JPH055441A - Intake air amount control device for engine - Google Patents

Abstract

(57) [Summary] [Purpose] In idle speed control by bypass air supply, control convergence is improved and overshoot during large flow rate control is prevented. [Configuration] In the intake system of the rotary piston engine 1,
Two systems of bypass air supply devices 16 and 17 that constitute an idle speed control device are provided, the outlet of the bypass passage 18 of one bypass air supply device 16 is opened immediately downstream of the throttle valve 14, and the other bypass air supply device 17 is provided. The outlet of the bypass passage 20 is opened to the working chamber 4a during the intake stroke. Then, the flow rate control valve 19 of the upstream side device 16 performs open control by a preset control amount with respect to the target rotation speed, and the flow rate control valve 21 of the downstream side device 17 performs feedback control according to the rotation speed deviation. Further, when the feedback control amount becomes equal to or larger than the predetermined value, a part of the feedback control amount is distributed to the upstream bypass air supply device 16.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an intake air amount control device for an engine, and more particularly to an intake air amount control device for controlling an engine idle speed to a target speed.

[0002]

2. Description of the Related Art As an idle speed control device (hereinafter referred to as ISC) for controlling an engine idle speed to a target speed according to a water temperature, a bypass air amount that bypasses a throttle valve is used as a target speed. It is known that feedback control is performed based on a deviation between the actual engine speed and the engine speed.

By the way, in order to expand the controllable range of the engine speed in the above ISC by controlling the bypass air amount, it is necessary to increase the maximum flow rate of the bypass air to expand the controllable range of the intake air amount. However, if the maximum flow rate of the bypass air is increased in this way, the control accuracy of the opening degree adjustment of the flow rate control valve is reduced, and the bypass air amount cannot be adjusted accurately. Therefore, as disclosed in Japanese Patent Publication No. 63-65820, for example, a plurality of flow control valves are provided in parallel in the bypass passage, and the flow control valves are sequentially opened according to the amount of bypass air. Proposed.

[0004]

In the ISC in which the idle speed of the engine is controlled by controlling the bypass air amount, when the maximum flow rate of the bypass air is increased in order to expand the controllable range of the intake air amount, the above-mentioned problem occurs. However, in the conventional device of this type, as in the device described in the above publication, the outlet of the bypass passage is located far away from the intake port of the engine at the upstream side. However, it takes time until the intake air amount actually increases due to bypass air even if the flow control valve opens, so the control response is not good and the target speed There was also a problem that convergence could not be obtained sufficiently. There is also the idea of providing the outlet of the bypass passage as close to the intake port as possible in order to improve the responsiveness, but if the outlet of the bypass passage is close to the intake port, the responsiveness at normal times will be improved. In case of large flow rate control with large control width, the response is too good and overshoot occurs,
The atomization of fuel by bypass air cannot be expected either.

The present invention has been made in order to solve the above problems, and it is possible to improve the response of the intake air amount control by the bypass air and prevent the control overshoot during the large flow rate control. An object is to obtain an intake air amount control device for an engine.

[0006]

An intake air amount control apparatus for an engine according to the present invention comprises a bypass passage for bypassing a throttle valve in an engine intake system and a flow control valve for controlling a flow rate of bypass air flowing through this passage. At least two bypass air supply devices are provided, and the respective passage outlets of these bypass air supply devices are arranged separately on the upstream side and the downstream side of the engine intake system, and the bypass air supply is arranged on the upstream side. It is characterized in that the device is of a large flow rate control type, and the bypass air supply device having the passage outlet on the downstream side is of a small flow rate control type.

In the intake air amount control device for the engine having the above construction, the first and second control means are provided, and the flow control valve of the bypass air supply device having the passage outlet on the upstream side is first controlled. Control means by open control according to the target rotation speed during idling, and the flow control valve of the bypass air supply device having the passage outlet on the downstream side is controlled by the second control means during idling. Feedback control can be performed according to the deviation between the engine speed and the actual engine speed.

Further, in the case where the first and second control valves are provided, when the feedback control amount of the flow rate adjusting valve of the bypass air supply device having the passage outlet on the downstream side is equal to or more than a predetermined value, A part of the feedback control amount by the second control means is partly distributed so that the bypass air supply device having the passage outlet on the upstream side shares an air amount corresponding to a part of the feedback control amount. Means can be provided for the transfer.

