JPH0476260A - Water injection diesel engine - Google Patents

Abstract

PURPOSE:To avoid variations in rotation and an increase in vibration in a diesel engine in which fuel and water are simultaneously injected from the same fuel injection valve by correcting and controlling the valve opening time of water supply solenoid valves for each cylinder in response to variations in exhaust gas temperature of each cylinder. CONSTITUTION:Fuel-water injection valves 140 are provided to each cylinder, water supply solenoid valves 116 are provided to each cylinder, along with the fuel-water injection valves 140, and the respective solenoid valves 116 are controlled by a control device 120. Each of output signals from a cam angle detecting device 201 for detecting rotational angle of a fuel injection pump 103, and temperature sensors 203 provided in exhaust gas passages for each cylinder, is inputted to the control device 120. Valve opening signals to the solenoid valves 116 are sent out in response to the valve opening time theta0 of the water supply solenoid valves 116 previously set in response to the number of revolutions, load of an engine. At this time, the differences between temperatures of respective cylinders and an average temperature of all the cylinders are determined, and in response to the temperature differences the valve opening time of the water supply solenoid valves 116 is corrected and controlled.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to water injection diesel engines.

[Conventional technology]

Since diesel engines have a high compression ratio, the combustion temperature is high and the exhaust gas contains a large amount of nitrogen oxides (NOX), which poses a pollution problem. As a means for reducing NOx, a diesel engine equipped with a fuel and water injection device that can simultaneously inject fuel and water from the same fuel injection valve is effective.

Such a water injection device is, for example, disclosed in Japanese Patent Application Laid-Open No. 1983-1980 shown in FIG.
227951 (Japanese Patent Application No. 62-59816). This can be realized with the configuration shown in FIG. 3 by utilizing the configuration and functions of the "injection system for dual fuel engine." That is, in FIG. 3, l is the fuel tank, 2 is the fuel supply pump, 3 is the fuel injection pump body, 4 is the plunger, 5 is the barrel, 6 is the discharge valve, and 7 is the side passage of the discharge valve 6. A check pressure regulating valve is provided, 8 is a fuel injection pipe, 40 is a fuel water injection valve, 9 is the same main body, 10 is the same injection hole, 1
1 is a needle valve, 12 is an oil reservoir, and 14 is a spring that presses the needle valve.

On the other hand, 19 is a water tank, 18 is a water supply pump, 17 is a water supply pipe, 1G is a water supply solenoid valve, 15 is a water supply pipe, and 13 is a water supply check valve that supplies fuel or water to the water control valve side. It is configured to limit the backflow of. A control device 20 controls the amount and timing of water supply, which inputs an engine crank angle signal and other engine operating conditions, and outputs an opening/closing signal to the control valve 16 via a line 23.

A fuel passage 22 is bored in the main body 9 of the fuel water injection valve 400 and communicates with the fuel injection pipe 8 and the fuel water injection valve oil sump 12 . Further, the water supply check valve 13 is connected to a merging portion 31 in the middle of the fuel passage via a waterway 30 similarly bored in the main body of the fuel water injection valve 40.

Next, the operation of the conventional example will be explained.

Water pumped from the water tank 19 by the water supply pump 18 passes through the supply pipe 17, and the plunger 4 of the fuel injection pump 3 is kept in an open state for a predetermined period during the idle period when the plunger 4 of the fuel injection pump 3 is not pumping fuel. The valve 16 allows a predetermined amount of water to be fed into the fuel water injection valve 40 through the supply pipe I5. At this time, when the valve opening pressure PR of the check valve 7 of the fuel injection pump 3 and the valve opening pressure P of the water supply check valve 13 are set, the needle valve 11
The valve opening pressure P. For,P,>p,,P,>p.

By doing so, the supplied water passes through the check valve 13, passes through the waterway 30 and the confluence part 31, and enters the fuel path 2.
Enter the road 2.

