JP3036340B2 - Switching control system for cylinder-stop engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a switching control system for a cylinder-stop engine which stops the operation of a predetermined cylinder in accordance with a load condition or the like.

[0002]

2. Description of the Related Art In a cylinder-stop engine in which the operation of a predetermined cylinder is stopped in accordance with a load state or the like, a large output shaft torque can be obtained in a cylinder-stop operation when a throttle valve opening is small at a certain rotational speed. It is known that when the opening of the throttle valve increases, a larger output shaft torque can be obtained in all-cylinder operation.

Therefore, switching between the cylinder-stop operation and the all-cylinder operation in such a cylinder-stop engine is performed by changing the output shaft torque at the same throttle opening degree during the cylinder-stop operation and the all-cylinder operation as shown in FIG. It is customary to do this at equal points (cross points). If switching is performed at such a point, there is essentially no torque difference and no shock is generated.

[0004]

However, at the time of transition from the cylinder-stopped operation state to the all-cylinder operation state, the intake pipe pressure does not immediately reach the required value for all cylinders due to the capacity of the intake system. The pipes are high and will switch after a lot of air enters, so a large torque is generated, which appears as a body shock through the engine mount, drive train and wheels.

[0005] The shock due to the torque difference is generated at high speeds (3rd, 4th, 5th speed, etc.) where the transmission gear ratio is small.
I don't mind much, but the low gear (1, 2,
In the case of (speed), a slight change in torque greatly affects the vehicle body shock. In order to solve such a problem, switching from the cylinder-stop operation state to the all-cylinder operation state is performed by changing the switching characteristic LA during operation with a low-speed gear as shown in FIG. It is conceivable that the switching is performed using different characteristics using the two characteristics of the switching characteristic HA.

Incidentally, the switching characteristic L in FIG.
A is set to smoothly transition from the cylinder-stop operation state to the all-cylinder operation state during low-speed gear operation, but the transition from the all-cylinder operation state, which is the transition in the opposite direction, to the cylinder-stop operation state is the same. When the switching is performed with the switching characteristic LA, the state immediately before the switching remains and affects, so that the intake pipe internal pressure immediately after the switching is lower than the required pressure, and the occurrence of a shock is predicted.

Therefore, as shown in FIG. 13, in order to smoothly transition from the all-cylinder operation state to the closed cylinder operation state,
It is conceivable to set a switching characteristic LB different from the switching characteristic LA. This is to set a so-called hysteresis component, which has different characteristics depending on the switching direction in the switching characteristics between the all-cylinder operation state and the closed cylinder operation state.

The situation in which the hysteresis component should be provided is the same even in a high-speed gear operation as shown in FIG. 14, and it is desirable to provide a switching characteristic HB for smooth transition. Here, the above-mentioned hysteresis component is set to be larger than that at the time of the low-speed gear when the driving force is small and the accelerator pedal needs to be depressed more in the case of the high-speed gear driving with a large throttle opening change for the same acceleration. Will be.

Incidentally, as described above, the switching characteristic between the all-cylinder operation state and the cylinder-stop operation state and the amount of hysteresis are as follows.
It is necessary to set according to the transmission gear ratio of the transmission,
In an automatic transmission vehicle (AT vehicle), since the output torque ratio changes due to the torque converter, there is a problem that the optimum switching characteristics cannot be set only by the detection signal from the transmission.

The present invention has been made in view of the above problems, and has been developed in consideration of an automatic transmission vehicle (A).
It is an object of the present invention to provide a switching control system for a cylinder-stop engine that can set an optimum switching characteristic even in a T-car.

