JPH0776534B2 - Engine fuel supply controller - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a fuel supply control device for an engine.

(Prior Art) Generally, during the internal combustion period, it is not possible to extract all of the heat energy generated in the cylinder as a shaft output, and a considerable part thereof is lost as various losses such as heat loss and mechanical loss, which results in fuel consumption. It is one of the obstacles to improvement. One of the mechanical losses is the pump loss in the intake and exhaust strokes, which is particularly large at low loads than at high loads, so that it is especially important for automobile engines that are frequently used in the middle and low load regions. However, this greatly hinders the improvement of fuel efficiency.

On the other hand, it is known that fuel efficiency improves when an engine with a small stroke volume is installed in the same vehicle, but this is largely because the engine operates under relatively high load, which reduces pump loss. Is considered to be one of the. Therefore, if the engine is made to perform the same function as a small stroke volume engine only at low load, the pump loss at low load is reduced and the fuel consumption is improved without compromising the required characteristics at high output of the engine. It is thought that it can be done.

That is, in order to reduce the pump loss at the time of low load, it is sufficient to reduce the throttle loss due to the suction negative pressure increase based on the small throttle valve opening degree at the intake stroke and the compression loss at the compression stroke at the time of the low load. . This applies not only to the reciprocating piston type engine, but also to the rotary piston engine, and as a means for this, for example, in the rotary piston engine, as described in JP-A-50-59610, in addition to the intake passage, An intake air recirculation passage that exposes part of the intake air during the compression stroke is provided, and an opening / closing control valve for output adjustment is arranged in this intake air recirculation passage, and the opening degree of this opening / closing control valve is adjusted according to the load condition of the engine. Then, a structure for controlling the intake air recirculation amount is known. That is, this known structure, the intake device of the rotary piston engine, the intake passage for supplying the intake air from the atmosphere into the cylinder during the intake stroke of the engine, and the middle of the intake passage and the cylinder to communicate, An intake air recirculation passage that recirculates a part of the intake air in the cylinder to the intake air passage during an engine compression stroke, and an open / close control valve that opens and closes the intake air recirculation passage, and operates the open / closed state of the open / close control valve. The intake air recirculation amount is controlled according to the region to adjust the intake air recirculation amount to control the substantial intake air filling amount.

In this intake system for a rotary piston engine, it is considered that pump loss at low load is reduced, and fuel economy is greatly improved from this point. However, on the other hand, a conduit for the above-mentioned return passage must be newly formed, and therefore,
There is a drawback that the structure of the engine becomes complicated and extra space is required. Further, in this intake device, a part of the intake air that has been once supplied to the cylinder and thermally expanded therein flows back into the atmosphere when being discharged from the cylinder during the compression stroke, resulting in an increase in intake noise. As it may occur, special measures had to be taken to prevent this backflow into the atmosphere.

Therefore, among the rotary piston engines as described above,
In particular, in a two-cylinder rotary piston engine, a rotary structure having a simple structure and requiring no extra space, and having a recirculation passage which does not require special means for preventing the above-mentioned recirculation intake air from flowing back to the atmosphere is provided. There is a piston engine intake device (see Japanese Patent Laid-Open No. 59-172429).

This prior art is a trochoid space formed by an intermediate housing, two rotor housings arranged on both sides of the intermediate housing, and two side housings respectively arranged outside the two rotor housings. In an intake device of a two-cylinder type rotary piston engine in which two rotors axially supported by an eccentric shaft are made to rotate in a planetary manner, a compression stroke working chamber of one of the first trochoid spaces in accordance with the rotation of the rotor. And a communication state with the other intake stroke working chamber of the second trochoid space, and a communication state with the compression stroke working chamber of the second trochoid space and the suction stroke working chamber of the first trochoid space. A communication port as an intake / recirculation passage is formed in the intermediate housing and the communication port is formed. And it is configured to open and close a control valve port in response to the magnitude of the engine load to limit the aeration of the communicating port provided.

According to this intake device for the rotary piston engine, the communication port is provided in the intermediate housing itself as described above, and it is made to act as the intake gas recirculation passage. It is not necessary to provide, therefore the structure is simple and
No extra space is required for forming the intake air recirculation passage. Further, since the intake air discharged from the compression stroke working chamber of the one trochoid space through the communication port is supplied to the intake stroke working chamber of the other trochoid space, the discharged intake air is discharged without taking any special means. It is possible to prevent backflow into the atmosphere in the same manner as in the prior art.

