JPS6371521A - Intake device for engine - Google Patents

Abstract

PURPOSE:To achieve the enhancement in acceleration characteristics and an engine brake effect, by decreasing the operating region, in which the communication between cylinders for reducing pumping loss is carried out, at the time of acceleration or deceleration. CONSTITUTION:On the respective side surfaces of the front and rear sides of intermediate housings 4 of a rotary piston engine, communicating ports 15f, 15r are formed so as to be positioned slightly on the leading side looking from respective intake ports 6f, 6r in the rotating directions of rotors 2f, 2r. In the intermediate position of a communicating passage 16 communicating both communicating ports 15f and 15r, a rotary type control valve 17 being controlled to be opened or closed via a control circuit 19 and a control mechanism CR is provided. The control circuit 19 sets the target opening of the control valve 17 on the basis of the detected values from an air flowmeter 9 and a revolution sensor 34, and when an acceleration or deceleration is detected on the basis of the change in the throttle opening, it decreases the operating region in which the control valve 17 is opened.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to an intake system for an engine.

[Prior art] Engine load is throttled [J throttle valve is used to control the engine load] In an male-cycle engine, the intake air amount is normally throttled by the throttle valve, and the intake stroke is operated with the intake air pressure lower than atmospheric pressure. It is well known that so-called pumping loss, which is a type of resistance loss, occurs. In particular, at low loads when the intake air volume is strongly throttled, the intake pressure is low (for example, -07 kg/cm2 gauge), and the bombing loss caused by this is estimated to account for about 30% of the total of various resistance losses. There is. Therefore, if this bombing loss can be reduced, the fuel efficiency of the engine can be significantly improved.

Conventionally, as a method to reduce this pumping loss, when the engine is under low load, the intake valve is closed earlier than the bottom dead center of the intake stroke, thereby virtually eliminating the negative work after the intake valve closes. , a so-called early closing system of the intake valve that reduces pumping loss (for example, see Japanese Patent Publication No. 10573/1983. However, in this reference example, a throttle valve is not provided), or a main intake valve. In addition to providing a communication bow 1 which is independent of the main intake boat and closes later than the main intake boat, a communication passage is provided to communicate between the communication bows 1 and the plurality of cylinders. This is a late-closing method using so-called inter-cylinder communication, which suppresses the negative pressure of the intake air and reduces pumping loss by allowing part of the intake air from the cylinder at the beginning of the compression stroke to flow into other cylinders at the front stage of the intake stroke. (For example, see Japanese Patent Application Laid-open No. 1724.29/1983.) Alternatively, a reflux boat that is closed later than the main intake boat is provided independently of the main intake boat, and a reflux boat that closes later than the main intake boat is provided. A recirculation passage is provided that communicates with the intake passage downstream of the slot valve, and at low loads, a portion of the intake air at the beginning of the compression stroke is recirculated to the intake passage through the recirculation passage, thereby reducing the load and increasing the For the same load, a recirculation passage is installed (the throttle valve opening is larger than that of a normal intake system without J) to suppress the negative pressure of intake air and reduce pumping loss. Late closing methods using slow reflux have been proposed.

On the other hand, when the engine accelerates, high output is required, which means that the intake air filling efficiency is increased. Since pumping loss control is performed in the operating range of 1, when the operating state in which pumping loss is controlled is shifted to acceleration operation, sufficient filling efficiency cannot be obtained, and furthermore, the response delay of the actuator that drives the control valve may be delayed. Due to this, there was a problem that the engine's follow-up performance during acceleration deteriorated.

Furthermore, when the engine decelerates, it is necessary to utilize pumping loss to increase the braking effect, but in the conventional pumping loss braking method, pumping loss control was performed regardless of the presence or absence of deceleration in a predetermined operating range. sometimes,
There was a problem that a sufficient braking effect could not be obtained and the followability of the engine deteriorated.

[Object of the Invention] The present invention provides an engine intake system that improves fuel efficiency by controlling pumping loss, solves the above problems, and improves the followability of the engine during acceleration and deceleration. The purpose is to provide

[Structure of the Invention] In order to achieve the object stated in "-", the present invention provides an engine that performs load control using a throttle valve and is provided with means for performing pumping loss control to reduce pumping loss. An intake system for an engine is provided, characterized in that it performs pumping loss control at the time of acceleration or deceleration, and is provided with means for reducing the region in which pumping loss control is performed during acceleration or deceleration.

