JPH0538334U - Control device for engine with rotary valve - Google Patents

Abstract

(57) [Summary] [Object] The present invention relates to an engine control device having a rotary valve, and by controlling the air-fuel ratio without changing the rotational phase of the rotary valve, idle control is performed only by controlling the air-fuel ratio. The purpose is to be able to do. An air-fuel ratio leaning means 22 for setting an air-fuel ratio such that the air-fuel ratio of an air-fuel mixture supplied to the engine becomes an air-fuel ratio on a lean side when the idle detecting means 21 detects an idle operation state of the engine. With the air-fuel ratio on the lean side set by the air-fuel ratio leaning means 22, the rotation speed detecting means 17
The air-fuel ratio correction means 23 that corrects the air-fuel ratio is provided so that the difference between the actual engine speed detected in 1 and the target engine speed becomes zero.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a control device for an engine having a rotary valve that is rotatably provided in an intake passage separately from an intake valve that opens and closes an intake port and that can change its rotation phase.

[0002]

[Prior Art]

 Conventionally, the amount of air in the intake passage is limited by providing a rotary valve in the intake passage of the engine, eliminating the throttle valve, and changing the rotational phase of this rotary valve [this is called rotary VVT (variable valve timing)]. However, the engine is operated in the stoichio (theoretical air-fuel ratio) state.

That is, as shown in FIGS. 7A, 7B, and 7C, the VVT of the rotary valve, that is, the phase is controlled by the intake valve when the engine is idle [FIG. 7A]. The phase of the rotary valve is largely shifted, the phase is slightly shifted at the partial time [Fig. 7 (b)], and the phase is overlapped at the full opening [Fig. 7 (c)].

[0004]

[Problems to be solved by the device]

 However, if such an engine with a rotary valve is operated in an unslotted state (a state without a throttle valve) at the time of idling, at the time of idling, as shown in FIG. Adiabatic expansion occurs during periods b and c, and the intake air temperature decreases at point c. The compression temperature at point d also drops compared to the engine with a throttle valve. Further, since there is no throttle valve, the intake pressure approaches atmospheric pressure, and as shown in FIG. 9, the torque T becomes almost constant with respect to the rotational speed N, and the automatic governing phenomenon in the coastal current region cannot be used.

Accordingly, the intake air temperature at the compression top dead center becomes low, so that the misfire rate becomes high. Further, since the automatic governing phenomenon in the critical flow region cannot be used, it is necessary to slightly change the air amount. The rotary valve has a problem that it is difficult to make such a subtle change.

The present invention was devised in view of such problems, and in an engine provided with a rotary valve, the air-fuel ratio is controlled by controlling the air-fuel ratio without changing the rotational phase of the rotary valve. It is an object of the present invention to provide a control device for an engine with a rotary valve, which enables idle control only by itself.

[0007]

[Means for Solving the Problems]

 For this reason, the control device for an engine with a rotary valve according to the present invention is provided in an engine having a rotary valve that is rotatably provided in the intake passage and is capable of changing its rotation phase, separately from the intake valve that opens and closes the intake port. The engine opening speed is detected by providing an accelerator opening detection means for detecting the opening degree and a phase determining means for determining the rotation phase of the rotary valve from the accelerator opening degree detected by the accelerator opening degree detecting means. When the engine speed detection means, the idle detection means for detecting the idle operation state of the engine, and the idle operation state of the engine are detected by the idle detection means, the air-fuel ratio of the air-fuel mixture supplied to the engine becomes lean. The air-fuel ratio leaning means for setting the air-fuel ratio so as to obtain the air-fuel ratio and the air-fuel ratio leaning means for leaning the air-fuel ratio The difference between the actual engine speed and the target engine rotational speed detected by the number detecting means so that zero, is characterized in that the air-fuel ratio correction means for correcting the air-fuel ratio is provided.

[0008]

[Action]

 In the control device for an engine with a rotary valve according to the present invention described above, when the idle detection state of the engine is detected by the idle detection means, the air-fuel ratio leaning means leans the air-fuel ratio of the air-fuel mixture supplied to the engine. The air-fuel ratio is set to the air-fuel ratio on the side of the engine. The air-fuel ratio is corrected so that the difference between the engine speed and the target engine speed becomes zero.

[0009]

【Example】

 An embodiment of the present invention will be described below with reference to the drawings. FIGS. 1 to 6 show an embodiment of a control device for an engine with a rotary valve of the present invention, and FIG. 1 is a block diagram showing its control system. 2 is a configuration diagram showing the engine system, FIG. 3 is a schematic perspective view showing the rotary valve phase varying mechanism, FIG. 4 is a flow chart for explaining the air-fuel ratio correction procedure, and FIG. 5 is the air-fuel ratio. FIG. 6 is a diagram for explaining that the correction is performed on the lean side of the air-fuel ratio, and FIG. 6 is a characteristic diagram of the air-fuel ratio correction coefficient.

