JP2000205051A - Diesel engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent water separation from emulsified fuel oil and damage to engine sliding portions economically, and lower the concentration of nitrogen oxides in exhaust while ensuring desirable engine operations. SOLUTION: A waterline 11 in which a variable displacement pump 13 is interposed leads a prescribed quantity of water from a water tank 12 to a mixer 10 interposed in a fuel oil line 9. During an engine operation, based on the output torque, fuel flow rate, charging pressure, fuel rack quantity and engine speed that are from a torque sensor 17, fuel flow rate transmitter 14, charging pressure sensor 16 and rack scale sensor 18, a computer 7 that preliminary stores water mixing ratios as a function of the output torque, fuel flow rate, charging pressure, fuel rack quantity and engine speed refers to the stored water mixing ratios to compute a necessary quantity of water added and outputs a signal indicative of the computed added water quantity to the variable displacement pump 13.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a diesel engine having a water adding device for adding a predetermined amount of water to fuel oil in order to reduce nitrogen oxides in exhaust gas.

[0002]

2. Description of the Related Art Conventionally, as a diesel engine for reducing NOx in exhaust gas, for example, Japanese Patent Publication No. 6-58 by the present applicant.
No. 058 is known. This diesel engine is designed to further reduce the NOx concentration in the exhaust gas of a diesel engine equipped with a selective reduction ammonia denitration device in the exhaust system to a constant low level irrespective of the seasonal air supply.
The air supply is humidified by adding a predetermined amount of water vapor or fine water droplets.

However, according to a recent study by the present applicant,
By adding a predetermined amount of water to the fuel oil and supplying it to the diesel engine as an emulsified fuel oil, the NOx concentration in the exhaust gas can be reduced, and the reduction effect is about 20% higher than the above method of humidifying the supply air. Was revealed. However, this method of adding water to the fuel oil and supplying it to the diesel engine as an emulsified fuel oil has not yet been put into practical use at the experimental stage. A technique has been adopted in which water is added at a constant rate over the entire output range in proportion.

[0004]

However, as a result of further research conducted by the present applicant, the above-mentioned method involves adding water at a constant rate in proportion to the flow rate of fuel oil over the entire output range of the engine. Therefore, when the engine output is high and the fuel flow rate is large, the amount of water cannot suppress the increase in the combustion temperature, and the combustion temperature increases to increase the nitrogen oxides in the exhaust gas. It was found that when the flow rate was small, the amount of added water was too large, resulting in deterioration of combustion. Also, if water is mixed and emulsified with fuel oil, especially high-quality fuel oil with low viscosity, water separates from the fuel oil early after mixing, and if operation is continued in this state, the separated water mass will cause a large amount of engine damage. It is necessary to inject an additive such as a surfactant into the emulsified fuel oil in order to prevent the separation of water and to prevent the loss of lubrication of the sliding portion of the engine due to mixing with water, thereby preventing damage. However, as a result of the applicant's research, if the additive is injected at a constant rate proportional to the fuel flow rate regardless of the engine output, the additive is too small to fulfill its function, or the additive is too large to be uneconomical. The problems, such as becoming, became clear.

Therefore, an object of the present invention is to change the ratio of water and additives to be added to fuel oil according to the engine output, thereby economically preventing the separation of water from emulsified fuel oil. It is an object of the present invention to provide a diesel engine that can reduce the concentration of nitrogen oxides in exhaust gas while operating the diesel engine well.

[0006]

In order to achieve the above object, a first aspect of the present invention relates to a diesel engine capable of reducing the concentration of nitrogen oxides in exhaust gas, provided in a fuel oil pipe system of the diesel engine. An emulsifying apparatus in which a predetermined amount of water is added to an emulsified fuel oil, and a water addition rate which is a rate of an amount of water to be added to the fuel oil, the shaft torque, fuel flow rate, air supply pressure,
Means for storing at least one of the fuel rack amount and function data of the engine speed, and at least one of the shaft torque, fuel flow rate, supply pressure, fuel rack amount and engine speed detected during operation of the engine. Based on the number, calculate the amount of water by referring to the water content stored in the water content storage means, comprising a water content control means for outputting a signal representing the calculated water content to the emulsifier. I do.

