JPH0665852B2 - Scavenging device for rotary piston engine - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a scavenging device for a rotary piston engine.

(Prior Art) Conventionally, a scavenging port is provided between an intake port and an exhaust port for a working chamber of a rotary piston engine, and the scavenging port is passed through an air pump (supercharger) for supplying pressurized air, Pressurized air is supplied to the working chamber as secondary air according to the operating region of the engine, and the exhaust gas sucked into the intake chamber side is replaced with the secondary air to substantially increase the intake charge amount. There is a scavenging device for a rotary piston engine designed to increase torque (see Japanese Patent Laid-Open No. 59-10738).

However, the air pump that supplies the pressurized air deteriorates over time, and the discharge pressure thereof gradually decreases.
As a result, the amount of secondary air supplied especially to the intake side of the engine also decreases accordingly, and the actual filling amount also changes, making it impossible to expect the same torque-up effect as when a new vehicle is used. Become. On the other hand, in spite of the above circumstances, the control of the fuel injection amount, the ignition timing, etc. is performed on the premise of the same filling amount as in the non-deterioration state, so that an appropriate air-fuel ratio,
It is conceivable that the ignition timing cannot be obtained and, as a result, an unstable combustion state is brought about and the driving performance is deteriorated.

(Object of the invention) The present invention has been made based on the above circumstances, and a pressure detecting means is provided in the above-mentioned supply passage for pressurized air, and an increase correction and ignition of secondary air are performed in accordance with the detected pressure value. An object of the present invention is to provide a scavenging device for a rotary piston engine, which solves the problems expected due to the deterioration of the air pump as described above by performing timing correction and the like.

(Means for Achieving the Purpose) In order to achieve the above object, the present invention provides a scavenging port between an intake port and an exhaust port in a working chamber, as shown in FIGS. 1 and 2, for example. In a scavenging device of a rotary piston engine, which is opened and supplies pressurized air from a supercharger that is driven in synchronization with the engine from the scavenging port, a pressure for detecting the pressure value of the pressurized air. The detection means and the correction means for correcting the combustion state control elements such as the ignition timing of the engine and the primary or secondary air supply amount according to the detection value of the detection means are provided.

(Operation) According to the above means, the change in the pressure value of the pressurized air from the supercharger is detected by the pressure detecting means, and the ignition timing, the supply amount of the primary or secondary air, etc. are detected according to the detected value. The combustion state control element of is corrected. Therefore, even if the secondary air supply pressure decreases due to aging deterioration of the supercharger, the ignition timing advances, the primary side bypass air amount increases, and the secondary side air injection valve A correction action such as an increase in the air amount due to an increase in the valve opening time is performed, a stable combustion state is maintained, and deterioration of operating performance is prevented.

(Embodiment) First, FIG. 1 shows a scavenging device for a rotary piston engine according to an embodiment of the present invention. In FIG. 1, reference numeral 1 denotes a rotary piston engine. The rotary piston engine 1 includes a rotor housing 2 having an epitrochoidal inner peripheral surface 2a and a pair of side housings for covering both side surfaces of the rotor housing 2. The rotor 3 having a substantially triangular shape is fitted in a casing made of a material such that the rotor 3 can rotate about a shaft 4 as a planet.

Spark plug fitting holes are formed in the center of one side wall on the major axis side of the rotor housing 2 so as to be appropriately separated in the rotor sliding direction, and the spark plugs have electrode portions of the spark plug fitting in the fitting holes. It is screwed into the housing.

The other side wall of the rotor housing 2 on the major axis side is appropriately separated in the rotor sliding direction (sandwiching the trochoid minor axis), for example, on the upper side of the intake port 6 on the side housing side.
An intake passage 5 that communicates with the above is provided, and an exhaust port 7 is formed on the lower side so as to communicate with the working chamber 8 in the casing. The intake passage 5 is connected to a surge tank 14 via an intake pipe 9a, and the exhaust port 7 is connected to an exhaust purification device (not shown) via an exhaust pipe.

A boost pressure sensor 10 for detecting the boost pressure P is provided immediately downstream of the surge tank 14 of the intake pipe 9a, and the surge tank 14 is further connected to an air cleaner (not shown) via the intake pipe 9b. . An air flow meter 13 for detecting the intake air amount is provided in the middle of the intake passage of the intake pipe 9b, and a surge tank 14 of the intake pipe 9b.
Throttle valves 11 are provided at the inlets, respectively.
The throttle opening θ corresponding to the movement of the throttle valve 11 is detected by the throttle opening sensor 12 and input to the control unit 20. Also, reference numeral 23
Is provided in the middle of a bypass passage that bypasses the throttle valve 11 and connects the intake pipe 9b to the intake port side of the surge tank 14, and supplies air to the surge tank 14 during idling and in a secondary air supply region described later. Amount of throttle valve
11 is a bypass air control valve for controlling independently, and its opening is determined by the duty ratio of the air amount control signal from the control unit 20.