At this time, the fuel located upstream of the confluence 31 in the fuel passage 22, that is, on the fuel pump 3 side, is pushed back through the injection pipe 8 in the direction of the fuel injection pump 3, pushes open the check valve 7, and enters the plunger chamber. flow backwards. As a result, the fuel passage 22 in the fuel water injection valve 40 is filled with a predetermined amount of water.

Next, when the plunger 4 of the fuel injection pump 3 starts pumping fuel, the injection pipe 8, the fuel passage 22, and the oil reservoir 12
When the internal pressure increases and reaches the valve opening pressure of the needle valve 11 of 20 or more, the needle valve 11 is opened and fuel, water, and fuel are injected one after another. At this time, the water in the waterway 30 is not pushed back to the water tank 19 side due to the action of the check valve 13. As described above, when the needle valve 11 is opened, fuel and water are injected one after another from the injection hole 10 of the fuel and water injection valve.

As a result, the combustion temperature in the fuel chamber of the engine is reduced, the generation of NOx in the combustion flame is suppressed, and the amount of NOx in the exhaust gas is reduced.

[Problem to be solved by the invention]

However, when this fuel water injection device is applied to a multi-cylinder diesel engine, even if the opening and closing times of the solenoid valve 16 are set to be the same during the fuel injection suspension period for each cylinder of the engine, the shape and size of the water supply line Due to a slight difference between cylinders, there will be a difference in the amount of water supplied to the injection valve 40 of each cylinder. Therefore, if the same amount of water is injected from the fuel pump 3 to each cylinder, there will be a difference in the amount of water. This means that the amount of fuel injected into each cylinder will be different, and especially in the high engine load range, the cylinder with a large amount of fuel will have too much fuel, leading to increased smoke and failure due to increased thermal load on the combustion chamber. . Furthermore, changes in output from cylinder to cylinder will lead to increased rotational fluctuations, increased vibrations, and the like.

An object of the present invention is to solve the problems of the conventional device and focus on the fact that the amount of water supplied to each cylinder can be easily controlled by the solenoid valve 116. To provide a water-injected diesel engine that reduces the difference between each cylinder and makes the output of each cylinder uniform.

[Means to solve the problem]

The water injection diesel engine of the present invention supplies water to the fuel water injection valve via a water supply pump, an electromagnetic on-off valve, and a check valve so that fuel and water can be injected simultaneously from the same fuel injection valve. Water is supplied by an electromagnetic on-off valve.
In a multi-cylinder diesel engine that has a fuel water injection device that controls opening and closing between the end of injection by the fuel injection pump and the next injection, a temperature sensor is installed in the exhaust pipe passage of each cylinder of the engine to detect the exhaust temperature. established,
The temperature difference of each cylinder with respect to the average temperature of all cylinders is determined via the output signal, and the water supply solenoid valve opening time is corrected and controlled according to this temperature difference.

That is, the present invention is characterized in that the amount of water supplied is controlled so that the difference in exhaust gas temperature between cylinders is minimized, thereby reducing variations in the amount of fuel injected into each cylinder.

[For production]

Exhaust temperature T for each cylinder, (where i=1 to NUN,
The open period θ of the water supply solenoid valve for each cylinder.

(i=1-N) is θ, =θ. 10K (Ti-T).

Here θ. is a target valve opening period given by the control device according to operating conditions such as engine speed and output, and K is a correction coefficient for correcting the opening period for each cylinder, which is also given according to operating conditions.

As a result, there is a possibility that the amount of water supplied to each cylinder will vary somewhat, so the NOx generation suppression effect will vary slightly from cylinder to cylinder, but the amount of fuel injected for each cylinder will vary. Variations can be reduced.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 and 2.