[Effects of the Invention] According to the present invention, when the engine accelerates or decelerates, the operating range in which pumping loss control is performed is reduced, and anticipatory control is performed that takes into consideration the responsiveness of the actuator or predicts the final point of the operating state. Therefore, by performing pumping loss control, it is possible to improve fuel efficiency and improve the followability of the engine during acceleration and deceleration.

[Embodiment] Hereinafter, a first embodiment of the present invention will be explained regarding a two-cylinder rotary piston engine.

As shown in FIG. 1, the rotor piston engine RE has rotors 2f, 2r in casings If, lr.
It is composed of front and rear mountain cylinders F and R that make planetary rotational motion around an eccentric shaft 3 and continuously repeat suction, compression, explosion, expansion, and exhaust. Front and rear working chambers 5f are provided on each rear side of the intermediate housing 4 that forms the partition wall of the mountain cylinders F and H, respectively.

Front and rear intake boats 6f and 6r for supplying intake air to 5r are open.

A common intake passage 7 is provided in order to supply intake air to the front and rear working chambers 5f and 5r, and in this common intake passage 7, an air cleaner 8 detects the amount of intake air from moment to moment. An air flow meter 9 and a throttle valve 11, which is opened and closed in response to depression of an accelerator pedal (not shown), are interposed.

The common intake passage 7 is connected at a branch part 12 slightly downstream of the throttle valve 11 to a front side branch intake passage 1.3f that communicates with the front side intake port 1-6f and a rear side intake bow 1-6r. The front side of these branches into a rear side branch intake passage 13r.

In the rear branch intake passages 13f and +3r, there is freon l-, and in the vicinity of the rear intake bows 1-6f and 6r,
Freon L-, rear injector In' for injecting fuel during intake, 14. r is interposed so that the injection port is slightly inclined in the downstream direction.

By the way, in order to reduce pumping loss by a late closing method using communication between cylinders, the rotors 2f, 2 are connected to the front and rear intake bows (6f, 6r) on the front and rear sides of the intermediate housing 4, respectively. The front,
The rear communication boats], 5f, and 15r are opened, and both the front and rear communication boats 1-1.5 are opened.
A communication passage 16 that communicates f, ], 5r is formed to penetrate the intermediate housing 4 in its thickness direction.

A rotary type control valve 17 that opens and closes the communication passage 16 is interposed at an intermediate position of the communication passage 16 in order to control pumping loss depending on the operating state. By changing the cross-sectional area of the air in the communication passage 16, that is, the opening degree of the control valve can be freely changed. Feedback control is performed so that the opening degree becomes a predetermined target value.

Next, the control valve control mechanism CR will be explained.

As shown in FIG. 3, the control valve 1 interposed in the communication passage 16
7 is provided with an actuator 20 consisting of a negative pressure responsive diaphragm device, and in order to introduce negative pressure in the intake passage downstream of the throttle valve 11 into the pressure chamber 22 of the actuator 20, a A negative pressure introduction passage 26 is provided that communicates the intake passage 22 with the intake passage downstream of the throttle valve. This negative pressure introduction passage 26 includes a boost tank having an appropriate capacity in order to stably secure the negative pressure introduced into the pressure chamber 22 of the actuator 20 near the opening to the intake passage downstream of the throttle valve 11. A boost tank 27 is provided to maintain the negative pressure in the boost tank 27 at a predetermined value.
A regulator 28 is interposed near the negative pressure introduction type.

And then, Akuji from Bipedal Boost Tank 27.

A first solenoid valve 29 for opening and closing the negative pressure introduction passage 26 is interposed at a position on the actuator 20 side, and furthermore, at a position on the actuator 20 side from the first solenoid valve 29, An atmosphere introduction passage 31 communicating with the atmosphere is connected to the negative pressure introduction passage 26, and a second solenoid valve 32 for opening and closing the atmosphere introduction passage 31 is interposed.

