JPH05202761A - Ignition device for rotary engine - Google Patents

Abstract

PURPOSE:To improve exhaust gas cleaning performance while maintaining the reliability of an engine with combustion stability properly. CONSTITUTION:This is an ignition device of the rotary engine, in which ignition plugs are arranged to the trailing side and leading side in the rotation direction of the rotor of a rotor housing 1. On either trailing side or leading side, a plurality of ignition plugs 11-14 in the cross direction of the rotor housing 1 are provided. In addition, a cold detecting means, which detects the cold state of an engine, is provided, and while the engine is cooled, only the ignition plugs on the side, to which a plurality of ignition plugs 11-14 are provided in the cross direction of the rotor housing, are ignited.

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 engine.

[0002]

2. Description of the Related Art Conventionally, in rotary engines,
From the viewpoint of ensuring sufficient ignition energy and maintaining combustion stability, as shown in FIG. 3, one ignition plug 51, 52 is provided for each of the trailing side and the leading side of the rotor housing 50 in the rotor rotation direction. A technique is known in which the two ignition plugs 51 and 52 are used for simultaneous ignition (for example, Japanese Patent Laid-Open No. 63-1813).
(See Japanese Patent Publication No. 7).

[0003]

However, in a conventional rotary engine having spark plugs on both the trailing side and the leading side, this type of ignition is always used regardless of the engine warm-up state. Since the ignition is performed by the plug, there is a problem that the exhaust purification performance is deteriorated as described below, especially when the engine is cold.

That is, generally, in a rotary engine, an unburned component such as HC in exhaust gas is removed by a catalyst provided in the exhaust passage, and this uncatalyzed component is removed by this catalyst. Performance, that is, exhaust purification performance, is greatly influenced by the activity of the catalyst, and the activity of the catalyst is proportional to the catalyst temperature. Therefore, when the engine is cold, how quickly the catalyst temperature is raised to the required activation temperature after the engine is started is important in terms of exhaust purification performance. This results in how to flow the high temperature combustion gas to the exhaust passage side while maintaining the high temperature.

However, in the conventional rotary engine, as described above, the trailing-side spark plug 51 and the leading-side spark plug 52 are simultaneously operated to ignite regardless of the engine temperature. .. Therefore, since the flame is propagated from both the trailing side and the leading side, the combustion speed is high, and therefore, the decrease in the gas temperature during the period during which this combustion gas is discharged to the exhaust passage side in the exhaust stroke is large, As a result, the activation of the catalyst due to the exhaust gas temperature becomes slower, and as a result, the exhaust purification performance when the engine is cold deteriorates.

On the other hand, as a means for suppressing such a decrease in exhaust gas temperature, for example, the ignition timing itself is delayed when the engine is cold, or the leading side of the two spark plugs 51, 52 on the trailing side and the leading side. It is conceivable that by igniting only with the spark plug 52, a so-called post-combustion phenomenon that brings the combustion state to the exhaust stroke side is generated, and thus the exhaust gas temperature is supplied to the catalyst side while being kept higher.

However, in the former case, the retard of the ignition timing has a certain limit from the viewpoint of the rotational stability of the engine, and it is difficult to obtain a sufficient effect only by this. In the latter case, when the ignition plug 52 on the leading side is used to ignite when cold, there is no problem as long as the ignition plug 52 on the leading side ignites reliably, but single ignition is performed. Therefore, since the ignition energy is less than in the case of double ignition, combustion stability is poor and there is concern that misfire may occur, and there is no way to compensate for such misfire. The engine will soon be stalled, and the reliability in operating the engine will be impaired.

Therefore, the present invention has been made as an attempt to provide an ignition device for a rotary engine, which can improve exhaust purification performance while maintaining good combustion stability and engine reliability. is there.

[0009]

According to the invention of claim 1, as a concrete means for solving such a problem in the present invention, in the invention of claim 1, spark plugs are respectively provided on the trailing side and the leading side in the rotor rotation direction of the rotor housing. An ignition device for a rotary engine in which at least one of the trailing side and the leading side is provided with a plurality of spark plugs in the width direction of the rotor housing and detects a cold state of the engine. It is characterized in that cold detection means is provided and only the respective spark plugs on the side provided with a plurality of spark plugs are ignited in the rotor housing width direction when the engine is cold.

