JPS629726B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an ignition device for a rotary piston engine.

(Prior art) In a rotary piston engine that has a rotor that rotates eccentrically within a casing that has an inner circumferential surface of a trochoid curve, it is ideal for the spark plug to be installed near the short axis of the inner circumferential surface of the trochoid. be. However, as the rotor rotates, the compressed air-fuel mixture also rotates, so the flame generated by the ignition of the spark plug advances to the forward side of the rotor.
Therefore, it has the property of being difficult to propagate to the lagging side of the rotor. Therefore, the lag side of the rotor is not completely combusted, and the exhaust gas contains a large amount of unburned components. Furthermore, due to the non-uniformity of the flame propagation, the temperature distribution of the casing becomes non-uniform,
There was a risk that the strain on the casing would become uneven and the airtightness would be compromised.

Therefore, Jikko No. 50-36104 and Jikko 50-
No. 42254, etc., solves the problem of ignition in the ignition device of the rotary piston engine by providing a plurality of spark plugs and devising their arrangement. According to the ignition system shown in the above-mentioned Jikkosho Publication, when the engine is operating in a certain predetermined condition,
It is believed that a somewhat satisfactory result can be obtained. However, engines are operated in various conditions such as high rotation and low rotation, and the ignition system disclosed in the above-mentioned Utility Model Publication has the disadvantage of not being able to follow changes in these operating conditions. It was hot.

(Objective of the Invention) Therefore, an object of the present invention is to provide an ignition device for a rotary piston engine that changes ignition conditions according to the rotational state of the engine and provides good ignition performance over the entire rotation speed range. It is something.

(Structure of the Invention) The ignition device for the rotary piston engine of the present invention includes a plurality of spark plugs provided on the leading side and one spark plug on the trailing side from the short axis of the rotor housing, and at least one spark plug on the leading side when the engine is running at low speed. The present invention is characterized in that it includes a control means for igniting all the ignition plugs, while alternately igniting the leading-side ignition plug and igniting the trailing-side ignition plug when the engine is running at high speed.

(Embodiments) Hereinafter, an ignition device for a rotary piston engine according to a preferred embodiment of the present invention will be described with reference to the accompanying drawings.

FIG. 1 is a schematic diagram of an ignition system for a rotary piston engine according to an embodiment of the present invention.

In FIG. 1, the symbol E indicates a rotary piston engine (hereinafter simply referred to as the engine), and this engine E includes a rotor housing 1 having a trochoidal inner circumferential surface 1a, and disposed on both sides of the rotor housing 1. It includes a casing 2 consisting of a side housing (not shown). A triangular rotor 3 is rotatably supported within the casing 2 by an eccentric shaft 4. The rotor 3 performs planetary rotational movement in the direction of arrow A while its apex is in sliding contact with the trochoidal inner circumferential surface 1a, thereby forming a working chamber 5 that gradually moves.

The engine E includes a first ignition device 10 on the leading side of the short axis 2a of the casing 2.
A second ignition device 40 is provided on the trailing side.

The first ignition device 10 includes a first ignition coil 11
One end of the primary coil 11a of this ignition coil 11 is grounded to the battery B via the ignition switch 1g, and the other end is grounded via the first contact breaker 12. The first ignition device 10 also includes two first and second spark plugs 13a and 13b, and these first and second spark plugs 13a and 13b are connected via contacts 14 or rotary contacts 15 to 1 is connected to the secondary coil 11b of the ignition plug 11.

The contact breaker 12 is connected to the rotor 3
The rotor 3 has a cam 12a with two peaks that rotates by half of the rotation.
During rotation, contact 12b is switched on and off three times, thus generating three high voltages for spark plugs 13a, 13b.

