JPH03260332A - Fuel jet device for engine - Google Patents

Abstract

PURPOSE:To decrease transferring delay of acceleration fuel, increase flowing speed of the fuel and improve evaporation thereof by minutely opening an opening/closing valve arranged on an intake delay closing passage, and performing fuel jet by means of a plurality of injectors arranged on the intake delay closing passage, at the time of acceleration. CONSTITUTION:In a rotary piston engine E, intake circulation ports 15, 16 which are closed with a slow timing are respectively opened to housings 3 of a plurality of cylinders 5, 6, which ports 5 and 6 are communicated with each other through an intake delay closing passage 23 provided with an opening/ closing valve 24. First injectors 31a, 31b are arranged respectively on intake passages 10a, 10b, while second injectors 32a, 32b are arranged on the intake delay closing passage 23. All the injectors 31a to 32b are controlled by a control unit 28 according to an operation condition of the engine E. The opening/closing valve 24 is opened minutely and fuel jet is performed by means of the injectors 31a to 32b at the time of acceleration.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a fuel injection device for an engine equipped with an intake recirculation port whose intake closing timing is set to a late closing timing that has substantially shifted to the compression stroke. It is.

(Prior art) Conventionally, for example, as seen in Japanese Patent Application Laid-Open No. 63-71525, the intake closing timing is delayed in a low-repetition piston engine, and a part of the fresh air that has been sucked into the combustion chamber is compressed. An intake recirculation port is provided to recirculate the air at the beginning of the stroke.
A technique is known that reduces compression work and substantially reduces filling efficiency to alleviate intake negative pressure, reduce pumping loss, and improve fuel efficiency. In particular, in addition to the above-mentioned intake late closing system, it is effective to improve fuel efficiency while ensuring output by increasing the compression ratio of the engine and using supercharging.

Further, the intake recirculation port having a slow intake closing timing is communicated with the intake recirculation port of another cylinder through an intake slow closing passage, so that the recirculated intake air is mutually circulated so as to be supplied to the intake stroke of the other cylinder, An on-off valve is provided in the intake slow-closing passage, and for example, a lack of filling amount due to the late closing timing in a low rotation and high load region is corrected by closing the on-off valve and stopping the intake late closing.

(Problem to be Solved by the Invention) However, in fuel injection in an engine having an intake recirculation port as described above, an injector is installed in an intake passage for an intake port that is arranged separately from the intake recirculation port. However, those in which fuel is injected into a manifold have the problem of delayed response during acceleration.

That is, in the manifold injection described above, there is a time delay between the detection of acceleration and the correction of the injected fuel for each cylinder, and in order to cope with the delay in accelerating fuel, acceleration is detected separately from normal synchronous injection. Asynchronous injection, which adds injection at an instant, is performed, but this asynchronous injection also has its limits, and the problem of response delay remains. In other words, by injecting fuel into the intake passage, the acceleration response is reduced due to a transportation delay until the injected fuel is actually supplied into the combustion chamber.

By the way, in the intake late closing system provided with the intake recirculation port and the intake late closing passage as described above, in order to secure torque during acceleration, the intake closing timing is advanced by closing the intake passage late and closing the passage. There is a conflicting demand between the requirement to secure the amount of fuel filling and the requirement to improve responsiveness by opening the intake late-closing passage and injecting atomized fuel into the passage into the cylinder.

SUMMARY OF THE INVENTION In view of the above circumstances, an object of the present invention is to provide a fuel injection device for an engine that improves responsiveness during acceleration and vaporization and atomization of fuel while improving fuel efficiency through an intake recirculation port. That is.

(Means for Solving the Problems) In order to achieve the above object, the fuel injection device of the present invention includes an intake recirculation port whose closing timing is set to a late closing timing that has substantially shifted to the compression stroke, and an intake recirculation an intake slow-closing passage connected to the port and communicating with the intake recirculation port of other cylinders, and an on-off valve that opens and closes the intake slow-closing passage;
The injector is arranged in the intake slow-closing passage, and the operation of the on-off valve and fuel injection from the injector are controlled depending on the operating state, and during acceleration, the on-off valve is opened to a minute opening and fuel is injected from the injector. This configuration includes a control means for performing the following steps.