When applied to a rotary piston engine, the passage outlet of one bypass air supply device is opened in the intake passage, and the passage outlet of the other bypass air supply device is operated during the intake stroke of the rotary piston engine. It can be opened to the chamber.

[0010]

The bypass air supply device, which has the passage outlet on the downstream side and is of the small flow rate control type, is easy to ensure the control accuracy because it is the small flow rate control, and the passage outlet is the intake port. Since they are close, the response of the intake air amount control is good. In addition, the bypass air supply device, which has the passage outlet on the upstream side and is of the large flow rate control type, is easy to secure the maximum flow rate because of the large flow rate control, and the bypass air supply device from the passage outlet to the intake port Absorbs the overshoot at the time of large flow rate control by the volume of. Therefore, by combining the bypass air supply devices of at least two systems in which the passage outlets are separately arranged on the upstream side and the downstream side, both the responsiveness of the intake air amount control and the overshoot prevention during the large flow rate control are realized. Further, in particular, the flow speed adjusting valve of the bypass air supply device having the passage outlet arranged on the downstream side is feedback-controlled according to the deviation between the target engine speed during idling and the actual engine speed, so that the idle speed control is performed. The convergence of is improved. Further, at that time, when the feedback control amount becomes equal to or larger than a predetermined value, the air amount corresponding to a part of the feedback control amount is distributed to the bypass air supply device having the passage outlet arranged on the upstream side. The control connection becomes smooth.

In the rotary piston engine, when the passage outlet of the bypass air supply device on the downstream side opens into the working chamber during the intake stroke, the control response is further improved.

[0012]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is an overall view of an embodiment of the present invention applied to a rotary piston engine. In this embodiment, the rotary piston engine 1 is composed of a combination of a housing 2 having a two-node trochoidal inner peripheral surface and a substantially triangular rotor 3 having an inner envelope as a basis. Three working chambers 4a, 4b, 4c are formed between the rotors 3. Then, in the housing 2, the intake port 5 and the exhaust port 6 are sandwiched across the short axis.
Further, two spark plugs 7, 8 on the trailing side and the leading side are provided in the vicinity of the short axis on the side facing the ports 5, 6.

The rotary piston engine 1 has two cylinders (two rotors), and an intake passage 10 extending from the air cleaner 9 is branched into two and connected to an intake port 5 of each cylinder. A primary injector 11 is arranged near the intake port 5 of each cylinder, and a secondary injector 12 is arranged upstream of the branch portion of the intake passage 10. A surge tank 13 is provided in the intake passage 10 upstream of the secondary injector 12, and a throttle valve 14 is provided on the inlet side of the surge tank 13.
An air flow meter 15 is provided directly downstream of the air cleaner 9.

The intake system of the rotary piston engine 1 is provided with upstream and downstream bypass air supply devices 16 and 17 constituting ISC, respectively. Among them, the upstream bypass air supply device 16 includes the intake passage 10
The bypass valve 18 is branched from the upstream side of the throttle valve 14 and the passage outlet is opened to the downstream side of the throttle valve 14, and a duty solenoid type flow rate control valve 19 for controlling the amount of air flowing through the bypass passage 18. On the other hand, the downstream bypass air supply device 17 has a bypass passage 20 that branches from the upstream side of the throttle valve 14 and has a passage outlet that opens into the working chamber 4a during the intake stroke of the rotary piston engine 1, and the amount of air flowing through the bypass passage 20. Duty solenoid type flow control valve 2 for controlling
In the bypass passage 20, the boost tank 2 is provided immediately upstream of the flow control valve 21.
Two are provided. Further, the flow rate control valve 21 on the downstream side is set to have a smaller valve diameter than the flow rate control valve 19 on the upstream side.

The intake system is also provided with an air passage 23 for idle adjustment, which branches from just upstream of the throttle valve 14 of the intake passage 10 and opens to the surge tank 13.
An idle adjustment screw 24 is provided in the air passage 23.
Is provided. Further, another air passage 25 that branches from the upstream side of the throttle valve 14 is provided, and the air passage 25 branches into two, one of which is the air bleed passage 2
6 is connected to the primary injector 11, and the other is connected to an oil plug 28 mounted on the housing 2 as an air passage 27 for oil diffusion.