The contacts 14 include plugs 13a and 13b.
This is a contact that connects the ignition coil 11 and the ignition coil 11 at the same time, and is actuated by a diaphragm type first actuator 16. This actuator 16 is connected to the diaphragm 1
The diaphragm 16a has an actuating chamber 16b defined by 6a, and a contact actuating rod 16c is attached to the diaphragm 16a. An air passage 17 is connected to the working chamber 16b, and the air passage 17 is provided with a switching valve 18 for switching the air introduced into the working chamber 16b through the passage 17 between the atmosphere and intake air. It is being Note that the valve 1 for introducing intake air into the working chamber 16b will be described below.
The position of the valve 18 that introduces the atmosphere into the working chamber 16b is referred to as the second position. The actuator 16 connects the contact 14 when air is introduced into the working chamber 16b, and connects the contact 14 when air is introduced into the working chamber 16b.
I'm starting to cut off 4. Above switching valve 1
8 is adapted to be driven and controlled by a drive circuit 19, and this drive circuit 19 includes a comparator 20.
is connected. One input terminal of this comparator 20 has a rotation speed sensor 21 that detects the engine rotation speed and outputs a rotation speed signal S1 indicating this rotation speed.
is connected to the other input terminal, and a power source 22 that generates a reference voltage Vr ₂ indicating the r ₂ rotation speed shown in FIG. 2 is connected to the other input terminal. The comparator 20 causes the drive circuit 19 to set the switching valve 18 to the first position when the rotation speed signal S1 is smaller than the reference voltage _Vr2 , and on the other hand, when the rotation speed signal S1 is lower than the reference voltage Vr2.
When the valve 18 is larger than the drive circuit 1, the valve 18 is
9 and set it to the second position.

The rotary contact 15 has a disk 15a that rotates in synchronization with the rotation of the contact breaker 12, and one contact 15b connected to the secondary coil 11b of the ignition coil 11 is provided on the outer periphery of the disk 15a. It is equipped with This contact point 15b alternately contacts the lead wires of the spark plugs 13a and 13b to alternately ignite the spark plugs 13a.

On the other hand, the second ignition device 40 has a second ignition coil 41. One end of the primary coil 41a of this ignition coil 41 is connected to the battery B via the ignition switch lg, and the other end is connected to the second ignition coil 41. It is grounded via a contact breaker 42. Second
The ignition device 40 also includes one third spark plug 43, which is connected to the secondary coil 41b of the second ignition coil 41 via a contact 44.

The contact breaker 42 is connected to the rotor 3
The rotor 3 has a cam 42a with two peaks that rotates by half of the rotation.
During rotation, contact 42b is turned on and off three times, thus generating high voltage for sparking spark plug 43 three times.

A contact 44 is provided between the ignition coil 41 and the ignition lg to connect and disconnect the ignition coil 41 and the ignition lg. This contact 44 is actuated by a second actuator 45 of diaphragm type. The actuator 45 has an operating chamber 45b defined by a diaphragm 45a, and a contact operating rod 45c is attached to the diaphragm 45a. An air passage 46 is connected to the working chamber 45b, and the air passage 46 is provided with a switching valve 47 for switching the air introduced into the working chamber 45b through the passage 46 between the atmosphere and intake air. It is provided. In addition, below, the position of the valve 47 that introduces intake air into the working chamber 45 is the first position, and the valve 4 that introduces the atmosphere into the working chamber 45b is the first position.
The position No. 7 is referred to as the second position.

The actuator 45 has the working chamber 45b.
The contact 44 is connected when air is introduced into the air, and the contact 44 is disconnected when air is introduced into the air. The switching valve 47 is driven and controlled by a drive circuit 48, and an AND circuit 49 is connected to the drive circuit 48. This AND circuit 49-2
Comparators 50 and 51 are connected to the two input terminals, respectively. At one input terminal of the comparator 50,
The rotation speed sensor 21 is connected to the other input terminal, and a power source 52 that generates a reference voltage Vr ₁ indicating the r ₁ rotation speed is connected to the other input terminal. The comparator 50
is adapted to output a signal S2 when the rotational speed signal S1 is smaller than the reference voltage _Vr1 . On the other hand, at one input terminal of the comparator 51,
A load sensor 53 is connected to detect the engine load and output a load signal S3 indicating the magnitude of this load, and the other input terminal is connected to the l
A power supply 54 is connected which generates a reference voltage Ve representing the load. The comparator 51 outputs a signal S when the load signal S3 is larger than the reference voltage Ve.
It is designed to output 4.