[0011]

Therefore, the switching control system for a cylinder-stop engine according to the present invention can change the number of working cylinders at least according to an operating state including a load state of the engine, and can control the number of operating cylinders via a torque converter. An input shaft rotation speed detecting means for detecting a rotation speed of an input shaft of the torque converter, and an output shaft for detecting a rotation speed of an output shaft of the torque converter. Rotation speed detection means, drive shaft torque calculation means for obtaining a drive shaft torque of the engine from the input shaft rotation speed and the output shaft rotation speed detected by the input shaft rotation speed detection means and the output shaft rotation speed detection means, respectively; An engine output torque calculating means for detecting an engine load to obtain an engine output torque; and Equivalent gear ratio calculating means for obtaining an equivalent gear ratio from a transmission gear ratio and a ratio between a dynamic shaft torque and an engine output torque calculated by the engine output torque calculating means; and an equivalent gear calculated by the equivalent gear ratio calculating means. Hysteresis characteristic setting means for setting the hysteresis characteristic of the cylinder deactivation region according to the ratio; It is characterized by having been configured with.

[0012]

In the switching control apparatus for a cylinder-stop engine according to the present invention, the input shaft rotation speed detecting means detects the rotation speed of the input shaft in the torque converter, and the output shaft rotation speed detecting means detects the output of the torque converter. The drive shaft torque is calculated by the drive shaft torque calculating means based on the input shaft speed and the output shaft speed detected by the input shaft speed detector and the output shaft speed detector, respectively. Ask. Further, the engine output torque calculating means detects the load of the engine to determine the engine output torque. Then, an equivalent gear ratio is calculated by an equivalent gear ratio calculating means, based on a transmission gear ratio and a ratio between the drive shaft torque calculated by the drive shaft torque calculating means and the engine output torque calculated by the engine output torque calculating means.
Further, the hysteresis characteristic of the cylinder deactivation region is set by the hysteresis characteristic setting means based on the equivalent gear ratio calculated by the equivalent gear ratio calculation means, and the cylinder deactivation control is performed based on the load level having the hysteresis characteristic set by the hysteresis characteristic setting means. The means switches between the cylinder-stopped operating state and the all-cylinder operating means.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIGS. 1 to 11 show a switching control system for a cylinder-stop engine as an embodiment of the present invention, and FIG. FIG. 2 is an overall configuration diagram showing an engine system equipped with the present device, FIG. 3 is a flowchart illustrating a control procedure by the present device, FIG. 4 is a characteristic diagram showing hysteresis characteristics, and FIG. FIG. 6 is a diagram showing an output torque characteristic, FIG. 6 is a diagram showing a capacity coefficient characteristic, FIG. 7 is a diagram showing a torque ratio characteristic, and FIGS.

Now, the engine 21 equipped with the present apparatus,
As shown in FIG. 2, an intake pipe 22, a surge tank 23, an air cleaner 24 at the inlet of the intake pipe, a throttle valve 25, and the like are provided. The opening of the throttle valve 25 is detected by a throttle position sensor,
The data is input to a control device (ECU) 26.

Further, a boost sensor (pressure sensor) 27 is attached to the surge tank 23, and the detected boost pressure is input to a control device (ECU) 26 so as to reduce the volume flow as the engine intake air amount. The corresponding filling efficiency Ev is detected. A shift position detection sensor 129 is provided for detecting an excitation state of a shift solenoid in the automatic transmission 106 to detect a transmission shift position and a shift gear ratio ρ.
U) 26.

The torque converter 106A of the automatic transmission 106 is provided at its input side with an engine speed sensor 130 as input shaft speed detecting means for detecting the engine speed Ne. The detection signal is output to the reference numeral 26. Further, the torque converter 106A of the automatic transmission 106 includes:
The output side is provided with a turbine speed sensor 131 as output shaft speed detecting means for detecting the turbine speed Tt, and is configured to output a detection signal to the control device (ECU) 26.

A control unit (ECU) 26 performs cylinder closing control in response to detection signals from a boost sensor (pressure sensor) 27, a shift position detection sensor 129, an engine speed sensor 130, a turbine speed sensor 131, and the like. Therefore, the following various means are provided. That is, as shown in FIG. 1, the control device (ECU) 26 controls the charging efficiency Ev as the intake air amount of the engine detected by the boost sensor (pressure sensor) 27 and the engine speed detected by the engine speed sensor 130. It has a function as an engine output torque detecting means (engine output torque calculating means) 102 for detecting the engine output torque Te from the rotational speed Ne.