The fuel injection and ignition are controlled by the control unit 29, and the two bypass air supply devices 16 and 17 on the upstream side and the downstream side are also controlled by the control unit 29. Therefore, the control unit 29 receives an engine speed signal from a rotation sensor (not shown), an intake air amount signal from the air flow meter 15, a throttle opening signal from a throttle sensor attached to the throttle valve 14, an engine water temperature signal and the like. It is entered as information. Control unit 29
Calculates the fuel injection amount and the ignition timing based on these information, and also calculates the bypass air supply amount by each bypass air supply device 16, 17. Then, the control unit 29 outputs an injection signal to each of the primary and secondary injectors 11 and 12, and the igniter 3 is connected to the ignition coils 30 and 31 connected to the trailing-side and leading-side ignition plugs 7 and 8, respectively.
An ignition signal is output via 2 and 33, and a duty signal corresponding to the required bypass air amount is output to the flow rate control valves 19 and 21 of the bypass air supply devices 16 and 17, respectively.

The flow rate control valve 19 of the upstream side bypass air supply device 16 is controlled by open control by a preset control amount with respect to the target rotation speed according to the engine water temperature during idling. In addition, the downstream bypass air supply device 17
The flow control valve 21 is controlled by feedback control according to the deviation between the target engine speed and the actual engine speed. Further, when the feedback control amount becomes large and it is not possible to catch up only by the control of the downstream flow control valve 19,
Control is performed such that a part of the feedback control amount is transferred to the upstream bypass air supply device 16 and the flow rate of the upstream flow control valve 19 is increased. In the downstream bypass air supply device 17, the outlet of the bypass passage 20 opens directly into the working chamber 4a of the rotary piston engine 1, and the flow control valve 21 is a small flow control type with a small valve diameter. Since the control accuracy is high, feedback control with a high responsiveness of the intake air amount can be performed, and the convergence of the idle speed control is improved. Further, since the upstream bypass air supply device 16 is provided with the flow control valve 19 having a large valve diameter, the maximum bypass air flow rate is secured thereby.

FIG. 2 is a flow chart for executing the above control of this embodiment. This will be described below. In addition,
S1 to S22 indicate each step.

When the engine starts, at S1, the engine speed N
e is read, and the throttle opening is read in S2.

Next, to see if the engine speed Ne is the predetermined rotation speed Ne ₁ or less in S3, if Ne is Ne ₁ or less, then the throttle opening in S4 to see whether fully closed. If the throttle is fully closed in S4, it means that the engine is idling. Therefore, the process goes to S5 to start the idle speed control. If either S3 or S4 is NO, it means that the engine is not idle, and the process returns.

If it means idling, the engine water temperature is read in S5, and the target engine speed N ₀ in idling is read in from the engine water temperature map in S6.

Then, in S7, the basic control amount Gb of the open control preset according to the target rotational speed N ₀ is calculated, and then in S8, the power steering or the on / off state of the load of the air conditioner (load state) is calculated. ) Is read, and the load correction amount G _H according to the load state is calculated in S9.

Next, in S10, it is determined whether the engine speed Ne is less than or equal to the target speed N ₀ . If Ne is higher than N _O , the feedback control amount G _{FB is} determined in S11.
The reduced, Ne is increasing G _FB equal to or less than N _O.

Next, in S13, it is checked whether or not the flag F for executing the control for shifting a part of the feedback control amount is set in the flow rate control valve 19 (upstream ISC) of the upstream bypass air supply device 16. If the flag F is not set, it is _checked in S14 whether G _FB exceeds the predetermined value G _FB1. If not, the process goes to S15 to drive the upstream ISC with the control amount of Gb ₁ + _GH. , S16
Go to Gb ₂ + G _FB to downstream bypass air supply device 1
7 to drive the flow control valve 21 (downstream ISC). Here, Gb ₁ + Gb ₂ = Gb, and the values of Gb ₁ and Gb ₂ are preset.