The AND circuit 49 outputs the signals S2 and S.
4, the drive circuit 48 sets the switching valve 47 to the first position, and at other times, the drive circuit 48 sets the switching valve 47 to the second position.
It is now set to the position.

In addition, the above-mentioned spark plugs 43, 13a, 13
b can be arranged as shown in Figures 1a, 1b, 1c, 1d and 1e. In these figures, P indicates a cooling water passage for cooling the plug on the leading side.

(Effects of the Invention) Hereinafter, the effects of the ignition device with the above configuration will be explained with reference to FIG.
This will be explained while explaining the ignition state of 13b.

First, the ignition state in the low rotation high load zone shown in FIG. 2 will be explained. In this low rotation high load zone, as shown in the zone in FIG. Cut the two spark plugs 1 on the leading side.
Both 3a and 13b are ignited at the same time. By igniting only the leading side spark plug in this way, as shown by the chain line in Figure 4, the output torque obtained when both the trailing side and leading side spark plugs, shown by the solid line, are ignited. Larger output torque can be obtained.

Next, to explain the ignition state in the medium speed rotation light, medium load zone shown in FIG. 2, in this medium speed rotation light, medium load zone, as shown in the zone of FIG. Plug 43,
13a and 13b are all ignited at the same time. By igniting all the spark plugs in this way, the fuel consumption rate as shown by the solid line is lower than the fuel consumption rate when only the leading side spark plugs 13a and 13b are ignited, which is shown by the chain line in FIG. Consumption rate improves. This is considered to be because the combustion speed becomes faster by igniting all the spark plugs. Furthermore, the reason why both of the two leading-side spark plugs are ignited is to ensure that even if one misfires, the other spark plug can be reliably ignited.

Finally, to explain the high speed rotation zone shown in Fig. 2, in this high speed rotation zone, as shown in the zone of Fig. 3,
The ignition plug 43 on the trailing side is ignited in a normal state, while the two ignition plugs 13a and 13b on the leading side are ignited alternately. When ignited in this way, the fuel consumption rate improves as in the case of the above zone.
Also, if both leading-side spark plugs are ignited during such high-speed rotation, the wall temperature around the plugs may rise excessively, causing damage to the plugs and cracks in the rotor housing. By alternating ignition as in the invention, it is possible to prevent the wall temperature around the plug from rising.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of an ignition system for a rotary piston engine according to an embodiment of the present invention;
Figures b, 1c, 1d, and 1e each show an example of the arrangement of three spark plugs, Figure 2 is a diagram showing the ignition combination of three spark plugs according to the present invention, and Figure 3 is a diagram showing an example of the arrangement of three spark plugs. FIGS. 4 and 5 are diagrams showing the ignition states of three spark plugs according to the present invention.
FIG. 2 is a diagram showing output torque--engine rotation speed characteristics and a diagram showing fuel consumption rate--output torque for explaining the effects of the ignition device of the present invention. E...Rotary piston engine, 11,41
...Ignition coil, 14,44...Contact, 1
6, 45... Actuator, 15... Rotary contact, 21... Rotation speed sensor.

Claims (1)

[Claims] 1 A plurality of spark plugs are provided on the leading side and one on the trailing side from the short axis of the rotor housing, and when the engine is running at low speeds, at least all the spark plugs on the leading side are ignited, while when the engine is at high speeds, the leading side is ignited. An ignition device for a rotary piston engine, comprising control means for alternately igniting side spark plugs and igniting a trailing side spark plug.