JP2908281B2 - Supply valve control method and apparatus for large marine diesel 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 method and an apparatus for opening and closing an air supply valve of a large marine diesel engine, and more particularly to a method for easily starting an air supply valve by switching the operation of the air supply valve at startup. The present invention relates to a method and an apparatus for opening and closing an air supply valve of a large marine diesel engine.

[0002]

2. Description of the Related Art Conventionally, when starting a large marine diesel engine, it is necessary to rotate it with another driving force until a driving force is generated by igniting and exploding fuel. There is. As a general method, the starting air stored at a high pressure in the starting air reverser is supplied into a cylinder during an expansion stroke of an engine cycle, and the confined starting air is compressed as the piston rises in a compression stroke. The temperature is raised, and when the temperature rise becomes higher than the ignition temperature near the top dead center, fuel is injected to ignite the fuel and explode.

According to this method, the air in the cylinder is trapped after the air supply valve is closed in the compression stroke until the exhaust valve is opened in the exhaust stroke.
In the case of a cycle, the air supply cam is made so that the air supply valve closes at 20 to 60 ° after the bottom dead center.
If the ignition temperature is not reached before starting compression to 0-60 ° and reaching the top dead center, no matter how much fuel is injected, no ignition will occur.
This is because a so-called “ignition failure” may occur.
In particular, when the diesel engine is cold in winter or a cold region, such ignition failure is likely to occur.

For this reason, a special fuel having a low ignition temperature may be used at the time of starting in order to make it easy to ignite. However, since this fuel is expensive, the fuel cost increases. Also,
If the air temperature in the cylinder does not reach the ignition temperature during the compression stroke, the engine may be turned with the starting air to a high rotation speed to reduce the heat that escapes to the cylinder wall.
It is necessary to make the diameter of the starting valve extra large and also to make the starting air reverser large in accordance with the starting valve, so that an expensive starting device is required.

Therefore, conventionally, a so-called "warm-up" is generally performed in which the compression stroke is repeated by starting air, that is, so-called air-run is performed, or the engine is warmed by turning the cylinder wall with lubricating oil warmed before starting. The method of starting after going is commonly used.

[0006] This "warm-up" occurs in a normal ship.
A method has been adopted in which an operator empirically determines the completion of "warm-up", injects fuel, and stops and starts the starting air. However, in this case, depending on the empirical judgment of the operator, "ignition failure" may occur frequently for some operators, and it is difficult for some operators to start large marine diesel engines. It may be.

In a marine diesel engine,
A multi-cylinder large-sized diesel engine employing a long-stroke engine that obtains a high output at a low rotational speed is installed so that the efficiency is high when the vehicle sails for a long time at a substantially constant output. Therefore, in such a large marine diesel engine, the starting time is long, and for example, about 1 minute may be required. In addition, at the time of this start, it is difficult for all of the plurality of cylinders to start ignition at the same time, and the cylinders are sequentially fired while causing a temporal ignition shift between the cylinder that fired and the cylinder that caused the ignition delay. Therefore, in such a case, diesel knocking may occur, or unignition may continue to adversely affect the engine.

On the other hand, in order to maximize the compression effect and raise the temperature of the air in the cylinder, the cam of the air supply valve may be shaped so that the air supply valve closes at the bottom dead center. As described above, if the engine speed is increased by performing normal operation with the air supply valve closed at the bottom dead center, the ignition delay becomes relatively large, causing a sudden increase in pressure and diesel knocking. The occurrence of such a diesel knock adversely affects the durability of the engine, so that normal fuel operation cannot be continued with the closing angle of the air supply valve at the bottom dead center.

[0009] Therefore, in the future large marine diesel engines, there is a demand for an engine that can be easily started even in winter or cold regions.

[0010] As a prior art for an automobile diesel engine, there is an invention described in Japanese Patent Application Laid-Open No. 1-315631. However, since the present invention relates to a small automobile diesel engine, it is necessary to determine whether the engine has started. This is a method for simultaneously changing the supply valve opening / closing timing of all cylinders by judging whether or not the state of each cylinder is observed. Therefore, even if the present invention is applied to a large marine diesel engine, if a specific cylinder is ignited or not ignited, it is ignored, and diesel knocking or unigniting continues, and the above-mentioned application is described. It cannot solve the problem of the invention.

Another prior art is disclosed in Japanese Patent Application Laid-Open No. 48-7111.
There is an invention described in Japanese Patent Application Laid-Open No. H11-159465 and an invention described in Japanese Patent Application Laid-Open No. 1-159465, but since both are start assist devices in a small diesel engine such as an automobile diesel engine, these are also targeted for the invention according to this application. Problems in large marine diesel engines cannot be solved.