This engine output torque detecting means 102
Is configured such that the characteristic of FIG. 5 is provided by a control device (ECU) 26 as a map, and the charging efficiency as an intake air amount of the engine is determined by a detection signal of a boost sensor (pressure sensor) 27. Ev (load information) is detected, and one of the characteristics using the engine speed Ne as a parameter is selected and determined.

The control unit (ECU) 26 detects the rotation speed Ne of the input shaft of the torque converter 106A based on the detection signal of the engine speed sensor 130, and detects the rotation speed Ne of the torque converter 106A based on the detection signal of the turbine speed sensor 131. It has a function as a drive shaft torque detecting means (drive shaft torque calculating means) 101 for detecting the rotational speed Nt of the output shaft and obtaining a drive shaft torque Tt as a turbine output torque from the rotational speeds Ne and Nt. .

The drive shaft torque detecting means 101 is shown in FIGS.
Are provided as a map, and the torque capacity coefficient C is determined corresponding to the rotation speed ratio Nt / Ne according to the characteristics of FIG. 6, and the torque ratio λ is changed to the rotation speed ratio Nt / Ne by the characteristics of FIG. It is determined so as to calculate the drive shaft torque Tt according to the following equation. Tt = λ (Nt / Ne) · C (Nt / Ne) · Ne ² Further, the control device (ECU) 26 detects the gear ratio ρ of the automatic transmission 106 based on the detection signal of the shift position detection sensor 129. It has a function as the ratio detecting means 103.

The drive shaft torque Te detected by the drive shaft torque detection means 101 and the engine output torque T detected by the engine output torque detection means 102
The function of the equivalent gear ratio detecting means (equivalent gear ratio calculating means) 104 for obtaining the equivalent gear ratio ρe from the transmission gear ratio ρ detected by the transmission gear ratio detecting means 104 and the ratio (Tt / Te) to t is also controlled. The device (ECU) 26 has it.

Here, the calculation of the equivalent gear ratio ρe by the equivalent gear ratio detection means 104 is performed by the following equation. ρe = Tt / Te · ρ Further, a cylinder-stop region hysteresis characteristic setting unit (a hysteresis characteristic setting unit) for setting a hysteresis characteristic of the cylinder-stop region in accordance with the equivalent gear ratio ρe detected by the equivalent gear ratio detection unit 104. 105 functions are also controlled by the control unit (EC
U) 26.

That is, the cylinder switching characteristics shown in FIG. 4 are stored as a map, and the switching characteristics A1 to A2 from the cylinder-stop operation state to the all-cylinder operation state correspond to the equivalent gear ratio ρe.
Is set to a predetermined state in response to.
Here, the switching characteristic A1 is a characteristic when the equivalent gear ratio ρe is small, and the switching characteristic A2 is a characteristic when the equivalent gear ratio ρe is maximum.

The portion from the switching characteristics A1 to A2 to the switching characteristic B constitutes a hysteresis characteristic, and is set corresponding to the equivalent gear ratio ρe.
The function of the cylinder-stop control means 107 for switching between the cylinder-stop operation state and the all-cylinder operation means based on the load level having the hysteresis characteristic set by the cylinder-stop region hysteresis characteristic setting means 105 is also provided by the control unit (ECU). ) 26
The control device (ECU) 26
Is performed.

That is, the engine is configured to be able to switch between the cylinder-stopped operation state and the all-cylinder operation state in accordance with the speed and load with the switching characteristics A1 to A2, B shown in FIG. The position of the horizontal axis in FIG. 4 is determined by the engine speed Ne from 130, and the position of the vertical axis is determined by the intake pipe negative pressure as a load based on the detection signal from the boost sensor (pressure sensor) 27. Or in the all-cylinder region, and switching between the cylinder-stop operation state and the all-cylinder operation state is performed.

By the way, the valve device 1 for realizing the above-mentioned cylinder-stop operation state is configured as shown in FIGS.
That is, the camshaft 2 and the rocker shaft 3 are provided, and the low-speed cam 4 with a small lift and the high-speed cam 5 with a large lift are fixed to the camshaft 2.

