JP3835565B2 - Engine cylinder deactivation control device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention belongs to the technical field of engine cylinder deactivation control.
[0002]
[Prior art]
For example, in a two-cycle engine for an outboard motor, the exhaust port of each cylinder is connected to the collective exhaust pipe due to space constraints, so the engine is low in intake, such as in a low speed and low load range. Exhaust pulses enter the cylinder and exhaust remains in the cylinder, causing irregular combustion. As a method for improving this, cylinder deactivation control is performed in which the operation of some cylinders is stopped to reduce the number of operating cylinders. By this cylinder deactivation control, exhaust interference is suppressed, so that an effect of increasing the intake amount per cylinder and stabilizing the engine rotation can be obtained.
[0003]
[Problems to be solved by the invention]
However, if the cylinder deactivation control is performed when the engine is in an abnormal state or when changes in the engine speed and the throttle opening are large, a problem arises in engine stability. For example, if the cylinder deactivation control is performed at the time of start-up, the engine does not start until the ignition cylinder comes, and the temperature rise around the deactivation cylinder is slow, so the time until start-up becomes longer. Since the temperature is low and combustion is not stable, there is a problem that low-speed stability is worse than that in all-cylinder operation. In addition, if cylinder deactivation control is performed during sudden acceleration, there is a problem that the increase in engine speed is delayed, and cylinder deactivation occurs when the engine is abnormal, such as when a sensor fails or when the air-fuel ratio sensor is inactive during air-fuel ratio control. When the control is performed, there is a problem that combustion instability of the engine is promoted.
[0004]
The present invention solves the above problem, and prevents the engine from being unstable due to cylinder deactivation control by not performing cylinder deactivation control when the engine is not in normal operation or steady operation. An object of the present invention is to provide an engine cylinder deactivation control device.
[0005]
[Means for Solving the Problems]
In order to achieve the above object, according to the first aspect of the present invention, in an engine having a plurality of cylinders and connecting the exhaust passages of the respective cylinders to the collective exhaust pipe and performing cylinder deactivation control, the engine is not operating in an abnormal state. In this case, the cylinder deactivation control is performed when the engine speed and the throttle opening are small, and the cylinder deactivation control is not performed when the engine is not in normal operation or steady operation. ,
The invention according to claim 2 is the case where the engine is not in normal operation or steady operation in the case of claim 1, during start control, sudden acceleration / deceleration, air / fuel ratio sensor inactive, knock control, oil empty control It is a case corresponding to at least one of overheat control, sensor failure control, and dual engine system control.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, according to the first aspect of the present invention, there is provided an engine having a plurality of cylinders, wherein the exhaust passage of each cylinder is connected to a collective exhaust pipe, and cylinder deactivation control is performed . A crankshaft vertical V-type engine, in which an air-fuel ratio sensor is provided in the exhaust passage of the uppermost cylinder of the engine, and when the engine is in a normal operation that is not in an abnormal state, and the engine speed and throttle opening change are small Performs cylinder deactivation control for other cylinders without deactivating the uppermost cylinder in which the air-fuel ratio sensor is installed during steady operation, and performs cylinder deactivation control when the engine is not in normal operation or steady operation The invention according to claim 2 is characterized in that, in claim 1, when the engine is not in a normal operation or a steady operation, the start control, the sudden acceleration / deceleration, the air-fuel ratio sensor is inactive, During click control, the oil empty control, in overheating control, during sensor failure control, characterized in that it is a case corresponding to at least one of dual engine system control.
[0007]
An arrow F indicates the forward direction of the hull (not shown), and an outboard motor 1 as a driving device is detachably mounted on the rear part of the hull. The outboard motor 1 includes a propulsion unit 2, an engine 3 is attached to the upper portion of the propulsion unit 2, and a cowling 4 that covers the engine 3 from above is provided. The engine 3 is a fuel-injected water-cooled two-cycle V-type six-cylinder crankshaft vertical engine, and has a crankcase 5. A crankshaft 6 having a substantially vertical axis is rotatably supported by the crankcase 5. . In the crankcase 5, a cylinder body 7 constituting each cylinder protrudes so as to form a V shape. A piston 8 is slidably fitted to the cylinder body 7 for each cylinder, and each piston 8 is connected to the crankshaft 6. A spark plug 9 is disposed facing the combustion chamber in the space surrounded by the cylinder body 7 and the piston 8.
