JPS6287657A - Seal oil control device for gas injection valve - Google Patents

Abstract

PURPOSE:To aim at reducing the consumption amount of seal oil and at enhancing the safety of an engine, by controlling a seal oil supply pump for a gas injection valve in accordance with the pressure of seal oil and the pressure of fuel gas. CONSTITUTION:A pump 1 driven by a motor M feeds seal oil into a gas injection valve 4 from a tank 2 through a supply pipe 3. Further fuel gas is fed into the gas injection valve 4 through a fuel gas supply pipe 5. Electrical pressure detectors 7, 8 disposed in the seal oil supply pipe 3 and the fuel gas supply pipe 5 deliver their detection signals to a two input differential computer 9. The computer 9 controls the motor M and a solenoid valve 6 in accordance with the deviation between the two input signals to always maintain the pressure deviation at a constant value. With this arrangement, the pressure of seal oil may be automatically adjusted even if the pressure of fuel gas is changed, thereby it is possible to reduce the amount of consumption of seal oil.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a seal oil control device for a gas injection valve for a gas-fired engine.

(Prior Art) Conventionally, various structures of gas injection valves for gas-fired engines have been put to practical use or proposed. A specific example thereof is shown in FIG. 2, and this gas injection valve 50 has a needle valve 52 slidably held in an injection valve body 51.
The structure is such that, by movement of the fuel gas flow path 53 formed in the valve body 51 and the injection hole 55 provided in the nozzle 54, communication is established or interrupted. In this case, the needle valve 52 is always urged downward by the spring 56, that is, in the direction of closing the flow path 53. A piston portion 57 is formed in the needle valve 52, and this piston portion 5
7 is led out into the pressure chamber 58. That is, the hydraulic oil flows through the hydraulic oil passage 59 bored in the valve body 51.
When the fuel gas is introduced into the pressure chamber 58, this pressure presses the piston portion 57, moves the needle valve 52 against the force of the spring 56, and opens the flow path 53 for the fuel gas. Thus, fuel gas can be injected from the injection hole 55. Furthermore, the tip of the needle valve 52 and the pressure chamber 58
A seal portion 60 is provided between the valve body 5t and a flow path 6 for supplying seal oil to the seal portion 60.
1 is provided.

The seal portion supplied from this flow path 61 to the seal portion 60 serves to prevent fuel gas from leaking from the gap between the valve body 51 and the needle valve 52, and also serves as a lubricant. It is. In this case, in order to prevent the fuel gas from leaking, it is necessary to maintain the pressures of the fuel gas and seal oil such that the relationship 1 is satisfied: seal oil pressure>fuel gas pressure.

For example, a control device as shown in Fig. 3 can be considered as a control device for the pressure of the seal portion to achieve such a function. The motor M drives the pump 62 to supply seal oil to the gas injection valve 50. For example, if the seal oil pressure is lower than the set value of the pressure gas isotiro 3, the switch 63 is activated and this activation signal is transmitted to the motor M to drive the motor M and seal oil If the seal oil pressure increases too much, the relief valve 64
By relieving the seal portion, the seal oil pressure can be lowered. That is, the lower limit of the seal oil pressure is determined by the pressure gas inochiro 3, i''>44, and the upper limit of the force is determined by the relief valve 64.
This is determined by the relief pressure of K). In this case, the pressure is maintained within the above pressure range.

(Problem to be Solved by the Invention) By the way, in the seal oil control device for the gas injection valve described above, each time the fuel gas pressure changes, the setting value of the pressure gas isotiro 3 and the relief of the relief valve 64 are changed. Since both the pressure and the pressure must be changed again to optimal setting values, there is a drawback that this operation requires a lot of effort. Also, if you set this setting value incorrectly,
If the seal oil pressure becomes excessive, the seal part will flow back toward the fuel gas, resulting in an increase in seal oil consumption and uneconomical conditions. - If the amount of seal oil that flows backward increases, there is also a drawback that the needle valve 52 may malfunction due to the amount of seal oil leaking. On the other hand, if the pressure of the seal oil drops significantly, a safety problem of gas leakage will also occur.

