JPH0610809A - Starter for marine diesel engine - Google Patents

Abstract

PURPOSE:To provide a starter for a marine diesel engine, allowing an engine speed to be quickly lowered at the time of idling after fuel supply interruption, upon issuing an astern instruction, or the number of propeller revolutions to be quickly lowered without consuming a large amount of the engine starting compressed air, and thereby enabling a distance to be shortened for stopping a ship. CONSTITUTION:This starter is constituted of a sensor 1 to detect a signal related to the rotation angle of a crankshaft and speed thereof, a starting air valve 4 to blow the starting compressed air into a cylinder, and an exhaust valve 5 to discharge the air from the cylinder to the outside during the idling of an engine. The starter is further constituted of a starting control device 6 to receive signals from the sensor 1, an engine remote control device or the like, and to generate a control signal necessary for the control system of the starter, a control valve 2a to control the open/close operation of the valve 4 according to a signal from the device 6, another control valve 2b to control the open/close operation of the valve 5, and a starting air feed valve 3 to control the open/close operation of a main line for the starting compressed air.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a starting device for a marine diesel engine. It can also be applied to a reversible diesel engine.

[0002]

2. Description of the Related Art In a diesel engine, there is an invention (Japanese Patent Application No. 60-168641) for reducing the consumption of starting air and improving the starting performance and the reversing performance. FIG. 5 is a block diagram of a diesel engine starting device according to the present invention. In the figure, 01 is a position and rotation speed sensor, and 0.
Reference numeral 2 is a crank angle (or cam angle) compensator, 03 is a rotation speed compensator, 04 is an acceleration sensor, 05 is a calculator, 06 is a timing controller, 07 is a control valve, and 08 is a start valve.

Next, the operation of the above configuration will be described. The signal of the sensor 01 is input to the crank angle compensator 02, and when the crank angle when the engine is stopped is in the unstartable position, the calculator 05 corrects the opening timing of the start valve 08 (increases the period). ). A signal from the sensor 01 is input to the rotation speed compensator 03, and a timing delay of opening / closing of the start valve 08 associated with an increase in the rotation speed is detected according to the mechanical delay α, and a signal is sent to the calculator 05. On the other hand, when the engine starts to rotate and it is confirmed that the engine speed has increased, the signal from the crank angle compensator 02 is cut by the acceleration sensor 04. That is, this compensation is performed only for a short time until acceleration is achieved. The crank angle can be detected manually by reading the stop angle instead of the sensor 01. The signal from the arithmetic unit 05 is transmitted to the timing controller 06 and an appropriate opening / closing signal is output to the control valve 07. Compressed air for starting and reverse braking is
It is sent to the start valve 08 through the control valve 07, and the start valve 08
The piston inside is pushed down to eject compressed air into the cylinder of the engine.

[0004]

[Problems to be Solved by the Invention] (Japanese Patent Application No. 60-168)
641) makes it possible to accurately open and close the start valve 08 by compensating for the response delay of the start valve 08 in accordance with the engine speed, and as a result, the starting performance and reverse rotation It is possible to improve the brake performance of. However, the following problems have not been solved. That is, immediately after the fuel cutoff at the time of the reverse command, the ship continues to move forward due to inertial force, so that the engine also rotates in the forward direction via the propeller shaft. Under such circumstances, even if the starting air is jetted into the cylinder in an attempt to reverse the braking of the engine, it cannot overcome the accompanying force in the forward direction and the engine speed decreases, but the reverse rotation occurs. However, in order to ensure reliable braking and reverse rotation, the ship speed is sufficiently reduced by the propulsion resistance of the ship, and the engine speed can be reversed by braking. The actual situation is that the braking reverse rotation is applied after the required time for the value to fall to the level has passed.

The object of the present invention is to solve the above-mentioned problems,
Without consuming a large amount of starting air, the engine speed, in other words, the propeller speed is quickly reduced and propeller resistance is added to the ship propulsion resistance, so that the engine speed can be reversed as quickly as possible. (EN) Provided is a starting device for a marine diesel engine capable of reducing the fuel consumption.

[0006]

A starting device for a marine diesel engine according to the present invention is a sensor 1 for detecting signals of a rotation angle and a rotational speed of a crankshaft in a marine diesel engine.
And a starting control device 6 for inputting signals from the sensor and a remote control device of the engine to generate a control signal required by the control system of the starting device, and a starting air valve for injecting compressed air into the cylinder at the time of starting. 4, an exhaust valve 5 having a function of discharging the air in the cylinder to the outside of the cylinder during the engine idling period after the fuel is cut off at the time of a reverse command to the ship, and a signal from the start control device 6 A control valve 2a for controlling the opening / closing of the starting air valve 4, a control valve 2b for controlling the opening / closing of the exhaust valve 5, and a starting air supply valve 3 for controlling the opening / closing of the main conduit for compressed air for starting. It is characterized by becoming.

