JPH11324729A - Fuel control device of diesel engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To establish the engine output to a designated output at a high control speed without hunting by correcting the actuator output, that is, the fuel regulating rack position corresponding to the change of engine output. SOLUTION: An actuator correction amount computing unit 163 compares the actuator output corresponding to the detection value of engine output calculated by an actuator output computing unit 161 with the actuator output set in an actuator output setting device 162 to obtain a deviation to the actuator output from both of the above. This deviation becomes correction amount (y) of actuator output, and the displacement of the fuel regulating rack of a fuel injection pump is corrected by the correction amount (y). Thus, the detection signal L of the engine output is directly input to a governor 16 to correct the actuator output (y) to a designated injection quantity, that is, the total injection quantity of fuel and water, so that the control speed for convertion from only fuel injection to injection of fuel and water is increased.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a diesel engine,
In particular, the present invention relates to a fuel control device for a water-injection diesel engine that injects fuel and water from a single injection valve into a cylinder.

[0002]

2. Description of the Related Art FIG. 4 is a schematic diagram showing a configuration of a fuel / water injection system of a water injection diesel engine for injecting fuel and water from a single injection valve into a cylinder. In FIG. 4, reference numeral 1 denotes a fuel injection valve configured to inject fuel and water from an injection hole 1a into a cylinder, 2 denotes a fuel injection pump having a discharge valve 2a and an equal pressure valve 2b, and 3 denotes a fuel injection pump. This is a fuel injection pipe connecting the pump 2 and the fuel injection valve 1.

Reference numeral 9 denotes a water tank, 8 denotes a water pump, and 5 denotes a water passage connecting the water tank 9 and a water inlet of the fuel injection valve 1. 4 is a check valve provided in the injection valve 1, 6 and 7 are check valves provided in the water passage 5, and these check valves are water flows from the water tank 9 side to the fuel injection valve 1. Only allow.

In such a fuel / water injection system, the fuel supplied from the fuel injection pump 2 and the water supplied from the water pump 8 are distributed in the fuel passage of the fuel injection valve 1 in a layered manner. Due to the injection pressure from 2, the stratified fuel is injected first, then water and finally fuel. Such stratified injection of fuel and water makes it possible to significantly reduce NOx (nitrogen oxide) in exhaust gas, and also keeps the fuel consumption rate as low as that of a conventional engine using only fuel injection.

FIG. 6 is a configuration diagram showing an outline of a fuel control system of a power plant using a diesel engine that only performs normal fuel injection. 6, reference numeral 10 denotes an engine (diesel engine), 13 denotes a generator, and the generator 13 is directly connected to the engine 10 via a coupling 12.

2 is a fuel injection pump for the engine 10;
Reference numeral 11 denotes an actuator. The output end of the actuator 11 is connected to a fuel adjustment rack (not shown) of the fuel injection pump 2 via a link 14, and the rack is moved to adjust the fuel injection amount. ing. Reference numeral 16 denotes a governor, and the actuator 11 is operated by an actuator output signal y from the governor 16.

Reference numeral 15 denotes a generator control panel. In the generator control panel 15, a detection signal L of a generator load, that is, an engine output, is output.
, A set value increase / decrease signal of the engine speed, that is, a speed set value increase / decrease signal x is transmitted to the governor 16.

The governor 16 calculates an actuator output y corresponding to the speed set value increase / decrease signal x, that is, a fuel injection amount, based on the speed set value increase / decrease signal x.
1, the actuator 11 drives the fuel adjustment rack of the fuel injection pump 2 to a position corresponding to the fuel injection amount, as described above.

[0009]

FIG. 7 shows the relationship between the engine output and the injection amount of the fuel injection pump 2 in the fuel / water injection diesel engine as described above. In FIG. 7, line A shows the case where fuel and water are injected from one fuel injection valve 1 (see FIG. 4), and line B shows the case where only fuel is injected. As is clear from this figure, in order to inject fuel and water simultaneously, it is necessary to increase the injection amount of the fuel injection pump as compared with the case where only fuel is injected.

FIG. 8 shows a control diagram of the governor 16 in the diesel engine for power generation as shown in FIG. 6, in which the horizontal axis represents the actuator output y and the vertical axis represents the engine speed N. In FIG. 8, the lines A, B, and C correspond to the generator control panel 15.
Is the speed set value x given to the governor 16 from

However, when a plurality of plants are operated in parallel in the power plant shown in FIG. 6, the engine speed N is restricted by the receiving frequency of each generator 13 and the engine is operated at a constant speed. Governor 1
6, as the power receiving frequency constant i.e. the engine 10 in the engine speed constant line D as shown in FIG. 8 is operated, i.e. the working point is a ₁ point A line in the actuator output 0 of the governor 16, the actuator B ₁ on line B at 50% output
Point, and controls so that c ₁ point of the actuator output 100% in C line, the control speed of the speed setpoint has become very slow as will be described later.