Now, the engine system controlled by this device is configured as shown in FIG. 2. In FIG. 2, reference numeral 1 is an engine, which communicates with a combustion chamber 2 of the engine 1 and an intake passage. 3 and an exhaust passage 4 are provided, an intake valve 5 is provided at an intake port 3a of the intake passage 3, and an exhaust valve 6 is provided at an exhaust port 4a of the exhaust passage 4.

Further, the intake valve 5 and the exhaust valve 6 are driven by a valve operating mechanism 8 which is interlocked with a crank shaft connected to a piston 7, and the intake / exhaust ports 3 a, 4 of the intake / exhaust passages 3, 4 are driven. By opening and closing a, the combustion chamber 2 is sucked and exhausted.

An injector (electromagnetic valve) 9 for injecting fuel toward the intake port 3a is provided on the upstream side of the intake port 3a of the intake passage 3, and a rotary valve 10 and a rotary valve 10 are provided on the upstream side thereof. An air cleaner 11 is provided.

The rotary valve 10 has a substantially columnar shape, has an air passage hole 10 a penetrating therethrough in parallel with a diameter direction thereof, and is rotatably provided to open and close the intake passage 3.

That is, the rotary valve 10 described above is rotatably supported in the valve housing 3A provided in the intake passage 3, and as shown in FIG. 3, the rotary support shaft 10A of the rotary valve 10 is provided. Is rotationally driven by a drive force transmission mechanism from the engine side, which is attached to a phase variable mechanism 30 described later.

As shown in FIG. 3, the phase changing mechanism 30 is composed of a planetary gear mechanism. The sun gear 31 in this mechanism is a belt transmission mechanism that uses the rotation of the crankshaft of the engine as a drive source. It is provided integrally with the shaft of the pulley 31A used.

The sun gear 31 meshes with the planetary gear 32 at an equidistant position on the outer peripheral surface, that is, at a position divided into three in this embodiment, and the planetary gear 32 is a worm wheel provided as a carrier. It is rotatably supported by 33.

The planetary gear 32 described above meshes with the inner teeth 34 A of the ring gear 34 located on the outer periphery thereof, and the outer teeth 34 B formed on the outer periphery of the ring gear 34 are integrated with the drive shaft of the rotary valve 10. Drive gear 35 is engaged. Therefore, the rotation of the crankshaft is transmitted to the planetary gear 32 via the sun gear 31, and the planetary gear 32 rotates the ring gear 34 to rotate the drive gear 35 and transmit the rotational force to the rotary valve 10. It is supposed to be.

On the other hand, a worm gear 36 meshes with the above-mentioned worm wheel 33, and this worm gear 36 is provided integrally with the output shaft of the drive motor 13.

Further, as the drive motor 13, a stepping motor capable of rotating in the forward and reverse directions is used, and its rotation direction and rotation amount are set by an electronic control unit (ECU) 12 which will be described later. The rotation variable position of the drive gear 35 for the rotary valve meshing with 34 is controlled in a variable phase, that is, the rotation phase is adjusted and controlled.

That is, the above-described ECU 12 is composed of a microcomputer, and the input side via the I / O interface attached to this microcomputer is connected to the accelerator opening degree as shown in FIG. In addition to the accelerator depression amount information from the accelerator position sensor 14 as a detection means, detection information from another sensor 19 'is input.

A drive circuit (driver) of the drive motor 13 is connected to the output side of the ECU 12 described above, and the drive motor 13 having a built-in phase sensor is connected to the drive circuit.

The phase sensor equipped with the drive motor 13 outputs phase information to the ECU 12 to determine the phase control status.

Then, in this case, when the rotary valve 10 is controlled, the ECU 12 basically changes the phase of the opening / closing timing of the rotary valve 10 with respect to the intake valve 5 based on the signal from the accelerator position sensor 14. Works like.

That is, in the fully open region, the phases are set so as to overlap the entire opening / closing period of the intake valve 5 (see FIG. 7C), and in the partial region, the intake valve 5 opens later than the opening timing of the intake valve 5. At the same time, the phase is set so as to obtain a period in which the introduction of intake air is completed later than the closing timing of the intake valve 5 (see Fig. 7 (b)). In the idle region, the phase is set to further shorten the overlap period. It is set as shown in FIG. 7 (a).

Therefore, as shown in FIG. 1, the ECU 12 has the function of the phase determining means 15 that determines the rotational phase of the rotary valve 10 from the accelerator opening detected by the accelerator position sensor 14. Become.