In the diesel engine according to the first aspect, the water storage ratio storage means stores the water storage ratio to be added to the fuel oil as at least one of a shaft torque, a fuel flow rate, a supply pressure, a fuel rack amount, and a function data of an engine speed. It is remembered as. The water addition amount control means refers to the water addition rate stored in the water addition rate storage means based on at least one of the shaft torque, fuel flow rate, supply pressure, fuel rack amount, and engine speed detected during operation of the engine. Then, a signal representing the calculated amount of water is output to the emulsifier, and the emulsifier adds the water having the amount of water to the fuel oil and supplies the fuel oil to the engine as an emulsified fuel oil.

The engine output is represented as a monotonically increasing function using any one of the shaft torque, fuel flow rate, supply pressure, fuel rack quantity and engine speed as variables of the water addition rate as the function data. The rate of water addition to the fuel oil by the emulsifier increases as the engine output during operation increases. Therefore, when the engine output increases, the fuel flow rate increases, and the combustion temperature rises, water is added to the fuel oil at a higher rate to suppress the rise in combustion temperature. Can be suppressed. Further, when the engine output is reduced and the fuel flow rate is reduced, an appropriate amount of water is added to the fuel oil at a lower rate, so that combustion does not deteriorate and the engine operates properly.

According to a second aspect of the present invention, in the diesel engine of the first aspect, a predetermined amount is provided in the fuel oil pipe system of the diesel engine so as to prevent separation of fuel oil and water and damage to a sliding portion of the engine. An addition device for adding the above-mentioned additive to the fuel oil, and an addition rate, which is a rate of the amount of the additive to be added to the fuel oil, to at least one of a shaft torque, a fuel flow rate, a supply pressure, a fuel rack amount, and an engine speed. The addition rate storage means for storing as a function data of the number, and the addition rate storage means based on at least one of shaft torque, fuel flow rate, supply pressure, fuel rack quantity and engine speed detected during operation of the engine. It is characterized by further comprising an addition amount control means for calculating an additive amount with reference to the stored addition ratio and outputting a signal representing the calculated additive amount to the addition device.

[0010] In the diesel engine of claim 2, the addition rate storage means stores the addition rate, which is the rate of the amount of the additive to be added to the fuel oil in order to prevent separation of the fuel oil and water and damage to sliding parts of the engine. At least one of shaft torque, fuel flow rate, supply pressure, fuel rack amount, and function data of the engine speed are stored. The addition amount control means refers to the addition rate stored in the addition rate storage means based on at least one of a shaft torque, a fuel flow rate, a supply pressure, a fuel rack amount, and an engine speed detected during operation of the engine. To calculate the amount of the additive, and to output a signal indicating the calculated amount of the additive to the addition device, and the addition device adds the additive amount of the additive amount to the fuel oil and supplies the fuel oil to the engine.

The engine output is expressed as a monotonically increasing function using one of shaft torque, fuel flow rate, supply pressure, fuel rack quantity and engine speed as variables of the addition rate as the function data. The addition rate of the additive added to the fuel oil by the addition device increases as the engine output during operation increases. Therefore, when the engine output is increased and the fuel flow rate is increased, and when the water is added at a high rate by the fuel oil in order to suppress the increase in the combustion temperature and the accompanying increase in the nitrogen oxides in the exhaust gas, the additive is increased at a higher rate. In addition, separation of water from the emulsified fuel oil and damage to sliding parts of the engine are suppressed. Also,
When the engine output is reduced, the fuel flow rate is reduced, and the fuel oil is added at a lower rate with an appropriate amount of water to prevent combustion deterioration, a lower rate and a minimum amount of additives are added to reduce the water from the emulsified fuel oil. Separation and damage to sliding parts of the engine are economically suppressed.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the illustrated embodiments. FIG. 1 is a schematic view showing an example of a diesel engine according to claim 1 of the present invention. Reference numeral 1 denotes an engine body including an air supply pipe 2, an exhaust pipe 3, and a fuel supply system 4. Compressor 5a at the inlet of the exhaust pipe 3
The turbocharger 6 is provided with a turbine 5b connected to the compressor at the outlet of the compressor.
The air cooler 7 is a computer which also serves as a water content storage means and a water content control means, which will be described later. The fuel supply system 4 includes a fuel tank 8 connected to the engine body 1 via a fuel oil supply pipe 9, and a fuel oil supplied via the fuel oil supply pipe 9, to which a predetermined amount of water is added to emulsified fuel. And an emulsifying device for making oil. This emulsifying device is provided with a mixing mixer 10 which is provided in a fuel oil supply pipe 9 and mixes water with fuel oil.
A water tank 12 connected to the mixing mixer 10 via a water pipe 11, a variable displacement pump 13 provided in the water pipe 11, and a fuel tank 8 closer to the fuel tank 8 than the mixing mixer 10. A fuel flow transmitter 14 is provided in the pipe 9 and detects a flow rate of fuel oil supplied to the engine body 1 and outputs a detection signal to the computer 7.

