JPH0318009B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a control device for a cylinder-deactivated engine.

In an engine, it is not necessary to operate all cylinders depending on the operating condition, for example, when the engine is idling or under low load, so in order to save fuel consumption, some cylinders are deactivated and all cylinders are operated again depending on the operating condition. A deactivated cylinder engine has already been proposed.

In this control system, the engine is operated in a deactivated state in response to a normal load. Since the engine operates in a deactivated state at low loads, a vehicle equipped with this deactivated engine starts from a deactivated state when starting. I will do it. Therefore, when the clutch engages when starting the vehicle, the engine is in a deactivated state and is likely to stall due to insufficient output.

Furthermore, when switching the engine to all-cylinder operation by making a normal switching determination based on manifold negative pressure, etc., the following problem occurs when the vehicle starts.

(1) After the determination, there is a time delay before the switch to all-cylinder operation is completed and output is obtained from all-cylinder operation of the engine, as in the case of the valve operation stop method, the engine rotates several times until the valve operation stop is completed. occurs,
Furthermore, since the determination itself is made after the accelerator pedal has been operated to a certain extent, there is a possibility that the clutch will be engaged before the output from all cylinder operation is obtained, causing the engine to stall.

(2) When starting, the engine speed suddenly increases before the clutch engages, and at the time of clutch engagement, the engine speed drops below the idle speed, and the engine speed changes suddenly. Also, the engine speed changes rapidly due to small changes in the opening of the throttle valve. Since the state changes greatly, the detection of the switching condition becomes unstable using normal switching determination based on the engine load and rotation speed.

(3) When the engine load is detected and a switching command is issued, due to the delay described above, the switch to all-cylinder operation will occur when the throttle valve has finished opening and reached a high opening, so even if (1) Even if the engine stall described above does not occur, a sudden increase in output will occur and a shock will occur.

The main object of the present invention is to quickly switch the engine from a cylinder-deactivated operation state to an all-cylinder operation state when starting a vehicle.
To provide a control device for a cylinder-deactivated engine that prevents engine stalling and switching shock during clutch engagement.

To this end, the present invention provides a cylinder deactivation means for deactivating some cylinders of an engine, and a means for changing the number of activated cylinders based on information on operating conditions including at least engine load conditions. a first control means for controlling the cylinder deactivation means so that operation of some cylinders is stopped during operation; and a first control means for detecting clutch operation and detecting that the clutch has been switched to a disengaged state; a second control means for controlling the cylinder deactivation means so as to operate all cylinders regardless of the operating state of the first control means; and means for detecting whether or not the clutch operation is for starting the vehicle. The means for detecting whether the clutch operation is for starting the vehicle detects that the vehicle speed is equal to or higher than a set value and determines that the clutch operation is not for starting the vehicle. The present invention proposes a control device for a cylinder-deactivated engine, which is characterized in that the first control means sometimes performs control even when the clutch is in a disengaged state.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

A deactivated engine has a cylinder group that is always operated and a cylinder group that is activated or deactivated depending on the operating state.The structure of the deactivated cylinder will be explained with reference to FIG.

In FIG. 1, a combustion chamber 10 is defined by a cylinder head 12, a cylinder block 14, and a piston 16 that slides within the cylinder block. The intake port 18 is opened and closed by an intake valve 20, which is biased in the closing direction by a spring 22, and an intake cam 2 provided on a camshaft 24.
6 is driven to open and close via an intake valve drive device 28. The exhaust port 30 is opened and closed by an exhaust valve 32, and the exhaust valve 32 is biased in the closing direction by a spring 34.
6 is driven to open and close via an exhaust valve drive device 38.

The intake valve drive device 28 and the exhaust valve drive device 38 have valve actuation stop mechanisms provided in the rocker arms 40 and 42, respectively, and the hydraulic pressure of the lubricating oil supply pump 46 is applied to the intake valve rocker shaft 48 by the hydraulic switching valve 44. The intake valve 20 and the exhaust valve 32 are driven to open and close when the air is supplied to the passage 50 provided in the passage 50 and the passage 54 provided in the exhaust valve rocker shaft 52, and the hydraulic switching valve 4 is driven to open and close.
4 maintains both valves 20 and 32 in the closed position when passages 50 and 54 are vented to the atmosphere.