In view of the above problems, the invention according to this application has
One object of the present invention is to provide a method for opening and closing a supply valve of a large marine diesel engine that can be easily started even in a winter or a cold region in a large marine diesel engine. Another object of the present invention is to provide an air supply valve device.

[0013]

In order to achieve the above object, a method for controlling a supply valve of a large marine diesel engine according to claim 1 employs a four-stroke long stroke engine.
In a large marine diesel engine with multiple cylinders,
For each cylinder of several cylinders, set the closing angle of the air supply valve to the bottom dead center.
Start opening / closing timing that has been advanced to the vicinity and closing of the air supply valve
Set the regular opening / closing timing with the valve angle set to the regular angle,
At start-up, the air supply valve is opened and closed at a start opening / closing timing in which the closing angle of the air supply valve is advanced for each cylinder, and if ignition is determined by an ignition determination signal for each cylinder, the above-described starting operation is performed for each cylinder that has fired. switching on the normal closing timing from the switching timing to open and close the air supply valve, and is characterized in that for opening and closing the air supply valve is switched to the conventional opening and closing timing from the start-off timing for each cylinder sequentially ignited.

According to a second aspect of the present invention, there is provided an air supply valve device for a large marine diesel engine which employs a four-stroke long stroke engine.
In marine large diesel engine plurality of cylinders that use, the startup pickup sensor you output the starting-off timing of early closing angle of the air supply valve when starting each cylinder
It is provided on the normal pickup sensor you output common opening and closing timing of the intake valve during regular each cylinder
In providing, to wear fire determiner you outputs ignition determination signal by determining that ignited in each cylinder provided for each cylinder, conventional from the conventional pickup sensor and the starting-off timing from the starting pickup sensor An open / close timing is input, and a signal switch is provided for each cylinder and switched from the open / close timing for starting to the normal open / close timing according to an ignition determination signal of the ignition determiner, and an air supply valve opening / closing timing from the signal switch is provided for each cylinder. is characterized in that constitute Rikyu valves to open <br/> closes so by the.

According to a third aspect of the present invention, there is provided a method for controlling a supply valve of a large marine diesel engine, comprising: a four-stroke long stroke engine.
For multi-cylinder large marine diesel engine with
A crank angle signal is detected by a pickup sensor, and each of the plurality of cylinders is detected based on the crank angle signal.
For each cylinder, quickly close the intake valve close angle to near the bottom dead center.
The open / close timing for starting and the closing angle of the air supply valve
Generate a normal opening / closing timing at the required angle, output the starting opening / closing timing for each cylinder at the time of starting,
When the ignition is determined by the ignition determination signal for each cylinder, the air supply valve is opened and closed by switching from the opening / closing timing for start to the normal opening / closing timing for each ignited cylinder,
The present invention is characterized in that the supply valve is opened and closed by switching from the opening / closing timing for starting to the regular opening / closing timing for each cylinder that has been sequentially ignited.

According to a fourth aspect of the present invention, there is provided an air supply valve device for a large marine diesel engine which employs a four-stroke long stroke engine.
In a large marine diesel engine with multiple cylinders used, a pickup sensor that outputs a crank angle as a signal at fixed angular intervals is provided , and the closing angle of the air supply valve is advanced to near the bottom dead center by a signal from the pickup sensor. A start timing generator for generating and outputting the open / close timing for each cylinder is provided for each cylinder, and the closing angle of the air supply valve is set to a normal angle by a signal from the pickup sensor.
Generates a common closing timing every time by providing a common timing generator for outputting for each cylinder, provided with ignition determination unit for outputting an ignition judgment signal is determined to be ignited in the cylinder for each cylinder, wherein A signal for inputting a start opening / closing timing from a start timing generator and a regular opening / closing timing from the regular timing generator, and switching from the opening / closing timing to the regular opening / closing timing according to an ignition determination signal of the ignition determiner, and outputting the signal. it is characterized in that to constitute a switching unit <br/> to open and close by Rikyu valves in air supply valve opening and closing timing from the signal switching device is provided for each cylinder.

According to a fifth aspect of the present invention, there is provided a method for controlling a supply valve of a large marine diesel engine, comprising: a four-stroke long stroke engine;
For multi-cylinder large marine diesel engine with
Te, during start closing the intake valve closing angle for each cylinder
When the valve angle is switched to the starting cam that has been advanced to near the bottom dead center and ignition is determined by the ignition determination signal for each cylinder,
From the starting cam for each cylinder ignition of the air supply valve
By switching to conventional cam and the closing angle common angle by opening and closing the air supply valve, and is characterized in that for opening and closing sequentially ignited air supply valve is switched to the regular cam from the starting cam for each cylinder.