[0007]

With the above-mentioned technical means, when the piston reaches the top dead center during engine idling, that is, when the compression stroke is completed, the exhaust valve is opened to discharge the air inside the cylinder to the outside of the cylinder, and the bottom dead center is reached. Further, the exhaust valve is closed to allow the engine to perform only negative work in the subsequent compression stroke to eliminate positive work to the piston due to expansion of the compressed gas at that time. Or
The exhaust valve is kept open during the compression stroke, and the exhaust valve is closed when the piston reaches the vicinity of the top dead center, thereby causing the engine to perform negative work in the expansion stroke. As a result,
Since the engine performs only negative work in each cycle, it is possible to rapidly reduce the engine speed, that is, the propeller speed.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a block diagram of a starting device for a marine diesel engine according to a first embodiment of the present invention. In the figure, 1 is a position and rotation speed sensor, 2a and 2b are control valves, 3 is a start air supply valve, 4 is a start air valve, 5 is an exhaust valve, and 6 is a start control device.

Next, the operation of the above configuration will be described. The start control device 6 outputs signals of the rotation angle and the rotation speed of the crankshaft detected by the position and the rotation speed sensor 1.
To the control valve 2a communicating with the starting air valve 4 of each cylinder and the control valve communicating with the exhaust valve 5 in response to the signal and a command signal transmitted from a remote control device of the engine or the like. 2b to send a control signal to start air valve 4
Also, the exhaust valve 5 is driven. At the time of starting or reverse rotation, compressed air is sent to the engine through the starting air supply valve 3.
At the time of starting from the engine stopped state, the starting air supply valve 3 is opened by a control signal from the starting control device 6 and the control valve 2a communicating with the starting air valve 4 of each cylinder is driven during the expansion stroke to start the starting air. The valve 4 is opened and compressed air is ejected into the cylinder to start the engine.

During the engine idling period after the fuel is cut off at the time of the reverse command, the starting air valve 4 is closed and at the timing shown in FIG. 3, that is, at the end of the compression stroke when the piston reaches the top dead center. By controlling the control valve 2b communicating with the exhaust valve 5 of each cylinder, the exhaust valve 5 is opened, the air in the cylinder is discharged to the outside of the cylinder, and the exhaust valve 5 is closed at the bottom dead center. Subsequently, in the compression stroke starting from the bottom dead center, the engine is made to bear the compression work to reduce the engine speed. The same effect can be obtained by opening and closing the exhaust valve 5 at the timing shown in FIG. That is, the exhaust valve 5 is opened at the bottom dead center where the compression stroke starts, and is closed when the piston moves up and reaches the vicinity of the top dead center, so that the engine has a negative (minus) work during the expansion stroke. The engine speed is reduced by performing the above.

FIG. 2 is a block diagram of a starting device for a marine diesel engine according to a second embodiment of the present invention. In the second embodiment, the starting air valve 4 has the functions of the starting air valve and the exhaust valve in the first embodiment, and a discharge valve 5 common to each cylinder is provided to discharge the air in the cylinder to the outside of the cylinder. ing. The names 1 and 2, 3 and 6 and their functions are the first
Same as the embodiment. Next, the operation of the second embodiment will be described. The starting air valve 4 is opened and closed at the timings shown in FIGS. 3 and 4 described above, and the common discharge valve 5 continues to maintain the excited state. As a result, similarly to the case of the first embodiment, by causing the engine to bear the compression work in the compression stroke, or by causing the engine to perform negative work in the expansion stroke, the engine speed is rapidly reduced.

[0012]

Since the present invention is constructed as described above, the following effects can be obtained. It is possible to quickly reduce the engine speed at the time of engine idling after the fuel is cut off at the time of the reverse command, that is, the propeller speed without consuming a large amount of compressed air for starting, and to shorten the stop distance of the ship.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a starting device for a marine diesel engine according to a first embodiment of the present invention.

FIG. 2 is a configuration diagram of a starting device for a marine diesel engine according to a second embodiment of the present invention.

FIG. 3 is a timing diagram and P- of the exhaust valve in FIG.
V diagram

FIG. 4 is a timing diagram and P- of the exhaust valve in FIG.
V diagram

FIG. 5 is a block diagram of a conventional diesel engine starting device.

[Explanation of symbols]

1 ... Position and rotation speed sensor, 2, 2a, 2b ... Control valve, 3 ... Start air supply valve, 4 ... Start air valve, 5 ... Exhaust valve, 6 ... Start control device.

Claims (1)

[Claims] 1. A sensor (1) for detecting signals of a rotation angle and a rotation speed of a crankshaft in a marine diesel engine.
And a starting control device (6) for inputting signals from the sensor and a remote control device of the engine to generate a control signal required by a control system of the starting device, and a starting device for ejecting compressed air into the cylinder at the time of starting. An air valve (4), an exhaust valve (5) having a function of discharging the air in the cylinder to the outside of the cylinder during the engine idling period after the fuel is cut off at the time of a reverse command to the ship, the start control device (6). Control signal (2a) for controlling opening and closing of the starting air valve (4) by inputting a signal from
A starting device for a marine diesel engine, comprising a control valve (2b) for controlling opening / closing of an exhaust valve (5), and a starting air supply valve (3) for controlling opening / closing of a main pipe for compressed starting air.