On the other hand, reference numeral 15 indicates the intake passage 5 of the rotor housing 2.
Is a scavenging port formed at a position slightly above the trochoidal short axis portion between the exhaust port 7 and the exhaust port 7, and is in communication with the working chamber 8. The scavenging port 15 is, for example, an engine via a pressurized air supply passage 16. It is connected to an enpump (supercharger) 17 driven in synchronization with rotation. A secondary air injection valve 18 is provided in the middle of the pressurized air supply path 16, and the supply state of the pressurized air as the secondary air is controlled by the secondary air supply control signal Sc from the control unit 20. To be done. The supply of the pressurized air is performed in the engine light load and medium-low speed operation region shown in FIG. 4, and the intake air is taken in at the rotor position (working chamber extending from the exhaust stroke to the intake stroke) shown by a virtual line 3'in FIG. By replacing the exhaust gas sucked into the chamber A side with the secondary air by the pressurized air, the amount of intake air charged is substantially increased and the output torque is improved.

Reference numeral 27 is a fuel injector for fuel injection, the fuel injection amount of which is determined by a fuel injection pulse PWSo from the control unit 20 which will be described later. Reference numeral 19 is an rpm sensor for detecting the engine speed, and its detection signal Ne is input to the control unit 20. Further, reference numeral 25 is a pressure sensor provided in the pressurized air supply path 16, and the detection value PF thereof is input to the control unit 20.

Next, the control operation of the apparatus of the above embodiment will be described with reference to FIGS.
This will be described with reference to the flowchart in the figure.

First, a case where the primary side air amount is controlled according to the deterioration of the air pump 17 will be described.

First, in step S ₁ , engine speed Ne and boost pressure P
B, throttle opening θ, and intake air amount V are read. Next, the secondary air supply area shown in FIG. 4 is determined based on the input data, the solenoid ON / OFF values (pulse width and timing) of the secondary air injection valve 18 are determined, and the ON Then, the OFF value is output to the secondary air injection valve 18 (step S ₂ ).

Then, then the process proceeds to step S _3, the operating state of the vehicle to determine whether it is in all閉減speed. The determination of the fully closed deceleration state is made in the following secondary step S ₄ because the engine speed is stable and the secondary air supply pressure is relatively constant as compared with other operating states. This is done as a premise for reading the air supply pressure detection value.

Then, in step S ₃ , it is determined that the fully closed deceleration is being performed (YE
S), then in step S ₄ , the pressure value P of the secondary supply air
F is read and compared with the characteristic value of the discharge pressure deterioration line of FIG. 5 based on the value PF (step S ₅ ).
As a result, the pressure value PF is equal to or less than the value on the deterioration line (different depending on the engine speed).
In the case of YES, the process proceeds to step S ₆ and the correction amount flag FAF for increasing the air amount is set to 1 (correction required), while in the case of NO (non-deteriorated state), the process of step S ₇ is performed. Then, the correction amount flag FAF is set to 0 (correction unnecessary).

In the case of NO in step S ₃ (if not in all閉減speed), and when completing the processing operation in steps S _6, S ₇ are both proceeds to step S _8, the current operating state is the It is determined whether or not it is in the secondary air supply region determined in step S ₂ . As a result, in the case of YES, the value of the correction amount flag FAF stored in the memory is read and the value is 1
It is confirmed whether or not (correction required) (step S ₉ ). As a result, when the FAF = 1 (YES), the control valve 23 for the bypass air control to ON in step S _10, step S ₁₄ to set the step S ₁₁ the air-fuel ratio correction value CAF to A
Proceed to.

On the other hand, if it is not the secondary air supply region in step S ₈ is determined, and if it is not the FAF = 1 is determined in step S _9, the control valve for the bypass air control in step S ₁₂ 23 Is turned off, the value of the air-fuel ratio correction value CAF is set to 0 in step S ₁₃ , and then the process proceeds to step S ₁₄ .

In step S ₁₄ , the basic fuel injection pulse PWS ₀ is first calculated, and then in step S ₁₅ , the final fuel injection pulse PWS ₀ is calculated based on the value of the air-fuel ratio CAF set in steps S ₁₁ and S _{13. 0} (CAF + 1) is determined and output.

Next, FIG. 3 shows a flow chart in the case of ignition timing control in the embodiment of the present invention.

First, in step S ₁ , engine speed Ne, boost pressure PB,
Read the throttle opening θ. Next, based on those input data, the secondary air supply area shown in FIG. 3 is determined to determine the ON / OFF value (pulse width and timing) of the solenoid of the secondary air injection valve, and the ON・ OFF
The value is output to the secondary air injection valve (step S ₂ ).

