JPH051560A - Igniter of rotary piston engine - Google Patents

Abstract

PURPOSE:To secure good combustibility by adjusting the ignition timing of a spark plug in time of a driving state where combustion turns to instability in a rotary piston engine. CONSTITUTION:Three spark plugs, consisting of an L plug 13, a T plug 14 and a Far-T plug 15 are installed in a rotor housing 2 in order extending over the trainling side from the rotor rotation leading side. In such an engine driving range that combustion stability in a combustion chamber 11 becomes worsened, ignition timing of the Far-T plug 15 is set earlier than the conventional ignition timing, and a misfire and self-ignition at an end zone at the trailing side of the combustion chamber 11 are prevented from occurring.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ignition device for a rotary piston engine, and more particularly to an ignition device provided with three ignition plugs.

[0002]

2. Description of the Related Art Conventionally, a general rotary piston engine has a rotor housing in the vicinity of a minor axis thereof, and the minor axis of the rotor housing is sandwiched between the rotor side and the leading side of the rotor rotation direction.
Spark plugs are provided in parallel at two positions on the ring side, and the ignition of the spark plugs burns the air-fuel mixture compressed in the working chamber.

Further, as a constitution for the purpose of improving the equal volume by homogenizing the propagation velocity of flame in the working chamber at the time of high rotation of this rotary piston engine, Japanese Patent Laid-Open No. 63-309728. As shown in Japanese Patent Laid-Open Publication No. 2003-242242, there is known one in which spark plugs are arranged at three positions. The ignition order of the ignition plugs in the rotary piston engine configured as described above is from the ignition plug located closest to the leading side in the rotational direction of the rotor (hereinafter, simply referred to as the leading side). In the rotation direction, the ignition plug is sequentially ignited toward the spark plug on the trailing side (hereinafter, simply referred to as the trailing side), and the flame is propagated from the reading side to the trailing side. . As a result, the flame propagation is directed to improve the equal volume in the combustion chamber.

[0004]

However, in the case where the ignition sequence of each spark plug is set so that the flame propagation is directional as described above, the following problems may occur.

That is, at the time of engine idle operation or light load operation, since the amount of air-fuel mixture filled in the working chamber is small, the propagation speed of the flame in this working chamber is slow, and this flame causes a trace in the operating chamber. Difficult to propagate to the ring end zone. Therefore, the tray in this working chamber
Misfire may occur at the ring end zone. When such a misfire occurs, not only the combustion efficiency is lowered, but also unburned gas burns in the exhaust system to adversely affect the exhaust system, or the unburned gas is directly released to the atmosphere. Therefore, there is a problem that the emission property is lowered.

On the other hand, during high-load operation of the engine, the amount of air-fuel mixture filled in the working chamber is large, so that the propagation speed of the flame in this working chamber becomes high, and the flame propagates from the reading side to the trailing side. Due to the transmission of the pressure wave of the combustion gas, the trailing side end zone in the working chamber becomes a high pressure state. Therefore, before the ignition plug located closest to the trailing side is ignited, the air-fuel mixture may self-ignite in the trailing end zone, resulting in knocking. And
When such knocking occurs, not only the engine performance is deteriorated, but also vibration occurs, which causes an unpleasant occupant.

As described above, in the conventional rotary piston engine, it is difficult to improve the combustibility of the air-fuel mixture during the idle operation, the light load operation, and the high load operation. Was required.

The present invention has been made in view of this point, and an object of the present invention is to obtain a structure capable of sufficiently ensuring the combustibility in the combustion chamber according to the operating state of the rotary piston engine. .

[0009]

In order to achieve the above-mentioned object, the present invention provides a dedicated ignition plug for the air-fuel mixture in a region where misfire and self-ignition are likely to occur depending on the operating state of the engine. To prevent misfire, and to set the combustion timing early so that the air-fuel mixture in this region is not affected by the pressure wave due to the combustion of the air-fuel mixture in other regions, and self-ignition occurs. I tried not to get it. Specifically, according to the first aspect of the invention, as shown in FIG. 1, the first spark plug 13 is arranged on the rotor rotation direction reading side with respect to the minor axis D of the rotor housing 2. , The second spark plug 14 and the third spark plug 15 are arranged on the rotor rotation direction trailing side of the minor axis D of the rotor housing 2, and the third spark plug 15 is connected to the second spark plug 14. The target is the ignition device of the rotary piston engine 1 which is arranged on the trailing side in the rotation direction of the rotor. Then, a driving state detecting means 20 for detecting the driving state of the engine 1 and the driving state detecting means 2
In the engine operating state in which the combustion stability in the combustion chamber II is deteriorated by receiving the output of 0, the ignition timing of the third spark plug 15 is set earlier than in the engine operating state in which the combustion stability is good. The ignition timing setting means 21 to be set is provided.