(Function) In the engine fuel injection system as described above, an intake recirculation port is provided with a delayed closing timing, and this intake recirculation port and the intake recirculation ports of other cylinders are communicated through an intake delayed closing passage. During the intake stroke, a large amount of the air-fuel mixture is introduced into the combustion chamber to reduce the negative pressure, and during the compression stroke, the excess air-fuel mixture is recirculated and discharged from the late-closed intake port, filling the combustion chamber according to the load. Bumping loss is reduced while the amount is adjusted.

In addition, an on-off valve and an injector are provided in the intake slow-closing passage, and the on-off valve is opened and closed according to the operating condition, and during acceleration, the on-off valve is opened to a minute opening by the control means, and fuel is injected from the injector, thereby transporting the acceleration fuel. In addition to reducing delays and increasing responsiveness, by narrowing the opening and closing valve to a minute opening, the flow velocity in the passage is high and the atomization of the injected fuel can promote vaporization and atomization, and the amount of fuel adhering to the wall can be reduced. This reduces fuel consumption and improves fuel efficiency, while at the same time reducing emissions of unburned components.Furthermore, the small opening degree suppresses the recirculation amount and increases the filling amount, thereby improving torque.

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

FIG. 1 shows a schematic structure of a two-cylinder rotary piston engine in an expanded state.

The casing 1 of the two-cylinder rotary piston engine E is
Two rotor housings 2.2 each having a trochoidal inner circumferential surface and arranged in parallel, one intermezoate housing 3 located between each of these rotor housings 2.2, and The cylinder includes two side housings (not shown), which form two cylinders: a first cylinder 5 (front cylinder) and a second cylinder 6 (rear cylinder). Approximately triangular rotors 8 and 9 are accommodated in the spaces within each of these cylinders 5 and 6, respectively.
Each rotor 8, 9 is supported on a common eccentric shaft 11, 180
The planet rotates with a phase difference of '. The rotors 8, 9 divide the space inside the first cylinder 5 into three working chambers F1 to F3, and the space inside the second cylinder 6 into three working chambers R1 to R3. As the engine rotates, intake, compression, explosion, expansion, and exhaust strokes occur.

The intermediate housing 3 (or side housing) has working chambers F1 to FB and R1 to R at positions where the intake stroke is to be performed for each cylinder 5 and 6, respectively.
Intake ports 13 and 14 are formed, respectively, which open at the end of the intake port 3 and open and close at normal opening/closing timing (early closing timing). Further, each rotor housing 2, 2 has working chambers F1 to F3. at positions where the exhaust stroke is to be performed. R1~R3
An exhaust port 1.7.17 is formed which opens to the spark plug 18.1 in the position where the explosion stroke is to take place.
8 is attached.

A surge tank 1 is provided in each of the intake ports 13 and 14.
Intake passages 10a and 10b from 9 are connected to the surge tank 19, and a throttle valve 21 is interposed in the upstream portion of the surge tank 19. Although not shown, a turbo supercharger is provided which performs supercharging by driving a blower disposed in the intake passage upstream of the surge tank using a turbine interposed in the exhaust passage.

Also, there is an intermediate housing 3 between the first cylinder 5 and the second cylinder 6 (or side housings on both sides).
, intake recirculation ports 15 and 16 are opened at positions with slow closing timing so as to close at the point when the compression stroke is substantially entered as the third intake port for the air volume @5.6. . The intake recirculation bows 15 and 16 of the first cylinder 5 and the second cylinder 6 are communicated with each other by an intake slow closing passage 23. Due to this communication, 18 of rotors 8 and 9
Depending on the rotation with a phase shift of 0 degrees, the compression working chambers F1 to F3 of the first cylinder 5 are communicated with the intake working chambers R1 to R3 of the second cylinder 6, and the compression working chamber R1 of the second cylinder 6 is connected. ~R3
It is formed such that the intake air flows through the intake air by alternately repeating the state of communication between the first cylinder 5 and the intake working chambers F1 to F3 of the first cylinder 5.

An on-off valve 24 for opening and closing the intake late-closing passage 23 is interposed in the middle of the intake late-closing passage 23. The opening/closing valve 24 is linked to an actuator 26, and its opening degree is controlled according to the operating state by a control signal from a control unit 28 serving as a control means.

In addition, first injectors 31a and 31b (manifold injectors) are disposed in the intake passages 10a and 10b for each cylinder 5.6, while the intake slow closing passage 23
a second injector 32a.