In the diesel engine, a shaft torque T, a fuel flow rate Q, a supply pressure P, a fuel rack amount F and an engine speed R are selected as parameters for obtaining an engine output L. 1a is provided with a torque sensor 15 and a rotation speed sensor 17, an air supply pressure sensor 16 in an air supply pipe 2, a rack scale sensor 18 in a fuel rack, and the fuel flow transmitter 14 in a fuel supply pipe 9, respectively. The detection signals from these sensors are all input to the computer 7.

The computer 7 stores, as a water storage rate storage means, a water storage rate Y ′, which is a rate of the amount of water to be added to the fuel oil in order to reduce the nitrogen oxide concentration in the exhaust gas, in advance in a test operation of this diesel engine. The obtained shaft torque T,
The function data Y ′ = f (T, Q, P, F, R) of the fuel flow rate Q, the supply pressure P, the fuel rack amount F, and the engine speed R is stored. The variables T, Q, P, F, and R are the engine output L
Therefore, the water addition rate Y ′ is represented by a function of each of the above variables via the engine output L. In addition, the computer 7 includes
During the operation of the engine, based on the shaft torque Tm, the fuel flow rate Qm, the supply pressure Pm, the fuel rack amount Fm, and the engine speed Rm represented by the detection signals from the sensors 15, 14, 16, 18, 17 respectively.
The water addition amount Y is calculated with reference to the stored data of the water addition ratio Y ′ = f (T, Q, P, F, R), and a signal representing the calculated water addition Y is a variable that forms a part of the emulsifying apparatus. Output to the displacement pump 13.

FIGS. 2 to 4 schematically show the water content Y ′ stored in the computer 7. FIG. 2 shows the relationship between the water addition rate Y ′ and the shaft torque T, the fuel flow rate Q, the supply pressure P, and the fuel rack quantity F, that is, the engine output, in a diesel engine such as a generator with a constant engine speed during operation. Shows the relationship,
Hydrolysis rate Y 'are linearly gradually increases toward the upper limit value in accordance with the engine output L as shown by curve C ₁ is increased. this is,
Engine output L is, as a monotonically increasing function of the engine speed R _c is variable which takes the respective variable and constant value, L = g (T, Q,
P, F, R _c ), because the higher the engine output L, the higher the water addition rate Y ′ in order to suppress the nitrogen oxide concentration in the exhaust gas.

FIG. 3 shows the water addition rate Y′i in a marine diesel engine or the like in which the engine speed changes during operation. In this figure, the engine speed when each of the above variables is fixed to a specific value is shown. Rotational speed R (horizontal axis) and engine output L at that time (vertical axis)
Is stored as a characteristic curve Lj, and a plurality of equal water content curves Y′i whose water content values increase as going upward in the vertical axis are stored. This is because L = g ( _Tc1 , _Qc2 , _Pc3 , _Fc4 , R) = Lj when the engine output L is a monotonically increasing function of the engine speed R when each of the above variables is fixed to a specific value. In order to reduce the concentration of nitrogen oxides in the exhaust,
This is because the greater the engine output L, the greater the water addition rate Y ', the more the water content on the vertical axis must be selected. Since a large number of the characteristic curves Lj are obtained by variously changing the variables, the computer 7 refers to the characteristic curves Lj corresponding to the variable values Tm, Qm, Pm, and Fm actually measured during operation. The engine output L (vertical axis), which is the intersection with the actually measured engine speed Rm (horizontal axis), is obtained, and the amount of water to be added to the fuel oil is determined from the water addition value indicated by the isohydration curve Yi ′ closest to this intersection Is calculated.

FIG. 4 shows the water addition rate Y ′ stored in the computer 7 and applicable to both diesel engines in which the engine speed R during operation is constant and changes. In this figure, the horizontal axis indicates the engine speed. Engine output L = g including number R as a variable
(T, Q, P, F, R) is taken, and the vertical axis represents the water addition rate Y ′. Hydrolysis rate Y ', as indicated by the stepped straight C _2, the engine output L is increased stepwise to keep the nitrogen oxides concentration in the exhaust exceeds a threshold value Ls. FIG.
Shows the relationship between the water addition amount Y calculated from the water addition ratio Y ′ and the rotation speed Rw of the variable displacement pump 13 driven by receiving a signal representing the water addition amount. As is apparent from FIG. Is proportional to the amount of water Y.