According to a second aspect of the present invention, in the rotary piston engine ignition device according to the first aspect, the ignition timing setting means 21 is provided in an engine operating state in which combustion stability in the combustion chamber II is not deteriorated. At this time, the ignition timing of the first spark plug 13 is set earlier than the ignition timings of the second spark plug 14 and the third spark plug 15.

The invention according to claim 3 is the same as claim 1
In the rotary piston engine ignition device described,
The ignition timing setting means 21 is configured to set the ignition timing of the third spark plug 15 earlier than the ignition timings of the first spark plug 13 and the second spark plug 14 when the engine 1 is in a light load operation state. .

Further, in the invention as set forth in claim 4, in the ignition device for a rotary piston engine as set forth in claim 1, the ignition timing setting means 21 is provided with a third spark plug 15 when the engine 1 is in a high load operation state. The ignition timing is set earlier than the ignition timings of the first spark plug 13 and the second spark plug 14.

[0013]

With the above construction, the present invention provides the following actions. First, in the invention according to claim 1,
When the operating state detecting means 20 detects an engine operating state (for example, a region where the amount of air-fuel mixture is small or large) in which the combustion stability in the combustion chamber II deteriorates, the ignition timing setting means 21 causes the third ignition. The ignition timing of the plug 15 is set earlier than when the engine is operating with good combustion stability. As a result, in an operating state in which misfire occurs in the trailing end zone of the combustion chamber II, the air-fuel mixture is actively burned in this portion, and this misfire is avoided. Further, in the trailing side end zone of the combustion chamber II, in an operating state in which the air-fuel mixture self-ignites due to the influence of the pressure wave of the combustion gas from the center side of the combustion chamber II, the air-fuel mixture in this part is Since the combustion is performed before the pressure wave is transmitted, self-ignition cannot occur and knocking is prevented.

According to the second aspect of the present invention, in the engine operating state in which the combustion stability in the combustion chamber II is not deteriorated, the ignition timing setting means 21 sets the ignition timing of the first ignition plug 13 to the second ignition plug 14 and the third ignition plug. It is set earlier than the ignition timing of the spark plug 15. As a result, it is possible to obtain the propagation of the flame from the reading side in the rotor rotation direction to the trailing side, and, in combination with the action of claim 1, the improvement of the equal volume in a stable combustion state. It is possible to improve the combustibility in the unstable combustion state.

According to the third aspect of the present invention, when the engine 1 is in a light load operation state, that is, when the amount of air-fuel mixture is small, the ignition timing of the third ignition plug 15 is set by the ignition timing setting means 21. 13 and second spark plug 14
Set earlier than the ignition timing of. This allows the combustion chamber II
At the same time as avoiding the occurrence of misfire in the trailing side end zone, the ambient temperature in the trailing side end zone of the combustion chamber II rises to ignite the first and second spark plugs 13 and 14. Along with the accompanying flame, the combustibility of the entire combustion chamber is improved.

According to the fourth aspect of the present invention, the ignition timing of the third ignition plug 15 is set by the ignition timing setting means 21 even when the engine 1 is in a high load operation state, that is, in a state where the amount of air-fuel mixture is large. 13 and second spark plug 14
Set earlier than the ignition timing of. This allows the combustion chamber II
In the trailing side end zone, the self-ignition of the air-fuel mixture is prevented and knocking is prevented.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 2 shows a schematic overall configuration diagram of a two-rotor type rotary piston engine 1 according to the present embodiment.
The casing of the rotary piston engine 1 comprises two rotor housings 2 each having a trochoidal inner peripheral surface 2a.
And an intermediate housing 3 arranged between the two rotor housings 2 and a side housing (not shown) arranged on the opposite side of each rotor housing 2 from the intermediate housing 3. Made of Reference numeral 4 designates a substantially triangular rotor which makes a planetary rotational movement around an eccentric shaft 5 in the casing, and 6 designates the rotor.
The apex seal is attached to the top of the rotor 4 and is in sliding contact with the inner peripheral surface 2a of the rotor housing 2. These two rotors 4 rotate with a phase difference of 180 degrees with respect to the eccentric shaft 5. Then, the rotor 4 forms three working chambers I, II, and III in the casing.
With each rotation, the intake, compression, expansion, and exhaust strokes are performed in each of the working chambers I, II, and III. An intake port 7 opens on the inner wall surface 2a of the rotor housing 2 and is opened and closed by the rotor 4 at a predetermined timing in the intake stroke.
, 8 is an air cleaner, 9 is an air flow meter, 10 is a pair of throttle valves, 11 is an intake manifold, 1
Reference numeral 2 denotes an exhaust port which opens on the inner peripheral surface 2a of the rotor housing 2.

