rise rapidly between the boundary values Ψ21 and Ψ22. Note that this increase can be determined according to a predetermined function.

The conduction times and durations of the conduction of the drive circuit 22 are calculated according to the input variables input to the control unit 31. The input signals are, as mentioned above, the result of the comparison between the actual value and the setpoint value as well as the operating characteristics of the internal combustion engine. These operating characteristic quantities are, for example, the rotational speed of the internal combustion engine, the position of the accelerator pedal, the air-fuel ratio, the driving temperature of the internal combustion engine, the signal regarding the top dead center of the internal combustion engine,
These are signals related to the flow velocity in the combustion chamber, etc.

The pulses generated by the control unit 31 and causing a rapid increase in the temperature of the heat generating part may be high frequency pulses, ie, a large number of short pulses appearing in succession. After the temperature of the heat generating part rises rapidly, that is, in the region to the right of the boundary value Ψ22 in FIG.
A constant current flows, which is obtained by . As a result, the temperature of the heat generating part decreases again to its initial value. This reduction can be determined by a predetermined function.

Preferred results can be obtained by combining the constant temperature control shown in FIG. 2a with the pulsed temperature control shown in FIG. 2b. For example, in Fig. 2b, the temperature of the heat generating part is not only rapidly raised by the pulse obtained from the control unit 31, but also the drive circuit 22 is operated by the pulse to perform constant temperature control. This is made possible by Particularly when constant temperature control and pulsed temperature control are combined, it is preferable to input a signal coming from the ignition source 20 to the control unit 31 as an input signal. In this case, the amount of heat supplied to the ignition source 20 is measured by passing a current through the ignition source 20 or by applying a voltage to the ignition source 20 immediately before applying the original pulse. This measured value provides information about the flow velocity of the mixture in the region of the ignition source 20 of the combustion chamber. This information is used to adjust the subsequent pulses together with other variables characterizing the operating state of the internal combustion engine.

The difference between the circuit shown in FIG. 2b and the circuit shown in FIG. 2a is that a control unit 31 is provided. In FIG. 2a, the drive circuit 22 is driven in an analog manner, whereas in FIG. 2b, the drive circuit 22 is clock-controlled due to the provision of a control unit 31. Although the power supply 30 of FIG. 2b is not necessary in principle, its use makes it possible to shorten the pulse duration and thereby increase the slope of the temperature rise of the heat generating part.

Similarly, the amplifier circuit 26 is not necessarily necessary, but
By using it, the signal from the actual value formation circuit 25 can be adapted to the signal from the setpoint value formation circuit 27. Similarly, by using the amplifier circuit 26, it becomes possible to cut off the comparison circuit 28 and the subsequent control unit 31 in terms of direct current.

Various orders of the series circuit consisting of the ignition source 20, the drive circuit 22, and possibly the resistor 21 can be considered, and the basic idea of the present invention is basically influenced by the connection thereof. do not have.

The circuit elements shown in FIGS. 2a and 2b can be realized using a correspondingly programmed microcomputer, and it is particularly advantageous if the control unit 31 is implemented by a microprocessor.

To summarize what has been said so far, it is possible to control the ignition point of the air-fuel mixture in the combustion chamber of an internal combustion engine using the circuits shown in FIGS. 2a and 2b. In that case, the variation width of the ignition timing when using the circuit of FIG. 2b can be made considerably smaller than that of the circuit of FIG. 2a. This makes it possible, in accordance with the basic idea of the invention, to dramatically increase the actual temperature of the heating element at the desired ignition point of the air-fuel mixture.

Figures 3a to 3b include Figures 2a and 2.
In Figure b, ignition devices 32' and 32'', which are used as heat generating parts or ignition sources 20, are shown.
Figures 3a to 3b show an ignition device 3 generally corresponding to the ignition device described in U.S. Pat. No. 2,039,529.
2' is shown. This igniter is attached to the support 3
It has a heat generating glow wire 33' attached to the electrically insulated external surface of 4'. The support 34' is preferably rod-shaped and is made of a heat-resistant metal material such as a nickel alloy or heat-resistant steel.
A screw 35' is formed around the support 34', and this screw 35' is connected to the thin ceramic insulating layer 3.
6'. In principle, ceramic materials such as oxides, carbides, nitrides or borides are suitable for the insulating layer 36', but a ceramic insulating layer 36' consisting of a mixture of zirconium dioxide and silicon dioxide is particularly preferred. Insulating layer 3
6' is preferably a support 3 formed by a plasma injection method.
Although the coating is applied onto the thread 35' of the 4', it can also be formed on the thread 35' by other methods (physicochemical methods). Alternatively, a ceramic insulating layer 36' may be formed on the support 34', followed by the formation of the screws 35'.