[0008]
An intake pipe 10 that communicates the inside and outside of the crankcase 5 is connected to each cylinder. The intake pipe 10 is provided with a reed valve 11 and a throttle valve 12 that adjusts the cross-sectional area of the intake pipe 10 by manual operation. . Each intake pipe 10 is provided with a fuel injection valve 13 for each cylinder, and each fuel injection valve 13 is a solenoid open / close type that is opened and closed by a magnetic force so that fuel can be injected upstream of the reed valve 11. ing. The fuel injection valve 13 is connected to a fuel tank 21 installed on the hull side via a high-pressure fuel pump 15, a regulator valve 16, a vapor separator tank 17, a filter 19, and a manual low-pressure fuel pump 20.
[0009]
Of the six cylinders (1) to (6) of the cylinder body 7, the air-fuel ratio sensor 22 is attached only to the uppermost cylinder, for example, the cylinder (1), and each cylinder (1) to (6) It is connected to the collective exhaust pipe 24 via the exhaust passage 18. In the outboard motor, since the leading end of the collective exhaust pipe 24 is below the water surface, water droplets scatter and enter the air-fuel ratio sensor. When the water droplets adhere to the sensor, the sensor element portion is made of ceramics and heated by the heater. Since the sensor element is heated, the sensor element unit is broken. Therefore, the air-fuel ratio sensor 22 is provided in the exhaust passage of the uppermost cylinder of the engine.
[0010]
Detection signals from various sensors indicating the operation state of the engine 3 and the state of the outboard motor 1 and the hull are input to the control device 23. That is, as the sensor, the air-fuel ratio sensor 22, the crank angle sensor 25 for detecting the rotation angle (rotation speed) of the crankshaft 6, the crank chamber pressure sensor 26 for detecting the pressure in the crankcase 6, and each cylinder (1) to (6) In-cylinder pressure sensor 27 for detecting the internal pressure, intake air temperature sensor 29 for detecting the intake air temperature, engine temperature sensor 30 for detecting the temperature in the cylinder 7, and the back pressure in each cylinder (1) to (6) A back pressure sensor 31 for detecting the throttle valve 12, a throttle opening sensor 32 for detecting the opening of the throttle valve 12, a cooling water temperature sensor 33 for detecting the temperature of the cooling water, a knock sensor 35 for detecting the knocking state of the engine 3, and the engine 3 Engine mount height detection sensor 36 for detecting the mount height of the vehicle, neutral sensor 37 for detecting the neutral state of the propulsion unit 2 of the outboard motor 1, A trim angle detection sensor 39 for detecting the vertical rotation position of the machine 1, a ship speed sensor 40 for detecting the ship speed, a ship attitude sensor 41 for detecting the attitude of the ship, an atmospheric pressure sensor 42 for detecting atmospheric pressure, and mixing with fuel An oil level sensor 43 is provided for detecting the amount of oil (in the oil tank). The control device 23 computes the detection signals of these various sensors and transmits the control signals to the spark plug 9, the fuel injection valve 13, the throttle valve 12 and the ISC 46.
[0011]
Next, the cylinder deactivation control according to the present invention will be described with reference to FIGS. As described above, in a two-cycle engine for an outboard motor, because the exhaust port of each cylinder is connected to the collective exhaust pipe due to space limitations, the intake air can be reduced like a low-speed, low-load region. When the amount is small, an exhaust pulse enters and the exhaust gas remains in the cylinder, causing irregular combustion. As a method for improving this, cylinder deactivation control is performed in which the operation of some cylinders is stopped to reduce the number of operating cylinders. By this cylinder deactivation control, exhaust interference is suppressed, so that an effect of increasing the intake amount per cylinder and stabilizing the engine rotation can be obtained.
[0012]
FIG. 2 is a diagram for explaining the influence of the exhaust pulse of each cylinder, and FIG. 3 is a diagram showing the opening / closing timing of the exhaust port of each cylinder. As shown in FIG. 2, cylinders (1), (3) and (5) are moved up and down on the right side (S bank), and cylinders (2), (4) and (6) are moved up and down on the left side (P bank). The cylinders are ignited at equal intervals of a crank angle of 60 degrees in the order of (1) to (6). As shown in FIG. 3, the opening timing of the exhaust port of the cylinder {circle around (1)} and the closing timing of the exhaust port of the cylinder {circle around (5)} are wrapped to increase the area where the exhaust is emitted. (1) and (5) communicate with each other, and as shown in FIG. 2, a strong exhaust pressure from the cylinder (1) acts on the cylinder (5). Similarly, the opening timing of the exhaust port of the cylinder (3) and the closing timing of the exhaust port of the cylinder (1) are overlapped, and the exhaust pressure from the cylinder (3) acts on the cylinder (1). The timing of opening the exhaust port of (5) and the timing of closing the exhaust port of the cylinder (3) are overlapped, and the exhaust pressure from the cylinder (5) acts on the cylinder (3). This relationship is the same in the P bank.