On the other hand, even in the place where the intake device having such a configuration is adopted, in the case where high output and high torque are required, for example, during acceleration, the fuel supply device side is improved to improve acceleration response. In general, a predetermined amount of fuel is accelerated and increased by operating the acceleration detecting means. However, from the viewpoint of improving the acceleration response, even if the fuel supply amount is simply increased as described above, the intake recirculation passage may be wide open due to the opening / closing control valve opening as described above. Since the effective compression ratio is reduced by the intake air recirculation amount and the output torque is also reduced, sufficient acceleration response performance cannot always be obtained. Therefore, even in an engine that employs the intake device having the above-described configuration, a control system that generally closes the opening / closing control valve to increase the effective compression ratio when the acceleration state is detected as described above and improves the output is adopted. To be done.

(Problems to be Solved by the Invention) However, as described above, when the intake air recirculation passage is closed at the same time when the fuel amount is increased during acceleration, the output torque is improved by increasing the fuel amount when the intake air recirculation passage is closed. With a sudden increase in output torque due to the closing of the intake return passage,
There is a problem of generating a large torque shock.

Such a problem is not limited to the case of the engine in which the pump loss is reduced by the intake gas recirculation passage that communicates the working chambers between the cylinders as described above.
As described in Japanese Patent Publication No. 5, the intake passage itself is provided with an intake passage opening / closing valve different from the intake valve, and the pump loss is reduced by substantially changing the closing timing of the intake port according to the load region. In the case of the engine, the same problem occurs, and in short, it is a problem common to the engine configured so that the effective compression ratio (pump loss reduction amount) can be changed substantially according to the operating region.

(Means for Solving Problems) The present invention has been made for the purpose of solving the above problems, and is a pump loss that reduces pump loss by substantially shortening an intake stroke in a specific operating region of an engine. In a fuel supply control device for an engine equipped with a reduction means, a pump loss reduction cancellation request detection means for detecting a cancellation request for the engine pump loss reduction action, and a pump loss reduction cancellation request detection for this pump loss reduction cancellation request detection means. Sometimes, a fuel supply amount control means for increasing the fuel supply amount to the engine, and a pump loss reduction function of the pump loss reduction means when a request for canceling the pump loss reduction function is detected by the pump loss reduction cancellation request detection means. Delaying means for delaying the releasing operation for a predetermined time, and a delay means for delaying after the predetermined delay time by the delaying means The fuel supply amount correction means is provided to reduce the increase value of the fuel supply amount by the fuel supply amount control means to a predetermined value.

(Operation) According to the above means, when the request for canceling the pump loss reducing operation such as the acceleration state is detected, the fuel supply amount is increased simultaneously with the detection of the state, and the pump loss reducing operation canceling operation of the pump loss reducing means is predetermined. Since I tried to delay it,
First, a predetermined amount of torque is improved by promptly increasing the fuel supply amount corresponding to the acceleration detection, and then the pump loss reducing means is stopped after a predetermined time to substantially improve the output by increasing the effective compression ratio. It will be. for that reason,
Compared to the case where both the torque fluctuation due to the increase of the fuel supply amount and the torque fluctuation due to the increase of the compression ratio act at the same time, they are much smaller and the torque shock is not felt.

Moreover, since the increase value of the fuel supply amount is reduced to a predetermined value at the same time as the effective compression ratio is increased by canceling the pump loss reduction action of the pump loss reduction means, the torque shock when the pump loss reduction means is deactivated is smaller. It will be suppressed.

(Embodiment) FIG. 2 and FIG. 3 show an engine fuel supply control device according to an embodiment of the present invention applied to a rotary piston engine.