32b (interinjector) is provided for each cylinder 5, 6, respectively.

Here, the working chambers F1 to F3 of each cylinder 5, 6. R1~R3
intake port 13.14 and intake reflux port 1 for
If we explain the opening/closing timing of 5.1.6 according to FIG. 2, the exhaust port 17 closes from top dead center to the intake stroke, while the intake hoods 13 and 14 (solid line) open first. The intake recirculation bow) 15.16 (dashed line) opens with a delay. Then, after the intake bottom dead center, the intake port 13.14
After closing at the early closing timing, the intake recirculation port 15 is closed at the late closing timing when the compression stroke is actually started.
．． It is set to close at 16.

In addition, the rotational phases of the rotors 8 and 9 in the first cylinder 5 (front cylinder) and the second cylinder 6 (rear cylinder) are shifted by 180 degrees, and the adjacent working chambers F1 to F1 of each cylinder 5 and 6 are
F3. Since the phases of R1 to R3 are 360° out of phase (the distance between top dead center and bottom dead center is 270°), during the intake stroke, the intake is closed late and the air is transferred from the preceding working chamber of the other cylinder via the passage 23. Intake air is introduced just before the intake recirculation ports 15 and 16 close, and the intake air enters the compression stroke and is transferred to the intake recirculation port 1.
5. Recirculate the intake air from 16 to the subsequent working chamber of the other cylinder. In this way, the state in which the intake slow closing passage 23 communicates the working chamber during the compression stroke with the working chamber during the intake stroke of another cylinder occurs alternately and equally between both cylinders, so that the filling amount and the intake port are changed. The intake air inflow amount from 13 and 14 is equally obtained in both cylinders 5 and 6.

Then, during the intake stroke, a large amount of air-fuel mixture flows into the working chamber F1~
F3. Introduced into R1 to R3, the negative pressure is reduced, and during the compression stroke, excess air-fuel mixture closes the intake late, passes through the passage 23, and is discharged into the working chamber of another cylinder during the intake stroke. Bumping loss is reduced while adjusting the filling amount accordingly.

Furthermore, when the on-off valve 24 of the intake late closing passage 23 is closed, the flow of intake air through the intake recirculation ports 15 and 16 as described above is stopped, and the early closing timing of the intake ports 13 and 14 is stopped. Inhalation takes place.

Opening degree control of the on-off valve 24, first and second injectors 31. Fuel injection control from a, 31b, 32a, and 32b is performed by outputting a drive signal from the control unit 28. This control unit 28 receives an engine rotation signal N, an intake pressure signal PBS, an intake air amount signal Qa, a throttle opening signal θ, etc., and performs on-off valve control based on the control map shown in FIG. The on-off valve 24 is controlled to be closed in region I, low rotation and high load region (■), and opened in other slow-closing regions (■), and the opening is slightly opened from the fully closed state during acceleration. Control the operation.

Further, the fuel injection control by the control unit 28 is performed when the on-off valve 24 is fully opened in the late closing region (3) and when the on-off valve 24 is opened to a minute opening during acceleration. , fuel is injected from the second injectors 32a, 32b of the intake slow closing passage 23, and on the other hand, when the on-off valve 24 is in the fully closed state in the low load region 11 low rotation high load region (2), the intake passages 10g, 10b The fuel is injected from the first injectors 31a and 31b.

The processing of the control unit 28 will be explained along the flowcharts of FIGS. 4 and 5.

FIG. 4 shows a routine for fuel control, and FIG. 5 shows a routine for on-off valve control.

First, to explain the opening/closing valve control routine shown in FIG.
In step S22, it is determined whether or not the engine speed N is less than or equal to the cranking speed N1 during cranking, and at the start of cranking, the on-off valve 24 is fully opened in step S27 to increase the engine speed by reducing cranking resistance. . Further, when the cranking rotation speed is equal to or higher than N1, step 82 is performed in the rotation range below the complete combustion rotation speed N2 as determined in step S24.
8, the on-off valve 24 is controlled to be fully open.

When the engine starting is completed, it is determined in step S25 whether or not the amount of change dθ/dt in the throttle opening θ is in an acceleration state equal to or greater than a predetermined value α.

