JPH07149287A - Device and method for controlling variable pitch propeller and diesel engine - Google Patents

Abstract

PURPOSE: To largely reduce generation quantity of smoke in increasing an engine load or an engine output of a turbo diesel engine, and to restrict environmental pollution caused by smoke. CONSTITUTION: For improving at least either of dynamic characteristics and output increase characteristics of a boost diesel engine for driving a variable pitch propeller, the pitch of the variable pitch propeller is first decreased till a rotation speed of the diesel engine and the variable pitch propeller is increased to reach a new rotation speed desired. Fuel injection quantity and diesel engine output (L) are then increased for the first time, and the propeller pitch is increased simultaneously with that for maintaining a roughly constant rotation speed.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to boost diesel
The present invention relates to a control method for a variable pitch propeller with an unsteady engine operating condition.

[0002]

Developments in the construction of marine diesel engines are characterized by improvements in power concentration, power density and movement efficiency. Improving engine efficiency is
Since the output of the engine itself is improved, the exhaust turbocharger does not need to have a large output, which may lead to a reduction in the output range. This deteriorates the characteristics of the engine when the load applied to the engine changes, particularly when the output increases, and also deteriorates the operating characteristics, that is, the operating characteristics during unsteady operation. Note that the unsteady operation here means an operation state accompanied by a change in engine output.

In addition to the dynamic characteristics in the braking and starting regions,
The characteristics of a diesel engine in unsteady operation with a significant increase in load and fuel consumption for ship safety are obvious. Therefore, it is necessary to guarantee the maneuverability of the ship at all times, including the response of the diesel engine to the instruction to increase the power as quickly as possible and the prevention of damage to important parts due to thermal overload. is there.

The percentage of fuel consumption is a function of cylinder charge. Then, the cylinder filling amount depends on the absolute intake pressure and the scavenging amount. That is, the cylinder charge depends on the transient reaction characteristics of the turbocharger, especially the exhaust turbocharger, and the pressure forming time. Therefore, the torque characteristic under the unsteady operation condition substantially depends on the moment of inertia and the characteristic of the turbocharger.

Conventional variable pitch propellers and turbo
In the control method of the diesel engine, the area "B" for the intermittent operation in the drawing is
That is, the mechanical and thermal load limit curves are displaced in the direction of decreasing the area for acceleration. As a result, the engine load that occurs under unsteady operating conditions, that is, when operating with changes in load, reaches the limit value more easily or exceeds the limit value. During this time, the total amount of air sent from the turbocharger to the engine will be below the value required for good combustion of the injected fuel. That is, when increasing the engine load or output, the rotation speed of the diesel engine does not immediately increase, and the amount of exhaust gas becomes insufficient, resulting in insufficient rotation of the turbocharger,
It becomes impossible to supply a sufficient amount of air to burn all the fuel injected into the combustion chamber. As a result, smoke is generated due to incomplete combustion of fuel. This results in the generation of undesired soot, as well as valves, valve seats and injection nozzles.
This causes an increase in operating temperature and temperature of parts located in the cylinder region such as the head, piston, piston ring and engine cylinder. Increased operating and component temperatures can cause damage to diesel engines. In addition, smoke generation has a negative impact on the environment, and in particular, if a coastal inhaler inhales smoke generated when operating in a port or at the coast, it may cause a health hazard. Smoke generation continues until the engine speed increases and the turbocharger can supply the sufficient amount of air needed for good combustion of the fuel.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to reduce the amount of smoke produced when increasing the engine load or engine power of a turbo diesel engine, thereby reducing the environmental pollution caused by smoke. .

[0007]

In order to achieve the above object, in the fuel injection control method for a variable pitch propeller and a diesel engine according to the present invention, the propeller pitch is first adjusted under a constant output. Decrease and increase the rotational speed of diesel engines and variable pitch propellers. Then, the fuel injection amount and the output of the diesel engine are increased, and the propeller pitch is increased in accordance with the increase of the fuel injection amount and the output in order to maintain the substantially constant rotation speed. The output of the diesel engine is increased until the propeller efficiency reaches its optimum value.
Further, the above operation is repeated as necessary to increase the output.