First, in FIG. 2, reference numeral 1 indicates, for example, a two-cylinder type rotary piston engine main body, and this rotary piston engine main body 1 has trochoid spaces 2 and 3 formed inside thereof as shown in FIG. One rotor housing 4,5, and three side housings located on both sides of these two rotor housings 4,5 and closing both side portions of the rotor housings 4,5 (the common side housing at the center is particularly It is called a mediate housing) 6,7,8. In the trochoid spaces 2 and 3 of the rotor housings 4 and 5, the trochoid inner peripheral surfaces 4a and 5a inside the rotor housings 4 and 5 are inscribed around the eccentric shaft 9 by 180 degrees. Two substantially triangular rotors 10 and 11 which are planetary rotated with a phase difference of 10 are loosely fitted.

The three outer peripheral surfaces 10a to 10c, 11a to 11c of the rotors 10 and 11 and the trochoid inner peripheral surfaces 4a and 5a of the rotor housings 4,5.
And three working chambers 13A to 13c and 14A to 14C are formed between them. Further, exhaust ports 15 and 16 are opened in the trochoid inner peripheral surfaces 4a and 5a corresponding to the lower portions of one side of the rotor housings 4 and 5, and the exhaust ports 15 and 16 are opened.
Are commonly connected to an external exhaust pipe 19 through exhaust ports 17 and 18.

On the other hand, in the side housing located between the rotor housings 4 and 5 among the three side housings 6 to 8, that is, in the intermediate housing 7, two intake ports 21 and 22 communicating with the intake pipe 42 are provided. The openings are opened toward the working chambers in the trochoid spaces on the rotor housings 4 and 5 side. In addition, in this intermediate housing, the compression stroke working chamber of the one side (front side) first rotor housing 4 (corresponding to the planetary rotation having the phase difference of 180 degrees between the two rotors 10 and 11) A first communication state in which any one of 13A to 13C) communicates with the intake stroke working chamber (any of 14A to 14C) of the other rotor side (rear side) second rotor housing 5 and the other side (rear side) Second communication state in which one of the compression stroke working chambers 14A to 14C of the second rotor housing 5 is communicated with the intake stroke working chamber (one of 13A to 13C) of the one side (front side) first rotor housing 4 An intake air recirculation passage 25 that alternately forms and is formed. This intake air recirculation passage 25 can be easily provided by forming a through hole at a predetermined position of the intermediate housing 7 for allowing the trochoid spaces 2 and 3 to communicate with each other, as shown in FIG. A disk-shaped butterfly type opening / closing control valve 26 is installed in the center of the intake air recirculation passage 25.
As shown in FIG. 5, 26 is controlled to be fully closed in the high-speed and high-load region, while in the low-speed and low-load region, the valve is opened according to the load amount, and the opening cross-sectional area of the intake recirculation passage 25 is varied to recirculate The intake amount is controlled, the effective compression ratio is reduced, and the pump loss is reduced.

The intake air recirculation passage 25 and the open / close control valve 26 together with the duty solenoid 41, the open / close valve actuator 40, and the intake air recirculation control means of the engine control unit 50, which will be described later, are included in the scope of the claims as "specific operating region of engine (low speed In the load region), a pump loss reducing means that substantially reduces the pump loss by shortening the intake stroke (reducing the effective compression ratio) is configured.

The opening / closing control valve 26 is opened / closed by an opening / closing valve actuator 40 having a diaphragm structure which is driven according to an operating state (valve position) of a duty solenoid 41 which is controlled by an engine control unit 50 which will be described later. The state is specifically controlled. The opening / closing valve actuator 40 is provided with a valve opening detection device 90 that detects the valve opening f of the opening / closing control valve 26.

On the other hand, the intake ports 21 and 22 are respectively communicated with the air cleaner 43 through the intake pipe 42, a surge tank 44 is formed in the middle of the intake pipe 42, and an intake passage is formed between the air cleaner 43 and the surge tank 44. Is equipped with an air flow meter 45 and a throttle valve 46, respectively.
The intake air amount signal Q detected by the air flow meter 45 is input to the engine control unit 50. Further, the throttle valve 46 is provided with a throttle opening sensor 47 incorporating an acceleration sensor 48, and the detection signal θ (throttle valve opening) of the throttle opening sensor 47 and the acceleration detection signal U are also described above. Input to the engine control unit 50. Reference numeral 49 is a fuel injector for supplying fuel to each cylinder in accordance with the operating state, and is provided in the intake passage 42 immediately before the intake ports 21 and 22.
Incidentally, reference numerals 30 and 31 are auxiliary intake ports.

The engine control unit 50 is composed of a microcomputer, and together with the intake air amount Q detected by the air flow meter 45, the throttle valve opening θ detected by the throttle opening sensor 47 and the acceleration detection signal U detected by the acceleration sensor 48. The engine speed N detected by the crank angle sensor, the engine cooling water temperature T detected by the water temperature sensor, the intake negative pressure P detected by the negative pressure sensor, etc. are respectively input to perform a predetermined calculation, and an acceleration state described later. (High speed / high load region), Low speed / low load region, Fuel supply amount increase control at acceleration condition determination, Intake recirculation control by effective control of duty solenoid 41 at low speed / low load region determination (effective compression Ratio reduction control), release control of the intake recirculation control based on the acceleration determination, delay of the intake recirculation control release control operation Please performs reduction control of fuel supply amount reduction the increase value of the fuel supply amount increasing control at a predetermined value after a lapse of the delay time of the delay control. Therefore, the engine control unit 50 corresponds to each of the above controls, acceleration state determination means based on a change in the detected value of the throttle opening sensor 47, fuel supply amount increase and decrease control means, operation control of the duty solenoid 41. The control means functions such as intake air recirculation control means, intake air recirculation control release means, intake air recirculation control release delay means, and the like.

The duty solenoid 41, which is a three-way solenoid valve, selectively connects the working chamber of the opening / closing valve actuator 40 having the diaphragm configuration to either the atmosphere side P ₁ or the intake pipe 42 side (negative pressure side) P ₂ side. By doing so, the drive state of the on-off valve actuator 40 (valve opening / closing) is controlled.

The throttle opening sensor 47 and the acceleration state determination means of the engine control unit 50 constitutes "pump loss reduction cancellation request detection means for detecting cancellation request of engine pump loss reduction action" in the claims, For example, when the change in the throttle opening detected by the throttle opening sensor 47 per unit time is in an acceleration state above a predetermined value (high speed and high load region), the intake recirculation control operation for reducing the pump loss is canceled. It is detected and determined that there is a request.

Further, the fuel supply amount increase control means of the engine control unit 50 is a fuel for increasing and controlling the fuel supply amount to the engine at the time of detecting "a pump loss reduction cancellation request request of the pump loss reduction cancellation request detection means" in the claims. The "supply amount control means" and the intake-air recirculation control cancellation delay means of the engine control unit 50 are the pump loss reduction cancellation request detection means in the claims and the acceleration state of a predetermined value or more is determined, and the pump loss `` Delaying means for delaying the pump loss reducing action releasing operation of the pump loss reducing means for a predetermined time when a request for releasing the reducing action is detected '', and further, the fuel supply amount reducing control means of the engine control unit 50 is the above-mentioned patent. In the claims, "after the elapse of the predetermined delay time by the delay means, the fuel supply amount control is performed. Respectively constitute the fuel supply amount correcting means "to lose weight the boost value of the fuel supply quantity to a predetermined value by means.

Next, the intake air recirculation and fuel supply amount control operations by the various control means of the engine control unit 50 will be described with reference to the flowchart of FIG.

First, in step S ₁ , the engine cooling water temperature T, the engine speed N, and the intake negative pressure P are input, and a correction ratio calculation of the fuel injection amount according to the engine cooling condition or warming condition and the rotation or load region is performed. Data processing and storage operation are performed. Then, the process proceeds to step S _2, and inputs the acceleration detection signal U described above for the acceleration state determination (high-speed high-load region). The acceleration sensor 48 incorporated in the throttle opening sensor 47 detects, for example, a change in the throttle opening θ by a pulse signal and inputs the pulse signal as an acceleration detection signal to the engine control unit 50 as described above. To do.

Then, the engine control unit 50 uses the pulse signal to calculate the rate of change dθ of the throttle opening θ per unit time.
/ dt is calculated, and if the calculated value is equal to or greater than a predetermined value, it is determined that the vehicle is in an accelerated state. Then, in that case, the engine control unit 50 first forms an acceleration signal shown in FIG. 6 (a) (this acceleration signal is originally subdivided corresponding to the change rate of the throttle opening θ). Although it is shown in the form of a pulse signal, it is shown here in the form of a simple square wave showing its output period for convenience of description.

Then, the process proceeds to step S _3, from the viewpoint of acceleration response improving basic fuel injection quantity in the normal synchronous injection (Fig. 6 b) acceleration increase value by asynchronous injection for increasing correction of (Fig. 6 c) Calculate. This calculation is performed as a total correction coefficient by multiplying the correction ratios α and β respectively specified by the engine speed N and the engine cooling water temperature T at that time, as shown in FIGS. 7 and 8. This is done by multiplying the coefficient (see FIG. 6g) by a predetermined reference value a.

Further, the process proceeds to step S _4, ON of the opening and closing control valve 26 for controlling the intake reflux of the intake recirculation passage 25 (open state)
Or, determine the OFF (valve closed) state. This determination is made by a valve opening detection device provided in the opening / closing valve actuator 40.
For the current detection values (identified by the previous operating region) f ₁ of 90, or pre-determined valve opening degree f ₂ is controlled to the fully closed state by the detection of the acceleration state how changes Is.

As a result, OFF from ON, i.e. last time by in acceleration state detection to the current step S ₂ In the open area, is controlled closed fully closed (target valve opening degree 0 °) from the viewpoint of the output torque increase If so, first, in step S ₅ , the valve closing delay means is operated to delay the closing operation of the opening / closing control valve 26 by a predetermined time t ₁ second from the time when the acceleration state is detected as shown in FIG. 6 (e). By performing the closing operation, the fuel amount increase control (acceleration amount increasing control) in step S ₆ described below is given priority, and the output torque is first improved to some extent by increasing the fuel amount, and then the opening / closing control valve 26 is closed. It is like this.

That is, the basic fuel injection quantity (Fig. 6 b) to increase correction by acceleration increase value calculated by the detection at the same time as the step S ₃ of the acceleration state in step S ₆ (FIG. 6 c), less co the closed During the above t ₁ seconds while the delay means is operating, the fuel injection is transiently performed with the increase correction value (FIG. 6d) to improve the output torque early to a predetermined level. This allows
Improvement of output torque by increasing fuel quantity during acceleration and opening / closing control valve 26
First, the occurrence of torque shock due to the simultaneous increase in the output due to the fully closed state is prevented.

Then, operating time of the valve closing delay means proceeds to step S ₇
When the elapse of t ₁ is judged, and when the time t ₁ elapses, step S ₈
And the acceleration increase value of the fuel injection amount calculated in step S ₃ (FIG. 6c), as shown in FIGS. 7 and 8, a predetermined reduction correction (this correction is performed in FIG. each correction factor Figure 8 alpha, beta and [Delta] [alpha], the routine proceeds to step S ₉ after the done is) by reducing only Δβ close the opening and closing control valve 26 (see FIG. 6 e).
No calculation of the final fuel injection amount due to the reduced amount correction proceeds to S _10, actually injects fuel in step S ₁₁ based on the calculated value (Fig. 6 f).

Therefore, the amount of fuel actually injected in the step S _11, from the time when the intake recirculation passage 25 by closing the opening and closing control valve 26 is closed, it is reduced thereby in response to the output is improved As a result, the output increase amount when the opening / closing control valve 26 is closed is also suppressed accordingly, so that the torque shock when the valve is closed is also suppressed to a predetermined value or less.

That is, the amount of increase in the average effective pressure in the engine operating chamber due to the closing of the opening / closing control valve 26 is 4 kg / m when the opening / closing control valve 26 is opened at an engine speed of 1500 rpm as shown in FIG. 9, for example.
₂ was 4.5 kg / m _{2 when the on-} off control valve 26 was closed.
Until, also would be those was 4 Kg / m ₂ at 2000rpm until 6 Kg / m _2, greatly increased respectively. Therefore, the output torque is also greatly improved correspondingly, which inevitably causes a torque shock. Therefore, in this case, the amount of fuel supplied to the other side is reduced to suppress the torque improvement at that time to an optimum range that does not deteriorate the acceleration performance, thereby preventing the torque shock.

On the other hand, OFF from OFF in step S _4, i.e. when in the operating region where off control valve 26 has been already closed, as the step S from the operation in step S ₅ to S ₉ are not necessary
Proceeds to _10, acceleration increase value calculated in step S ₃ (6
After calculating the final fuel injection amount (Fig. 6d) by the logical sum of Fig. C) and the basic fuel injection amount (Fig. 6b), step
The fuel is injected at the calculated value proceeds to S _11.