On the rocker shaft 3, a main rocker arm 6 and a pair of sub rocker arms 7, 8 are mounted. The above-mentioned main rocker arm 6 has its base end fixed to the rocker shaft 3 by, for example, spline connection, and is equipped so that its swinging end abuts on the valve stem end of the intake valve 9.

On the other hand, the sub rocker arms 7 and 8 are rotatably mounted with their base ends pivotally supported by the rocker shaft 3, and have a roller bearing 10 attached to the swinging end. The swinging ends of the sub rocker arms 7 and 8 extend in a direction different from the supporting portion of the roller bearing 10 as shown in FIG. 7A (8A) is formed.

The arm portion 7A (8A) is in contact with the upper end of the plunger 13 inserted into the cylinder head 11, and the plunger 13 is
2, the sub rocker arm 7,
8 is urged clockwise to press the roller bearing 10 against the low speed cam 4 and the high speed cam 5.

On the other hand, the sub rocker arms 7 and 8 have engaging holes 7B,
8B are formed, and the engagement holes 7B, 8B are configured to allow insertion when the connecting plunger 14 described later projects outward. A hydraulic passage 3A is formed inside the rocker shaft 3 and extends in the axial direction at the center of the shaft. The hydraulic passage 3A extends in the radial direction perpendicular to the hydraulic passage 3A, and Through holes 3B, 3B that can be aligned with the holes 7B, 8B are formed.

A connecting plunger 14 is loaded in the through holes 3B, 3B. The connecting plunger 14 has a flange 14A having an enlarged diameter at its base end.
A compression spring 15 is interposed between the through hole 3B and the step of the inner wall of the through hole 3B. Thereby, the connecting plunger 14
Normally, the head is urged downward in the figure, and the head is
B, 8B are retracted into the through holes 3B, 3B, and are immersed.

On the other hand, the output path of the hydraulic pressure setting means 16 is connected to the hydraulic path 3A in the rocker shaft 3 described above. The hydraulic pressure setting means 16 includes low-speed and high-speed electromagnetically driven directional switching valves 16A and 16B for setting the pressure in the hydraulic passage 3A according to the operation state. Valves 16A, 16B
Is controlled by the control device (ECU) 26 described above.

Then, the electromagnetically driven directional switching valve 16A, 1
6B are respectively provided in two paths, one for low speed and one for high speed, each of which is provided with a passage from the oil pump 17, a return path in which the atmospheric pressure release pressure is set, and a hydraulic pressure in the rocker shaft 3. It is configured to be able to be connected to the passage 3A in three directions, and is configured such that oil from the oil pump 17 is introduced into the return path at normal times when excitation is not performed.

In FIG. 11, an electromagnetically driven directional control valve 1 is shown.
The connection state of 6A to the high-speed side is not shown. On the other hand, the control device (ECU) 26 receives information from various sensors for detecting an operating state, such as an engine speed sensor, an O ₂ sensor for detecting an air-fuel ratio, and a throttle position sensor for detecting a load state. The electromagnetically driven directional control valves 16A and 16A are used to determine a low-speed state, a high-speed state, and a load state according to an input from each of these sensors to selectively set a connection state to both low-speed and high-speed systems.
It is configured to output a drive signal to 16B.

When the electromagnetically driven directional switching valve 16A is excited, the oil from the oil pump 17 is supplied to the hydraulic passage 3A, and the pressure in the passage is increased. Therefore, the control device (ECU) 2
In 6, when a relatively low-speed state is determined based on input information of the engine speed, the air-fuel ratio, and the accelerator opening, the electromagnetically driven directional switching valve 16 </ b> A located on the low-speed side is excited, The drive type directional control valve 16B is set to the normal position.

The low-speed electromagnetically driven directional control valve 1
When the motor 6A is excited, the oil pump 17 is switched to pump oil from the oil pump 17 toward the hydraulic passage 3A, and the high-speed electromagnetically driven directional switching valve 16B is not excited, so that the oil in the high-speed hydraulic passage 3A is not supplied. It is configured to maintain a state in which oil is not supplied to the pump. As a result, the connection plunger 14 located on the low speed side projects toward the engagement hole 7B in the first sub rocker arm 7 against the bias of the compression spring 15, as indicated by the two-dot chain line in FIG. The rocker shaft 3 and the first sub rocker arm 7 are integrated.