Fig. 1 is a configuration diagram of the embodiment, and Fig. 2 is a control device 1.
FIG. 20 is a block diagram showing the control flow of No. 20;

In figures 1 to p, 200 is a multi-cylinder engine main body, 1
03 is a fuel injection pump, 108 is a fuel injection pipe, 140 is a fuel water injection valve provided for each cylinder 6 119 is a water tank, 118 is a water supply pump, 117 is a water supply pipe,
116 is a water supply solenoid valve, and a fuel water injection valve 140 is provided for each cylinder.
is provided with. 120 is a control device, 1
23 is a line that transmits a signal from the same device to the electromagnetic valve 116 of each cylinder, and the internal structure of the fuel injection pump 103 and the fuel water injection valve 140 is
30 A cam angle detection device that detects a rotational position signal, 202 is a line that transmits the signal to the controller device 120, 203
204 is a temperature sensor provided in the exhaust passage of each cylinder, and 204 is a line that transmits the same signal to the controller.

The opening period θ of the water supply solenoid valve 116 is preset according to the operating state such as engine speed and load. When a valve opening signal is sent from the controller device 120 to the solenoid valve 116 in accordance with A signal T from the exhaust gas temperature sensor 203 (i=i to N, N is the number of cylinders) is output to the controller device.

Therefore, in the controller device 120, as shown in FIG. 2, the input signal from the exhaust gas temperature sensor 203 is converted by the input signal conversion device, and the average temperature calculation section is converted to the period θ. The set values for the correction coefficients are set by external set value inputs or detected values of the engine rotation speed and load lever position. Using these, the corrected open period θi−θ for each cylinder
. By calculating 10K (Ti-T) and sending a valve opening signal from the output signal conversion device to the solenoid valve 116 of each cylinder according to the result, the variation among the T10 cylinders is controlled to be always minimized. .

Note that the output of the valve opening signal of the solenoid valve 116 is determined by calculating the rotational speed and cylinder discrimination based on the signal of the cam angle detection device 201, and then calculating the output of the valve opening signal of the solenoid valve 116 during the period when fuel injection for each cylinder is suspended.
The setting is controlled so that it is output.

〔Effect of the invention〕

Since the water injection diesel engine of the present invention is configured as described above, by correcting and controlling the opening time of the water supply solenoid valve to each cylinder according to the variation in exhaust gas temperature for each cylinder, The variation in exhaust temperature is minimized, and although some variation occurs due to the effect of suppressing NOx generation due to the water supply to each cylinder, as a result, it is possible to avoid rotational fluctuations and increases in vibration caused by variations in output between cylinders. In addition, in high engine load ranges, it is possible to avoid failures due to increased smoke emissions due to variations in the amount of fuel in specific cylinders or increased heat load on the fuel chamber, and it is possible to avoid failures due to increased smoke emissions due to variations in the amount of fuel in specific cylinders, increased heat load on the fuel chamber, etc. An injection diesel engine can be realized.

[Brief explanation of the drawing]

1 and 2 are related to the present invention; FIG. 1 is a configuration diagram of an embodiment, FIG. 2 is a block diagram showing a control flow of the control device 120, and FIGS. 3 and 4 are conventional examples, and FIG. 4 is a block diagram showing the configuration of a water fuel diesel engine, and FIG. 4 is a diagram corresponding to FIG. 3 of a dual fuel diesel engine. 7... Check pressure regulating valve, 13... Check valve, 103...
Fuel injection pump, 116...Solenoid on-off valve, 120...
・Control device, 140... Water fuel injection valve, 20
0...Engine, 203...Exhaust temperature sensor. 120 Control device

Claims (1)

[Claims] a check pressure regulating valve (7) that is provided in parallel with the discharge valve (6) of the fuel injection pump and allows flow only in the opposite direction to the discharge valve;
A control device (12
a control valve (116) that sends water to the fuel injection valve with an appropriate amount and timing through the water supply channel (21); and a check valve (13), and the valve opening pressure of the check pressure regulating valve, the check valve, and the fuel injection valve is set to P_R, respectively.
When P_P and P_O, P_R<P_O, P_P<P
A temperature sensor (203) that detects the exhaust gas temperature of each cylinder; and a temperature sensor (203) that detects the exhaust gas temperature of each cylinder; and the water supply is controlled according to the deviation of the temperature of each cylinder from the average temperature of all cylinders using the signal. A water injection diesel engine comprising a control device that corrects and controls the opening time of a valve (116).