[0008]

In the above control method, the pitch of the variable pitch propeller is reduced, so that the resistance of water to the propeller is reduced, and the rotation speeds of the diesel engine and the propeller are increased under a constant output. diesel·
Due to the increase in the rotation speed of the engine, the rotation speed of the turbocharger increases and the amount of air supplied into the combustion chamber of the engine increases. As a result, a sufficient amount of air for burning the fuel is supplied into the combustion chamber. As a result, the amount of smoke generated is greatly reduced. Furthermore, since the output of the diesel engine can be increased while maintaining a sufficient engine rotation speed, the turbocharger will function sufficiently even when the output of the engine is increased, and the generation of smoke will be suppressed.

[0009]

The present invention will now be described in detail with reference to the load diagram (load range diagram). In this load diagram, each different area and position has the following meaning. CMCR: Contract maximum continuous output (Contract M
Axium Cotinuous Rating) is shown. A: Diesel engine without restrictions /
The operation range in which the propeller device can be operated is shown. B: Off-design condition (off-design c)
Fig. 3 shows an operating range that allows temporary operation of the diesel engine / propeller system under restrictions called "onions". This operating range depends on the cylinder power and is determined by mechanical and thermal load limits. Curved part b of the figure shows the limit line of region B, which shows the limit line of the thermal load at an output per cylinder of 720 kW. C: It is an overload region and shows a rotation speed region of 100 to 104% in the figure. This is 100% in the operation test
Is only allowed when proving the output of. D1: Fixed pitch propeller area (Fixed-Pi)
tch-Propeller-Bereich). It was calculated under ideal conditions for maximum power, with a clean hull, new propellers and ideal weather and water conditions. In addition, this region is also the region where the movement efficiency of the variable pitch propeller is the best. D2: Shows the recommended operation area. It combines fuel optimization in the high power region with better acceleration capability in the low power region. And D2 is mainly recognized as a part of the area of A. Until today, variable pitch
The recommended operating area for propeller design is area D2. This region is selected so that there is sufficient margin for changes in engine power P due to ship acceleration, ie, increasing engine speed. In this area, the interaction between the control of the variable pitch propeller and the engine controller is optimized. When the propeller operation curve is displaced to the right from the fixed pitch propeller curve, the propeller movement efficiency decreases. This is not preferable during continuous operation. As a result, either one of obtaining a low propeller efficiency by securing a sufficient preliminary output, and achieving a high kinetic efficiency with a small preliminary output and allowing a slow characteristic at the time of output change, One is selected due to the design of the variable pitch propeller.

The chain line drawn in the load range diagram shows an example of change in load according to a new operating method. C
Operating state E at low output L at a rotational speed exceeding 20% of MCR output and 60% of CMCR speed
Starting with, the pitch of the variable pitch propeller is first decreased to increase the rotational speed of the propeller above 70% of the CMCR speed to point F at the same output L.

Next, at the same rotation speed, the engine output L is increased to a point G slightly above 30% of CMCR. During this period, the pitch of the variable pitch propeller is increased at the same time as the engine output is increased in order to increase the engine output L while maintaining at least the rotation speed substantially constant.

When the point G in the area D1 is reached, the output is not increased any further. The area D1 is an area in which the variable pitch propeller moves most efficiently. In yet another cycle, the pitch of the variable pitch propeller is reduced once more if necessary. At this time, at the same output L, the propeller rotation speed is 95% of the CMCR speed.
Increase to point H, which is slightly above%.

Then, the output L of the engine increases to a point K slightly exceeding 75% of CMCR at the same rotation speed. During this time, the rotation speed is maintained constant. In order to keep the rotation speed almost constant, the engine output increase L
With this, the pitch of the variable pitch propeller is simultaneously increased.

Proper combustion of the fuel is achieved by using a diesel engine optimized by the above method and having a high efficiency, without the above problems.
It is possible to easily change the output in one or a few steps. In particular, the new operating method according to the invention makes it possible to significantly reduce the production of undesired smoke and soot. The size and number of steps are each selected based on the required power change.

The design of the controller which automatically performs the above steps is accomplished by using the means of conventional control techniques.
Since a person skilled in the art can easily realize the whole or a part thereof,
It does not require any special disclosure.