According to a second aspect of the present invention, in the ignition device for a rotary engine according to the first aspect, a plurality of ignition plugs are provided on the leading side of the rotor housing in the width direction of the rotor housing, and the ignition plug is provided when the engine is cold. The feature is that only each spark plug on the leading side is ignited.

[0011]

With each of the inventions of the present application, the following effects can be obtained by adopting such a configuration.

According to the first aspect of the present invention, when the engine is cold, only one of the trailing side and leading side spark plugs having a plurality of spark plugs in the width direction of the rotor housing is ignited. Therefore, flame propagation occurs only from one side of the trailing side or the leading side.For example, the combustion speed becomes slow compared to the case where the flame propagates from both the trailing side and the leading side. The temperature of the exhaust gas (combustion gas) brought into the exhaust passage side is maintained at a high temperature, and the activation of the catalyst by the exhaust gas is promoted.

On the other hand, when ignition is performed only by the spark plug on either the trailing side or the leading side, a plurality of spark plugs are arranged in the width direction of the rotor housing, so that sufficient ignition energy is secured. As a result, combustion stability is improved and misfiring rarely occurs, and even if one of the multiple spark plugs is misfired, it will be ignited by the other spark plugs, so it is certain that an engine stall will occur due to a complete misfire. It is something that can be avoided.

According to the second aspect of the invention, in addition to the above-described operation, a plurality of spark plugs are arranged on the leading side in the width direction of the rotor housing, and only the leading side spark plug is ignited when the engine is cold. Since it is made possible (in other words, it is made to ignite at a position closer to the exhaust port), higher temperature exhaust gas can be introduced to the catalyst side, and that much activation of the catalyst Is further promoted.

[0015]

Therefore, according to the rotary engine ignition device of each invention of the present application, the following effects are obtained.

(A) According to the rotary engine ignition device of the first aspect, when the engine is cold, ignition is performed only on the trailing side or the leading side on which a plurality of spark plugs are arranged in the width direction of the rotor housing. By delaying the combustion speed and promoting afterburning and activating the catalyst early by the exhaust gas of even higher temperature, the exhaust gas purification performance during cold conditions is further improved and By arranging multiple spark plugs on the fire side for the inter-time point to secure ignition energy and prevent complete misfire, the occurrence of engine stall is prevented as much as possible,
The effect that the reliability in engine operation is improved to that extent is obtained.

(B) According to the rotary engine ignition device of the second aspect, a plurality of spark plugs provided in the width direction of the rotor housing are set on the leading side to introduce hotter exhaust gas to the catalyst side. Since the activation is further promoted, it is possible to achieve an even higher exhaust purification performance than in the case described in (a) above.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A rotary engine ignition device of the present invention will be described below in detail with reference to the embodiments shown in the accompanying drawings. FIG. 1A shows a rotor housing 1 of an automotive rotary engine to which the inventions of the present application are applied. It is shown. On the side wall 1a of the rotor housing 1 on the minor axis side farther from the exhaust port 2, two trailing sides and a leading side in the rotor rotation direction (arrow R direction) are provided with a predetermined interval in the rotor housing width direction. Spark plug 1
1, 12 and 13, 14 are arranged.

The two spark plugs 11 and 12 on the trailing side and the two spark plugs 13 and 14 on the leading side are respectively connected to the first ignition coil 21 to the fourth ignition coil 24 as shown in FIG. 1B. While being connected, the first ignition coil 21 and the second ignition coil 22, and the third ignition coil 23 and the fourth ignition coil 24 are simultaneously operated by the same control signal output from the control unit 10, respectively. Thus, two different ignition modes corresponding to the operating state of the engine are adopted. That is, the two spark plugs 13, 1 on the leading side
No. 4 always ignites the engine regardless of the operating state of the engine, while two ignition plugs 1 on the trailing side are provided.
Nos. 1 and 12 do not ignite in the no-load operation region where exhaust gas purification is most required, and when the engine is cold where quick activation of the catalyst is required, and only in other operation regions. It operates so that two ignition modes of four ignitions by all the ignition plugs 11 to 14 and two ignitions by only the two ignition plugs 13 and 14 on the leading side are selected.

The specific control of each of the spark plugs 11 to 14 will be described with reference to the flowchart of FIG. 2. After the control is started, first, the engine speed signal from the engine speed sensor 31 and the boost Boost signal from sensor 32
(Load signal) and the water temperature signal from the engine water temperature sensor 33 are read (step S1), and the current operating region is determined based on these state signals (step S
2).