The operation of the diesel engine having the above configuration is as follows. When the engine speed of the diesel engine is constant, the computer 7 controls each of the sensors 15 and 1 during operation of the engine.
Based on the shaft torque Tm, the fuel flow rate Qm, the supply pressure Pm, and the fuel rack amount Fm represented by the detection signals input from 4, 16, and 18, that is, the fuel rack amount Fm, that is, the water addition rate Y 'in FIG. The amount of water to be added to the fuel oil is calculated from the obtained water addition rate Y ′, and a signal representing the calculated water addition Y is output to the variable displacement pump 13. Variable capacity pump 1 from water tank 12
3 is mixed with fuel oil by the mixing mixer 10 to become emulsified fuel oil and supplied to the engine body 1. Therefore, when the engine output L increases, the fuel flow rate increases, and the combustion temperature attempts to increase, water is added to the fuel oil at a higher rate to suppress the increase in the combustion temperature. The increase is suppressed.
Further, when the engine output is reduced and the fuel flow rate is reduced, an appropriate amount of water is added to the fuel oil at a lower rate, so that combustion does not deteriorate and the engine operates properly.

When the engine speed of the diesel engine changes, the computer 7 controls each of the sensors 15, 1 during the operation of the engine.
Detection values Tm, Qm, Pm, Fm input from 4, 16, and 18
3, an engine output L (vertical axis) which is an intersection with an engine speed Rm (horizontal axis) which is a detection value from the engine speed sensor 17 is obtained. The amount of water to be added Y to the fuel oil is calculated from the value of the water content indicated by the closest equal water content curve Yi ', and a signal representing the calculated water content is output to the variable displacement pump 13. Therefore, as described above, when the engine output L increases, the fuel flow rate increases, and the combustion temperature rises, water is added at a high rate by the fuel oil to suppress the rise in the combustion temperature. An increase in the nitrogen oxide concentration is suppressed. In addition, when the engine output decreases and the fuel flow rate decreases, an appropriate amount of water is added at a low rate by the fuel oil, so that combustion does not deteriorate and the engine operates satisfactorily.

FIG. 6 is a schematic diagram showing an example of the diesel engine according to the second aspect of the present invention. In this diesel engine, an addition device is added to the fuel oil supply pipe 9 of FIG.
1 is the same as the diesel engine described with reference to FIG. 1 except that the addition rate storage means and the addition amount control means are added to the computer 7 to form a new computer 27. Is omitted. The addition device includes a liquid tank 22 connected to the fuel tank 8 closer to the fuel tank 8 than the mixing mixer 10 of the fuel oil supply pipe 9 via a liquid supply pipe 21, and a signal from a computer 27. The liquid tank 22 stores a surfactant as an additive that prevents separation of fuel oil and water and damage to sliding parts of the engine.

The computer 27 stores, as an addition rate storage means, an addition rate Z 'which is a rate of the amount of the additive to be added to the fuel oil, a shaft torque T and a fuel flow rate previously obtained by a test operation of the diesel engine. Q, supply pressure P, fuel rack amount F and engine speed R function data Z ′ = h (T,
Q, P, F, R). Note that the above variables T, Q,
Since P, F, and R are parameters for obtaining the engine output L, the addition rate Z ′ is represented by a function of each of the above variables via the engine output L. In addition, the computer 27
Is a sensor for controlling the amount of each sensor 1 during engine operation.
The shaft torque Tm, the fuel flow rate Qm, the supply pressure Pm, and the fuel rack amount Fm represented by the detection signals from 5, 14, 16, 18, and 17, respectively.
And the stored addition rate Z ′ based on the engine speed Rm and
= H (T, Q, P, F, R), the addition amount Z is calculated, and a signal representing the calculated addition amount Z is output to the variable displacement pump 23 which is a part of the addition device.