As one of the features of this embodiment, spark plugs 13, 14, 15 are provided at three locations on the rotor housing 2.
Is provided. This spark plug 13, 14, 15
Is the minor axis D of the rotor housing 2 as shown in FIG.
With one on the leading side and two on the trailing side, the working chamber (compression chamber) II as shown in FIGS. 2 and 3 has the smallest volume. The respective spark plugs 13, 14 and 15 are set in such arrangement positions as to face the working chamber II. That is, in such a rotor position, the L plug 13 as the first ignition plug located closest to the reading side is located at the center of the working chamber II, slightly toward the reading side. The T plug 14 as the second spark plug adjacent to the ring side is located slightly in the center of the working chamber II on the trailing side, and further Fa as the third spark plug located closest to the trailing side.
The r-T plug 15 is the end ring on the trailing side of the working chamber II.
It is set so that it is located at E.

During operation of the engine 1, the fuel pressure-fed from a fuel tank (not shown) is fed to the fuel injection valve 11a provided in the intake manifold 11.
In the intake manifold 11, a mixture is formed with the intake air sucked through the air cleaner 8, and the mixture is sucked into the working chamber (suction chamber) I. And then
When the volume of the suction chamber I is reduced by the rotation of the rotor 4 into the compression chamber II and the mixture is brought to a high pressure state, the spark plugs 13, 14 and 15 are ignited in a predetermined ignition sequence described later. It is designed to burn the air-fuel mixture.

As described above, the rotary piston engine 1 has the spark plug 1 depending on the operating condition.
The ignition timings of 3, 14, and 15 are controlled. Hereinafter, this control system will be described. CU in FIG. 2 is a control unit, and is the air flow unit.
The amount of intake air detected by the meter 9, the throttle opening detected by the throttle opening sensor 16 provided in the throttle valve 10, and the boost sensor 17 provided immediately downstream of the throttle valve 10. Various detection signals such as the intake negative pressure to be generated and the engine speed detected by the crank angle sensor 18 are transmitted, and the ignition timing of each spark plug 13, 14, 15 is based on these signals. Are trying to control. Further, a knocking detection signal from a knock sensor 19 provided in the rotor housing 2 is also transmitted to the control unit CU. Further, reference numeral 22 in FIG. 2 is a late closing on-off valve.