If the determination in step S25 is NO and the state is in a non-accelerating state such as a steady state, then in step S26 the intake pressure PB
It is determined from the engine speed N and engine speed N whether the operating state is in the late closing region (3) of the control map for the third factor. If this determination is YES and the state is in the late closing region ■, step S
The on-off valve 24 is fully opened in 3D to control the intake closing timing to a late closing timing, and step S
At step 33, the flag L is set to 1. Further, if the determination in step 826 is No and the state is in the low load region I or the low rotation high load region ■, in step S29 the on-off valve 2
4 to the fully open state to control the intake closing timing to an early closing timing, and at the same time, in step S32, the flag L is set.
Clear to O.

On the other hand, if the determination in step S25 is YES and the state is in the acceleration state, the opening degree of the on-off valve 24 is controlled to a predetermined minute opening degree in step S31 to be in the throttle state, and then the process proceeds to step S33. Set flag L to 1.

To explain the fuel injection control routine shown in FIG. 4 in response to the setting of the flag L as described above, after the control is started, the engine rotation speed N is determined from the input signal in steps 81 to S3.
1 Throttle opening degree θ and intake air amount Qa are detected respectively.

Then, in step S4, it is determined whether the flag L is set to 1 or not. If this determination is NO and the on-off valve 24 is in the fully closed state at the time of startup, step S5
Step S6 calculates the basic injection pulse width Tpm corresponding to the operating condition from the engine speed N, intake air amount Qa, etc., and then waits for the injection timing in step S6.
In step S7, the first injectors 31a and 31b of the intake passages 10a and 10b are driven to perform fuel injection.

On the other hand, if the determination in step S4 is YES, the on-off valve 24
is fully open! I! i (late closing region m) or in a micro-opening state during acceleration, the process proceeds to step S8 and similarly calculates the basic injection pulse width Tpl corresponding to the operating state from the engine speed N, intake air amount Qa, etc. After calculating, wait until the injection timing is reached in step S9, and then start the second injector 32 of the intake late closing passage 23 in step S10.
g, 32b to perform fuel injection.

According to the above embodiment, basically the low load region I
The on-off valve 24 is opened in the slow-closing region (■) excluding the low-speed, high-load region (■) to reduce pumping loss by recirculating the intake air, and to inject and supply fuel from the second injectors 32a, 32b of the intake late-closing passage 23. and good vaporization,
I am trying to obtain atomization characteristics. In addition, in the acceleration state, the on-off valve 24 is throttled to a predetermined minute opening degree, and fuel is injected and supplied from the second injectors 32g and 32b of the intake slow-closing passage 23, and the recirculation amount is suppressed by the throttle of the on-off valve 24 to slow down the opening. While suppressing the reduction in the filling amount due to the closing timing, it is possible to ensure good vaporization and atomization characteristics of the fuel by injection at a high flow rate.

In addition, in the above embodiment, when the engine is started, when the engine speed is lower than the cranking speed N1 due to activation of the starter, the on-off valve 24 is opened to lower the effective compression ratio and the cranking resistance is reduced. promote the rise,
When the cranking rotational speed increases to N1 or more, the on-off valve 24 is closed to increase the filling amount and improve the ignition performance, thereby improving the engine startability.

On the other hand, when a supercharger is used in conjunction with the above engine E, the pumping loss is reduced by slow intake closing in the late closing region ■, while the late closing region expands to the fully open region in combination with supercharging from the supercharger. When the geometric compression ratio is increased, the late closing region expands toward light loads, and fuel efficiency can be improved over a wide range while maintaining output performance. Furthermore, increasing the geometric compression ratio improves the combustion efficiency itself and improves fuel efficiency, and also improves the expansion ratio, lowers the exhaust gas temperature, and increases the amount of fuel required to lower the exhaust gas temperature. This is no longer necessary, improving fuel efficiency at high speeds.

Furthermore, in the low rotation high load region ■, the on-off valve 24 closes,
The intake air closing timing is early opened according to the closing timing of the intake ports 13 and 14, so that the filling amount is ensured against insufficient supercharging by the supercharger, and knocking resistance is ensured to improve low speed torque. Furthermore, by setting the intake closing timing in the low-load region I, which includes idling, to an earlier opening than in the low-speed high-load region ■, the effective compression ratio increases, further ensuring combustion stability and improving fuel efficiency. can get.