If the engine water temperature is equal to or higher than the predetermined value even in the no-load operation region or in the load operation region (step S3), normal ignition by four ignition is executed (step S6). .. This is because when the engine is operating under load, the combustibility is good, the amount of unburned components such as HC emitted is small, and the engine temperature is high even in the no-load operating region where the amount of unburned components generated is large. This is because when the catalyst temperature is high, the catalyst temperature has already reached a predetermined activation temperature and a good exhaust gas purification action has been executed, and therefore in any case, there is no requirement for early activation of the catalyst.

On the other hand, in the no-load operation region and when the engine water temperature is lower than the predetermined value, the catalyst has not reached the predetermined activation temperature and the amount of unburned component itself is large. Since it is a region, it is necessary to raise the catalyst to a predetermined activation temperature more quickly. Therefore,
In this case, each spark plug 11, 1 on the trailing side
The output of the ignition signal to 2 is stopped and ignition is performed only by the respective spark plugs 11 and 12 on the leading side (step S4), and the ignition timing is retarded by a predetermined amount (step S5).

In this way, when ignition is performed only by the two spark plugs 13 and 14 arranged side by side in the width direction of the rotor housing 1 on the leading side, as will be described below, while maintaining combustion stability, The catalyst can be activated early to improve the exhaust gas purification performance. That is, by igniting only with the two spark plugs 13 and 14 on the leading side close to the exhaust port 2, for example, compared to the case of igniting with both spark plugs on the trailing side and the leading side, the propagation of flame is increased. Since the distance becomes longer, the burning speed slows down and the afterburning state occurs,
Due to the synergistic effect, higher temperature combustion gas is introduced to the exhaust port 2 side, and the time until the combustion gas itself reaches the exhaust port 2 is shortened and the temperature drop is small during that time. , The temperature of the exhaust gas in contact with the catalyst becomes higher, and it becomes possible to increase the temperature of the catalyst to a predetermined activation temperature more quickly to perform a predetermined exhaust gas purification action, and as a result, even in the cold state. It is possible to achieve a higher level of exhaust purification performance.

On the other hand, since the ignition is performed by the two spark plugs 13 and 14 on the leading side, compared with the case of igniting with only one leading spark plug provided conventionally, the spark plug A large number of ignition energy is secured and combustion stability is improved accordingly, and even if one ignition plug is misfired, ignition can be performed by the other ignition plug, so a situation of complete misfire is unlikely to occur. Therefore, highly reliable driving characteristics without engine stall are secured.

In this embodiment, as described above, the ignition is performed only by the leading-side spark plugs 13 and 14 in the no-load operation region and when the engine is cold.
Since the afterburning phenomenon is promoted by retarding the ignition timing itself, it is possible to secure an even higher level of exhaust gas purification performance.

[Brief description of drawings]

FIG. 1A is a perspective view of a rotor housing portion of a rotary engine including an ignition device according to an embodiment of the present invention.

FIG. 1B is a control system diagram of the ignition device shown in FIG. 1A.

FIG. 2 is a control flowchart of the ignition device shown in FIG. 1A.

FIG. 3 is a perspective view of a rotor housing portion of a rotary engine equipped with an ignition device having a conventional structure.

[Explanation of symbols]

1 is a rotor housing, 2 is an exhaust port, 10 is a control unit, 11 and 12 are trailing spark plugs, 13 and 14 are leading spark plugs,
Reference numerals 21 and 22 are trailing side ignition coils, and 23 and 24 are leading side ignition coils.

Claims (2)

[Claims] 1. An ignition device for a rotary engine, wherein ignition plugs are respectively arranged on a trailing side and a leading side in a rotor rotation direction of a rotor housing, the ignition device being provided on at least one of the trailing side and the leading side. Is provided with a plurality of spark plugs in the width direction of the rotor housing and cold detection means for detecting the cold state of the engine. An ignition device for a rotary engine, characterized in that only each spark plug is ignited. 2. A plurality of ignition plugs are provided on a leading side of the rotor housing in a width direction of the rotor housing, and only the respective ignition plugs on the leading side are ignited when the engine is cold. An ignition device for a rotary engine, which is characterized in that: