JPH1018873A - Cylinder suspending control device of engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent hard vibration of a hull while providing a comfortable feeling vibration by changing the number of operating cylinders so as to match an engine side vibration frequency and an engine mount side vibration frequency with each other at the time of cylinder suspending control. SOLUTION: During operation of an outboard motor 1, in a control device 23, a cylinder suspending operation range is judged on the basis of a throttle opening and engine speed. In the case of 'YES', it is judged whether engine speed is a prescribed value N, or less. In the case where it is the prescribed value NB and more, normal cylinder suspending operation is carried out. In the cylinder suspending operation of the value NB or less, a suspending cylinder is selected since an engine side vibration frequency and an outboard engine mounting side vibration frequency are not matched with each other. Namely, in the case where the engine speed is the prescribed value NB or less, five cylinder operation which is enabled to avoid resonance is carried out. In the case where the engine speed is the value NB and more, and NA (>NB) or less, four cylinder operation is carried out.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention belongs to the technical field of cylinder deactivation control of an engine.

[0002]

2. Description of the Related Art For example, in a two-stroke engine for an outboard motor, the exhaust port of each cylinder is connected to a collective exhaust pipe due to space restrictions. When the amount of intake air is small, an exhaust pulse enters and the exhaust remains in the cylinder, causing irregular combustion. As a method of improving this, cylinder deactivation control is performed to stop the operation of some cylinders and reduce the number of operating cylinders. This cylinder deactivation control suppresses exhaust interference, so that an effect of increasing the intake air amount per cylinder and stabilizing the engine rotation can be obtained.

[0003]

By the way, when the cylinder is deactivated, the ignition cylinder burns every cycle and the frequency of the vibration generated by the combustion becomes a peak at which the vibration value protrudes at a certain frequency as shown in FIG. And its peak frequency changes in accordance with the engine speed. On the other hand, the outboard motor is mounted on the hull via the vibration isolating rubber, and the engine vibration is transmitted to the hull, so that the engine-side vibration frequency matches the outboard motor mount-side vibration frequency. Then, resonance occurs.

[0004] As shown in FIG. 9, when the vibration frequency on the outboard motor mount side is f _M , as shown in FIG. Therefore, for example, when the engine having six cylinders performs the cylinder deactivated operation of the four-cylinder operation in the low-speed region and shifts from the four-cylinder operation to the six-cylinder operation at the engine speed N _A , the engine is operated at the point G in the four-cylinder operation. Since the side vibration frequency matches the outboard motor mount side vibration frequency, resonance occurs and the hull vibrates violently.

The present invention has been made to solve the above-mentioned problem, and it is an object of the present invention to prevent an engine-side vibration frequency from being coincident with an engine-mount-side frequency, thereby obtaining a comfortable bodily sensation vibration. The purpose is to provide.

[0006]

According to a first aspect of the present invention, there is provided an engine having a plurality of cylinders and performing cylinder deactivation control, wherein an engine-side vibration frequency and an engine-mount-side vibration frequency are identical. The invention according to claim 2 is characterized in that the number of operating cylinders is changed so as not to perform the engine-side vibration frequency and the engine-mount-side vibration frequency in an engine having a plurality of cylinders and performing cylinder deactivation control and air-fuel ratio control. The number of operating cylinders is changed so that does not coincide with each other, and the cylinders to be stopped are cylinders that do not cause exhaust interference to the cylinders except for the cylinders provided with the air-fuel ratio sensor.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an overall configuration diagram of a control system relating to an engine cylinder deactivation control device of the present invention. FIG. 1A is a side view of the engine, and FIG.
A longitudinal sectional view along line B, and FIG. (C) shows a side view of the outboard motor.