According to a sixth aspect of the present invention, there is provided an air supply valve device for a large marine diesel engine employing a four-stroke long stroke engine.
In a large-sized multi-cylinder marine diesel engine, a starting cam is provided for each cylinder that starts and closes the intake valve at the time of start up to near the bottom dead center.
In each case, a regular cam is provided for each cylinder to create a regular opening and closing operation with the closing angle of the air supply valve at the regular angle during regular use.
Only, the ignition determination unit for outputting an ignition judgment signal is determined to be ignited in the cylinder provided for each cylinder, a cam switching device for switching on the normal cam from the starting cam by ignition determination signal該着fire determiner by the starting or customary cam switches in the cam switching device is provided for each cylinder Rikyu valves
It is characterized in that it has configured to open and close the.

[0019]

According to the air supply valve control method for a large marine diesel engine according to the first aspect, at the time of starting, the opening and closing timing of the air supply valve is advanced for each cylinder of a plurality of cylinders to near the bottom dead center. When the ignition valve is opened and closed by the ignition determination signal for each cylinder, the closing angle of the air supply valve is set to the normal angle from the start opening / closing timing for each ignited cylinder. It is switched to opening / closing timing, and thereafter, for each cylinder that has been ignited, it is switched from starting opening / closing timing to regular opening / closing timing to open and close the air supply valve. Since the compression is earlier, the compression of the air in the cylinder is started earlier, the compression temperature at the top dead center becomes higher, and the fuel becomes easier to ignite.

In addition, since ignition is determined for each cylinder, even if there is an unignited cylinder and an ignited cylinder due to variations among the cylinders, the unignited cylinder increases the closing angle of the air supply valve. The cylinder that ignites can delay the closing angle of the air supply valve to prevent diesel knock.

According to the air supply valve device for a large marine diesel engine according to the second aspect, in the air supply valve control method according to the first aspect, the start-up opening / closing timing is provided by a start-up pickup sensor provided for each cylinder. Is output, and ignition is determined by an ignition determination signal provided by an ignition determination device provided for each cylinder. It is switched to the normal opening / closing timing by the pickup sensor, and then the air supply valve is opened and closed by switching from the starting opening / closing timing to the normal opening / closing timing by the signal switch for each cylinder that has ignited sequentially. Since the angle is advanced to near the bottom dead center, the compression of air in the cylinder starts earlier, and the top dead center It can easily ignite the fuel is high temperature compression.

[0022] wherein, according to the intake valve control method for marine large diesel engine according to claim 3, the detected crank angle signal, the bottom dead closing angle of the air supply valve which is generated for each cylinder of the plurality of cylinders during start-up The intake valve is opened and closed by the start opening / closing timing advanced to near the point , and when the ignition is determined by the ignition determination signal for each cylinder, the closing angle of the supply valve for each ignited cylinder is changed from the start opening / closing timing for each ignited cylinder. The opening / closing timing is switched to the normal closing angle with the valve closing angle set to the normal angle, and then the opening / closing timing for starting is switched from the opening / closing timing for normal use to the normal opening / closing timing for each fired cylinder. The closing angle is advanced to near the bottom dead center, so that the compression of the air in the cylinder is started earlier, the compression temperature at the top dead center is increased, and the fuel can be easily ignited. Moreover, diesel knock can be prevented as in the case of the first aspect.

According to the air supply valve device for a large marine diesel engine according to a fourth aspect, in the air supply valve control method according to the first aspect, the starting timing generator provided for each cylinder opens and closes the starting valve. In addition to generating the timing, the regular opening / closing timing is generated by the regular timing generator, the ignition is determined by the ignition determination signal provided by the ignition determiner provided for each cylinder, and the cylinders ignited by the signal switch provided for each cylinder. Is switched from the opening / closing timing for starting by the starting timing generator to the regular opening / closing timing by the regular timing generator, and thereafter, the starting / closing timing is switched from the starting / closing timing to the regular opening / closing timing by the signal switch for each cylinder sequentially fired. To start and close the air supply valve, close the air supply valve at startup near the bottom dead center. In so fast compression start of air in the cylinder is faster, it can easily ignite the fuel becomes higher compression temperature at the top dead center. In addition, diesel knock can be prevented as in the case of the second aspect.