As a result, the first sub rocker arm 7
The drive force is transmitted to the rocker shaft 3 from the motor, and the low-speed cam 4 engaging with the first sub rocker arm 7 through the rocker shaft 3 drives the opening and closing of the valve. I have. At this time, the high-speed side connection plunger 14 is kept immersed in the through hole 3B of the rocker shaft 3 as shown by a solid line in FIG. 10, and the high-speed side second sub rocker arm 8 and the rocker shaft 3 are connected to each other. During this time, the transmission of the driving force is maintained in a disconnected state, so that the high-speed cam 5 does not open or close the valve.

By the way, when the rotation of the engine rises and reaches the high-speed rotation region, the corresponding excitation setting on the high-speed side becomes opposite to the excitation setting for the electromagnetically driven directional switching valves 16A and 16B at the low speed described above. Is being done.
Thereby, the connection plunger 14 on the high-speed side (right side in FIG. 10) in FIG. 10 is protruded into the engagement hole 8B of the second sub rocker arm 8, and the rocker shaft is brought into the state shown by the two-dot chain line. 3 and the second sub rocker arm 8 are integrated.

Accordingly, in this state, the driving force is transmitted between the second sub rocker arm 8 and the rocker shaft 3, and the valve is moved by the high speed cam 5 via the second sub rocker arm 8 and the rocker shaft 3. Is configured to be driven to open and close. At this time, the connection plunger 14 on the low speed side is connected to the first sub rocker arm 7.
Is retracted from the engaging hole 7B in the inside and is immersed in the through hole 3B of the rocker shaft 3, and the transmission of the driving force between the first sub rocker arm 7 on the low speed side and the rocker shaft 3 is cut off. , The high-speed cam 4 does not drive the valve to open or close.

On the other hand, when the control unit (ECU) 26 determines that the cylinder should be brought into the cylinder-stopped operation state, the opening / closing drive by the low-speed cam 4 and the high-speed cam 5 in the selected cylinder is not performed. , Control device (ECU) 2
6, the excitation setting for the electromagnetically driven directional switching valves 16A and 16B is released. Therefore, in this case, neither the low-speed side nor the high-speed side electromagnetically driven directional switching valves 16A and 16B are set to the pumping state, and the hydraulic passage 3A in the rocker shaft 3 does not increase in pressure. Thereby, the connecting plunger 14,
14 is kept in a state of being immersed in the through holes 3B, 3B by the urging of the compression springs 15, 15, the first and second
The transmission of the driving force between the sub rocker arms 7, 8 and the rocker shaft 3 is maintained in a disconnected state.

Such a configuration is a state in which the valve is not stopped by the low-speed cam 4 and the high-speed cam 5 so that the valve is not opened and closed, and the cylinder is closed. This cylinder rest state
When the low load state is released, the operation state of the connection plunger 14 is switched to the operation state according to the engine speed. This embodiment is configured as described above, and the operation according to the flowchart of FIG. 3 is performed with such a configuration.

First, in step S1, the engine speed Ne is detected and read from the engine speed sensor 130 and the turbine speed Nt from the turbine speed sensor 131, and a boost sensor (pressure sensor) is read.
Efficiency E as intake air amount using detection signal of No. 27
v is detected. Next, in step S2, the transmission gear ratio detection means 103 determines the gear ratio ρ using the detection signal of the shift position detection sensor 129 provided in the automatic transmission 106.

In step S3, the engine output torque detecting means 102 estimates the engine torque Te in accordance with the characteristics shown in FIG. That is, the output torque Te is estimated from the intake air amount (volume efficiency) Ev detected in step S1 and the engine speed Ne by the characteristics of FIG. 5 provided as a map. In step S4, the turbine output torque Tt is estimated by the drive shaft torque detecting means 101 according to the following equation.