Then, then the process proceeds to step S _3, the operating state of the vehicle to determine whether it is in all閉減speed.

Then, in step S ₃ , it is determined that the fully closed deceleration is being performed (YE
S), then in step S ₄ , the secondary air supply pressure value P
F is read and compared with the characteristic value of the discharge pressure deterioration line of FIG. 5 based on the value PF (step S ₅ ).
As a result, the pressure value PF is equal to or less than the value on the deterioration line (different depending on the engine speed).
In the case of S, the process proceeds to step S ₆ and the correction advance angle IGA for advancing the ignition timing is set to A, while in the case of No (non-deteriorated state), the process proceeds to step S ₇ and Set the correction advance angle IGA of 0 to.

Then, after setting the value of the coefficient K for the ignition timing correction thereon in the next step S ₈ to K = 1 (main correction), step S
First, in step ₁₄ , the basic ignition timing IGo is calculated, and then step S ₁₅
Determines the final ignition timing, IGo + K · IG, and controls the ignition timing.

On the other hand, when the present flowchart is not being total閉減speed in step S ₃ is determined, followed by an idle judgment performed (Step S _9), if the non-idle region (N
The o), it executes the control in step S _14, S ₁₅ in the data of the previous step S ₆ or S ₇ proceeds to the step S _8. On the other hand, when the idle region (YES), firstly the idle confirms whether or not immediately rush from the non-idle region in step S _10, if YES, the next step S ₁₁ , The value of timer TM for a predetermined time TMo
Set to subsequent predetermined period, i.e. T in step S ₁₂
Performs control of K = 1 in step S ₈ until the M = 0, to perform advance correction of the ignition timing. As a result, it is possible to prevent the rotation speed from decreasing at the time of idling. Then, in the above, a predetermined period has elapsed, that is, TM =
0 becomes, so the correction of the primary air amount as a control of the original idle speed is made sufficiently in step S ₁₃ K =
Proceeds to step S ₁₄ after having set to 0, the variation of the idle speed is prevented by stopping the advance correction of the ignition timing.

By the above control operation, even if the discharge pressure of the air pump itself is reduced, it is compensated by increasing the primary or secondary side air amount and advancing the ignition timing, so that the engine speed eventually becomes as shown in FIG. Therefore, the regular rotation speed will be secured.

(Effects of the Invention) As described above, the present invention opens the scavenging port between the intake port and the exhaust port in the working chamber to supply the pressurized air by the supercharger driven in synchronization with the engine. In a scavenging device for a rotary piston engine, which is configured to supply the working air from the scavenging port, pressure detection means for detecting the pressure value of the pressurized air, and engine ignition timing according to the detection value of the detection means, 1 A correction means for correcting the combustion state control element such as the secondary or secondary air supply amount is provided.

Therefore, according to the present invention, the change in the pressure value of the pressurized air from the supercharger is detected by the pressure detecting means, and the ignition timing and the combustion state with the primary or secondary air supply amount are detected according to the detected value. It is designed to correct the control element. Therefore, even if the secondary air supply pressure decreases due to the deterioration of the supercharger over time, the ignition timing advances, 1
The secondary bypass air amount is increased, and the secondary air injection valve is opened for a longer period to correct the air amount, etc., so that a stable combustion state is maintained and deterioration of operating performance is prevented. It

[Brief description of drawings]

FIG. 1 is a system diagram of a scavenging device for a rotary piston engine according to an embodiment of the present invention, FIGS. 2 and 3 are flowcharts showing a control operation of the device of the embodiment, and FIG.
FIG. 5 is a map characteristic diagram showing the secondary air supply region in the above control operation, FIG. 5 is a characteristic diagram showing the relationship between the engine speed and the secondary air supply pressure, and FIG. It is a characteristic view shown contrasting with. 1 ... Rotary piston engine 2 ... Rotor housing 3 ... Rotor 5 ... Intake passage 7 ... Exhaust port 8 ... Working chamber 10 ... Boost pressure sensor 11 ... Throttle valve 12 ... Throttle opening sensor 15 ... … Scavenging port 16 …… Pressurized air supply path 17 …… Air pump 18 …… Air control valve 19 …… rpm sensor 20 …… Control unit 23 …… Bypass air control valve 25 …… Pressure sensor

Claims (1)

[Claims] 1. A scavenging port is opened between an intake port and an exhaust port in the working chamber so that pressurized air from a supercharger driven in synchronization with the engine is supplied from the scavenging port into the working chamber. In the scavenging device for the rotary piston engine, pressure detecting means for detecting the pressure value of the pressurized air, and combustion state of engine ignition timing, primary or secondary air supply amount, etc., according to the detection value of the detecting means. A scavenging device for a rotary piston engine, which is provided with a correcting means for correcting a control element.