According to the air supply valve control method for a large marine diesel engine according to the fifth aspect, at the time of starting, the starting cam whose valve closing angle is advanced to near the bottom dead center by a cam switch for each cylinder of a plurality of cylinders is provided. When the ignition is determined by the ignition determination signal for each cylinder, the closing angle of the air supply valve is always set from the starting cam for each cylinder that has ignited.
The starting cam is switched to the working cam at the working angle, and then the cylinder is switched from the starting cam to the working cam for each fired cylinder to open and close the air supply valve. Since the compression speed is increased to the vicinity, the compression start of the air in the cylinder is accelerated, and the compression temperature at the top dead center is increased, so that the fuel can be easily ignited. Moreover, diesel knock can be prevented as in the case of the first aspect.

According to the air supply valve device for a large marine diesel engine according to the sixth aspect, in the air supply valve control method according to the fifth aspect, ignition is performed by an ignition determination signal provided by an ignition determiner provided for each cylinder. Judgment, the cam switch provided for each cylinder ignited, the valve closing angle of each cylinder ignited was switched from the starting cam with the advanced valve to the service cam to open and close the air supply valve, and then for each cylinder ignited sequentially Since the cam switch switches the starting cam from the regular cam to the regular cam to open and close the air supply valve, the angle of closing the air supply valve is shortened to near the bottom dead center at startup, so the compression of air in the cylinder starts earlier, The compression temperature at the dead center is increased, and the fuel can be easily ignited. In addition, diesel knock can be prevented as in the case of the fourth aspect.

[0026]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the invention according to the present application will be described below with reference to the drawings. FIG. 1 is a block diagram showing a first embodiment. As shown in FIG. 1, a starting pickup sensor 1 and a regular pickup sensor 2 are connected to a signal switch 3, and the signal switch 3 determines ignition. The signal from the signal switch 4 is input, and the signal from the signal switch 3
In this embodiment, the electromagnetic valve 5 is driven to open and close the air supply valve 6.

The starting pickup sensor 1 and the regular pickup sensor 2 are provided on a rotating shaft such as a cam shaft connected to an engine, for example, as shown in Table 1 below.
A sensor that outputs an ON signal when the air supply valve 6 opens and an OFF signal when the air supply valve 6 closes is used. As this sensor, for example, a rotating plate is provided on the rotating shaft side and a proximity switch is provided on the fixed side, and a detecting unit is provided on the rotating plate from a predetermined angle at which the air supply valve 6 opens to a predetermined angle at which the air supply valve 6 closes. May be configured to output an ON signal when is detected by the proximity switch and an OFF signal when the signal is cut off. In this embodiment, two types of detectors, one for starting and the other for normal use, are provided for each cylinder.

The pickup sensors 1, 2
The air supply valve opening angle and air supply valve closing angle are set as shown in [Table 2] below. Note that TDC represents the angle before top dead center, and BDC represents the angle after bottom dead center.

[0029]

[Table 1]

[0030]

[Table 2]

At this time, when the temperature rise of the air in the cylinder is generally considered by a polytrope change, it can be expressed as the following [Equation 1].

[0032]

(Equation 1)

Here, T2 is the air temperature in the cylinder at the top dead center, T1 is the air temperature in the cylinder when the air supply valve is closed and the cylinder is closed, V2 is the gap volume at the top dead center, V1 is the cylinder volume when the air supply valve is closed and the cylinder is closed, and n is the polytropic index. As can be seen from this equation, when the ratio between V1 and V2 is large, the air temperature in the cylinder at the top dead center increases significantly.

On the other hand, the ignition judging device 4 has a function of judging that the fuel has ignited in the cylinder. In this embodiment, as an example of the ignition judging, as shown in the diagram of FIG. Ignition is determined based on the rate of change in the number of revolutions for each cylinder. That is, in this example, a three-cylinder diesel engine is taken as an example, and a rotation speed detector 7 provided for each cylinder is provided.
The ignition determination is made by detecting the rotation speed of each cylinder and reading the rate of change of the rotation speed.
The rate of change (a) of the first cylinder is read by detecting the number of rotations of the cylinder. In this example, since the change rate is equal to or more than the predetermined value, the ignition is determined and the air supply valve is switched to the normal open / close timing. Similarly, by detecting the rotation speed of the second cylinder, the rate of change (b) of the second cylinder is read, and
Since the value of the cylinder is also equal to or more than the predetermined value, the ignition is determined and the air supply valve is switched to the normal opening / closing timing. Then, the rate of change (c) of the third cylinder is detected by detecting the number of revolutions of the third cylinder. In this example, the rate of change (c) is equal to or less than a predetermined value. The air supply valve 6 is opened and closed according to the start opening and closing timing. Then, when the rate of change (f) of the third cylinder is read by detecting the rotation speed of the third cylinder, the ignition rate of the third cylinder is determined because the rate of change is greater than or equal to a predetermined value, and the air supply valve is opened. Control is performed so as to switch to the normal opening / closing timing.