Tt = λ (Nt / Ne) · C (Nt / Ne) · Ne ² Here, the torque ratio λ is determined by the characteristic of FIG. 7 stored in advance as a map, and the rotational speed ratio between the input and output of the turbine. Nt / Ne. Also, the capacity coefficient C
Is determined from the rotational speed ratio Nt / Ne between the input and output of the turbine according to the characteristics of FIG. 6 stored in advance as a map.

Further, the engine speed Ne is determined in step S
The one detected in 1 is used. Then, in step S5, the equivalent gear ratio detecting means 104 calculates the equivalent gear ratio ρe using the following equation. ρe = Tt / Te · ρ Here, the turbine output torque Tt uses the value estimated in step S4, the engine torque Te uses the value estimated in step S3, and the gear ratio ρ is the one detected in step S2. Is used.

The gear ratio ρ calculated in this way is output to the control unit (ECU) 26, and is output to the control unit (EC
The map shown in FIG. 4 is stored in U) 26, and the switching characteristics are determined by this map. That is,
Switching characteristics from the cylinder-stop operation state to the all-cylinder operation state A1
A2 is determined corresponding to the gear ratio ρe.

In FIG. 4, the characteristic A1 corresponds to the case where the gear ratio ρe is the minimum, and the characteristic A2 corresponds to the case where the gear ratio ρe is the maximum. The corresponding switching characteristics are set. The switching from the all-cylinder operation state to the closed-cylinder operation state is performed based on the characteristic B, and a hysteresis component exists between the characteristic B and the characteristics A1 to A2.

In the cylinder deactivated operation, a predetermined cylinder stops its operation, and the operation is performed in a state where a larger output torque can be obtained. As described above, the switching between the full-cylinder operation and the closed-cylinder operation is performed by switching the excitation setting of the electromagnetically driven directional switching valves 16A and 16B in the hydraulic pressure setting means 16 according to the control signal of the control device (ECU) 26. This is performed by selecting whether the valve is driven or not driven by the cam 4 and the high-speed cam 5.

In this embodiment, the boost pressure is used as the load state detecting means. However, it is also possible to make a determination based on other factors such as the amount of intake air with respect to the engine speed. Further, the valve device 1 is also an example,
Other mechanisms that can achieve the cylinder rest state may be used.

Therefore, according to the apparatus of this embodiment, the cylinder deactivation hysteresis can be set in the automatic transmission vehicle (AT vehicle) as in the manual transmission vehicle (MT vehicle), and the accelerator operation with gentle acceleration is performed. Thus, there is an advantage that the cylinder-stop operation can be continued, and a change in drivability and deterioration of fuel efficiency can be prevented.

[0051]

As described above in detail, according to the switching control system for a cylinder-stop engine of the present invention, the number of working cylinders can be changed at least according to the operating state including the load state of the engine, and the torque converter can be changed. In a cylinder-stop engine having an automatic transmission attached thereto, an input shaft speed detecting means for detecting a speed of an input shaft in the torque converter, and a speed of an output shaft in the torque converter. Output shaft speed detecting means, and drive shaft torque calculating means for obtaining a drive shaft torque of the engine based on the input shaft speed and the output shaft speed detected by the input shaft speed detecting device and the output shaft speed detecting device, respectively. An engine output torque calculating means for detecting an engine load to obtain an engine output torque; Equivalent gear ratio calculating means for obtaining an equivalent gear ratio from a transmission gear ratio and a ratio of the drive shaft torque to the engine output torque calculated by the engine output torque calculating means; and an equivalent gear calculated by the equivalent gear ratio calculating means. Hysteresis characteristic setting means for setting the hysteresis characteristic of the cylinder deactivation region according to the ratio, and cylinder deactivation control means for switching between cylinder deactivation mode and all cylinder operation means based on the load level having the hysteresis characteristic set by the hysteresis characteristic setting means. With a simple configuration that has
As with a manual transmission vehicle (MT vehicle), automatic transmission vehicles (AT vehicles) can be set with cylinder deactivation hysteresis as well as a manual transmission vehicle (MT vehicle). There is an advantage that change and deterioration of fuel economy can be prevented.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a control system for a cylinder-stop engine switching control device as one embodiment of the present invention.

