JPH03213623A - Control device of engine - Google Patents

Abstract

PURPOSE:To control the output of an engine adequately by converting the engine output control amount of the air-fuel ratio, the ignition timing, and the like, responding to the operational condition of an air pump, in an engine in which the secondary air is fed to a combustion chamber from near an exhaust port by driving the air pump. CONSTITUTION:In the operation of a rotary piston engine 1, in a control unit 45 to which output signals of a suction air amount sensor 46, a rotation sensor 47, a throttle opening sensor 48, and the like, are input, the control area of the operating condition is decided, and an air pump 25 is controlled responding to the resultant decision. That is, the air pump 25 is driven in a light load operation area including the idling operation and in a middle load operation area. A change-over valve 26 is provided at the lower stream side of the air pump 25, and a port air passage 27 and a split air passage 28 are connected to the change-over valve 26. And the engine output control amount is controlled responding to the operating condition of the air pump 25. When the drive of the air pump 25 is stopped in a high load zone, for example, a reducing correction is carried out to correct to reduce the light load increasing amount.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an engine control device that supplies secondary air near an exhaust port to reduce dilution gas.

(Prior art) Conventionally, for example, in a rotary piston engine,
A displacement port is opened on the rotor sliding surface between the exhaust port and the intake port, and secondary air pressurized by an air pump is supplied from the displacement port to the working chamber transitioning from the exhaust stroke to the intake stroke, Exhaust gas, or dilution gas, brought into the intake stroke working chamber is replaced by secondary air supply, reducing the amount of dilution gas brought in and improving engine rotation by improving combustibility at idle and in light load regions. Techniques aimed at stabilizing fuel efficiency and improving fuel efficiency are well known, as seen, for example, in Japanese Patent Application Laid-open No. 73128/1983.

In addition to supplying secondary air from the displacement port that opens directly into the combustion chamber as described above, it is also supplied near the exhaust port and the displacement air is supplied to the combustion chamber through this exhaust port. It is also possible to do so.

(Problem 8 to be solved by the invention) However, when the pressurized air from the air pump is supplied as secondary air from the vicinity of the exhaust port as described above, for example, if the air pump is driven by the engine output, As the engine speed increases, the air pump speed also increases, and if such a high speed condition continues for a long time, the durability of the air pump will deteriorate and its reliability will decrease. Although it is preferable to control the air pump so that the air pump is temporarily stopped, there is a problem in that the output characteristics change significantly when the air pump stops operating in the area where secondary air is supplied.

In other words, the secondary air supplied from the vicinity of the exhaust port is replaced with dilution gas and taken in as fresh air in the next intake stroke, improving combustion performance by reducing dilution gas. In addition to this, the charging efficiency will increase and the output characteristics will increase significantly, but if the drive of the air pump is stopped, the supply of secondary air will decrease and the dilution gas will increase, resulting in a decrease in combustibility. As the air pressure decreases, the amount of fresh air also decreases, resulting in a decrease in output characteristics.

SUMMARY OF THE INVENTION In view of the above circumstances, it is an object of the present invention to provide an engine control device that ensures the reliability of an air pump and performs control corresponding to the supply of secondary air.

(Means for Solving the Problems) In order to achieve the above object, the control device of the present invention drives the air pump to supply secondary air to the combustion chamber from the vicinity of the exhaust port. A pump drive means is provided for controlling the air pump according to the operating state of the air pump, and an output control means is provided for changing engine output control amounts such as the air-fuel ratio and ignition timing in accordance with the operating state of the air pump.

(Function) The engine control device as described above drives the air pump in the secondary air supply region depending on the operating condition to supply pressurized air from the vicinity of the exhaust port to the combustion chamber to supply dilution gas. While obtaining the effect of improving flammability through substitution,
In this state, the amount of fuel supplied corresponding to the increase in the amount of fresh air charged,
While the output control amount such as ignition timing is adjusted by the output control means to obtain the optimum output control amount, the drive of the air pump is stopped by the pump drive means even in the secondary air supply region due to an increase in the air pump rotation speed. Then, in response to the increase in dilution gas and the reduction in the amount of fresh air charged, the output control means adjusts the fuel supply amount, ignition timing, etc. to appropriate values corresponding to the state where secondary air is not supplied. , to ensure good operating conditions.