The ignition determination is performed by comparing the rate of change of the number of revolutions with the rate of change of the number of revolutions after the previous fuel injection for each cylinder. If not, it is determined that no ignition has occurred. Therefore, when the engine is ignited and the rate of change in the number of revolutions increases from the rate of change in the number of revolutions of the starting air alone, it is determined that the engine has fired. The ignition determiner 4 outputs an ignition determination signal while the fuel is ignited and the engine is rotating. When performing the ignition determination for the entire engine together with the ignition determination for each cylinder, as shown in the diagram of FIG. The ignition is determined by reading the phenomenon of rapid rise to a rotation speed equal to or higher than the predetermined rotation speed of the ignition determination, or the rotation by the starting air is detected as shown in the acceleration detection diagram in FIG. 3 (b). From, fuel at a predetermined speed,
It is also possible to read the phenomenon (g) that rapidly rises to an acceleration equal to or higher than the predetermined acceleration for ignition determination to make an ignition determination, or to make an ignition determination based on both of them.

The signal switching unit 3 selectively switches the pickup sensors 1 and 2 according to the ignition determination signal from the ignition determination unit 4. When the ignition determination signal is OFF, the starting pickup sensor is used. 1 is output, and when the ignition determination signal is ON, a signal is output from the service pickup sensor 2 to control the opening / closing timing of the electromagnetic valve 5 for opening / closing the air supply valve 6.

The air supply valve 6 is opened and closed by an open / close timing signal output from the signal switch 3. In this embodiment, a hydraulic cylinder (not shown) linked to the air supply valve 6 is driven and controlled. It is configured by a combination with the solenoid valve 5. That is, the solenoid valve 5 is energized while the air supply valve 6 is opened by the opening / closing timing signal from the signal switch 3, and is deenergized while the air supply valve 6 is closed. Have been. Note that a servo valve may be used instead of the electromagnetic valve 5, or a pneumatic circuit may be used instead of the hydraulic circuit.

According to the air supply valve control device of the first embodiment configured as described above, the large-sized marine diesel engine can be started by the following operation.

That is, at the time of starting, as shown in the operation explanatory diagram of the air supply valve shown in FIGS. 4A and 4B, the signal is switched based on the signal from the starting pickup sensor 1 provided for each cylinder. from vessel 3 a signal is sent to the solenoid valve 5, the air supply valve 6 is opened and closed by a starter valve timing t ₁ in accordance with this signal. When an ignition determination F is made by an ignition determiner 4 provided for each cylinder, an ignition determination signal is input to a signal switch 3 of the cylinder, and the ignition pickup sensor 1 is sent from the starting pickup sensor 1 to the regular pickup sensor 2. since the switches, intake valves 6 are opened and closed by a conventional closing timing t ₂ from the signal switching device 3 is sent a signal to the solenoid valve 5. Note that o is open and c is closed.

Next, a second embodiment will be described with reference to the block diagram shown in FIG. This second embodiment is similar to the first embodiment described above.
In place of the starting pickup sensor 1 and the regular pickup sensor 2 in the embodiment, a signal from the common pickup sensor 8 is generated as a starting and closing timing by the starting timing generator 9 and a regular opening and closing timing by the regular timing generator 10. This is an embodiment in which the signal is output to the signal switch 3. The same components as those in the first embodiment will be described with the same reference numerals.

As shown, a pickup sensor 8 is provided with a start timing generator 9 provided for each cylinder.
The starting timing generator 9 and the regular timing generator 10 are connected to the
Are connected to a signal switch 3 provided for each cylinder. The signal from the ignition determiner 4 is input to the signal switch 3, and in the second embodiment, as in the first embodiment, the signal from the signal switch 3 is used to control the electromagnetic valve. 5 is driven to open and close the air supply valve 6.

The pickup sensor 8 of the second embodiment
Is connected to a camshaft or the like of the engine in the same manner as in the first embodiment described above, but may be any as long as it outputs a pulse signal at a constant angle interval from the reference angle, and may be, for example, a rotary encoder. .