If G _FB exceeds G _FB1 in S14, the process goes to S17 to reduce G _FB which is the feedback control amount on the downstream side by a predetermined value K, and a flag F is set in S18. Then, in S19, the upstream ISC is driven by the control amount of Gb ₁ + _GH + K, and thereby part of the feedback control amount is shared by the upstream side. Also,
In step S16, the downstream ISC is driven using the feedback control amount G _FB reduced by K.

If the flag F is already set in S13, the process goes to S20 and G _FB is set to the predetermined value G _FB2.
See if it becomes smaller than (G _FB2 <G _FB1 ), N
If it is O, the process proceeds to S19 to continue the control while shifting a part of the feedback control amount to the upstream ISC.

When the G _FB becomes smaller than the G _FB2 in S20, the process goes to S21, the G _FB is increased by the amount (K) reduced in S17, and the flag F is cleared in S22. Then, as before, the upstream ISC is driven by the control amount of Gb ₁ + _GH in S15, and the downstream ISC is driven by Gb ₂ + G _{FB in} S16.

In the above embodiment, the one applied to the rotary piston engine has been described, but the present invention is not limited to this and can be applied to a reciprocating engine.

[0030]

The present invention is constructed as described above, and the passage outlet of the bypass air supply device of the small flow rate control type with good control accuracy is arranged on the downstream side of the intake system. Is secured and the convergence of control is improved, and the passage outlet of the large flow rate control type bypass air supply device is arranged on the upstream side of the intake system, so it is easy to secure the maximum flow rate and large. It is possible to prevent overshoot during flow rate control.

Further, feedback control of the engine speed during idling is performed by the flow rate control valve of the bypass air supply device having the passage outlet arranged on the downstream side, whereby the convergence of the idle speed control is improved, and At this time, when the feedback control amount becomes equal to or larger than a predetermined value, the air amount corresponding to a part of the feedback control amount is distributed to the upstream bypass air supply device, so that the control connection becomes smooth.

Further, particularly in the rotary piston engine, the response of control is improved and the convergence is further improved by opening the passage outlet of the bypass air supply device on the downstream side into the working chamber during the intake stroke.

[Brief description of drawings]

FIG. 1 is an overall view of an embodiment of the present invention

FIG. 2 is a flowchart for executing the control of the above embodiment.

[Explanation of symbols]

 1 rotary piston engine 4a working chamber (intake stroke) 10 intake passage 14 throttle valve 16 upstream bypass air supply device 17 downstream bypass air supply device 18, 20 bypass passage 19, 21 flow control valve 29 control unit

Claims (1)

Claim: What is claimed is: 1. An engine intake system is provided with at least two bypass air supply devices each including a bypass passage for bypassing a throttle valve and a flow control valve for controlling a flow rate of bypass air flowing through the passage. The bypass outlets of these bypass air supply devices are separately arranged on the upstream side and the downstream side of the engine intake system, and the bypass air supply device having the passage outlets on the upstream side is a large flow control type An intake air amount control device for an engine, characterized in that the bypass air supply device having the passage outlet arranged in the inside is of a small flow rate control type. 2. A first control means for controlling, by open control, a flow rate adjusting valve of a bypass air supply device having a passage outlet on the upstream side, and a passage outlet on the downstream side. 2. The intake of the engine according to claim 1, further comprising second control means for controlling the flow rate adjusting valve of the bypass air supply device arranged by feedback control according to a deviation between the target engine speed at idle and the actual engine speed. Air volume control device. 3. When the feedback control amount of the flow rate adjusting valve of the bypass air supply device having the passage outlet on the downstream side is equal to or more than a predetermined value, an air amount corresponding to a part of the feedback control amount is set to the upstream side. The engine intake according to claim 2, further comprising means for transferring a part of the feedback control amount by the second control means to the first control means so that the bypass air supply device on which the passage outlet is arranged is assigned. Air volume control device. 4. At least two bypass air supply devices are provided in an intake system of a rotary piston engine, each bypass air bypass device bypassing a throttle valve and a flow control valve controlling a flow rate of bypass air flowing through the bypass valve. An intake air amount control for an engine, characterized in that a passage outlet of an air supply device is opened in an intake passage, and a passage outlet of the other bypass air supply device is opened in a working chamber during an intake stroke of the rotary piston engine. apparatus.