(Example) The present invention will be described in detail below with reference to the drawings.

FIG. 1 is an overall configuration diagram of a specific example of a rotary piston engine.

The rotary piston engine 1 consists of a rotary piston engine 1, a rotary piston engine, and a rotary piston engine.
A rotor 6 is supported on an eccentric shaft 5 in a casing 2 constituted by a side housing 4, and the top of the rotor 6 slides on the inner peripheral surface of the trochoid to form three working chambers 7 (combustion chambers). Each working chamber 7 sequentially performs intake, compression, explosion,
Each exhaust stroke is repeated.

An intake port 8 is opened in the side housing 4, and an exhaust port 11 is opened in the rotor housing 3.The intake port 8 has an intake passage 9, and the exhaust port 11 has an exhaust passage 12.
is connected. An injector 20 is disposed near the intake port 8, while an intake air flow sensor and a throttle valve (not shown) are interposed in the upstream intake passage 9, which communicates with the air cleaner 18. Further, the exhaust passage 12 is provided with front and rear catalyst devices 22 and 23 for purifying exhaust gas.

A port insert 19 is attached to the exhaust port 11, and a port air supply port 21 is formed in the port insert 19 to open from the circumferential surface of the insert to the inner circumferential surface of the rotor to supply secondary air. It is configured to supply secondary air to the working chamber 7.

Further, a secondary air passage 15 is provided branching from the air cleaner 18, and this secondary air passage 15 is connected to the air pump 2.
5, a switching valve 26 is interposed on the downstream side thereof, and a port air passage 27 and a split air passage 2 are connected to this switching valve 26.
8 is connected and the supply of secondary air is switched.

The downstream end of the port air passage 27 is introduced into the rotor housing 3 via a check valve 29 and communicates with a port air supply port 21 that opens on the rotor sliding surface near the exhaust port 11, and is connected to the port air supply port 21 from the exhaust stroke to the intake stroke. Port air is supplied to replace the moving exhaust gas in the working chamber 7 with pressurized air. On the other hand, the downstream end of the split air passage 28 is connected via a check valve 30 to the split air supply nozzle 24 in the middle of the rear catalyst device 23.

The switching valve 26 is operated by a diaphragm actuator 26a, and a switching solenoid valve 33 is interposed in a negative pressure introduction passage 32 that introduces intake negative pressure (boost) as an operation source to control the switching operation of the passage. .

The air pump 25 of the secondary air passage 15 is operated by an electromagnetic clutch 4 which is controlled on and off by a control unit 45.
The air pump 25 is rotatably driven by the engine output via the air pump 2, and includes a pump driving means 43 that controls the driving of the air pump 25 according to the operating state. Further, the operation of the switching solenoid valve 33 that operates the switching valve 26 of the secondary air passage 15 is controlled by outputting a control signal from the control unit 45. Further, the engine output is adjusted by controlling the fuel injection amount from the injector 20, and the control unit 45 controls the operation of the pump driving means 43 and the switching valve 26.
An output control means 44 is configured to change the engine output control amount by adjusting the amount of fuel injected from the injector 20 in accordance with the operating state.

In order to detect the operating state of the engine, the control unit 45 receives an intake air amount signal from an intake air amount sensor 46, an engine rotation signal from a rotation sensor 47, a throttle opening signal from a throttle opening sensor 48, and a water temperature sensor. Signals such as a water temperature signal from 49 and a catalyst temperature signal from catalyst temperature sensor 50 are input.

And the control unit 45i;! , based on the control area of the operating state shown in FIG.
By controlling the operation of the switching valve 26, supply of secondary air and switching between port air and split air are performed.
The fuel injection amount is corrected and controlled in response to changes in the port air amount. That is, the air pump 2 by the pump driving means 43
The drive in step 5 is performed in the low rotation zone I including idling, the medium rotation medium load zone ■, the medium rotation light load zone ■, the medium rotation deceleration zone ■, and the high rotation light load zone ■,
In the other high rotation high load zone (2) and high rotation deceleration zone (2), the drive is stopped in order to ensure the reliability of the air pump 25 and the required amount of secondary air.