This invention was made to solve the above-mentioned conventional drawbacks, and its purpose is to be able to automatically change seal oil pressure in response to changes in fuel gas pressure, thereby making it economical. It is an object of the present invention to provide a seal oil control device for a gas injection valve that has a high level of safety and high safety.

(Means for Solving the Problems) Therefore, in the seal oil control device for a gas injection valve of the present invention, a gas injection valve, a fuel gas supply pipe for supplying fuel gas to the gas injection valve, and a gas injection valve are provided. a pump for supplying seal oil to the injection valve via a seal oil supply pipe;
A first detection means for detecting the pressure of the seal oil in the supply pipe, a second detection means for detecting the pressure of the fuel gas in the supply pipe, and the detected values of both the detection means are compared and The comparison calculation means for outputting the difference and the second drive control means for controlling the drive of the pump based on the output from the comparison calculation means are shown in white.

(Function) For the above-mentioned seal oil control device]・? In this case, the seal oil supply pump is driven based on the 100 line difference between the seal oil pressure and the fuel gas pressure. Since it is driven to maintain a constant pressure difference with the fuel gas, even if the pressure of the fuel gas changes, the pressure of the unit oil will be automatically adjusted accordingly. It becomes possible.

(Example) Next, a specific example of the seal oil control device for a gas injection valve according to the present invention will be described in detail with reference to the drawings.

In Figure 1, the collar and l indicate the electric υJ formula 2 (minbu 7,
This pump 1 is driven by a motor M as a driving source. As the bong 1 is driven, the oil is supplied from the comb 72;
This seal oil is supplied to the gas injection valve 4 via the oil supply W3)1. Ru. This gas injection valve 4 has the same structure as the main gas injection valve 50 explained in the above conventional example.
Since this is just a topic, its explanation will be omitted.

Note that fuel gas is supplied to this gas injection valve 4 via a fuel gas supply pipe 5. Further, a solenoid valve 6 is connected in the middle of the seal oil supply pipe 3G, and this solenoid valve 6 supplies the seal oil in the seal oil supply pipe 3 to the tank 2 through a pipe line 6a. 1) - It is for opening. Furthermore, in the seal oil supply pipe 3, -L-
A first electric pressure detector 7 serving as a first detection means is connected to a position closer to the gas injection valve 4 than the recorder 6. This first electric pressure detector 7 outputs a voltage equivalent to the seal oil pressure Ps. - A second electric pressure detector 8 serving as a second detection means is connected to the fuel gas supply pipe 5 in the middle thereof.5. Since this second electric pressure detector 8 outputs a voltage corresponding to the fuel gas pressure Pg, the voltage from the first electric pressure detector 7 and the second electric pressure detector 8 is 6°. The output voltages are each input to a two-person force difference calculator 9 as a comparison calculation means. This two-man power difference calculator 9 calculates the difference between the two types of output voltages inputted above, and outputs the voltage difference (3
It is output as a number. In this case, the two-man power difference calculation unit 9 calculates a voltage (pg + ΔP-
Ps).

Note that such an output is the output (
Pg Ps). Further, the reason why the predetermined pressure ΔP is applied in this way is to maintain the pressure difference between the seal oil pressure and the fuel gas pressure at about 20 to 50 kg/-, as will be explained below.

The output from the two-person force difference calculator 9 is output to a meter relay 10, one output of this meter relay 10 is output to the motor M, and the other output is output to the solenoid valve 6. There is. This meter relay 10 inputs the output signal of 3: to the motor λ4 to drive the motor M when the output signal of the two manual force difference calculation units 1] or - is a positive output. And vice versa 6. When the second output signal is a negative output e and its absolute value is greater than or equal to the set value, this output fJ signal is input to the solenoid valve 6, and the solenoid valve 6 is opened. It is something. Note that in the meter relay 10, if the output from the two-manpower difference calculator 9 is a negative output and its absolute value is smaller than the set value in 1-, the meter relay 10 sets the 7-meter M to prevent hunting.
and solenoid valve 6.