The start timing generator 9 opens the air supply valve 6 when a pulse signal is input at a constant angle interval from the reference angle, and closes the air supply valve 6 when a pulse signal is input. This is registered in advance, and when a signal from the pickup sensor 8 is input, a start air supply valve opening / closing signal is output from the opening operation to the closing operation. The service timing generator 10 also has the same configuration as the start timing generator 9, and a pulse until the air supply valve 6 is closed by the start timing generator 9 as a service air valve opening / closing signal. Although it differs in that the number is large, it outputs a normal air supply valve opening / closing signal from the opening operation to the closing operation.

The ignition judging device 4 is the same as in the first embodiment.
The signal switch 3 determines the ignition state of the fuel in the cylinder and determines
The signal switching unit 3 outputs a normal open / close timing signal to the air supply valve 6 when the ignition determination signal is ON, and outputs a signal to the air supply valve 6 when the ignition determination signal is OFF. The start-up opening / closing timing signal is output to the controller. The air supply valve 6 opens and closes in accordance with the open / close timing signal output from the signal switch 3 as in the first embodiment described above.

According to the air supply valve control device of the second embodiment configured as described above, the large-sized marine diesel engine can be started by the following operation.

That is, at the time of starting, the signal from the starting timing generator 9 is selected by the signal switch 3,
On the basis of this signal, the solenoid valve 5 opens and closes the air supply valve 6 at the opening and closing timing for starting. When it is determined that the ignition has occurred by the ignition determiner 4 provided for each cylinder, an ignition determination signal is input to the signal switch 3 of the cylinder, and the starting timing generator 9 outputs the normal timing generator. The air supply valve 6 is driven by the solenoid valve 5 at the opening / closing timing by the signal from the regular timing generator 10.

Since the invention according to this application is intended for a marine diesel engine that runs for a long time at a substantially constant output and has a small fluctuation in the number of revolutions, the air supply valve 6 is provided as in the first and second embodiments described above. If it is configured to be opened and closed by the electromagnetic valve 5, the air supply valve 6 can be opened and closed by a constant angle at substantially constant intervals by a large force such as hydraulic pressure.

Next, a third embodiment will be described with reference to the block diagram shown in FIG. The third embodiment is an embodiment in which the starting cam 11 and the regular cam 12 provided for each cylinder are switched by the cam switching device 13 to open and close the air supply valve 6. These cams are switched based on a determination signal. In the third embodiment, the opening and closing timings for starting and normal use are switched by a mechanical configuration. Further, the same configurations as those of the first and second embodiments described above are denoted by the same reference numerals and described.

The starting cam 11 is formed in a shape in which the air supply valve 6 performs opening and closing operations for starting, similarly to the first and second embodiments described above. 6 is formed in a shape for performing a normal opening and closing operation. That is,
The starting cam 11 is shaped such that the air supply valve closes earlier than the regular cam 12. Note that the ignition determination device 4 is the same as that of the above-described embodiment, and an ignition determination signal is output to the cam switching device 13.

The cam switching unit 13 switches to the regular cam 11 when the ignition determination signal from the ignition determination unit 4 is ON, and switches to the starting cam 12 when the ignition determination signal is OFF to open and close the air supply valve 6. It is configured as follows. As the switching method, there is a method of switching the cams arranged in parallel by a clutch, a method of switching by a hydraulic pressure, and the like. The air supply valve 6 is opened and closed according to the switched starting cam 11 or regular cam 12.

According to the air supply valve control device of the third embodiment configured as described above, the large-sized marine diesel engine can be started by the following operation.

That is, at the start, the cam switch 13 is used to switch to the starting cam 11, and the starting cam 11 opens and closes the air supply valve 6 at the opening and closing timing for the start. When the ignition is determined by the ignition determiner 4 provided for each cylinder and an ignition determination signal is input to the cam switch 13, the cam switch 13 switches the normal cam from the starting cam 11. The air supply valve 6 is driven by the regular cam 12 at the regular opening / closing timing.

By the way, in the case of a large marine diesel engine, it is sometimes necessary to perform a voyage in which once a voyage is made, the port cannot be called for several days. In such a case, only some of the cylinders may break down on the sea, and may not be able to call at the port, and may be difficult to repair. In such a case,
In the case of a ship, after stopping only the failed cylinder and disconnecting it to cut off the influence on other cylinders, the voyage is continued only by the driving force of the other cylinder. Therefore, the failed cylinder is in a stopped state thereafter.

Therefore, according to the invention of this application, as in the above-described first to third embodiments, the ignition decision unit 4 is provided for each cylinder to perform the individual ignition decision. Even when some of the cylinders are stopped, the air supply valve 6 is opened and closed by switching between the opening and closing timings for starting and regular use. Can be started easily.