(Effects of the Invention) As described above, the present invention provides a fuel supply control device for an engine, which is provided with a pump loss reducing unit that reduces pump loss by substantially shortening an intake stroke in a specific operating region of the engine, Pump loss reduction cancellation request detection means for detecting a cancellation request for the pump loss reduction action of the engine, and fuel supply for increasing the fuel supply amount to the engine when the pump loss reduction cancellation request detection means detects the pump loss reduction cancellation request. When the amount control means and the pump loss reduction cancellation request detection means detect a pump loss reduction effect cancellation request for a pump loss reduction operation, a delay means for delaying the pump loss reduction operation cancellation operation of the pump loss reduction means for a predetermined time. After the elapse of the predetermined delay time by this delay means, the fuel supply amount control means The fuel supply amount correction means for reducing the increase amount of the fuel supply amount to a predetermined value is provided.

Therefore, according to the present invention, when the cancellation request for the pump loss reducing action such as the acceleration state is detected, the fuel supply amount is increased simultaneously with the detection of the state, while the pump loss reducing action canceling operation of the pump loss reducing means is delayed for a predetermined time. Therefore, first, the torque is increased by a predetermined amount by promptly increasing the fuel supply amount corresponding to the acceleration detection, and then the pump loss reducing means is stopped after a predetermined time to substantially increase the effective compression ratio. The output will be improved by. Therefore, compared to the case where both the torque fluctuation due to the increase in the fuel supply amount and the torque fluctuation due to the increase in the compression ratio act at the same time, they are much smaller and the torque shock is not felt.

Moreover, since the increase value of the fuel supply amount is reduced to a predetermined value at the same time as the effective compression ratio is increased by canceling the pump loss reduction action of the pump loss reduction device, the torque shock when the pump loss reduction device is deactivated is further reduced. It will be suppressed.

[Brief description of drawings]

FIG. 1 is a diagram corresponding to the claims of the present invention, FIG. 2 is a schematic system diagram of a fuel supply control device for an engine according to an embodiment of the present invention, and FIG. 3 is a cross-sectional view of an engine main body portion of the device, FIG. 4 is a flow chart showing the control operation of the engine control unit of the embodiment apparatus, FIG. 5 is a control map diagram used in the embodiment apparatus, and FIG. 6 shows the operation of the embodiment apparatus. Time charts, FIGS. 7 and 8 are correction characteristic diagrams used in the fuel supply control operation in the flow chart of FIG.
FIG. 9 is a characteristic diagram showing the relationship between the operation of the opening / closing control valve and the average effective pressure in the apparatus of the above embodiment. 1 …… Rotary piston engine body 2,3 …… Trochoid space 4,5 …… Rotor housing 6,8 …… Side housing 7 …… Intermediate housing 10,11 …… Rotor 13A-13C, 14A-14C …… Working chamber 21,22 …… Main intake port 25 …… Intake recirculation passage 26 …… Open / close control valve 40 …… Open / close valve actuator 41 …… Duty solenoid 45 …… Air flow meter 46 …… Throttle valve 47 …… Throttle opening sensor 48 ... Acceleration sensor 50 ... Engine control unit

Claims (1)

[Claims] 1. A fuel supply control device for an engine, comprising a pump loss reducing means for reducing pump loss by substantially shortening an intake stroke in a specific operating region of the engine, wherein a request for canceling the pump loss reducing action of the engine is issued. A pump loss reduction cancellation request detecting means for detecting, a fuel supply amount control means for increasing the fuel supply amount to the engine when the pump loss reduction cancellation request detecting means detects a pump loss reduction cancellation request, and the pump loss reduction cancellation request. When the detection means detects a request for canceling the pump loss reducing action, delay means delays the pump loss reducing action releasing operation of the pump loss reducing means by a predetermined time, and after the lapse of the predetermined delay time by the delay means. Is a fuel supply amount compensation means for reducing the increase value of the fuel supply amount by the fuel supply amount control means to a predetermined value. Fuel supply control apparatus for an engine, characterized in that a means.