Although not illustrated and described in detail, each valve actuation/stopping mechanism is a plunger that is slidably fitted into a cylinder 56 fixed to the rocker arms 40, 42 and abuts the valve shaft end of the intake valve 20 or exhaust valve 32. 58, and when hydraulic pressure is supplied to the passages 50 and 54, a piston (not shown) disposed in the rocker arm engages the stopper 60 with the plunger 58 to prevent the plunger 58 from sliding within the cylinder 56. Then, the plunger is integrally and fixedly connected to the rocker arm. When the hydraulic pressure in passages 50 and 54 is vented to atmosphere, movement of the piston into the rocker arm causes the stopper 60 to disengage from the plunger 58, allowing the plunger to slide within the cylinder 56, thus allowing the rocker arm to move. Even if the plunger 58 is oscillated, the valves 20 and 3 will simply slide.
2 is held in the closed position.

The hydraulic switching valve 44 is, for example, a three-way solenoid valve, and is controlled by the control device 6 depending on the operating state.
Passage 50 when the cylinder deactivation command is issued from 2.
and 54 are opened to the atmosphere, and the hydraulic pressure of the pump 46 is operated to be supplied to the passages 50 and 54 when an all-cylinder operation command is issued.

Next, the control device 62 will be explained with reference to FIG.

In FIG. 2, the control device 62 controls the engine load based on the engine load detected by the manifold negative pressure, throttle opening, or air flow rate, engine speed detected by the ignition pulse from the ignition coil, water temperature, etc. The first control circuit 64 determines whether to switch between cylinder-deactivated operation and all-cylinder operation, and issues a command corresponding to the cylinder-deactivated operation or all-cylinder operation. Second control circuit 66
When the vehicle is started, an all-cylinder operation command is issued regardless of the cylinder deactivation command from the first control circuit 64.The first input terminal is connected to the first control circuit 64, and the second input terminal is used to issue an all-cylinder operation command. It has a selector 70 connected to the circuit 68, a hold circuit 72 for switching and operating the selector 70, and a start clutch operation detection circuit 74 for detecting a clutch operation for starting the vehicle and triggering the hold circuit 72.

The output terminal of the selector 70 is connected to the active cylinder selection circuit 7.
6, and this selection circuit issues a single command when one hydraulic switching valve 44 is provided in common to the cylinder group to be deactivated, and separately outputs a command to the cylinder to be deactivated. If provided, independent commands can be issued. The selector 70 connects the active cylinder selection circuit 76 to the all-cylinder operation instruction circuit 68 only while the hold circuit 72 is issuing an output signal, and normally connects the selection circuit to the first control circuit 64. Hold circuit 72 generates an output signal when triggered by start clutch operation detection circuit 74, and stops outputting the signal in response to a signal from release condition detection circuit 78, which detects conditions other than vehicle start.

The starting clutch operation detection circuit 74 is connected to a clutch disengagement detection device 80 for detecting that the clutch is in the disengaged state, and is also connected to a vehicle speed detection device 86. In the case of a manual transmission, the clutch disconnection detection device 80 is a clutch pedal,
It is a switch that is turned on and off in conjunction with a clutch release lever, etc., or a switch that detects the movement of the clutch mechanism in the case of a transmission with an automatic clutch that uses an electromagnetic clutch, vacuum power, etc. The starting clutch operation detection circuit 74 basically assumes that the vehicle is in the starting state when the clutch disengagement detection device 80 detects that the clutch is disengaged. When it is detected that the vehicle speed is equal to or higher than a set vehicle speed close to when the vehicle is stopped, it is determined that the clutch operation to the disengaged state is not a clutch operation for starting the vehicle.

In the operation of the control device described above, the selector 70 of the second control circuit 66 connects the first control circuit 64 and the activated cylinder selection circuit 76 while the vehicle is running. The first control circuit 64 issues an all-cylinder operation command when detecting a high-speed, high-load operating state of the engine, and the operating cylinder selection circuit 76 directs the hydraulic pressure of the pump 46 to the passage 5.
0 and 54, and the plunger 58 of the valve operation stop mechanism described above is operated.
are integrally and fixedly connected to the rocker arms 40 and 42, and the intake valve 20 and the exhaust valve 32 are opened and closed by swinging of the rocker arms, and the engine is operated with all cylinders. Further, the first control circuit 64 issues a cylinder deactivation command when detecting a low speed, low load operating state of the engine, and the active cylinder selection circuit 76 cuts off the hydraulic pressure of the pump 46 and opens the passages 50 and 54 to the atmosphere. The hydraulic switching valve 44 is operated, the plunger 58 is made slidable within the rocker arms 40 and 42, and the intake valve 20 is opened.
The exhaust valve 32 is held in the closed position, and some cylinders of the engine are deactivated.

When the clutch is operated to the disengaged state in order to start the vehicle from a stopped state, the starting clutch operation detection circuit 74 detects this clutch operation using the clutch disengagement detection device 80. At this point, the circuit 74 detects by the vehicle speed detection device 86 that the vehicle speed is less than the set vehicle speed, determines that the clutch operation is for starting, and triggers the hold circuit 72.