[0013]
Here, the exhaust pressure (combustion pressure) of each cylinder is maximum in the most upstream cylinders (1) and (2), and becomes weaker toward the lower cylinder. This is because the most upstream cylinders {circle around (1)} and {circle around (2)} have a relatively long exhaust pipe length, so that exhaust pulsation can be used effectively, the amount of intake air can be increased, and exhaust gas can be sufficiently scavenged. Because. On the other hand, the most downstream cylinders {circle around (5)} and {circle around (6)} have a short exhaust pipe length, so that exhaust pulsation cannot be obtained sufficiently, and the flow direction of exhaust gas and the direction of action of exhaust pulses from the upper cylinder coincide. Therefore, the amount of intake air is small, the amount of residual exhaust gas is large, and combustion becomes unstable. Therefore, from this point of view, when performing cylinder deactivation, the cylinders of the S bank are arranged so that simultaneous combustion of the most upstream cylinder and the most downstream cylinder affected by the exhaust pulse from the cylinder does not occur. It is best to deactivate (5) or P bank cylinder (6), and as the next best measure, deactivate S bank cylinder (1) or deactivate P bank cylinder (2). It is good to let it.
[0014]
However, since the cylinder (1) is a cylinder that detects the air-fuel ratio, if it is deactivated, the air-fuel ratio control cannot be performed and a problem occurs. Therefore, the cylinder (1) is excluded when selecting the deactivated cylinder. As a result, it is best to deactivate the cylinder (5) or deactivate the cylinder (6), and it is better to deactivate the cylinder (2) as the next best measure.
[0015]
Furthermore, when only one cylinder is deactivated, the most downstream cylinder (5) or (6) may be deactivated. When two cylinders are deactivated, both cylinders (5) and (6) are deactivated. Cause problems. The reason is that each cylinder is ignited at an equal interval of 60 degrees in the order of (1) to (6), so when the cylinders (5) and (6) are stopped, the explosion interval Are not evenly spaced and combustion as a whole becomes unstable. Therefore, when the two cylinders are deactivated, the cylinder (1) is a cylinder that detects the air-fuel ratio, so it is not deactivated, but the most downstream cylinder (5) of the S bank and the most upstream cylinder (2) of the P bank. If ▼ is deactivated, one cylinder is deactivated each time two cylinders explode, and the overall explosion interval in the cylinder deactivated state is equal, and the balance of output generation timing is improved. Low speed stability is obtained. At this time, in the P bank, when the most downstream cylinder (6) is operated, the most upstream cylinder (2) is inactive, and the simultaneous combustion of the cylinders (2) and (6) does not occur. Maintained.
[0016]
FIG. 4 is a diagram for explaining cylinder deactivation control, and shows a map showing an operation region corresponding to the engine speed and the throttle opening. This control is performed so as to select a cylinder deactivation operation consisting of a 4-cylinder operation or a 5-cylinder operation and a 6-cylinder operation (all-cylinder operation) according to the throttle opening and the engine speed. Here, the idle cylinder is selected so that the engine-side vibration frequency and the outboard motor-mount-side vibration frequency do not coincide with each other, and if the engine speed is equal to or less than a predetermined value, the 5-cylinder operation that can avoid resonance is performed. If the engine speed exceeds a predetermined value, a 4-cylinder operation is performed. Here, cylinder deactivation is performed by stopping ignition, and fuel supply to the deactivated cylinder is continued by a fuel injection valve 13 provided independently for each cylinder.
[0017]
FIG. 5 shows an embodiment of the cylinder deactivation control device for an engine of the present invention, and is a diagram for explaining the flow of processing. First, in step S1, it is determined whether or not the engine is in normal operation and steady operation. Here, when the engine is in steady operation, as shown in FIG. 6, the change in the engine speed and the throttle opening is in a small range, and the next control is not performed. That is,
(1) During start-up control: Increase in fuel amount at start-up and advance of ignition timing
(2) During sudden acceleration: Increase in fuel amount and advance of ignition timing during sudden acceleration
(3) During sudden deceleration: An increase in fuel amount and retarded ignition timing during sudden deceleration.
[0018]
The normal engine operation is a case where the engine is not in an abnormal state and is not in the next state or control. That is,
(4) When the air-fuel ratio sensor is inactive: The temperature of the sensor element section of the air-fuel ratio sensor is lowered, the temperature for activating the sensor element cannot be maintained, and the air-fuel ratio detection signal varies, resulting in an appropriate air-fuel ratio. Inability to control
(5) During knock control: retarded ignition timing when knock sensor 35 detects a knock
(6) During oil empty control: When the amount of oil mixed with fuel by the oil level sensor 43 falls below a predetermined amount, the number of operating cylinders is reduced in order to prevent the ignition timing from retarding and the rotational speed from increasing.