An arrow F indicates a forward direction of a hull (not shown), and an outboard motor 1 as a driving device is detachably mounted at a rear portion of the hull. The outboard motor 1 includes a propulsion unit 2, an engine 3 is mounted on an 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-injection, water-cooled, two-cycle, V-type, six-cylinder crankshaft vertical engine with a crankcase 5. A crankshaft 6 having a substantially vertical axis is rotatably supported on the crankcase 5. . In the crankcase 5, a cylinder body 7 constituting each cylinder is provided so as to project in a V-shape. Pistons 8 are slidably fitted to the cylinder body 7 for each of the cylinders, and these pistons 8 are connected to the crankshaft 6. An ignition plug 9 is provided so as to face a combustion chamber in a space surrounded by the cylinder body 7 and the piston 8.

An intake pipe 10 for connecting 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 for manually adjusting the cross-sectional area of the intake pipe 10. Have been. Each intake pipe 10
, A fuel injection valve 13 is attached to 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. The fuel injection valve 13 is connected to a fuel tank 21 installed on the hull 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.

The six cylinders of the cylinder body 7
Among them, the air-fuel ratio sensor 22 is attached only to the uppermost cylinder, for example, only the cylinder, and each cylinder is connected to the collective exhaust pipe 24 via the exhaust passage 18. In the outboard motor, since the tip of the collecting exhaust pipe 24 is below the surface of the water, water droplets scatter and enter the air-fuel ratio sensor. , The sensor element is broken. Therefore, the air-fuel ratio sensor 22 is provided in the exhaust passage of the uppermost cylinder of the engine.

The control unit 23 receives detection signals from various sensors indicating the operating state of the engine 3 and the states of the outboard motor 1 and the hull. That is, as the sensors, the air-fuel ratio sensor 22, a crank angle sensor 25 for detecting the rotation angle (rotation speed) of the crankshaft 6, a crank chamber pressure sensor 26 for detecting the pressure in the crankcase 6, a pressure in each of the cylinders , An intake air temperature sensor 29 for detecting the intake air temperature, an engine temperature sensor 30 for detecting the temperature in the cylinder 7, a back pressure sensor 31 for detecting the back pressure in each of the cylinders, and a throttle valve 12. Throttle opening sensor 32 for detecting the opening degree, cooling water temperature sensor 33 for detecting the temperature of the cooling water, knock sensor 35 for detecting the knock state of the engine 3, engine mount height detection for detecting the mount height of the engine 3 A sensor 36, a neutral sensor 37 for detecting a neutral state of the propulsion unit 2 of the outboard motor 1, and a vertical rotation position of the outboard motor 1 are detected. Trim angle sensor 39, the boat speed sensor 4 for detecting the boat speed
0, a boat attitude sensor 41 for detecting the attitude of the boat, an atmospheric pressure sensor 42 for detecting the atmospheric pressure, and an oil level sensor 43 for detecting the amount of oil (of the oil tank) mixed with the fuel.
Is provided. The control device 23 performs arithmetic processing on the detection signals of these various sensors, and transmits the control signals to the ignition plug 9, the fuel injection valve 13, the throttle valve 12, and the ISC 46.

Next, cylinder deactivation control according to the present invention will be described with reference to FIGS. As described above, in a two-stroke engine for an outboard motor, since the exhaust port of each cylinder is connected to the collective exhaust pipe due to space constraints, the intake of the engine is low, such as in a low-speed, low-load region. When the amount is small, an exhaust pulse enters and the exhaust remains in the cylinder, causing irregular combustion. As a method of improving this, cylinder deactivation control is performed to stop the operation of some cylinders and reduce the number of operating cylinders. This cylinder deactivation control suppresses exhaust interference, so that an effect of increasing the intake air amount per cylinder and stabilizing the engine rotation can be obtained.