When the drive motor 13 rotates in the direction indicated by the symbol α in FIG. 3, the drive gear 35 moves from the position indicated by the symbol γ to the direction indicated by the symbol α through each gear in the transmission path. For example, when the drive motor 13 rotates in the opposite direction (direction indicated by reference sign β), the drive gear 35 is delayed from the position indicated by reference sign γ to the direction indicated by reference sign β. Horn

Then, the rotation amount and the rotation direction of the drive motor 13 are checked by a phase sensor in the drive motor 13 and feedback control is performed until a predetermined state is obtained.

In this way, the rotary valve 10 changes its phase due to its rotation, and the timing of the vent hole 10a with respect to the intake passage 3 when the intake valve is opened becomes a state orthogonal to or parallel to the intake passage 3, The intake passage 3 is designed to be opened and closed from fully closed to fully open.

The above is the description regarding the control of the rotary valve 10. Next, the fuel supply control (air-fuel ratio control) to the engine 1 will be described.

Regarding the air-fuel ratio control, as shown in FIG. 1, the ECU 12 has an accelerator position sensor 14 as an engine load sensor, an engine speed sensor 17 as an engine speed detection means, and an idle operation state. A detection signal from an idle switch 21 for detecting the temperature and other sensors (cooling water temperature sensor, intake air temperature sensor, atmospheric pressure sensor, etc.) 19 are input.

As a function relating to air-fuel ratio control, the ECU 12 has the functions of a basic drive time setting means 18, a correction coefficient setting means 20, an air-fuel ratio leaning means 22, and an air-fuel ratio correcting means 23.

Here, the basic drive time setting means 18 receives the detection signals from the accelerator position sensor 14 and the engine speed sensor 17, obtains the intake air amount Q, and determines the intake air amount Q and the engine speed N. The basic driving time T _B is set according to the engine operating state from the above, and the correction coefficient setting means 20 adjusts the correction coefficient according to the cooling water temperature information, the intake air temperature information, the atmospheric pressure information and the like from other sensors 19. Ru der used to set the K _H.

When the idle switch 21 detects the idle operation state of the engine, the air-fuel ratio leaning means 22 sets an air-fuel ratio _leaning coefficient K _{LEAN so} that the air-fuel ratio of the air-fuel mixture supplied to the engine is lean. The air-fuel ratio on the side is set.

Further, the air-fuel ratio correction means 23 is a target engine with the actual engine speed detected by the engine speed sensor 17 in a state where the air-fuel ratio leaning means 22 keeps the air-fuel ratio on the lean side. The air-fuel ratio is corrected so that the difference ΔN from the target engine speed set by the rotation speed setting means 24 becomes zero. This correction is made by setting the air-fuel ratio correction coefficient K ′. .. The relationship between the rotational speed difference ΔN and the air-fuel ratio correction coefficient K ′ is set as shown in FIG. 6, for example.

Then, the signal from the ECU 12 (the output of the air-fuel ratio correction means 23) is supplied to the injector 9, and the injector 9 _causes T = T _B (K _H · K _LEAN + K ′) = T _B · (K + K ') (where, in K = K _H · K _LEAN, and, if the idling state is not detected, K _LEAN = 1, K' has a = 0) control valve opening time As a result, the fuel injection amount and thus the air-fuel ratio are controlled according to the engine operating conditions.

Next, an air-fuel ratio control procedure in the ECU 12 will be described with reference to the flowchart shown in FIG. First, in step a1, the intake air amount Q is obtained from the accelerator opening θ detected by the accelerator position sensor 14 and the engine speed N detected by the engine speed sensor 17, and based on this intake air amount Q Then, the basic drive time T _B is calculated, and if it is determined in step a2 that the accelerator opening θ by the accelerator position sensor 14 is the idle opening θs, then in step a3 the air-fuel ratio leaning is performed. The air-fuel ratio leaning coefficient K _LEAN is set by the means 22 to set the air-fuel ratio to the lean side (lean side) air-fuel ratio.

If the idle switch 21 is turned on in step a4, the engine speed control mode during idle operation is entered in step a5, and the difference ΔN between the target engine speed N s and the actual engine speed N is reached. look, further at step a6, 'seeking, in step a9, (K + K' air-fuel ratio correction value K corresponding to the rotational speed difference ΔN by the air-fuel ratio amendments means 23 fuel from) and Q (T _B) The injection amount (injector drive time T 1) is determined.

On the other hand, if the accelerator opening degree θ does not detect the idle opening degree θs in step a2, the process proceeds to step a7 to set the air-fuel ratio to stoichiometric, and in step a8, the correction value K ′ = 0 is set and the process proceeds to step a9. Then, the fuel injection amount (injector drive time T) is determined from K and Q (T _B ).

With such a configuration, in the control device for an engine with a rotary valve according to the present invention, the amount of fuel supplied is controlled in order to control the idle rotation, and the air-fuel ratio is set to the lean side (lean side). The fuel control is performed in advance. By controlling the fuel on the lean side A where the torque gradient is steep as shown in Fig. 5, it is possible to use a large torque fluctuation. Control can be performed.