The first solenoid valve 29 and the second solenoid valve 32 are duty-controlled by a control circuit 19 composed of a microcomputer, and their opening degree can be freely adjusted. By duty-controlling the second solenoid valve 32, the pressure within the pressure chamber 22 of the actuator 20 is adjusted, and as a result, the control valve 17 is controlled via the link mechanism 33.
The opening degree can be adjusted freely.

The control circuit 19 controls the engine rotation speed detected by the rotation speed sensor 34 (see FIG. 1) and the air flow meter 9.
Intake amount detected by throttle valve opening sensor 3
Feedback control of the control valve 17 is performed using the throttle opening detected by 0 and the control valve opening detected by the control valve opening sensor 35 as input information, and this will be explained below. .

Control circuit 19 (J1
As shown functionally in FIG. 4, the opening degree target value of the control valve 17 is determined. is the engine rotational speed N, and the intake air amount Qa is divided by the engine rotational speed N (hereinafter referred to as 1 rotation intake @
A control valve opening storage circuit 36 stores, as digital information, a control valve opening map (see FIG. 6) expressed as a function of Qa/N, engine speed N, and throttle opening 'rv.

Calculate the target opening value I-o of the control valve 17 from time to time while referring to the two-legged control well opening map using manual information of intake fit Qa and intake fit Qa, and check whether the engine RE is in an acceleration/deceleration state. The control valve opening calculating circuit 37 determines whether or not the opening is correct and corrects the bipedal control well opening target value based on the result, and the momentary actual control valve opening.

Use this as input information to control valve opening target value. and a control valve drive circuit 38 that controls the first solenoid valve 29 or the second solenoid valve 32 in accordance with the deviation and causes the opening degree of the control valve 17 to reach the target value 1-o. .

Hereinafter, a method of controlling the control valve 17 by the control circuit 19 will be explained based on the control flowchart shown in FIG.

As shown in FIG. 5, when the control is started, first, in step S1, the engine rotation speed N detected by the rotation speed sensor 34 (see FIG. 1) and the air flow meter 9 (first
The intake air mQa detected by the throttle valve opening sensor 30 (see FIG. 1) and the throttle opening TVθ detected by the throttle valve opening sensor 30 (see FIG. 1) are read into the control valve opening calculation circuit 37 of the control circuit 19 as control information.

Subsequently, in the next step S2, one revolution intake lf&Qa/N is calculated from the engine rotation speed N and intake air amount Qa read by the step S1, and is stored in the control valve opening storage circuit 36. From a control valve opening map, an example of which is shown in FIG. 6, a temporary control valve opening target value Loi corresponding to the engine rotational speed N and the one-rotation intake amount Qa/N is read.

Next, in step S3, in order to determine whether the operating state of the engine RE is in an acceleration/deceleration state equal to or greater than a predetermined value, the absolute value 1dTVO/dt1 of the differential value of the throttle opening TVO with respect to time is set to a predetermined value. is compared with the limit value a. Here, the limit value a is a constant value that is the limit at which the operating range in which pumping loss control is performed should be reduced in order to improve the followability of the engine RE when the acceleration/deceleration of the throttle opening TVθ exceeds this value. Comparison result 1dT■θ
If /dtl≦a (NO), the acceleration/deceleration is substantially small, so no correction is made by acceleration/deceleration, and the control proceeds to step SI9, where the control valve opening target value (■) is determined in step SI9. -Loi, the process further proceeds to step S7.

On the other hand, as a result of the comparison in step S3 above, 1dTVf
If 9/dtl > a (YES), the operating state of the engine RE is in an acceleration/deceleration state equal to or higher than a predetermined value, so the operating range in which pumping loss control should be performed is reduced in order to improve the followability of the engine RE. In order to
You can proceed to

In step S4, the method for reducing the operating range in which pumping loss control should be performed differs depending on whether the low opening target value Loi of the control valve 17 is moving in the opening direction or in the closing direction. 17 low opening target value L
In order to determine whether oi is moving in the opening direction or in the closing direction, the temporary control valve opening target value Loi read in step S2 is read in step S2 of the previous scan. Temporary control valve opening target value), Oi
It is compared whether it is greater than + or not. As a result of the comparison, if Loi>Loi-1 (YES), control valve 1
The low opening degree target value Loi of No. 7 is moving in the opening direction, and in this case, the control proceeds to step S5.