In the secondary air supply zones I to IV, VT, that is, the driving region of the air pump 25 as described above, in the high rotation light load zone (■), the air pump 25 is basically driven to supply secondary air. When the air pump rotation speed rises above a set value, the drive of the air pump 25 is controlled to stop.

In addition, in the low rotation zone 11 medium rotation light load zone ■, medium rotation deceleration zone ■, high rotation light load zone ■ and high rotation deceleration zone ■, the switching valve 26 is operated to the port air side to open the port air passage 27. Then, the dilution gas is replaced and reduced by supplying port air to improve combustibility, while the switching valve 26 is opened to open the split air passage 28 in the medium-speed, medium-load zone (■) and the high-speed, high-load zone (V). It operates on the split air side and improves the purification performance of the rear catalyst device 23 by supplying split air.

Although the operation of the air pump 25 is stopped in the high rotation high load zone V and the high rotation deceleration zone (2), secondary air is supplied by the check valves 29 and 30 due to exhaust pulsation.

On the other hand, for the fuel supply amount, the basic injection amount is basically calculated so that a predetermined air-fuel ratio is achieved according to the intake air amount and engine rotation speed, but this basic injection amount is calculated as shown in Figure 2 above. Fuel injection characteristics, that is, fuel correction values are set corresponding to different operating ranges. In low rotation zone I, low rotation is increased,
In the medium rotation medium load zone ■, fuel feedback control is performed to maintain the predetermined air-fuel ratio, and in the medium rotation light load zone ■ and high rotation light load zone ■, a light load increase is performed, and in the medium rotation deceleration zone ■ and high rotation speed The respective correction characteristics are set so that a deceleration fuel cut is performed in the rotation deceleration sin ■, and furthermore, a high rotation and high load increase is performed in the high rotation and high load zone V.

In particular, in the medium rotation light load zone ■ and the high rotation light load zone ■ between the light load determination deceleration line A and the fuel cut determination deceleration line B, when port air is supplied as the air pump 25 is driven. The fuel load is increased in accordance with the increase in the intake air filling amount.

In the high rotation light load zone (2), when the drive of the air pump 25 is stopped in response to an increase in the air pump rotation speed, the output control means 44 performs a reduction correction so as to reduce the light load increase. be.

Figure 3 shows the switching valve 2 controlled by the control unit 45.
6 is a flowchart showing control of the relief valve 36 and the relief valve 36. After starting, various signals such as throttle opening, engine speed, intake air amount, etc. are read in step S1. Then, in step S2, it is determined whether or not the secondary air supply zone I-IV, Vl is present based on the throttle opening, etc., and when it is determined YES in the secondary air supply zone I-IV, Vl,
In step S3, it is determined whether or not the engine is in the high rotation light load zone (2).

When determining No in the above step S2, that is, the air pump 25
If it is in the non-driving zone V, ■, step S14
The drive of the air pump 25 is stopped in step S15.
Switching valve 26 according to each zone V, ■ in S1B
This is used to set the fuel correction amount.

Also, when the determination is No in step S3, that is, zones I to ■
If so, the air pump 25 is driven in step Sll, and the process proceeds to step S12. 513 and each zone I
The switching valve 26 is actuated in accordance with the times .about.(2) and the fuel correction amount is set.

Next, if the determination in step S3 is YES and the engine is in the high rotation light load zone (2), the process proceeds to step S4, where it is determined whether the air pump rotation speed is equal to or higher than a set value. This judgment is NO
If the air pump rotational speed is lower than the set value, the air pump 25 is driven in step S8, and the switching valve 26 is operated to the port air side in step S9 to supply secondary air from the port air supply port 21 near the exhaust port 11. At the same time, in step SIO, the fuel correction amount CTOTAL is changed to the zone correction amount C2ON! In other words, it is set to light load increase.

On the other hand, if the determination in step S4 is YES and the air pump rotation speed is equal to or higher than the set value, step S5 stops driving the air pump 25, and step S6 stops the operation of the switching valve 25.
is operated to the port air side to supply port air, and in step S7, the fuel correction amount Cl0TAL is changed to the zone correction amount CZONE, that is, the light load increase to decrease correction value CLL.
Set by subtracting D.