On the other hand, in the fuel / water injection diesel engine, since fuel and water are simultaneously injected during one cycle (two rotations for a four-cycle engine), the engine is rotated at an engine speed N: 750 rpm, for example. In the case of a four-cycle engine, fuel and water are stratified and injected in a very short time, such as once every 160 msec. Therefore,
The fuel control system in such a fuel / water injection diesel engine requires an extremely fast control speed.

However, in the conventional power plant shown in FIG. 6, the generator control panel 15 sends a pulse signal x as a signal for increasing / decreasing the speed set value to the governor 16 from the amount of power received by the generator 13, Since the hunting (abnormal vibration of the engine speed) occurs when the control speed of the governor 16 is increased in a normal engine, the control speed is extremely reduced as described above.

[0014] Accordingly, the fuel and the fuel
When a water-injected diesel engine is used, the control speed in the power plant is extremely slow as described above, so that it is impossible to control the engine output of the fuel-water-injected diesel engine to be constant.

In view of the above-mentioned problems of the prior art, the present invention provides a diesel engine for a power plant, in which a fuel / water injection diesel engine is used by increasing the governor fuel control speed as compared with the prior art. And the fuel / water injection diesel engine can be applied to a power plant engine with high control performance.

[0016]

According to the present invention, there is provided an actuator for operating an injection amount adjusting rack of a fuel injection pump via a link mechanism, a speed setting device for setting an engine speed, and A governor that outputs an actuator output corresponding to a fuel injection amount calculated based on an engine speed setting signal from a speed setting device to the actuator, and a diesel engine fuel control device comprising:
The governor is configured to calculate an adjustment value of an adjustment rack operation amount corresponding to the engine output based on a detection signal of the engine output, and output the adjustment value to the actuator. A control device is proposed.

According to the invention, an engine output detection signal detected by the engine output (or load) detection means such as a load detection signal is directly input to the governor, and the actuator corresponding to the detected engine output is input. The correction amount of the output is calculated and output to the actuator to correct the adjustment rack operation amount.

Accordingly, an operation in which there is a sudden change in the injection amount, that is, a change in the actuator output, such as when switching from operation using only fuel to operation using injection of fuel and water as in a fuel / water injection diesel engine. Even under the conditions, the actuator output, that is, the position of the fuel adjustment rack can be corrected immediately in response to the change of the engine output, so that the engine output is settled to a predetermined output at a high control speed without hunting. be able to.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will now be described in detail with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention unless otherwise specified, and are merely illustrative examples. Only.

FIG. 1 is an overall configuration diagram of a fuel control device for a diesel engine for a power plant according to an embodiment of the present invention, FIG. 2 is a main portion configuration diagram in the above embodiment, and FIG. 3 is a control block diagram. FIG. 4 is a schematic diagram of a fuel / water injection system in a known fuel / water injection diesel engine to which the present invention is applied.

In FIG. 4, reference numeral 1 denotes a fuel and water injection hole 1a.
, A fuel injection pump having a discharge valve 2a and a constant pressure valve 2b, and 3 a fuel injection pipe connecting the fuel injection pump 2 and the fuel injection valve 1. is there. 9 is a water tank, 8 is a water pump,
Reference numeral 5 denotes a water passage connecting the water tank 9 and a water inlet of the fuel injection valve 1. 4 is a check valve provided in the injection valve 1, 6 and 7 are check valves provided in the water passage 5, and these check valves are used for water flowing from the water tank 9 side to the fuel injection valve 1. Only the flow is allowed.

In the fuel / water injection system, the fuel supplied from the fuel injection pump 2 and the water supplied from the water pump 8 are distributed in the fuel passage of the fuel injection valve 1 in a layered manner. Due to the injection pressure from 2, the stratified fuel is injected first, then water and finally fuel. Such stratified injection of fuel and water makes it possible to significantly reduce NOx (nitrogen oxide) in exhaust gas, and also keeps the fuel consumption rate as low as that of a conventional engine using only fuel injection.

In the embodiment of the present invention, the fuel / water injection diesel engine having such a configuration is used as a power generating engine (hereinafter, referred to as an engine) shown in FIGS.

That is, in FIGS. 1 and 2, reference numeral 10 denotes an engine, 13 denotes a generator, and the generator 13
Are driven directly through the coupling 12. 2 is a fuel injection pump of the engine 10, 11 is an actuator, and the output end of the actuator 11 is a link 14a.
The fuel injection pump 2 is connected to a fuel adjustment rack (not shown) through the above, and the rack is moved to adjust the fuel injection amount.