Next, the operating state of the seal oil control device will be explained. 2. First, when the seal oil pressure decreases or the fuel gas pressure increases and a positive output signal is output from the two manual force difference calculator 9, , this output signal is sent to the meter relay 10.
This input is input to the motor M through the motor M, and this input causes the motor 4 to enter the C operating state. Therefore, the above pump 1
is driven.

Seal oil is discharged from the pump 1, and this causes...
The pressure of the seal oil in the oil supply pipe 3 will be increased. Conversely, if the seal oil pressure is too high or the fuel gas pressure is low and a negative output signal greater than the set value of the meter relay -10 is output, the meter relay 10 is activated. , the solenoid valve 6 is opened. Therefore, the seal oil in the seal oil supply pipe 3 is discharged to the tank 2, and the seal oil pressure is reduced. At this time, the motor M is in a non-operating state. In the above, if the negative output is smaller than the set value, both the solenoid valve 6 and the motor M are not operating.

As described above, the seal oil control device includes a motor M that drives the pump 1 to increase the seal oil pressure according to the pressure difference between the seal oil and the fuel gas, and a seal oil in the seal oil supply pipe 3. Since the solenoid valve 6 which releases the seal oil pressure to the tank 2 and lowers the seal oil pressure is selectively operated, the pressure difference between the seal oil pressure and the fuel gas pressure is maintained at a predetermined state. becomes possible. As a result, it becomes possible to automatically adjust the seal oil pressure in response to changes in fuel gas pressure. Furthermore, if the seal oil is discharged back into the tank 2, the amount of seal oil consumed can be reduced.

In the above embodiment, an example was explained in which the output of the two-person power difference calculation unit 9 was biased, but for example, the meter relay 1
0, the upper limit value and lower limit value of the output signal are set, and the output signal (Pg-Ps) from the two-person force difference calculator 9 is set.
It is also possible to selectively operate the motor M and the electromagnetic valve 6 when the value exceeds the constant value of both membranes. Further, in the above embodiment, as a drive control means for controlling the drive of the motor M, an example was shown in which the bias means for the two-person force difference calculator 9 and the meter relay 10 were used, but other means may be used. Of course, it is also possible to do so. Furthermore, in the above embodiment, the solenoid valve 6 is used, and by opening the solenoid valve 6, the seal oil supply pipe 3 is opened to the tank 2 and the pressure of the seal oil is reduced. In cases where natural pressure reduction can be expected, it is possible to omit this solenoid valve 6.
6 (Effect of the invention) Gas injection valve seal oil control IML device O4 of this invention:
, the pump for supplying seal n11 is driven based on the difference between the pressure of the seal oil and the pressure of the fuel gas. , the pressure difference between the seal oil and the fuel gas is maintained constant, so even if the pressure of the fuel gas changes, 1. This 1. ;: It is possible to automatically adjust the pressure of the seal oil accordingly, and therefore it is possible to lower the seal oil consumption and improve the safety of the engine.

[Brief explanation of drawings]

Figure 1 shows the seal 5 oil system f111 of the gas injection valve of this invention.
FIG. 2 is a vertical sectional view showing the structure of a conventional gas injection valve, and FIG. 3 is an explanatory view showing a seal oil control device. DESCRIPTION OF SYMBOLS 1... Pump, 3... Seal oil supply pipe, 4... Gas injection valve, 5... Fuel gas supply pipe 1, 7... First electric pressure detector 1, 8... 2nd N air pressure detector, 9
...2-person force difference calculator, 10...meter relay, M.
··motor. Patent applicant: Kawasaki Heavy Industries, Ltd. Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] 1. A gas injection valve, a fuel gas supply pipe for supplying fuel gas to the gas injection valve, a pump for supplying seal oil to the gas injection valve via a seal oil supply pipe, and inside the supply pipe. a first detection means for detecting the pressure of the seal oil in the supply pipe, a second detection means for detecting the pressure of the fuel gas in the supply pipe, and comparing the detection values of both the detection means and outputting the difference. 1. A seal oil control device for a gas injection valve, comprising: a comparison calculation means for controlling the pump; and a drive control means for controlling the drive of the pump based on the output from the comparison calculation means.