[0055]

The invention according to the present application is configured as described above, and has the following effects.

According to the air supply valve control method or the air supply valve device for a large marine diesel engine according to claim 1 or 2,
Cylinders ignited at start-up are sequentially switched from start-up open-close timing to normal open-close timing for each cylinder to open and close the air supply valve. As it is possible to raise the compression temperature at the top dead center of the air inside the cylinder and make it easier to ignite the fuel, there is no need to warm up the cylinder wall and warm up the cylinder wall before starting, as in winter and cold regions It is possible to easily start a large marine diesel engine even in a cold environment.

Therefore, it is not necessary to use a special fuel having a low ignition temperature at the time of starting in order to facilitate ignition, so that the fuel cost is reduced, and the diameter of the starting valve is increased in order to rotate the engine up to a high rotational speed with the starting air. Since it is not necessary to make it particularly large, it is not necessary to make the starting valve and the starting air reverser large.

Further, since ignition is determined for each cylinder, even if there is an unignited cylinder and an ignited cylinder due to variations for each cylinder, the unignited cylinder sets the closing angle of the air supply valve earlier. Since the ignition of the cylinder is promoted and the cylinder that has ignited can delay the closing angle of the air supply valve to prevent diesel knock, it is possible to improve the durability of the large marine diesel engine.

According to an air supply valve control method or an air supply valve device for a large marine diesel engine according to claim 3 or 4,
At start-up, the air supply valve is opened / closed by the start timing generator for each cylinder at the start opening / closing timing with the air supply valve closing angle advanced, and the ignited cylinders are sequentially turned on / off from the start / open timing for each cylinder. In order to open and close the air supply valve by switching to the normal opening and closing timing, at the start, the closing angle of the air supply valve is advanced to near the bottom dead center, the compression temperature at the top dead center of the air in the cylinder is raised, and fuel is ignited Therefore, it is not necessary to warm up the cylinder wall by warming up before starting, and the large marine diesel engine can be easily started even in a cold environment such as winter or a cold region.

Accordingly, the fuel cost is reduced as in the case of the first or second aspect, and it is not necessary to increase the size of the starting valve and the starting air reverser, and it is also possible to prevent diesel knock.

According to an air supply valve control method or an air supply valve device for a large marine diesel engine according to claim 5 or 6,
At start-up, each cylinder is switched to a start-up cam with the valve closing angle advanced by a cam switch to open and close the air supply valve, and the ignited cylinders are sequentially switched from the start-up cam to the regular cam for each cylinder. To start and close the air valve, the angle at which the air supply valve is closed should be advanced to near the bottom dead center during startup, and the compression temperature at the top dead center of the air in the cylinder can be increased to facilitate ignition of fuel. Therefore, it is not necessary to warm up the cylinder wall to warm up the cylinder wall, and it is possible to easily start the large marine diesel engine even in a cold environment such as winter or a cold region.

Accordingly, the fuel cost is reduced as in any one of the first to fourth aspects, and it is not necessary to increase the size of the starting valve and the starting air reverser, and diesel knock can be prevented.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a first embodiment of the invention according to this application.

FIG. 2 is a diagram illustrating an example of ignition determination in the invention according to the present application, and is a diagram illustrating ignition determination based on a rate of change in the rotational speed of each cylinder.

FIG. 3 is a diagram exemplifying another ignition determination in the invention according to the present application, wherein (a) is a diagram for detecting rotation speed and (b)
Is a diagram for detecting acceleration.

FIGS. 4 (a) and 4 (b) are explanatory diagrams showing a start-up operation and a normal operation of an air supply valve when the invention according to the present application is applied.

FIG. 5 is a block diagram showing a second embodiment of the invention according to this application.

FIG. 6 is a block diagram showing a third embodiment of the invention according to this application.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Pickup sensor for starting 2 ... Pickup sensor for regular use 3 ... Signal switcher 4 ... Ignition judging device 5 ... Solenoid valve 6 ... Supply valve 7 ... Rotation speed detector 8 ... Pickup sensor 9 ... Timing generator for starting 10 ... Regular use The timing generator 11 ... starting cam 12 ... common cam 13 ... cam changer t ₁ ... closing timing t ₂ ... customary closing timing F ... ignition determination for starting

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A 1-315631 (JP, A) JP-A 61-145806 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) F02D 13/02 F02D 41/06 351 F01L 1/34

Claims (6)