The heating wire 33' is attached and held in the spiral groove of the screw 35'. As the material of the heat generating glow wire 33', a material having a unique and clear correlation between its electric resistance and temperature is used. Examples of such materials include platinum and its alloys, rhodium,
Palladium and its alloys as well as nickel alloys and many ceramic materials.

By changing the inclination and depth of the screw 35',
Also, by varying the flow and diameter of the support 34', the thickness and material of the insulating layer 36', and according to how the glow wire 33' is attached to the end of the screw 35', the igniter 32 can be adjusted. ' can be adapted to the requirements imposed on various internal combustion engines. For example, various combinations of screws 35' and glow wires 33' are illustrated in Figures 3c and 3d. FIG. 3c shows a screw 35' covered with an insulating layer 36' and having a glow line 33' in an enlarged sectional view. In this embodiment, the glow line 33'
has a relatively large diameter and is arranged so that it only partially abuts the electrically insulating end 37' of 35'. Also shown in FIG. 3d is a screw 35' coated with an insulating layer 36'' and having a glow wire 33', the glow wire 33' having a relatively small diameter and forming an electrically insulating end of the screw 35'. It hits 37″ well.

FIG. 3e shows an ignition device 32 with glow wire 33 held in different ways. In this case, the glow line 33 is connected to a support 34 whose cross section is star-shaped.
wrapped around the top. This support 34 is formed with a screw (not shown) as shown in FIG. 3c or 3d.

The configuration of the ignition devices 32', 32'' described above corresponds in principle to the ignition device described in U.S. Pat. Favorable results occur when the glow line 33' is adapted to the rapidly changing conditions of In a specific embodiment, the glow wire 33' made of platinum has a diameter of 0.2 mm, and the diameter of the support 34 is greater than 2 mm, preferably having a value of 3 to 7 mm.

The heat generating part (glow plug) shown in Figures 3a to 3b can have a small heat capacity, and even if it is driven intermittently just before the target ignition point, the temperature will rise instantaneously (for example, within a few milliseconds). Moreover, it becomes a heat generating part that can withstand repeated use.

As mentioned above, by using the control device and the ignition device 32 already described, the ignition point of the air-fuel mixture can be reproduced well, thereby improving the overall combustion characteristics. Similarly, the limit values for lean mixtures or mixtures containing exhaust gases can be increased considerably over the entire speed range as well as the load range. Furthermore, even when the load is small or the mixture is lean or contains exhaust gas, energy conversion and therefore thermal efficiency can be improved.
When using the circuit shown in FIGS. 2a and 2b, all the equipment and components hitherto necessary for generating high voltages can be omitted. Similarly, there is no need to enrich the air-fuel mixture during cold start and warm-up mode. This is because the above-described circuit allows the air-fuel mixture to be reliably ignited even in this mode.

For example, preferable results can be obtained if an ion sensor is used to generate a signal related to the ignition of the air-fuel mixture and the signal is used to control the internal combustion engine. This creates a control loop in which each subsequent ignition point is inter alia related to the previous ignition point, making it possible to adapt the ignition point almost optimally to the operating state of the internal combustion engine.

(f) Effects As explained above, according to the present invention, a large amount of energy is supplied to the heat generating part immediately before the target ignition point, and the temperature of the heat generating part increases dramatically, so that the time range for igniting the air-fuel mixture or The crank angle range can be made extremely small, and the air-fuel mixture can be reliably ignited at the target ignition point. This makes it possible to optimally adapt the ignition point to the operating conditions of the internal combustion engine.

[Brief explanation of drawings]

Figure 1a is a characteristic diagram explaining the control method of constant temperature control, Figure 1b is an explanatory diagram explaining pulse-based temperature control, Figure 2a is a circuit diagram showing the configuration of the circuit used for constant temperature control, and Figure 2b is is a circuit diagram explaining the circuit used for pulse-based temperature control;
Figure a is a front view showing the specific configuration of the heat generating part used in the circuits of Figures 2a and 2b;
The figure is a cross-sectional view explaining the heat generating part in detail, 3c.
3e is a sectional view showing another configuration of the heat generating part. 10... Ignition temperature characteristics, 13... Temperature characteristics of the heat generating part, 14... Temperature variation width of the heat generating part, 16
... Variation width at the time of ignition of the air-fuel mixture, 21 ... Measuring resistance, 22 ... Drive circuit, 25 ... Actual value formation circuit, 26 ... Amplification circuit, 27 ... Target value formation circuit, 28 ... Comparison Circuit, 30... Power supply, 31...
...control unit, 33'...glow line, 34'...
Support, 35'...Screw, 36'...Insulating layer.