7 to 9 schematically show the addition rate Z 'stored in the computer 27, and the above-mentioned water addition rate Y' is also indicated by broken lines for reference. The water content curve C ₁ ,
Y'i, as can be seen from the shape of the C _2, relationship, engine speed 8 of the engine output when 7 the rotational speed is constant engine L (horizontal axis) and addition ratio Z '(vertical axis) Changes in the engine speed R
FIG. 9 shows the relationship between the (horizontal axis), the addition rate Z ′, the engine output Lj, and the isohydration curve Y′i (vertical axis). FIG. 9 shows the engine output L (horizontal axis) when the engine speed is constant and changes. And the addition ratio Z ′ (vertical axis). In FIGS. 7 and 9, the addition rate Z ′ is set so as to prevent separation of water from the emulsified fuel oil and damage to sliding parts of the engine in accordance with the water addition rate Y ′ that increases as the engine output L increases. Since it is necessary to add the additive at a high rate, it gradually increases as shown by straight lines D ₁ and D ₂ rising to the right.

In FIG. 8, the computer 27 controls the engine speed when the variables of the shaft torque T, the fuel flow rate Q, the supply pressure P, and the fuel rack amount F are fixed to specific values, and the engine output and addition at that time. The relationship between the rates is stored as a characteristic curve Lj and a curve Z′j, respectively, and the above-described plurality of equal water content curves Y′i are stored. The reason why the addition rate curve Z′j extends substantially parallel to the characteristic curve Lj is that the higher the engine output L, the higher the equal water content curve Y′i and the higher the water content, so that the emulsified fuel oil This is because it is necessary to add the additive at a higher rate in order to prevent separation of water from the water and damage to sliding parts of the engine. The above-mentioned curve Z′j is obtained by changing the respective variables in various ways,
Computer 2
Reference numeral 7 denotes an engine output that is an intersection with an actually measured engine speed Rm (horizontal axis) with reference to a characteristic curve Lj corresponding to each of the variable values Tm, Qm, Pm, and Fm actually measured during operation. In addition to finding the water content value indicated by the equal water content curve Y′i closest to the intersection, the above intersection is extended just above as shown by the arrow in the figure, and the addition rate Z ′ is obtained at the intersection with the curve Z′j. From the calculated addition rate Z ', the amount Z of the additive to be added to the fuel oil is calculated. FIG. 10 shows the relationship between the additive amount Z calculated by the computer 27 from the above-described additive rate Z ′ and the rotation speed Ra of the variable displacement pump 23 driven by receiving a signal indicating the additive amount. As is clear from FIG.
Is proportional to

FIGS. 1 to 5 show a diesel engine having the above configuration.
In addition to the control of the amount of water described above, the additive is added to the fuel oil while controlling the amount as described above. Therefore, when water is added to the fuel oil at a higher rate to suppress the increase in combustion temperature and the accompanying increase in the concentration of nitrogen oxides in the exhaust gas due to an increase in the engine output and an increase in the fuel flow rate, the water is added at a higher rate. The addition of an agent suppresses the separation of water from the emulsified fuel oil and damage to the sliding parts of the engine, and also reduces the engine output, reduces the fuel flow rate,
Minimal additives are added to the fuel oil at a lower rate to prevent combustion deterioration, so that the separation of water from the emulsified fuel oil and the damage to sliding parts of the engine are economically suppressed.

In the above embodiment, the computers 7, 2
7 to calculate the water addition rate and the addition rate via the engine output as a function of the five parameters of the shaft torque, fuel flow rate, supply pressure, fuel rack quantity, and engine speed detected by the sensors 14 to 18. Therefore, it is possible to obtain a more accurate water addition rate and addition rate, and it is possible to more reliably suppress the increase in the concentration of nitrogen oxides in the exhaust while operating the engine well without causing deterioration in combustion. There is an advantage. Note that, in the present invention, unlike the above-described embodiment, at least one of the shaft torque, the fuel flow rate, the supply pressure, the fuel rack amount and the function data of the engine speed are stored as the function data of the engine speed. You can also get the effect. Also,
The water storage rate storage means, the water storage rate storage means, the addition rate storage means, and the addition rate control means of the present invention may be different computers, unlike the above embodiment.

[0026]

As is apparent from the above description, the diesel engine having the emulsifying apparatus for adding a predetermined amount of water to the fuel oil according to the first aspect of the present invention has the following characteristics. At least one of the supply pressure, the fuel rack amount and the water addition rate are stored as function data of the engine speed, and at least one of the shaft torque, the fuel flow rate, the supply pressure, the fuel rack amount detected during the operation of the engine and Based on the engine speed, by the water control device, by referring to the water content stored in the water content storage means to calculate the water content, to output a signal representing the calculated water content to the emulsifier. Therefore, water can be added to fuel oil at a high rate in response to an increase in engine output to suppress the increase in combustion temperature and prevent combustion deterioration, so that while operating the engine well, the concentration of nitrogen oxides in exhaust gas can be reduced. To limit the increase Can.