FIG. 2 is a diagram for explaining the effect 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.
Are arranged vertically on the right side (S bank) and cylinders are shown on the left side (P bank), respectively.
In this order, ignition is performed at equal intervals of a crank angle of 60 degrees. As shown in FIG. 3, the timing at which the exhaust ports of the cylinders are opened and the timing at which the exhaust ports of the cylinders are closed are wrapped in order to increase the area from which the exhaust gas is emitted. As shown in FIG. 2, a strong exhaust pressure from the cylinder acts on the cylinder.
Similarly, the timing of opening the exhaust port of the cylinder and the timing of closing the exhaust port of the cylinder are wrapped,
The exhaust pressure from the cylinder acts on the cylinder, and the timing at which the exhaust port of the cylinder opens and the timing at which the exhaust port of the cylinder closes overlap, and the exhaust pressure from the cylinder acts on the cylinder. This relationship is the same in the P bank.

Here, the exhaust pressure (combustion pressure) of each cylinder is maximum in the cylinder at the most upstream side, and becomes weaker as it goes to the lower cylinder. This is because the most upstream cylinder, which has a relatively long exhaust pipe length, can effectively utilize exhaust pulsation, increase the intake air amount, and sufficiently scavenge exhaust gas. On the other hand, the most downstream cylinder,
Exhaust pulsation cannot be obtained sufficiently due to the short exhaust pipe length,
Since the direction of flow of the exhaust gas coincides with the direction of action of the exhaust pulse from the upper cylinder, the amount of intake gas 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 in the S bank are controlled 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 the cylinder of the P bank, or deactivate the cylinder of the P bank as the next best measure.

However, since the cylinders are cylinders for detecting the air-fuel ratio, if the cylinders are deactivated, the air-fuel ratio control cannot be performed, causing a problem. Therefore, when selecting the deactivated cylinders, the cylinders are excluded. As a result, it is best to deactivate the cylinder or deactivate the cylinder, and deactivate the cylinder as the next best measure.

Further, when only one cylinder is to be deactivated, it is sufficient to stop the cylinder or the cylinder at the most downstream side. However, when deactivating two cylinders, a problem arises when both cylinders are deactivated. The reason is that each cylinder ignites at an equal interval of 60 degrees of crank angle in the order of 〜, and when the cylinders are stopped, the explosion intervals do not become equal intervals and combustion as a whole is not possible. Become stable. Therefore, when the two cylinders are to be deactivated, the cylinders are cylinders for detecting the air-fuel ratio, and thus the deactivation is not performed. 2
One cylinder is deactivated every time one cylinder detonates, so that the overall explosion intervals in the cylinder deactivated state are equally spaced, the output generation timing is well balanced, and low-speed stability is obtained. At this time, in the P bank, the most upstream cylinder is stopped during the operation of the most downstream cylinder, and simultaneous combustion with the cylinder does not occur, so that the combustion stability is maintained.

FIG. 4 is a diagram for explaining the cylinder deactivation control, and shows a map indicating an operation region corresponding to the engine speed and the throttle opening. This control is performed so as to select a cylinder deactivated operation including four-cylinder operation or five-cylinder operation and a six-cylinder operation (all-cylinder operation) according to the throttle opening and the engine speed. Here, the cylinder deactivation is performed by stopping the ignition, and the fuel supply to the deactivated cylinder is continued by the fuel injection valve 13 provided independently for each cylinder.

FIGS. 5 and 6 show an embodiment of a cylinder deactivation control device for an engine according to the present invention. FIG. 5 is a diagram for explaining the flow of processing, and FIG. 6 is a specific example of FIG. FIG. In FIG. 5, in step S1, as described with reference to FIG. 4, it is determined whether or not the cylinder is in the cylinder deactivated operation range based on the throttle opening and the engine speed. . If cylinder deactivation operation zone, the predetermined value N _B is the engine speed in step S2
It is determined whether it is less than N _B , and if it is N _B or more, the cylinder deactivation operation based on the normal throttle opening and the engine speed is performed. If it is less than N _B , the cylinder deactivation operation for avoiding resonance is performed. .