This reduction correction value CLLD is used to reduce the fuel amount corresponding to the reduction amount of secondary air due to the stoppage of the air pump 25, with respect to the light load increase amount CZONE corresponding to the supply of secondary air.

In step S17, a basic injection amount Ti is calculated from the intake air amount Q, the engine speed N, and a coefficient, and in step S18, this basic injection amount Ti is converted to the fuel correction amount C.
The final injection amount T is calculated by correcting it with TOTAL, and in step S19, an injection pulse is output to the injector 20 to execute fuel injection.

A time chart is shown in Fig. 4. In an operating state where the throttle opening decreases midway and the engine speed increases, the air pump 25 is initially in the medium rotation medium load zone ■ and the split air Feedback correction of fuel is performed in the supply state. In this state, as the engine speed increases and the throttle opening decreases,
At point a, the engine shifts to the medium rotation light load zone (2) or the high rotation light load zone (2), switches to port air, and performs light load increase correction CZONE of fuel. Furthermore, as the engine speed increases, the air pump speed exceeds the set value at 5 points, and the air pump 25 is driven or stopped, and a reduction correction value CLLD is set to perform fuel correction 'EIL C.
Decrease TOTAL from light load increase correction CZONE.

Then, at the 0 point, as the throttle opening increases, the engine shifts to the high rotation/high load zone V, and switches to the split air side.

According to the embodiment described above, the air pump 25 is driven and the switching valve 26 is switched and operated according to the operating state,
Port air is supplied on the low load side to replace dilution gas to improve combustion stability, and output is improved by increasing the amount of fuel injection, while split air is supplied on the high load side. This improves eminence properties. Furthermore, when the air pump rotational speed increases, the drive of the air pump 25 is stopped to ensure reliability, and at the same time, the fuel supply amount is corrected in the direction of decrease in the increase correction corresponding to the supply of port air in the port air supply zone, It is possible to prevent a decrease in output due to excessive fuel supply and obtain good drivability.

In addition, in the above embodiment, the output of the engine corresponding to the supply of secondary air is adjusted by changing the fuel supply amount (air-fuel ratio), or together with or in place of this, other output such as ignition timing is adjusted. The control amount may be changed.

In addition, the port air supply amount is determined by the port air supply port 21.
However, the engine output is controlled to be corrected by the output control means 44 in response to the change in the amount of secondary air that corresponds to this change over time. Good too.

(Effects of the Invention) According to the present invention as described above, the air pump is driven in the secondary air supply zone depending on the operating state to supply pressurized air from the vicinity of the exhaust port to the combustion chamber to perform dilution. In order to obtain the effect of improving combustibility through gas replacement, reliability of the air pump is ensured by stopping the drive of the air pump by the pump drive means when a predetermined condition is reached even in the secondary air supply zone. Also, when the air pump is stopped in this secondary air supply zone, the output control means adjusts the fuel supply amount, ignition timing, etc. to appropriate values depending on the state where secondary air is not being supplied. This makes it possible to perform appropriate engine output control.

[Brief explanation of drawings]

Fig. 1 is an overall configuration diagram of an engine control device according to an embodiment of the present invention, Fig. 2 is a map diagram showing control areas, Fig. 3 is a flow chart diagram for explaining the processing of the control unit, and Fig. 4 FIG. 3 is a time chart diagram showing a control example. 1...Engine, 7...Combustion chamber, 11
...Exhaust photo, 12...Exhaust passage, 1
5... Secondary air passage, 21... Port air supply port, 25... Air pump, 26...
...Switching valve, 27...Port air passage, 43
... Pump drive means, 44 ... Output control means, 45 ... Control unit. Diagram design engine Hayato rescue

Claims (1)

[Claims] (1) In an engine configured to drive an air pump to supply secondary air to the combustion chamber from the vicinity of the exhaust port, a pump driving means for controlling the drive of the air pump according to the operating state is provided, and the operating state of the air pump is provided. 1. An engine control device comprising an output control means for changing engine output control amounts such as air-fuel ratio and ignition timing in accordance with the engine.