In step S5, 1701 + of the previous scan is substituted for the control valve opening target value I, 0 (L.-Lor-
3). In this case, since Lot+<LOI, the control valve opening target value Lo is determined by Loi−Lo from the control valve opening target value set in the control valve opening map shown in FIG.
Since i-+ becomes smaller, the operating range in which pumping loss control should be performed is correspondingly reduced. Thereafter, the control proceeds to step S7 to drive the control valve 17 according to this control valve opening degree target value 1-o.

On the other hand, the result of the comparison in step S4 is ■.

If 01≦Loi−+ (NO), the low opening target value Loi of the control valve 17 is moving in the closing direction. is advanced to step S6.

In this case, the low opening target value Loi of the control valve 17 is moving in the closing direction, and the control well opening target value is expected to reach O soon. Assign 0 to the degree target value Lo (+, 0==0)
, the operating range in which pumping loss should be controlled is reduced, and so-called predictive control is used to improve the followability of the engine. Thereafter, the control is performed using the control valve opening target value 1. ,
The process proceeds to step S7 to drive the control valve 17 according to y o.

In step S7, the operating state of the engine is such that the control valve 17 should be fully opened according to the control valve opening degree map, and therefore there is no need for duty control (1, , o-=100
), it is compared whether the control valve opening [1 target value 1-o is less than 100 or not. As a result of the comparison, if L, > l 00 (NO), the control valve 17 should be fully opened, so duty control is unnecessary, and the control is to fully open the control valve 17 and proceed to step S16. .

Thus, in step S]6, the second solenoid valve 32 is fully closed by the control valve drive circuit 38, and the first solenoid valve 32 is fully closed.
Solenoid valve 29 is fully opened.

As a result, the atmosphere introduction passage 31 for introducing atmospheric pressure into the pressure chamber 22 of the actuator 20 is closed, and the negative pressure in the boost tank 27 is completely introduced into the pressure chamber 22 through the negative pressure introduction passage 26. Therefore, the control valve 17 is fully opened via the link mechanism 33, and maximum pumping loss control is performed (see FIG. 3). Next, in step S18, it is determined whether or not the ignition switch is on. If it is on (YES), the engine RE continues to operate, so the control proceeds to step S18.
Returns to 1 and continues. On the other hand, if the ignition switch is off (NO), the operations of engines R and E are stopped, and the control ends.

On the other hand, as a result of the comparison in step S7 in -1-, I-.

< l O0 (YES), furthermore, the engine r
The operating state of the control valve 17 is determined according to the control valve opening degree map.
The control proceeds to step S8 in order to determine whether or not it is in a region (+, . . . o=0) where it is fully closed and therefore does not require duty control.

In step S8, a comparison is made to see if the control valve opening degree target value is greater than zero. As a result of comparison, L. ≦0(N
If o), there is no need to perform duty control, so control proceeds to step SI7 to fully close control valve I7.

Thus, in step S7], the first solenoid valve 29 is fully closed by the control valve drive circuit 38, and the second solenoid valve 32 is fully opened.

As a result, the negative pressure introduction passage 26 that introduces negative pressure into the pressure chamber 22 of the actuator 20 is closed, and atmospheric pressure is completely introduced into the pressure chamber 22 through the atmosphere introduction passage 31. Control valve 17 via mechanism 33
is fully closed and pumping loss control is stopped (see Figure 3). Subsequently, in step S18, it is determined whether or not the ignition switch is on. If it is on (YES), the engine RE continues to operate, so the control returns to step S1 and continues. On the other hand, if the ignition switch is off (NO), the operation of the engine RE has been stopped and the control can be terminated.

On the other hand, as a result of the comparison in step S8 above, L.

>0 (YES), the control valve opening target value 1. -o
Since the value is greater than 0 and less than 100, the control proceeds to step S9 to perform duty control on the first solenoid valve 29 or the second solenoid valve 32 in order to adjust the control valve opening degree.

In step S9, the control valve opening degree I7 detected by the control valve opening degree sensor 35, which is a so-called control item required for feedback controlling the control valve 17, is read into the control valve drive circuit 38.