The above processing will be specifically described with reference to FIG.
Engine side vibration frequency and outboard motor mount side vibration frequency f
Order not to match the _M, selects the stopped cylinders so as not to pass through the line frequency f _M. That is, in the cylinder deactivation operation region of the engine rotational speed is lower than N _A, the engine rotational speed is carried out 5 cylinder operation capable of avoiding the resonance is less than the predetermined value N _B, the engine rotational speed N _B or Then, the four-cylinder operation is performed. Therefore, it is possible to prevent resonance caused by the fact that the engine-side vibration frequency matches the outboard motor mount-side vibration frequency, and to obtain comfortable bodily sensation vibration. It should be noted that the determination may be made based on the throttle opening degree instead of the determination based on the engine speed. In short, a cylinder deactivation operation capable of avoiding resonance with a partial load may be performed.

In FIG. 6, the cylinders to be stopped during the five-cylinder operation are cylinders other than the cylinder on the bank side of the cylinder in which the air-fuel ratio sensor 22 is installed. The reason is that the cylinder on the bank S side of the cylinder in which the air-fuel ratio sensor 22 is installed is deactivated to reduce the back pressure on the S bank side, increase the intake air amount per cylinder, stabilize combustion, and ignite each time. The purpose of this is to obtain an accurate air-fuel ratio and to eliminate the influence of a cylinder in which combustion becomes unstable due to the combustion of the cylinder in which the air-fuel ratio sensor 22 is installed. During the four-cylinder operation, the cylinders are stopped as described above.

FIG. 7 is a diagram for explaining another embodiment of the present invention. In this embodiment, the engine speed is so as to implement a three-cylinder operation capable of avoiding the resonance is less than the predetermined value N _B. According to the present embodiment, fuel efficiency can be improved. Note that at least one of the cylinders to be stopped during the three-cylinder operation is a cylinder other than the cylinder on the bank side of the cylinder in which the air-fuel ratio sensor 22 is installed.

Although the embodiment of the present invention has been described above, the present invention is not limited to this, and various modifications can be made. For example, in the above embodiment, 6
Although an example in which the present invention is applied to a cylinder engine has been described, the present invention is not limited to this, and may be any engine having a plurality of cylinders. In the above-described embodiment, an example in which the present invention is applied to a two-cycle engine is described. However, the present invention is also applicable to a four-cycle engine, and is also applicable to a system in which fuel is directly injected into a cylinder. . further,
In the above embodiment, an example in which the present invention is applied to an outboard motor is described, but the present invention is also applicable to a vehicle driven by an engine and a battery.

[0023]

As is apparent from the above description, according to the present invention, it is possible to prevent the engine-side vibration frequency from matching with the engine-mount-side vibration frequency, and to obtain comfortable bodily sensation vibration.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of a control system relating to an engine cylinder deactivation control device of the present invention.

FIG. 2 is a diagram for explaining the influence of an exhaust pulse of each cylinder in cylinder deactivation control according to the present invention.

FIG. 3 is a diagram showing opening / closing timing of an exhaust port of each cylinder in the 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 illustrating an embodiment of an engine cylinder deactivation control device of the present invention and illustrating a flow of processing.

FIG. 6 is a diagram for explaining a specific example of FIG. 5;

FIG. 7 is a diagram for explaining another embodiment of the present invention.

FIG. 8 is a diagram illustrating engine vibration characteristics when cylinder deactivation is performed.

FIG. 9 is a diagram for explaining a problem of the present invention.

[Explanation of symbols]

 1 outboard motor, 3 engine, ... cylinder

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification number Agency reference number FI Technical display location F02D 45/00 301 F02D 45/00 301D 312 312Z

Claims (2)

[Claims] In an engine having a plurality of cylinders and performing cylinder deactivation control, the number of operating cylinders is changed so that the engine-side vibration frequency does not coincide with the engine-mount-side vibration frequency. apparatus. 2. In an engine having a plurality of cylinders and performing cylinder deactivation control and air-fuel ratio control, the number of operating cylinders is changed so that the engine-side vibration frequency does not coincide with the engine-mount-side vibration frequency. A cylinder deactivation control device for an engine, wherein the cylinder does not cause exhaust interference to the cylinder except for the cylinder in which the air-fuel ratio sensor is installed.