Next, the ignition timing control operation of the spark plug by the control unit CU will be described with reference to the flow chart of FIG.
A description will be given based on the chart and the graph of FIG. Star
After that, first, in step S1, the various signals described above are read. Then, in step S2, it is determined based on the various signals read in step S1 whether the operating state of the engine 1 is the idle state or the light load state. Specifically, the throttle opening sensor 1
When the throttle opening detected by 6 is in the fully closed state, it is determined that the engine is in the idle state, and the engine speed detected by the crank angle sensor 18 is detected by the boost sensor 17. When the suction negative pressure is low, it is determined that the engine 1 is in the light load state. And this step S2
When the operating state of the engine 1 is YES in the idle state or the light load state in step S3, the process proceeds to step S3, and the ignition timings of the spark plugs 13, 14, 15 are set in the ignition advance area A of the graph of FIG. Then, the ignition timing according to the engine load is set within the region A. That is, in this ignition advance A region, the Far-T plug 15 is ignited earliest, and then the L-plug 13 and the T-plug 14 are ignited in this order to ignite the Far-T plug 15. The timing is set earlier than when the engine is operating under normal combustion stability. When the operating state of the engine 1 is NO in the idle state or the light load state in step S2, the process proceeds to step S4, and the engine 1 is operated based on the various signals read in step S1.
It is determined whether the operating state of is the throttle fully open state or the high load state. Specifically, step S2 described above.
The throttle opening sensor 1
6, crank angle sensor 18 and boost sensor 1
The determination is made based on the signal from 7. Then, in step S4, if the operating state of the engine 1 is the throttle fully open state or the high load state is YES, the process proceeds to step S5, and each spark plug 13, 1
The ignition timings of 4 and 15 are set in the ignition advance B area of the graph of FIG. 4, and the ignition timing according to the engine load is set in this B area. In other words, even in this ignition advance area B, A
Similar to the region, the Far-T plug 15 is ignited earliest, and then the L plug 13 and the T plug 14 are ignited in this order, whereby the ignition timing of the Far-T plug 15 is
Set earlier than in normal engine operating conditions with good combustion stability. Further, when the operating state of the engine 1 is NO in the throttle fully closed state or the high load state in step S4, the process proceeds to step S6, and the ignition timing of each of the spark plugs 13, 14, 15 is set to the ignition shown in the graph of FIG. The advance angle is set in the C range, and the ignition timing is set in the C range according to the engine load. That is, in this ignition advance C region, each of the spark plugs 13 and 1 is designed so that the flame can be optimally propagated in the working chamber II according to the engine load.
Set ignition timings of 4 and 15. For example, in FIG. 5, when the engine load is 4 kg / cm ² , the ignition timing of the L plug 13 is set to 15 ° CA BTDC, and the ignition timing of the T plug 14 and the Far-T plug 15 is 10 ° CA BTDC.
Set to. That is, the L plug 13 is ignited the fastest, a flame is formed around the L plug 13, and then the T plug 14 and the Far-T plug 15 are ignited. With this,
One-way flame is propagated from the leading side of the rotor rotation to the trailing side, and the flame propagation is directional to improve the isochoricity and to secure the engine output. There is. Thus, in FIG. 4, steps S2 and S4 constitute the operating state detecting means 20 in the present invention, and steps S3, S5 and S6 constitute the ignition timing setting means 21 in the present invention.

Next, the combustion operation in each of the ignition advance areas A and B for performing the operation characteristic of this embodiment will be described.

In the ignition advance A range, which is performed when the engine 1 is in the idle state or the light load state, the amount of air-fuel mixture is small, so that the propagation speed of the flame in the working chamber (combustion chamber) II is high. However, since the flame is difficult to propagate to the trailing end zone E of the working chamber II, the Far-T plug 15 is ignited before the L plug 13 and the T plug 14. As a result, the air-fuel mixture of the trailing end zone E is surely burned, and the occurrence of misfire at this portion is avoided. After that, L plug 1
Ignition is performed in the order of 3 and T plug 14, and normal flame is propagated from the leading side to the trailing side.
In addition, during the propagation of this flame, Far-
Since the T plug 15 is ignited and the ambient temperature around the trailing side end zone E is raised, the flame can be rapidly propagated toward the trailing side and the combustibility is greatly improved. . Further, since there is no unburned gas in the exhaust gas, adverse effects on the exhaust system can be prevented and the emission property can be improved.

On the other hand, in the ignition advance B range, which is performed when the engine 1 is operating in the throttle fully open state or high load state, the flame propagation speed in the working chamber (combustion chamber) II is high, and Since knocking may occur in the ring side end zone E, the Far-T plug 15 is ignited before the L plug 13 and the T plug 14 in this case as well. As a result, the air-fuel mixture in the trailing end zone E is burned before the air-fuel mixture in the other parts. After that, L plug 13, T plug 14
The ignition is performed in this order, and the normal flame is propagated from the reading side to the trailing side. Further, when the propagation of the flame reaches the trailing side end zone E, the air-fuel mixture has already been burned in this region, so that self-ignition, that is, knocking of the air-fuel mixture occurs in this portion. There is no such thing.

As described above, according to the configuration of this example,
It is possible to avoid misfire during engine idle operation and light load operation where there is a risk of misfire, and to avoid knocking during engine full throttle opening and high load operation where there is a concern of knocking. , The operation performance of the rotary lipithrone engine 1 can be significantly improved, and by igniting in order from the reading side in a region other than these operating regions, the flame propagation can be directed to an equal volume. It is possible to improve the degree.

In this example, when the engine operating condition is such that the combustion stability in the combustion chamber II deteriorates, the Far-T
Ignition timing of the plug 15 is L plug 13 and T plug 14
However, the present invention is not limited to this, and the ignition timing of the Far-T plug 15 is set at the same time as the L plug 13 as long as the ignition timing does not cause misfire or knocking. The ignition may be performed, or the ignition may be performed later than the L plug 13.