(57) [Claims] 1. A four-stroke long-stroke engine is employed.
Of a large multi-cylinder marine diesel engine
For each cylinder of multiple cylinders, lower the closing angle of the air supply valve.
Start-up opening / closing timing that is advanced to near the dead center and air supply valve
Set the regular opening / closing timing with the regular closing angle of the valve
Then, at the start, the supply valve is opened and closed at a start opening / closing timing in which the closing angle of the supply valve is advanced for each cylinder, and ignition is determined by an ignition determination signal for each cylinder. A large marine diesel engine characterized by switching the start-up opening / closing timing to the regular opening-and-closing timing to open and close the air supply valve, and switching the starting-opening / closing timing to the normal opening / closing timing to open and close the supply valve for each fired cylinder. Engine air supply valve control method. 2. A four-stroke long stroke engine is employed.
In marine large diesel engine plurality of cylinders that use, provided with a startup pickup sensor you output the starting-off timing of early closing angle of intake valve at startup for each cylinder, intake valve conventional in civil time the normal pickup sensor you output close timing provided for each cylinder, provided with wear fire determiner you outputs ignition determination signal by determining that ignited in each cylinder for each cylinder,
Signal switching for inputting a start opening / closing timing from the starting pickup sensor and a normal opening / closing timing from the normal pickup sensor, and switching from the starting opening / closing timing to the normal opening / closing timing according to an ignition determination signal of the ignition determiner, and outputting the signal. intake valve device of marine large diesel engine, characterized by being configured so that vessel to <br/> open and close by Rikyu valves in air supply valve opening and closing timing from the signal switching device is provided for each cylinder . 3. A four-stroke long stroke engine is employed.
In a large-sized marine diesel engine having a plurality of cylinders, a crank angle signal is detected by a pickup sensor, and each cylinder of the plurality of cylinders is detected based on the crank angle signal.
The closing angle of the air supply valve has been advanced to near the bottom dead center
Normal opening / closing timing and the closing angle of the air supply valve
When the engine is started, the starting open / close timing is output for each cylinder, and the ignition is determined by the ignition determination signal for each cylinder. A supply valve control for a large marine diesel engine characterized in that the supply valve is opened and closed by switching to the opening and closing timing, and the supply valve is opened and closed by switching from the opening and closing timing for starting to the regular opening and closing timing for each cylinder that has ignited sequentially Method. 4. A four-stroke long stroke engine is employed.
In a large marine diesel engine with multiple cylinders used, a pickup sensor that outputs a crank angle as a signal at fixed angular intervals is provided , and the closing angle of the air supply valve is advanced to near the bottom dead center by a signal from the pickup sensor. A start timing generator for generating and outputting the opening / closing timing for each cylinder is provided for each cylinder, and the closing angle of the air supply valve is regularly used based on a signal from the pickup sensor.
The common timing generator for generating and outputting a common closing timing angle provided for each cylinder, provided with ignition determination unit that determines that the ignition in each cylinder and outputs an ignition judgment signal for each cylinder, wherein A signal for inputting a start opening / closing timing from a start timing generator and a regular opening / closing timing from the regular timing generator, and switching from the opening / closing timing to the regular opening / closing timing according to an ignition determination signal of the ignition determiner, and outputting the signal. Switch
The intake valve device marine large diesel engine, characterized by being configured to open and close the by Rikyu valves in air supply valve opening and closing timing from the signal switching device is provided for each cylinder. 5. A four-stroke long stroke engine is employed.
In a large-sized multi-cylinder marine diesel engine used at startup, the closing angle of each cylinder is determined by the closing angle of the supply valve at startup.
Switching the starting cam ahead until near the bottom dead center, when ignition determination by ignition determination signal for each respective cylinder, closing angle of intake valve from the starting cam for each cylinder and ignited
The supply of large diesel engines for ships is characterized by switching to a regular cam with a normal angle to open and close the air supply valve, and switching from the starting cam to the regular cam for each cylinder that has ignited and opening and closing the air supply valve. Valve control method. 6. A four-stroke long stroke engine is employed.
In each large cylinder diesel engine with multiple cylinders, a starting cam is provided for each cylinder to make the opening and closing operation of the intake valve advanced at the start to near the bottom dead center at startup.
Together, set the common cam produce <br/> conventional opening and closing operation that the common angle closing angle of intake valve during regular each cylinder
Only, the ignition determination unit for outputting an ignition judgment signal is determined to be ignited in the cylinder provided for each cylinder, a cam switching device for switching on the normal cam from the starting cam by ignition determination signal該着fire determiner by the starting or customary cam switches in the cam switching device is provided for each cylinder Rikyu valves
Intake valve device of marine large diesel engine, characterized by being configured to open and close the.