Subsequently, in the next step S1.0, the deviation Δ of the control valve opening degree I7 of the control valve 17 with respect to the control valve opening degree target value 1-o is determined.
I, = t, ot- (hereinafter referred to as control deviation ΔI7) is calculated. To this control deviation, depending on the value of I7,
Hereinafter, the control valve opening degree I7 is the control valve opening degree [target value 1. - whether the control valve 17 should be controlled in the closing direction, or whether the control valve opening I7 is substantially larger than the control valve opening [I
It is substantially smaller than the target value +-0, so either the control valve 17 should be controlled in the opening direction, or the absolute value 1ΔL of the control deviation ΔI7 is sufficiently small and duty control should be performed to stabilize the control. In order to determine whether the control valve opening degree I should be maintained as it is without performing the above operation, the control first proceeds to step S11.

In step Sl+, if the control deviation ΔL is less than that, the control deviation Lmin is the limit at which the valve opening should be maintained at the current level.
(>0 or less, this is referred to as the limit deviation Lmin). As a result of comparison, ΔL > L
If m1n (Y ES ), the control valve opening ■7 is the control valve opening target value. Since it is substantially smaller than the control valve 1
In order to carry out duty control in the opening direction of 7, the control is performed in step S.
Proceed to 12.

In step S12, the second solenoid valve 32 is fully closed and the atmosphere introduction passage 31 is closed in order to duty-control the control valve 17 in the opening direction. Then, the first solenoid valve 29 has an absolute value of 1ΔL of the control deviation ΔL, as shown in FIG.
In the broken line G that sets the duty ratio of the first solenoid valve 29 or the second solenoid valve 32 with respect to l,
It is opened according to the duty ratio corresponding to the absolute value 1ΔL1 of the control deviation. As a result, a negative pressure corresponding to the opening degree of the bipedal first solenoid valve 29 is introduced from the boost tank 27 into the pressure chamber 22 of the actuator 2o through the negative pressure introduction passage 26, and the opening degree of the control valve 17 increases. while approaching the control valve opening target value Lo. Thereafter, in step SI8, depending on whether the ignition switch is turned on or off, control returns to step SI, continues or ends, respectively.

On the other hand, as a result of the comparison with the above switch SKI, Δ■7≦
If Lmin (NO), it is further determined whether the control valve 17 should be duty-controlled in the closing direction, or whether the current opening degree of the control valve 17 should be maintained since the absolute value 1ΔL1 of the control deviation is less than the limit deviation Lmin. For determination, control proceeds to step SI3.

In step SI3, it is compared whether the control deviation ΔL is smaller than -Lmin. As a result of comparison, △L<-Lm
jn (YES), the control valve opening degree is substantially larger than the control valve opening degree target value Lo, so that control is performed in step S14? in order to duty-control the control valve 17 in the closing direction. I can move on.

In Step S4, the first solenoid valve 29 is fully closed and the negative pressure introduction passage 26 is closed in order to duty-control the control valve 17 in the closing direction. The second solenoid valve 32 is opened in accordance with the duty ratio corresponding to the absolute value 1ΔN, 1 of the control deviation at the broken line G shown in FIG. As a result, in the pressure chamber 22 of the actuator 20,
''Atmospheric pressure corresponding to the opening degree of the second solenoid valve 32 is introduced through the atmospheric air introduction passage 31, and the opening degree of the control valve 17 decreases to the control valve opening target value. approach.

Thereafter, in step S1.8, depending on whether the ignition switch is turned on or off, control returns to step S1, continues, or ends, respectively.

On the other hand, as a result of the comparison in step S13 above, ΔL≧−
If Lmin (No), the absolute value of control deviation 1ΔL1
is less than the limit deviation Lmin (1ΔL1≦Lmin), and the control proceeds to step SI5 in order to maintain the current opening degree of the control valve 17 in order to stabilize the control.

In step S+5, the first solenoid valve 29 and the second solenoid valve 32 are fully closed, and both the negative pressure introduction passage 26 and the atmosphere introduction passage 31 are closed. Therefore, the pressure chamber 22 of the actuator 20 is in a sealed state, and the internal pressure is maintained and does not change.

