JP4131418B2 - Gas engine fuel leak detection device - Google Patents

Description

  The present invention relates to a fuel leak detection apparatus for a gas engine that detects a fuel leak in a fuel supply system of a gas engine using a gas fuel such as compressed natural gas (CNG).

Compressed natural gas (CNG) or the like serving as fuel for the gas engine is filled in the fuel tank at a high pressure, decompressed by a fuel pressure regulator (pressure reducing valve), and supplied to the fuel injection valve. In order to detect fuel leakage from the fuel supply system, as shown in Patent Document 1 (Japanese Patent Laid-Open No. 8-93564) and Patent Document 2 (Japanese Patent Laid-Open No. 8-277750), a fuel tank is provided at predetermined intervals. The fuel pressure in the fuel tank and the fuel temperature are detected to estimate the amount of fuel decrease in the fuel tank, and the estimated fuel decrease amount is compared with the actual fuel consumption injected from the fuel injection valve. There is one that determines the presence or absence of fuel leakage.
JP-A-8-93564 JP-A-8-277750

However, the conventional fuel leak detection device has the following drawbacks.
(1) Although fuel leakage occurs even when the engine is stopped, the above-described conventional system compares the estimated fuel decrease amount with the actual fuel consumption to determine the presence or absence of fuel leakage. The leak cannot be detected. Therefore, even if a fuel leak occurs while the engine is stopped, the fuel leak cannot be detected unless the engine is actually operated.

  (2) Since the fuel pressure and the fuel temperature are different between the high pressure side (between the fuel tank and the fuel pressure regulator) and the low pressure side (between the fuel pressure regulator and the fuel injection valve) of the fuel supply system, By estimating the fuel pressure and fuel temperature in the fuel tank and estimating the fuel amount, only the fuel amount on the high pressure side of the fuel supply system can be estimated, and the fuel amount on the low pressure side of the fuel supply system can be estimated. Cannot be estimated. For this reason, even if a fuel leak occurs on the low pressure side of the fuel supply system, this cannot be detected.

  The present invention has been made in view of such circumstances. Accordingly, an object of the present invention is to provide a fuel leak detection device for a gas engine that can detect a fuel leak occurring on the low pressure side of a fuel supply system. It is in.

  In order to achieve the above object, the present invention provides a fuel supply system from a fuel tank to a fuel pressure regulator based on a high pressure fuel temperature and a fuel pressure detected by a high pressure fuel temperature detection means and a high pressure fuel pressure detection means. The fuel amount (hereinafter referred to as “high pressure side fuel amount”) is calculated by the high pressure side fuel amount calculation means, and the low pressure side fuel temperature and the fuel pressure detected by the low pressure side fuel temperature detection means and the low pressure side fuel pressure detection means The fuel amount in the fuel supply system from the fuel pressure regulator to the fuel injection valve (hereinafter referred to as “low pressure side fuel amount”) is calculated by the low pressure side fuel amount calculation means, and the fuel amount of both the high pressure side and the low pressure side is calculated. The fuel decrease amount of the entire fuel supply system within the predetermined period is calculated by the fuel decrease amount calculation means from the total value of the decrease amount within the predetermined period or the total amount of decrease in both the high pressure side and low pressure side fuel amounts within the predetermined period. Seek. Then, the injection pulses for driving the fuel injection valves are integrated for a predetermined period for all the cylinders, and the fuel consumption amount within the predetermined period is calculated by the fuel consumption amount calculation means. By comparing, the presence or absence of fuel leakage in the fuel supply system is determined by the fuel leakage determining means during operation. In this case, since both the high-pressure side fuel amount and the low-pressure side fuel amount are calculated and the fuel decrease amount of the entire fuel supply system is calculated, it is possible to detect the fuel leakage occurring on the low pressure side of the fuel supply system, The reliability of fuel leak detection can be improved.

  Hereinafter, examples embodying the best mode for carrying out the present invention will be described.

  A first embodiment of the present invention will be described below with reference to FIGS. The gas engine 11 basically has the same structure as a gasoline engine. A piston 13 is housed in a cylinder 12, and an intake valve 15, an exhaust valve 16, and a spark plug 17 are attached to a cylinder head 14. A fuel injection valve 19 is attached in the vicinity of the intake port 18 of each cylinder, and a throttle valve (not shown) is provided in the intake pipe 20 connected to the intake port 18. On the other hand, the exhaust pipe 22 connected to the exhaust port 21 is provided with an air-fuel ratio sensor 42 for detecting the air-fuel ratio of exhaust gas and a catalyst 43 for purifying exhaust gas.

  Next, the configuration of the fuel supply system will be described. The fuel tank 23 is filled with gaseous fuel such as compressed natural gas (CNG) at a high pressure. A high-pressure fuel pipe 24 connected to the fuel outlet of the fuel tank 23 is connected to a low-pressure fuel pipe 26 via a fuel pressure regulator 25, and the low-pressure fuel pipe 26 is connected to the fuel injection valve 19. As a result, the gas fuel filled in the fuel tank 23 at a high pressure is decompressed by the fuel pressure regulator 25 and supplied to the fuel injection valve 19.