Claims (1)

[Scope of Claims] 1. A heat generating part disposed in a combustion chamber of an internal combustion engine, a detection means for detecting an operating characteristic quantity of the internal combustion engine and generating a signal representing its driving state, and a heat generating part disposed in a combustion chamber of an internal combustion engine, An internal combustion engine control method for controlling ignition of an air-fuel mixture in an internal combustion engine, comprising: an adjusting means for adjusting, and a control means for controlling the adjusting means according to a driving state of the internal combustion engine, Therefore, the target ignition point is calculated, the temperature of the heat generating part is adjusted to below the ignition temperature before the target ignition point, and the temperature of the heat generating part is adjusted just before the target ignition point in order to ignite the mixture at the target ignition point. A control method for an internal combustion engine characterized by supplying electric energy that increases dramatically to a heat generating part. 2. The method according to claim 1, wherein the temperature of the heat generating part is adjusted to a constant value before the target ignition point. 3. The method according to claim 1 or 2, characterized in that the temperature of the heat generating part is decreased after increasing the electrical energy supplied to the heat generating part. 4. The method according to claim 1 or 2, wherein the temperature of the heat generating part is adjusted to a constant value after increasing the electrical energy supplied to the heat generating part. 5. A control device for an internal combustion engine that controls ignition of an air-fuel mixture in the internal combustion engine, which includes: a heat generating unit 20 disposed in a combustion chamber of the internal combustion engine; and a signal that detects operating characteristic quantities of the internal combustion engine and generates a signal representing its driving state. a detection means; an adjustment means 22 for adjusting the energy supplied to the heat generating section; and a means 31 for calculating a target ignition point according to a signal from the detection means and controlling the adjustment means according to the driving state of the internal combustion engine. and a means 27 for forming a target value of the temperature of the heat generating part, and the adjusting means 27 according to the target value of the temperature immediately before the calculated target ignition time in order to ignite the air-fuel mixture at the target ignition time. 1. A control device for an internal combustion engine, characterized by supplying electric energy to a heat generating part so that the temperature of the heat generating part increases dramatically. 6. Claims characterized in that the operating characteristic quantity of the internal combustion engine is a signal related to the angular position of the internal combustion engine, a signal related to the position of the accelerator pedal, a signal related to the rotational speed of the internal combustion engine, and a signal related to the flow velocity of the combustion chamber. Apparatus according to paragraph 5. 7. Apparatus according to claim 6, characterized in that the flow rate in the combustion chamber is measured immediately before applying a current pulse. 8. The device according to any one of claims 5 to 7, characterized in that an ion sensor is used to obtain a signal regarding ignition of the air-fuel mixture, and the internal combustion engine is controlled. 9. The device according to any one of claims 5 to 8, characterized in that a power source 30 is connected in parallel to the heat generating section 20. 10. Any one of claims 5 to 9, characterized in that the heat generating part 20 is formed by winding a glow wire of a small diameter onto a support having a large diameter and coated with an insulating layer. The equipment described in section. 11. A control device for an internal combustion engine that controls ignition of an air-fuel mixture in an internal combustion engine, which includes: a heat generating unit 20 arranged in a combustion chamber of the internal combustion engine; and a signal that detects operating characteristic quantities of the internal combustion engine and generates a signal representing its driving state. a detection means; an adjustment means 22 for adjusting the energy supplied to the heat generating section; and a means 31 for calculating a target ignition point according to a signal from the detection means and controlling the adjustment means according to the driving state of the internal combustion engine. and a means 27 for forming a target value of the temperature of the heat generating part, a means 25 for measuring the actual value of the temperature of the heat generating part, and a comparing means 28 for comparing the target value and the actual value of the temperature. In order to ignite at the target ignition point, the adjusting means is driven according to the comparison result of the comparing means immediately before the calculated target ignition point, and electric energy is applied to the heat generating part so that the temperature of the heat generating part increases dramatically. A control device for an internal combustion engine, characterized in that: 12. Claims characterized in that the operating characteristic quantity of the internal combustion engine is a signal related to the angular position of the internal combustion engine, a signal related to the position of the accelerator pedal, a signal related to the rotational speed of the internal combustion engine, and a signal related to the flow velocity of the combustion chamber. Apparatus according to paragraph 11. 13. Apparatus according to claim 12, characterized in that the flow rate in the combustion chamber is measured immediately before applying a current pulse. 14. The device according to any one of claims 11 to 13, characterized in that a signal regarding ignition of an air-fuel mixture is obtained using an ion sensor and is used for controlling an internal combustion engine. 15 Claims 11 to 1, characterized in that a power source 30 is connected in parallel to the heat generating section 20.
The device according to any one of items 4 to 4. 16. Device according to one of claims 11 to 15, characterized in that an amplifier circuit (26) is used to adapt the actual value of the temperature to the desired value of the temperature. 17. Any one of claims 11 to 16, characterized in that the heat generating part 20 is formed by winding a glow wire with a small diameter on a support having a large diameter and covered with an insulating layer. The equipment described in section.