JPH065031B2 - 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 this exhaust port is communicated with 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).

When the intake air amount is increased as described above, the fuel injection amount must be controlled so as to be correspondingly increased.

However, in general, the control of the fuel injection amount employs a control system that determines the fuel increase rate based on the intake air amount measured by an air flow meter in the middle of the intake passage. Pressurized air supplied independently does not become a calculation element at all, and therefore an optimum fuel injection amount corresponding to the actual intake amount cannot be obtained. Further, since the air pump for supplying the compressed air is generally driven by the engine output, the supply amount of the compressed air also varies depending on the engine speed (third part).
See figure). Therefore, if the fuel injection amount is simply controlled on the basis of the measured value of the air flow meter as in the conventional case, the tendency of over leaning is inevitable and the optimum air-fuel ratio cannot be controlled.

(Object of the Invention) The present invention has been made to solve the above problems, and predicts a supply amount of pressurized air to perform an increase correction of a fuel amount in accordance with an intake amount, and to increase the increase correction value. It is another object of the present invention to provide a scavenging device for a rotary piston engine, which is capable of obtaining an optimum air-fuel ratio by making a correction in accordance with the engine speed.

(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 in which pressurized air from a supercharger that is opened and driven in synchronization with the engine is supplied from the scavenging port into the working chamber, pressurization brought into the working chamber from the scavenging port Fuel increase correction means for predicting the air amount and increasing and correcting the fuel supply amount according to the intake air amount sucked from the intake port, and rotation for correcting the increase correction amount by the fuel increase correction means in accordance with the engine speed. And a number correction means.

(Operation) According to the above means, the amount of pressurized air supplied from the scavenging port to the working chamber is first predicted to correct the increase in the supplied fuel amount, and the increase correction value corresponds to the engine speed. Will be corrected.

Therefore, the fuel injection amount that is finally determined can be an optimum amount that is determined by the total intake amount including the supply amount of the pressurized air that is not measured by the air flow meter according to the engine speed. The air-fuel ratio can also be controlled appropriately.

(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 central portion 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 and the electrode portions thereof are respectively provided in the fitting holes. It is screwed into the rotor housing.

In addition, an intake port 5 is formed in the side wall of the rotor housing 2 on the other side of the major axis at an appropriate distance in the rotor sliding direction (with the minor axis of the trochoid interposed), and an intake passage 5 is formed in the side housing on the upper side. The exhaust port 7 is formed on the lower side so as to communicate with the working chamber 8 in the casing. Then, the intake passage 5
Is connected to the surge tank 14 via an intake pipe 9a, while the exhaust port 7 is connected to an exhaust purification device (not shown) via an exhaust pipe.

Immediately after the surge tank 14 downstream of the intake pipe 9a,
A boost pressure sensor 10 for detecting the boost pressure P is provided, and the surge tank 14 is further connected to an air cleaner (not shown) via an intake pipe 9b. An air flow meter 13 for detecting the amount of intake air is provided in the intake passage of the intake pipe 9b, and a throttle valve 11 is provided at the inlet of the surge tank 14 of the intake pipe 9b. The latter throttle valve 11 is provided with a throttle full open switch that is turned on when the throttle is fully opened corresponding to a high load region, and generates a throttle full open signal S ₁ when the switch is turned on. The throttle opening θ according to the movement of the throttle valve 11 is detected by the throttle opening sensor 12 and input to the control unit 20. Reference numeral 23 is the throttle valve 11
Is provided in the middle of a bypass passage that connects the intake pipe 9b and the intake port side of the surge tank 14 by bypassing the electromagnetic valve for controlling the amount of air supplied to the surge tank 14 at the time of idling independently of the throttle valve 11. It is a valve, and its opening is determined by the duty ratio of the control signal from the control unit 20.

On the other hand, reference numeral 15 is a scavenging port which is formed at a position slightly above the trochoid short shaft portion between the intake passage 5 and the exhaust port 7 of the rotor housing 2 and which is in open communication with the working chamber 8. The scavenging port 15 is connected via a pressurized air supply passage 16 to an air pump (supercharger) 17 driven in synchronization with engine rotation. An air control valve 18 is provided in the middle of the pressurized air supply path 16, and the secondary air supply control signal Sc from the control unit 20 controls the supply state of the pressurized air as the secondary air. . The supply of this pressurized air is
Exhaust that is performed at least in the high-load and medium-low speed operation region of the engine and is sucked into the intake chamber A side at the rotor position (the working chamber located at the position extending from the exhaust process to the intake process) indicated by imaginary line 3'in FIG. By replacing the gas with the secondary air by the pressurized air, the amount of intake air charged is substantially increased and the output torque is improved.