Boosted Diesel Engine Driving Variable Pitch Propeller In order to improve dynamic characteristics and increase efficiency, the pitch of the variable pitch propeller is such that the diesel engine and variable pitch propeller reach the desired rotational speed. First reduced until. Only after this,
The fuel injection quantity and the output L of the diesel engine are increased. After that, the pitch of the variable pitch propeller is increased again when the fuel injection amount increases. Advantageously, it is possible to maintain the desired new rotational speeds achieved earlier.

The control device according to the invention is implemented according to the method of the invention. The diesel engine according to the invention comprises a control device according to the invention. The ship according to the invention then has a diesel engine with a control device for a variable pitch propeller according to the invention.

The pitch of the variable pitch propeller is variable when the charge and load changes with the associated BA position (BA = fuel indication), ie the specific fuel injection quantity per cycle and the associated rotational speed. • Propeller control reduces first until the desired speed is reached. Only after that, an increase in the filling amount, that is, an increase in the fuel injection amount in each cycle, is allowed until the final BA position is reached. In this procedure, the propeller pitch is reset in each case in order to keep the rotational speed at the desired value.

As a result, each point of the quasi-steady propeller shown in the load diagram (load range diagram) is always within the maximum allowable thermal load limit value of the engine. In addition, each point of the quasi-steady propeller mentioned here means each point showing different output at a constant rotation speed, or each point showing different rotation speed at a constant output. More specifically, the points showing different outputs at a constant rotation speed are the points existing on the straight line connecting F to G or H to K in the figure. Further, the points indicating different rotation speeds at a constant output are E to F or G in the figure.
Points present on a straight line connecting from to H are shown. As a result,
An adequate supply of air from the turbocharger to the engine is always guaranteed in order to burn the fuel without producing smoke.

The present invention relating to the control of the variable pitch propeller and the fuel injection control is, when the ship moves in a state where a constant partial load is applied to the turbo diesel engine,
It maintains the ideal propeller efficiency while allowing a substantial improvement in acceleration characteristics during operation. The operation with partial load refers to the operation when the output level is below the cruising output or the maximum load. INDUSTRIAL APPLICABILITY The present invention operates extremely effectively on the basis of a diesel engine for a medium to high speed ship, that is, a 4-stroke system,
It has a rotational speed of 0 revolutions / minute and is particularly advantageous for engines equipped with a reduction transmission. But,
The control device according to the invention is also advantageous for direct drive low-speed two-stroke engines.

[0021]

As described in detail above, according to the present invention, the amount of smoke produced is reduced when the engine load or engine output of a turbo diesel engine is increased, and the environmental pollution caused by the smoke is reduced. It has an excellent effect that it can be prevented.

[Brief description of drawings]

FIG. 1 is a diagram showing a control method according to the present invention together with a general load range.

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Claims (7)

[Claims] 1. A dynamic characteristic of a boost diesel engine having a controller for driving a variable pitch propeller and adjusting a pitch of blades of the variable pitch propeller, and a boost diesel engine having a fuel injection controller for a diesel engine. A control method for improving at least one of output increase, the rotation speed of a diesel engine and a variable pitch propeller increasing, and the pitch of the variable pitch propeller decreasing until a new desired rotation speed is reached. And increasing the fuel injection amount and the output (L) of the diesel engine after the rotational speeds of the diesel engine and the variable pitch propeller reach the desired rotational speed, and increasing the fuel injection amount with the variable pitch propeller. Again increasing the pitch of the. 2. The pitch of the variable pitch propeller is increased again by the controller in order to maintain the desired rotational speed of the variable pitch propeller at least approximately constant with increasing fuel injection quantity. The method according to 1. 3. The desired rotational speed of the variable pitch propeller and the desired power output of the diesel engine are defined in claim 1.
Or a method achieved by successive steps based on the method described in 2. 4. The fuel injection amount in a boost diesel engine is increased, and the pitch of a variable pitch propeller driven by the diesel engine is adjusted, as claimed in any one of claims 1 to 3. A controller for performing the described method. 5. An analog or digital controller based on the controller of claim 4. 6. A boost diesel engine equipped with the control device according to claim 4 or 5, and a variable pitch propeller driven by the diesel engine. 7. A ship having a boost diesel engine according to claim 6 and a variable pitch propeller.