Next, in the above embodiment, the fuel injection during acceleration is switched from the first injectors 31a and 31b together with the basic injection pulse, and the second injector 32a of the intake late closing passage 23 is
, 32b, but only the increased amount of fuel during acceleration may be supplied by asynchronous injection from the second injectors 32a, 32b, and synchronous injection may always be performed from the first injectors 31a, 31b. An example of the control routine in this case is shown in FIG. In this example, control is performed to alternately inject the asynchronously injected fuel at intervals of 180'' so that the asynchronously injected fuel flows into the cylinders 5 and 6 on both sides.

In FIG. 6, after the control is started, the rotation angle of the eccentric shaft 11 is detected in steps S41 and S42, and the throttle opening degree θ is also detected. Next, in step S43, it is determined whether or not the alternating flag A is set to 1. If this determination is NO, the process proceeds to step S44, and the throttle opening change amount dθ/dt is greater than or equal to the predetermined value α. Determine whether or not it is in an acceleration state.

At the moment of acceleration, asynchronous injection (injection amount TK) from the second injector 32a on the front cylinder side is executed in step S45, and the alternating flag A is set to 1 in step 84B.

When the alternating flag A is set to 1, the determination in step 843 becomes YES and the process proceeds to step S47.
After waiting for the output shaft angle to rotate 180 degrees since the previous asynchronous injection from the second injector 32a on the front cylinder side, in step 548, the second injector 32a on the rear cylinder side
Execute asynchronous injection (10a to injection amount T-) from b,
In step S49, the alternate flag A is cleared to 0. Note that the asynchronous injection amount is changed at the moment of acceleration and thereafter.

In the example shown in FIG. 6, the second injectors 32a are alternately connected depending on the phase difference between the cylinders 5.6 on both sides.

32b (whichever comes first) is injected to prevent fuel from being supplied to only one cylinder depending on the direction of the flow in the intake late closing passage 23 at the time of injection. Incidentally, injection may be performed in sequence according to the phase difference depending on the number of cylinders communicating with the intake late closing passage 23, or injection may be performed simultaneously from each injector at intervals according to the phase difference.

The present invention is not limited to rotary piston engines, but is also applicable to other types of engines.

(Effects of the Invention) According to the present invention as described above, basically, fuel efficiency is improved by reducing pumping loss according to recirculation of intake air by adopting late intake closing timing, and at the same time, when accelerating, the intake is closed late. By simultaneously opening the opening/closing valve of the passage to a minute opening and injecting fuel from an injector into the passage, the delay in transporting acceleration fuel is reduced and responsiveness is increased.By narrowing the opening/closing valve to a minute opening, the flow rate is The high fuel atomization promotes vaporization and atomization, and the amount of fuel adhering to the wall is reduced, improving fuel efficiency and at the same time reducing emissions of unburned components.Furthermore, the small opening allows for recirculation. By reducing the amount of intake air, the amount of filling can be increased and torque can be increased, ensuring good acceleration and running performance.

[Brief explanation of drawings]

Fig. 1 is a schematic configuration diagram showing the developed state of a rotary piston engine in an embodiment of the present invention, Fig. 2 is an explanatory diagram showing the opening/closing timing of each port and the recirculation relationship, and Fig. 3 is a map diagram showing the control area. , FIG. 4 and FIG. 5 are flowcharts for explaining the processing of the control unit, and FIG. 6 is a flowchart showing a modification. E... Engine, 5, 6... Cylinder, F
1~FB. R1-R3... Working chamber, lQa, 10b...
...Intake passage, 13.14...Intake port,
15.16... Intake recirculation port, 17...
...Exhaust port, 21...Throttle valve,
23...Intake slow closing passage, 24...Opening/closing valve, 28...Control unit (control means). Figure 2 Figure 4 Figure Figure Figure

Claims (1)

[Claims] (1) An intake recirculation port whose closing timing is set to a late closing timing that has substantially shifted to the compression stroke, and an intake late closing passage connected to the intake recirculation port and communicating with the intake recirculation ports of other cylinders; An on-off valve that opens and closes the intake slow-closing passage, an injector disposed in the intake slow-closing passage, and an operation of the on-off valve and fuel injection from the injector are controlled according to the operating condition, and the on-off valve is turned off during acceleration. 1. A fuel injection device for an engine, comprising: control means that opens to a minute opening and injects fuel from the injector.