(7) During overheat control: When the coolant temperature sensor 33 exceeds the predetermined value by the coolant temperature sensor 33, the number of operating cylinders is decreased in order to prevent the ignition timing from retarding and the rotation speed from increasing.
(8) During sensor failure control: Advance the ignition timing so as not to stop the engine
(9) During dual engine system control: When two outboard motors are engaged and one engine is in knock control, oil empty control, or overheat control, the other engine is also controlled to prevent meandering. .
[0019]
Then, when the control or state of (1) to (9) described above is made, it is determined that the engine is not in normal operation or steady operation, and the process proceeds to step S4 where 6 cylinder operation (all cylinder operation) is performed. When the control or state is not in the above (1) to (9), it is determined that the engine is in normal operation and steady operation, and the process proceeds to step S2 as described in FIG. 4 according to the throttle opening and the engine speed. Thus, cylinder deactivation operation consisting of 4-cylinder operation or 5-cylinder operation is performed.
[0020]
FIG. 7 shows a modification of the present invention and is a diagram for explaining switching control between start control and cylinder deactivation control. As shown in FIG. 7A, the end of the start control is determined based on whether or not the detected value of the engine wall temperature sensor 30 exceeds the start end determination temperature T0 (fixed value). After the start temperature control is detected and the end of the start control is detected and the transition from the 6-cylinder operation to the cylinder deactivation operation is made, if the sensor is clogged with dust or the like and the temperature control becomes impossible, the 6-cylinder operation The problem of repeated pause operation occurs. Therefore, as shown in FIG. 7B, when the end of the start control is detected and the operation is switched from the 6-cylinder operation to the cylinder deactivation operation, the start end determination temperature is lowered to T1, and the sensor value changes. This is also intended to prevent switching from cylinder deactivation operation to 6-cylinder operation.
[0021]
Although the embodiment of the present invention has been described above, the present invention is not limited to this, and various modifications are possible. For example, in the above-described embodiment, an example applied to a 6-cylinder engine has been described. However, the present invention is not limited to this, and any configuration having a plurality of cylinders is acceptable. In the above-described embodiment, an example in which the present invention is applied to a two-cycle engine has been described. However, the present invention can also be applied to a four-cycle engine, and can also be applied to a method in which fuel is directly injected into a cylinder. .
[0022]
【The invention's effect】
As is apparent from the above description, according to the present invention, when the engine is not in normal operation or steady operation, the cylinder deactivation control is not performed, thereby preventing an unstable state of the engine caused by the cylinder deactivation control. can do.
[Brief description of the drawings]
FIG. 1 is an overall configuration diagram of a control system related to an engine cylinder deactivation control device according to the present invention;
FIG. 2 is a diagram for explaining an influence of an exhaust pulse of each cylinder in relation to cylinder deactivation control according to the present invention.
FIG. 3 is a diagram showing the opening / closing timing of the exhaust port of each cylinder in cylinder deactivation control according to the present invention.
FIG. 4 is a diagram for explaining cylinder deactivation control according to the present invention.
FIG. 5 is a diagram for explaining the flow of processing according to an embodiment of the cylinder deactivation control device of the present invention.
6 is a diagram for explaining a steady operation state of the engine with respect to FIG. 5; FIG.
FIG. 7 is a diagram illustrating a modification of the present invention and illustrating switching control between start control and cylinder deactivation control.
[Explanation of symbols]
3 ... Engine, 18 ... Exhaust passage, 24 ... Collective exhaust pipe, (1) to (6) ... Cylinder

Claims (2)

In an engine having a plurality of cylinders and connecting an exhaust passage of each cylinder to a collective exhaust pipe and performing cylinder deactivation control, the engine is a crankshaft vertical V-type engine for an outboard motor, and an air-fuel ratio sensor is provided. It is provided in the exhaust passage of the uppermost cylinder of the engine, and the uppermost air / fuel ratio sensor is installed in the normal operation where the engine is not in an abnormal state and in the steady operation where the engine speed and the throttle opening are small . cylinder deactivation control other cylinders carried without pause cylinders, when the engine is not normal operation or steady operation, cylinder deactivation control device for an engine characterized in that it does not implement the cylinder deactivation control. When the engine is not in normal operation or steady operation, it means that during start control, sudden acceleration / deceleration, air-fuel ratio sensor inactive, knock control, oil empty control, overheat control, sensor failure control, dual engine system 2. The engine cylinder deactivation control device according to claim 1, wherein the cylinder deactivation control device corresponds to at least one of the control modes.

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