Further, reference numeral 24 is a fuel injector for fuel injection, the fuel injection amount of which is the control unit 20.
Is determined by a calculation signal F described later. Reference numeral 19 is an rpm sensor for detecting the engine speed, and the detection signal N is input to the control unit 20.

Next, the control operation of the apparatus of the above embodiment will be described with reference to the flowchart of FIG.

First, in step S ₁ , the engine speed N, the intake air amount Qa, and the throttle fully open signal S ₁ are input. Next, the processing proceeds to step S _2, i.e. whether full throttle switch is ON from the full throttle signal S _1, performs the determination whether the high load region. As a result YES
In the case of (high load) further proceeds to the next step S _3, the step S ₁ the predetermined rotational speed N ₀ of the engine speed N which is input corresponding to the medium or low speed region in (3000～4000R
pm) It is judged whether it is below.

As a result, in the case of YES, that in the case of high load and low and middle speed operating range, the first secondary air supply (ON the air control valve 18) in step S _4, then Figure 3 at step S ₅ and the From the characteristics shown in FIG. 4, the secondary air amount at the engine speed in the medium to low speed region is predicted, and the fuel increase rate K is calculated according to the increase in the intake amount.

Then, the calculation of F = Qa / N · K a further fuel injection amount F = Qa · K by the increment rate K proceeds to step S ₈ in order to correspond to the engine speed N. Then, in step S ₉ , fuel is finally injected in an amount of F = Qa / N · K. As a result of the control operation, the fuel injection amount F as the final output is finally set to an optimum value by correcting the increase in the intake air amount due to the supply of secondary air in accordance with the engine speed N, as shown in FIG. You can

On the other hand, in step S ₂ above, the throttle fully open switch is turned off.
In the low load region of the FF and in the high speed region where the engine speed N is higher than the predetermined value N _{0 in} step S ₃ ,
Since it is not in the secondary air supply region, the secondary air cut operation is performed in step S ₆ , while the fuel increase rate K is set to 1 (correction value 0) (step S ₇ ) and the process proceeds to steps S ₈ and S ₉ . To do. Therefore, in this case, fuel injection is performed at F = Qa / N.

In the characteristic shown in FIG. 4, the secondary air supply amount decreases (and thus the correction amount decreases) on the high rotation side of the secondary air supply range in the above region because the exhaust pressure rises on the engine side. As a result, it becomes difficult for secondary air to enter.

(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 adapted to supply from the scavenging port into the working chamber, the amount of pressurized air introduced into the working chamber from the scavenging port is predicted, and the fuel corresponding to the intake amount sucked from the intake port is predicted. It is provided with fuel increase correction means for increasing and correcting the supply amount, and rotation speed correction means for correcting the increase correction amount by the fuel increase correction means in accordance with the engine speed.

Therefore, according to the present invention, first, the amount of pressurized air supplied from the scavenging port to the working chamber is predicted to correct the increase in the supplied fuel amount, and the increase correction value is further corrected corresponding to the engine speed. To be done.

Therefore, the fuel injection amount that is finally determined can be an optimum amount that is determined by the total intake amount including the supply amount of the pressurized air that is not measured by the air flow meter according to the engine speed. The air-fuel ratio will also be controlled appropriately.

[Brief description of drawings]

FIG. 1 is a control system diagram of a scavenging device for a rotary piston engine according to an embodiment of the present invention, FIG. 2 is a flow chart showing a control operation of the device of the embodiment, and FIG. 3 is an engine rotation in the control operation. 4 is a characteristic graph showing the relationship between the engine speed and the secondary air supply amount, and FIG. 4 is a characteristic graph showing the relationship between the engine speed and the air pump discharge pressure. 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 13 ... ... Air flow meter 15 ... Scavenging port 16 ... Pressurized air supply path 17 ... Air pump 18 ... Air control valve 19 ... rpm sensor 20 ... Control unit A ... Intake chamber

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. A scavenging device for a rotary piston engine, the fuel amount increase correction for predicting the amount of pressurized air brought into the working chamber from the scavenging port and correcting the fuel supply amount in accordance with the amount of intake air taken in from the intake port A scavenging device for a rotary piston engine, characterized by comprising: means and a rotation speed correction means for correcting an increase correction amount by the fuel increase correction means according to an engine speed.