Further, by performing the idle control by the fuel amount (air-fuel ratio) control, the phase of the rotary valve 10 can be fixed, and the idle control can be easily performed only by the fuel amount (air-fuel ratio) control. In the lean state, since the amount of air is relatively large, the compression temperature rises, the temperature is prevented from lowering, and ignition mistakes are reduced, and stable idle control can be performed.

Therefore, it is possible to solve the problem of unstable and high misfire rate like the idle control in the conventional rotary valve VVT.

[0042]

[Effect of the device]

 As described in detail above, according to the control device for an engine with a rotary valve of the present invention, a rotary valve that is rotatably provided in the intake passage and that can change its rotation phase is provided separately from the intake valve that opens and closes the intake port. The engine includes an accelerator opening degree detecting means for detecting an accelerator opening degree and a phase determining means for determining a rotation phase of the rotary valve from the accelerator opening degree detected by the accelerator opening degree detecting means. A rotation speed detection means for detecting the rotation speed, an idle detection means for detecting an idle operation state of the engine, and an idle air-fuel mixture supplied to the engine when the idle operation state of the engine is detected by the idle detection means. An air-fuel ratio leaning unit that sets the air-fuel ratio so that the fuel ratio becomes the lean-side air-fuel ratio, and an air-fuel ratio on the lean side by the air-fuel ratio leaning unit. In this state, the air-fuel ratio correcting means for correcting the air-fuel ratio is provided so that the difference between the actual engine speed detected by the speed detecting means and the target engine speed becomes zero. With the air-fuel ratio of the engine with a rotary valve set to the lean side, the idle control can be performed by correcting the air-fuel ratio so that the difference between the actual engine speed and the target engine speed becomes zero. Therefore, there is an advantage that stable idle control can be easily performed only by controlling the air-fuel ratio.

[Brief description of drawings]

FIG. 1 is a block diagram showing a control system of a control device for an engine with a rotary valve according to an embodiment of the present invention.

FIG. 2 is a configuration diagram showing an engine system including the present device.

FIG. 3 is a schematic perspective view showing a rotary valve phase varying mechanism.

FIG. 4 is a flowchart for explaining a control procedure of the present invention.

FIG. 5 is a diagram illustrating a control setting area of the present invention.

FIG. 6 is a characteristic diagram showing a relationship between a rotational speed difference and an air-fuel ratio correction coefficient.

FIG. 7 is a diagram illustrating opening / closing timing between a rotary valve and an intake valve.

FIG. 8 is a PV diagram when a conventional engine with a rotary valve is idle.

FIG. 9 is a torque characteristic diagram showing a comparison between a case with a conventional rotary valve engine and a case without a throttle valve.

[Explanation of symbols] 1 engine 2 combustion chamber 3 intake passage 3a intake port 3A valve housing 4 exhaust passage 4a exhaust port 5 intake valve 6 exhaust valve 7 piston 8 valve mechanism 9 injector 10 rotary valve 10a vent hole 11 air cleaner 12 electronic control Unit (ECU) 13 Motor 14 Accelerator opening detection means (accelerator position sensor) 15 Phase determination means 17 Engine speed detection means (engine speed sensor) 18 Basic drive time setting means 19, 19 'Other sensors 20 Correction coefficient setting Means 21 Idle detection means (idle switch) 22 Air-fuel ratio leaning means 23 Air-fuel ratio correction means 24 Target engine speed setting means 30 Phase changing mechanism 31 Sun gear 31A Pulley 32 Planetary gear 33 Worm wheel 34 Ring gear 34A Internal teeth 4B external teeth 35 drive gear 36 worm

Claims (1)

[Scope of utility model registration request] 1. An accelerator opening detection means for detecting an accelerator opening in an engine having a rotary valve rotatably provided in an intake passage and having a rotation phase thereof different from an intake valve for opening and closing an intake port. , A phase determining means for determining a rotational phase of the rotary valve from the accelerator opening detected by the accelerator opening detecting means, a rotational speed detecting means for detecting an engine rotational speed, and an idle operating state of the engine. Idle detecting means for detecting, and an air-fuel ratio for setting the air-fuel ratio so that the air-fuel ratio of the air-fuel mixture supplied to the engine becomes a lean side air-fuel ratio when the idle operating state of the engine is detected by the idle detecting means. The lean engine means and the actual engine speed detected by the engine speed detecting means in the state where the air-fuel ratio on the lean side is adjusted by the air-fuel ratio leaning means. A control device for an engine with a rotary valve, comprising: an air-fuel ratio correction means for correcting the air-fuel ratio so that the difference from the target engine speed becomes zero.