Numeral 16 denotes a governor. The actuator 11 is controlled by an actuator output signal y from the governor 16.
Is operated. 22 is the generator 13
This is a load detector for detecting the load, that is, the engine output. Fifteen
Is a generator control panel to which a detection signal L of a generator load from the load detector 22, that is, an engine output, is input. An increase / decrease signal x of the speed set value output from the generator control panel 15 is input to the governor 16.

During operation of the fuel / water injection diesel engine as a power generating engine using the fuel control device having the above-described configuration, the generator load detected by the load detector 22, that is, the engine output detection signal L is generated by the generator. It is input to the control panel 15 and also to the governor 16.

The generator control panel 15 transmits a set value increase / decrease signal of the engine speed, that is, a speed set value increase / decrease signal x to the governor 16 based on the detection signal L.

On the other hand, in the governor 16, a correction amount of the actuator output y is calculated so that the engine output L directly input from the load detector 22 to the governor 16 is constant, and the speed set value increase / decrease signal is calculated. An actuator output y obtained by adding the correction amount to x is calculated.

That is, in the control block diagram shown in FIG. 3, in the governor 16, the detection signal L of the engine output from the load detector 22 is output from the actuator output calculator 1.
61, the actuator output calculator 16
In step 1, the fuel injection amount corresponding to the detected engine output L is obtained, and the change amount of the fuel adjustment rack of the fuel injection pump 2 corresponding to the fuel injection amount, that is, the actuator output y is calculated. On the other hand, reference numeral 162 denotes an actuator output setter. An actuator output y serving as a reference corresponding to the engine output L, that is, an actuator output y required to hold a speed set value corresponding to the power receiving frequency of the generator 13 corresponds to the engine output L. And is changed by the speed set value increase / decrease signal x.

Reference numeral 163 denotes an actuator correction amount calculator.
By comparing the actuator output y ₀ which is set in the actuator output y ₁ and the actuator output setter 162 corresponding to the detected value of the calculated engine output at the actuator output calculator 161, from both the actuator output Find the deviation. This deviation becomes the correction amount y of the actuator output, and the displacement of the fuel adjustment rack of the fuel injection pump 2 is corrected by the correction amount y.

[0031] Thus, the fuel injection amount of the fuel injection pump 2 is a _1-dot of Figure 5, as in b ₁ point or c ₁ point, the engine speed is adjusted to be constant line D.

Therefore, in the above-mentioned power plant, when the fuel / water injection diesel engine is operated only with fuel at the point C in FIG. 7, when the water injection is started, the engine is operated at the point a in FIG. According to this embodiment, since the detection signal L of the engine output is directly input to the governor 16 and the actuator output y is corrected to a predetermined injection amount, that is, the total injection amount of fuel and water, the fuel-only injection is performed. The control speed of the conversion from oil to fuel and water injection is rapid.

[0033]

As described above, according to the present invention, a sudden change in the injection amount, that is, a change in the fuel / water injection diesel engine from a fuel-only operation to a fuel-water injection operation, i.e. Even under operating conditions in which there is a change in the actuator output, the actuator output, that is, the position of the fuel adjustment rack can be corrected in response to the change in the engine output, so that the engine output can be controlled at a high control speed without hunting. It can be settled to a predetermined output,
Stable control performance that wins with high responsiveness can be obtained.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of a fuel control device for a diesel engine for a power plant according to an embodiment of the present invention.

FIG. 2 is a main part configuration diagram near an actuator in the embodiment.

FIG. 3 is a control block diagram in the embodiment.

FIG. 4 is a schematic diagram of a fuel / water injection system of a fuel / water injection diesel engine.

FIG. 5 is a control characteristic diagram of the diesel engine for power generation in the embodiment.

FIG. 6 is a diagram corresponding to FIG. 1, illustrating a diesel engine for a power plant according to the related art.

FIG. 7 is an injection amount characteristic diagram of a fuel / water injection diesel engine.

FIG. 8 is a control characteristic diagram of a diesel engine for power generation according to the related art.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Fuel injection valve 2 Fuel injection pump 3 Fuel injection pipe 5 Water passage 8 Water pump 10 Engine 11 Actuator 13 Generator 14a Link 15 Generator control panel 16 Governor 22 Load detector

Claims (1)

[Claims] 1. An actuator for operating an injection amount adjusting rack of a fuel injection pump via a link mechanism, a speed setting device for setting an engine speed, and an engine speed setting signal calculated from the engine speed setting signal from the speed setting device. A governor that outputs an actuator output corresponding to a fuel injection amount to the actuator, wherein the governor adjusts an adjustment rack operation amount in accordance with the engine output based on a detection signal of the engine output. A fuel control device for a diesel engine, wherein the control value is calculated and output to the actuator.