The diesel engine according to a second aspect of the present invention is provided with an addition device for adding an additive to the emulsified fuel oil for preventing separation of water and damage to a sliding portion of the engine in addition to the configuration of the first aspect. In the storage means, shaft torque, fuel flow rate, supply pressure,
The addition rate is stored as function data of at least one of the fuel rack amount and the engine speed, and at least one of the shaft torque, the fuel flow rate, the supply pressure, the fuel rack amount and the engine speed detected during the operation of the engine is stored in the storage unit. Based on the addition amount control means, the additive amount is calculated with reference to the addition rate stored in the addition rate storage means, and a signal representing the calculated additive amount is output to the addition device. Since the additive is added to the fuel oil at a rate corresponding to the water addition rate of the fuel oil, separation of water from the emulsified fuel oil and damage to sliding parts of the engine can be suppressed without wasting the additive. Can operate the diesel engine well.

[Brief description of the drawings]

FIG. 1 is a schematic view showing an example of a diesel engine according to claim 1 of the present invention.

FIG. 2 is a diagram showing a relationship between an engine output and a water addition rate when the engine speed stored in the computer of FIG. 1 is constant.

FIG. 3 is a diagram showing the relationship between the engine speed, the engine output, and the water content when the engine speed stored in the computer of FIG. 1 changes.

FIG. 4 is a diagram showing the relationship between engine output and water content when the engine speed stored in the computer of FIG. 1 is constant and fluctuates.

5 is a diagram showing a relationship between the number of rotations and the amount of water of the variable displacement pump of FIG. 1.

FIG. 6 is a schematic view showing an example of the diesel engine according to the second aspect of the present invention.

FIG. 7 is a diagram showing the relationship between the engine output and the addition rate when the engine speed stored in the computer of FIG. 6 is constant.

8 is a diagram showing the relationship between the engine speed, the engine output, and the addition rate when the engine speed stored in the computer of FIG. 6 changes.

9 is a diagram showing the relationship between the engine output and the addition rate when the engine speed stored in the computer of FIG. 6 is constant and fluctuates.

10 is a diagram showing the relationship between the number of rotations of the additive variable displacement pump of FIG. 6 and the amount of additive.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Engine main body, 2 ... Air supply pipe, 3 ... Exhaust pipe, 4 ... Fuel supply system, 5 ... Supercharger, 7, 27 ... Computer, 8 ... Fuel tank, 9 ... Fuel oil supply pipe, 10 ... Mixing mixer, 11
... water pipe, 12 ... water tank, 13 ... variable capacity pump, 1
4 ... Fuel flow transmitter, 15 ... Torque sensor, 16 ... Air supply pressure sensor, 17 ... Rotation speed sensor, 18 ... Rack scale sensor, 21 ... Liquid supply pipe, 22 ... Liquid tank, 23 ... Variable displacement pump for additive .

Claims (2)

[Claims] 1. A diesel engine capable of reducing the concentration of nitrogen oxides in exhaust gas, comprising: an emulsifying device provided in a fuel oil pipe system of the diesel engine to add a predetermined amount of water to the fuel oil to obtain an emulsified fuel oil; The water addition rate, which is the rate of the amount of water to be added to the fuel oil, should be at least one of the following: shaft torque, fuel flow rate, supply pressure, and fuel rack quantity
And a function of storing the water addition rate as function data of the engine speed, and the shaft torque, fuel flow rate, supply pressure,
Based on at least one of the fuel rack amount and the engine speed, the amount of water is calculated by referring to the water content stored in the water content storage means, and a signal representing the calculated water content is output to the emulsifying device. A diesel engine comprising water amount control means. 2. The diesel engine according to claim 1, wherein a predetermined amount of an additive is provided in a fuel oil pipe system of the diesel engine so as to prevent separation of fuel oil and water and damage to sliding parts of the engine. An addition device to be added to the fuel oil;
Means for storing at least one of a shaft torque, a fuel flow rate, a supply pressure, a fuel rack amount and a function data of an engine speed; and an addition rate storage means for detecting a shaft torque, a fuel flow rate, a supply pressure, and the like detected during operation of the engine.
An additive amount is calculated based on at least one of the fuel rack amount and the engine speed with reference to the addition ratio stored in the addition ratio storage means, and a signal representing the calculated additive amount is output to the addition device. A diesel engine further provided with an addition amount control means.