Therefore, the actuator 20 is not displaced and the opening degree of the control valve 17 is maintained as it is. Thereafter, in step S+8, depending on whether the ignition switch is turned on or off, control returns to step S1, continues, or ends, respectively.

As described above, according to the first embodiment of the present invention, by performing pumping loss control, it is possible to improve fuel efficiency and improve followability of the engine during acceleration and deceleration.

Hereinafter, regarding the reciprocating engine, preferable ones of the present invention,
A second embodiment will be explained.

As shown in FIG. 2, when the intake valve 51 is opened, the reciprocating engine CE sucks the air-fuel mixture from the intake boat 53 communicating with the intake passage 52 into the combustion chamber 55 formed by the cylinder 54. The air-fuel mixture compressed by the piston 56 is ignited and burned by a spark plug (not shown), and when the exhaust valve 57 is opened, the exhaust gas in the combustion chamber 55 is exhausted to the exhaust passage 58. As a result of repeating these strokes, the piston 56 reciprocates within the cylinder 54 in the axial direction of the cylinder 54, and this reciprocating movement is converted into rotational movement of the crankshaft 61 via the connecting rod 59. , the basic structure is such that it becomes the output of the engine CE.

-1- In the intake passage 52, an air cleaner 62 and an air flow meter 6 for detecting the momentary intake air amount are installed in order from the upstream.
3. A throttle valve 64 that opens and closes in response to depression of an accelerator pedal (not shown), and an intake boat 53
An injector 65 for injecting fuel into intake air is provided nearby.

By the way, in order to reduce pumping loss by using the delayed closing method using reflux, a reflux boat 67 that closes slightly later than the intake boat 53 is opened at the upper end surface of the Kishu grilling chamber 55 by a reflux valve 66. The recirculation port 67 communicates with the intake passage 52 at a position slightly downstream of the throat valve 64 via a recirculation passage 68 .

The recirculation valve 66 has a control valve control mechanism C as in the first embodiment.
The control circuit 71 controls the operation or stop of the pumping loss control in accordance with the engine rotational speed through the control circuit 71, and its opening degree is feedback-controlled.

The configuration and operation of the control valve control mechanism CC and control circuit 71 are completely the same as those of the control valve control mechanism CR and control circuit I9 in the first embodiment, respectively, and therefore their description will be omitted.

Therefore, even in a reciprocating engine CE that employs such a late-closing method using recirculation, pumping loss control can improve fuel efficiency and improve the engine's follow-up performance during acceleration and deceleration. can do.

Furthermore, although no specific examples are given, the present invention
Of course, the present invention can also be applied to engines that employ an early closing method for intake valves.

[Brief explanation of the drawing]

FIG. 1 is a system configuration diagram of a two-cylinder rotary piston engine showing a first embodiment of the present invention. FIG. 2 is a system configuration diagram of a reciprocating engine, showing a second embodiment of the present invention. FIG. 3 is a detailed system configuration diagram of the control valve control mechanism shown in FIG. 1 or 2. FIG. FIG. 4 is a control block diagram of the control circuit shown in FIG. 1 or 2. FIG. FIG. 5 is a flowchart showing the control method of the control circuit.
It is. FIG. 6 is a diagram showing a control valve opening degree map in which the control valve opening degree target value is set according to the engine speed and the intake air amount per revolution. FIG. 7 is a diagram showing the duty ratio of the first solenoid valve or the second solenoid valve with respect to the absolute value of the control deviation. RE・Lower re-piston engine, CR・・Control valve control mechanism, II・・Throttle valve, 16・Communication path, 17
・・Control valve, I9・Control circuit, CE・Reciprocating engine, CC・・Control valve control mechanism, 64・・Throttle valve, 68・・Recirculation passage, 66・・
・Recirculation valve, 71・Control circuit.

Claims (1)

[Claims] (1) In an engine that performs load control using a throttle valve and is equipped with means for performing pumping loss control to reduce pumping loss, pumping loss is controlled in a predetermined operating range and pumping loss is lost during acceleration or deceleration. An intake system for an engine, characterized in that it is provided with means for reducing a region to be controlled.