When triggered, the hold circuit 72 issues an output signal to switch the selector 70, and the selector 70 connects the active cylinder selection circuit 76 to the all-cylinder operation instruction circuit 68. The active cylinder selection circuit 76 operates the hydraulic switching valve 44 in accordance with the all-cylinder operation command from the all-cylinder operation command circuit 68, and operates the valve operation stop mechanism as described above to open and close the intake valve 20 and the exhaust valve 32. Activate it and run the engine on all cylinders.

After the vehicle has started, the release condition detection circuit 78 detects that the vehicle has entered the running state and issues a signal.
Hold circuit 72 stops outputting the signal in response to this signal. As a result, the selector 70 of the second control circuit 66 switches to connect the active cylinder selection circuit 76 to the first control circuit 64 again, and the active cylinder selection circuit 76 switches from the first control circuit 64 to cylinder deactivation or full cylinder operation. In accordance with the command, the hydraulic switching valve 44 is operated to switch appropriately, and the engine is operated with cylinders inactive or with all cylinders in operation.

As described above, according to the control device 62 for a cylinder-deactivated engine according to the present invention, the starting clutch operation detection circuit 7
Basically, the clutch disengagement detection device 80 detects that the clutch has been operated to the disengaged state, and the vehicle speed detection device 86 detects that the vehicle speed is at or below a set vehicle speed close to stopping. The second control circuit 66 is activated to issue an all-cylinder operation command, and the engine is switched from the cylinder-deactivated operation state. Since the engine can be quickly and reliably switched to all-cylinder operation, the engine can switch to all-cylinder operation even when the clutch is not engaged, which prevents engine stalling, which conventionally tends to occur due to insufficient output due to engine cylinder deactivation when the clutch is engaged. can be reliably prevented. Furthermore, since the engine is switched to all-cylinder operation in an extremely low load range, the change in output is small, so switching shock can be effectively prevented.

Further, the start clutch operation detection circuit 74 is combined with the vehicle speed detection device 86 to determine that a clutch operation to a disengaged state for performing a gear change operation or coasting operation while the vehicle is running is not an operation for starting. Can be done. Therefore, when the vehicle is running at low speed and coasting with the clutch disengaged, the engine is maintained in a cylinder-deactivated state, which is extremely effective in reducing fuel consumption.

In the above embodiment, the control device 62 has been illustrated and explained in connection with a cylinder deactivation engine of a valve actuation/stop type that operates or stops the intake valve and exhaust valve of the engine, but it can be similarly applied to a cylinder cylinder deactivation engine of a fuel cut type. be able to. For example, in a fuel injection type deactivated cylinder engine, the activated cylinder selection circuit 76 selectively activates or deactivates all cylinders or a part of the fuel injection valves provided in each cylinder according to the cylinder deactivated activation command. The engine can be operated with all cylinders or with no cylinders.

[Brief explanation of the drawing]

FIG. 1 is a schematic sectional view of a cylinder-deactivated engine of a valve actuation stop type, and FIG. 2 is a block diagram illustrating a control device for a cylinder-deactivated engine according to the present invention. 20...Intake valve, 28...Intake valve drive device, 3
2...exhaust valve, 38...exhaust valve drive device, 44...
... Hydraulic switching valve, 46 ... Lubricating oil supply pump, 62
...Control device, 64...First control circuit, 66...
Second control circuit, 68... All-cylinder operation instruction circuit, 70
...Selector, 72...Hold circuit, 74...
Starting clutch operation detection circuit, 76...Activated cylinder selection circuit, 78...Release condition detection circuit, 80...Clutch disconnection detection device, 86...Vehicle speed detection device.

Claims (1)

[Claims] 1. Cylinder operation stopping means for stopping the operation of some cylinders of the engine, and changing the number of activated cylinders based on information on the operating state including at least the load condition of the engine, and operating at least some of the cylinders when the engine is idling. a first control means for controlling the cylinder operation stop means so that the cylinder operation stop means is stopped; and a first control means for detecting a clutch operation and detecting that the clutch has been switched to a disengaged state and controlling the operation state of the first control means. a second control means for controlling the cylinder deactivation means so as to operate all cylinders without any problem; and means for detecting whether or not the clutch operation is for starting the vehicle. The means for detecting whether the clutch operation is for starting the vehicle detects that the vehicle speed is higher than the set value and determines that the clutch operation is not for starting. A control device for a cylinder-deactivated engine, characterized in that the control is performed by the first control means even if there is a problem.