FIG. 2 is an overall configuration diagram showing an engine system equipped with a switching control device as one embodiment of the present invention.

FIG. 3 is a flowchart illustrating a control procedure of a cylinder-stop engine switching control device as one embodiment of the present invention.

FIG. 4 is a characteristic diagram illustrating a hysteresis characteristic of the switching control device for the cylinder-stop engine as one embodiment of the present invention.

FIG. 5 is a diagram showing an output torque characteristic of the switching control device for the cylinder-stop engine as one embodiment of the present invention.

FIG. 6 is a diagram showing a capacity coefficient characteristic by the switching control device for the cylinder-stop engine as one embodiment of the present invention.

FIG. 7 is a diagram showing a torque ratio characteristic of the switching control device for the cylinder-stop engine as one embodiment of the present invention.

FIG. 8 is a schematic view showing a cylinder stop mechanism by a cylinder stop engine switching control device as one embodiment of the present invention.

FIG. 9 is a schematic view showing a cylinder-stop mechanism by a cylinder-stop-engine switching control device as one embodiment of the present invention;

FIG. 10 is a schematic view showing a cylinder-stop mechanism by a cylinder-stop-engine switching control device as one embodiment of the present invention.

FIG. 11 is a schematic view showing a cylinder stop mechanism by a cylinder stop engine switching control device as one embodiment of the present invention.

FIG. 12 is a graph showing cross points of cylinders that are closed.

FIG. 13 is a schematic diagram showing a switching control characteristic of a conventional cylinder-stop engine.

FIG. 14 is a schematic diagram showing switching control characteristics of a conventional cylinder-stop engine.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Valve apparatus 2 Cam shaft 3 Rocker shaft 3A Hydraulic passage 3B Through hole 4 Low speed cam 5 High speed cam 6 Main rocker arm 7 First sub rocker arm 7A Arm part 7B Engagement hole 8 Second sub rocker arm 8A Arm Part 8B Engagement hole 9 Intake valve 10 Roller bearing 11 Cylinder head 12 Lost motion spring 13 Plunger 14 Connecting plunger 15 Compression spring 16 Hydraulic pressure setting means 16A Electromagnetic driven directional switching valve 16B Electromagnetic driven directional switching valve 17 Oil pump 18 Signal conversion Circuit 22 Intake pipe 23 Surge tank 24 Air cleaner 25 Throttle valve 26 Control device (ECU) 27 Boost sensor (Pressure sensor) 101 Drive shaft torque detecting means 102 Engine output torque detecting means 103 Transmission Gear ratio detecting means 104 equivalent gear ratio detecting means 105 cylinder deactivation region hysteresis characteristic setting unit 106 automatic transmission 106A torque converter 107 cylinder deactivation control means 129 shift position detecting sensor 130 engine speed sensor 131 turbine rotation speed sensor

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) F02D 13/06 F01L 13/00 F02D 17/02 F02D 29/00

Claims (1)

(57) [Claims] 1. A cylinder-stop engine in which the number of working cylinders can be changed according to at least an operation state including a load state of the engine and an automatic transmission is provided via a torque converter. Input shaft rotation number detecting means for detecting the rotation number of the input shaft, output shaft rotation number detecting means for detecting the rotation number of the output shaft in the torque converter, input shaft rotation number detecting means, and the output shaft rotation number A drive shaft torque calculating means for obtaining a drive shaft torque of the engine based on the input shaft speed and the output shaft speed detected by the detecting means; an engine output torque calculating means for detecting an engine load to obtain the engine output torque; The drive shaft torque calculated by the drive shaft torque calculating means and the engine shaft torque calculated by the engine output torque calculating means. Equivalent gear ratio calculating means for obtaining an equivalent gear ratio based on the ratio with the output torque and the transmission gear ratio; and hysteresis characteristic setting means for setting the hysteresis characteristic of the cylinder-stop region based on the equivalent gear ratio calculated by the equivalent gear ratio calculating means. And a cylinder-stop control means for switching between a cylinder-stop operation state and all-cylinder operation means based on a load level having a hysteresis characteristic set by the hysteresis characteristic setting means. Engine switching control device.