[0027]

As described above, the present invention has the following effects. First, according to the invention of claim 1, in an engine operating state in which the combustion stability in the combustion chamber deteriorates, the ignition timing of the third spark plug is set to a value lower than that in the engine operating state in which the combustion stability is good. Since it is also set early, in the engine operating state where misfire occurs in the trailing side end zone of the combustion chamber, the air-fuel mixture is actively burned in this part, and this misfire is avoided. It is possible to improve combustion efficiency, prevent adverse effects on the exhaust system, and improve emission performance. Further, in the trailing side end zone of the combustion chamber, in an engine operating state in which the air-fuel mixture self-ignites due to the influence of the pressure wave of the combustion gas from the center side of the combustion chamber, the air-fuel mixture in this portion has the above-mentioned pressure. Since the combustion is performed before the waves are transmitted, self-ignition cannot occur, knocking is prevented, engine performance can be improved, and vibration can be reduced.

According to the second aspect of the invention, in the engine operating state in which the combustion stability in the combustion chamber is not deteriorated,
Since the ignition timing of the first spark plug is set earlier than the ignition timings of the second and third spark plugs, the flame from the reading side of the rotor rotation to the trailing side is changed. Propagation can be obtained, and in combination with the operation of claim 1, improvement of the equal volume in an engine operating state where combustion is stable and improvement of combustibility in an engine operating state where combustion becomes unstable. We can work together.

According to the third aspect of the present invention, the ignition timing of the third spark plug is set to the first ignition timing in the light load operating state of the engine.
Since the ignition timings of the spark plug and the second spark plug are set earlier than the ignition timing, the occurrence of misfire in the trailing end zone of the combustion chamber is avoided and at the same time,
The ambient temperature in the trailing end zone rises, and the combustibility of the combustion chamber as a whole is improved together with the flame generated by the ignition of the first and second ignition plugs.

According to the fourth aspect of the present invention, the ignition timing of the third spark plug is set to the first ignition timing in the high load operation state of the engine.
Since the ignition timings of the spark plug and the second spark plug are set earlier than the ignition timing, the self-ignition of the air-fuel mixture is prevented and knocking is prevented in the trailing end zone of the combustion chamber. It is possible to avoid abnormal combustion.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of the present invention.

FIG. 2 is a schematic overall view of a rotary piston engine.

FIG. 3 is an enlarged view of the vicinity of a position where an ignition plug is arranged.

FIG. 4 is a flow chart for explaining the operation of the control unit.
It is a chart.

FIG. 5 is a diagram showing a relationship between engine load and ignition timing of each spark plug.

[Explanation of symbols]

1 rotary piston engine 2 rotor housing 13 L plug (first ignition plug) 14 T plug (second spark plug) 15 Far-T plug (3rd spark plug) 20 Operating state detection means 21 Ignition timing setting means II Working chamber (combustion chamber) D short axis

Claims (4)

[Claims] 1. A first spark plug is disposed on the reading side of the rotor housing in the direction of rotation of the rotor housing in the direction of rotation of the rotor, and the direction of rotation of the rotor in the direction of rotation of the rotor is shorter than that of the shaft in the direction of rotation. A second spark plug and a third spark plug are arranged on the trailing side, and the third spark plug is arranged on the trailing side in the rotor rotation direction relative to the second spark plug. An ignition device for a piston engine, wherein an operating state detecting means for detecting an operating state of the engine and an engine operating state which receives an output of the operating state detecting means and deteriorates combustion stability in a combustion chamber, Third
An ignition device for a rotary piston engine, comprising: ignition timing setting means for setting the ignition timing of the spark plug earlier than when the engine is operating with good combustion stability. 2. The rotary piston engine ignition device according to claim 1, wherein the ignition timing setting means sets the ignition timing of the first spark plug to the first ignition plug when the engine operating state in which combustion stability in the combustion chamber is not deteriorated. An ignition device for a rotary piston engine, characterized in that the ignition timing is set earlier than the ignition timings of the second spark plug and the third spark plug. 3. The rotary piston engine ignition device according to claim 1, wherein the ignition timing setting means sets the ignition timing of the third spark plug to the first spark plug and the second spark plug when the engine is in a light load operation state. It is configured so that it is set earlier than the ignition timing of the spark plug.
Ignition device for Taripiston engine. 4. The rotary piston engine ignition device according to claim 1, wherein the ignition timing setting means sets the ignition timing of the third spark plug to the first spark plug and the second spark plug when the engine is operating under a high load. It is configured so that it is set earlier than the ignition timing of the spark plug.
Ignition device for Taripiston engine.