  The high-pressure side fuel pipe 24 has a high-pressure side fuel pressure sensor 27 (high-pressure side fuel pressure detecting means) for detecting the fuel pressure Phigh on the high-pressure side of the fuel supply system (that is, between the fuel tank 23 and the fuel pressure regulator 25). And a high-pressure side fuel temperature sensor 28 (high-pressure side fuel temperature detecting means) for detecting the high-pressure side fuel temperature Thigh. The low pressure side fuel pipe 26 has a low pressure side fuel pressure sensor 29 (low pressure side fuel pressure detecting means) for detecting the fuel pressure Plow on the low pressure side of the fuel supply system (that is, between the fuel pressure regulator 25 and the fuel injection valve 19). ) And a low-pressure side fuel temperature sensor 30 (low-pressure side fuel temperature detecting means) for detecting the low-pressure side fuel temperature Tlow.

  Outputs of the various sensors described above are input to an engine control circuit (hereinafter referred to as “ECU”) 31. The ECU 31 is mainly composed of a microcomputer, and includes a CPU 32, a ROM 33, a RAM 34, a backup RAM 36 (storage means) to which power is supplied from the battery 35 (see FIG. 2) even when the engine is stopped.

  Next, the configuration of the engine start control circuit will be described based on FIG. The ignition switch 37 can be switched to OFF (OFF), ON (ON), and START (start) positions by rotating a key (not shown), and when switched from the OFF position to the ON position. Then, power is supplied from the battery 35 to the ECU 31, and the ECU 31 starts operating. As a result, the ECU 31 reads signals from various sensors that detect engine operating conditions such as the intake air temperature, intake pipe pressure, cooling water temperature, engine speed, and air-fuel ratio, and the fuel injection amount (of the injection pulse) of the fuel injection valve 19 is read. Width), injection timing, ignition timing of the spark plug 17, and the like, and the fuel pressure and fuel temperature on the high pressure side and the low pressure side are detected, and the presence or absence of fuel leakage in the fuel supply system is determined by the processing described later.

  Further, when the ignition switch 37 is switched from the ON position to the START position, DC power is supplied from the battery 35 to the starter motor 38, and the gas engine 11 is started (cranked). A first starter relay 39 and a second starter relay 40 are provided in series on the energization path to the starter motor 38. The first starter relay 39 is a self-holding relay, and the first starter relay 39 is held in the ON state while the ignition switch 37 is switched to the START position. The second starter relay 40 is driven by a relay drive circuit 41 based on a start permission signal from the ECU 31. As will be described later, when a fuel leak in the fuel supply system is detected when the ignition switch 37 is switched from the OFF position to the ON position (that is, immediately before starting the engine), a start inhibition signal is output from the ECU 31 to the relay drive circuit 41. The second starter relay 40 is held in the OFF state, the engine start is prohibited, and a warning lamp 44 is lit (or blinked) to warn the driver. An ACC position (position for supplying power to an electric load such as a radio or a light) is provided between the OFF position and the ON position of the ignition switch 37, but the ACC position is not shown in FIG. Has been.

  Further, the ROM 33 of the ECU 31 stores programs for fuel supply system fuel leakage diagnosis shown in FIGS. 3 to 5. Hereinafter, the processing contents of these programs executed by the ECU 31 will be described.

[Fuel leak diagnosis program]
The fuel leakage diagnosis program shown in FIG. 3 is activated at predetermined time intervals, and when the ignition switch 37 is switched from the OFF position to the ON position, the presence or absence of fuel leakage in the fuel supply system is diagnosed as follows. First, in step 101, it is determined whether or not the ignition switch 37 has been switched from the OFF position to the ON position. If “No”, the process proceeds to step 108 described later without diagnosing fuel leakage.

  On the other hand, when the ignition switch 37 is switched from the OFF position to the ON position, the routine proceeds from step 101 to step 102, where it is determined whether or not the fuel leakage diagnosis condition immediately before the engine start is satisfied. Here, the fuel leakage diagnosis conditions immediately before the engine start include, for example, that the high-pressure side fuel pressure Phigh is within a predetermined range, that the high-pressure side fuel temperature Thigh is not in a low temperature region where measurement is not possible, and that the sensor system and control system are normal. The fuel leakage diagnosis condition is satisfied when all of these conditions are satisfied. However, if any one of the conditions is not satisfied, the fuel leakage diagnosis condition is not satisfied. If the fuel leakage diagnosis condition is not satisfied, the routine proceeds to step 108 described later without performing the fuel leakage diagnosis.

  If it is determined in step 102 that the fuel leakage diagnosis condition is satisfied, the process proceeds to step 103, where the high pressure side immediately before engine start detected by the high pressure side fuel temperature sensor 28 and the high pressure side fuel pressure sensor 27 is detected. The fuel temperature Thigh and the high-pressure side fuel pressure Phigh are read. Thereafter, in step 104, the high-pressure side fuel temperature Thighmem, the high-pressure side fuel pressure Phighmem at the time of the previous engine stop, and the high-pressure side fuel temperature Thigh read in step 103 are used. An estimated fuel pressure value Phighexp is calculated.

Phighexp = Phighmem / Thighmem xThigh
Here, the high pressure side fuel temperature Thighmem and the high pressure side fuel pressure Phighmem at the time of the previous engine stop are stored in the backup RAM 36 by the processing of steps 108 and 109 described later. The above equation is derived from the characteristic that in a system without fuel leakage, the amount of change in fuel pressure is proportional to the amount of change in fuel temperature.

  In the next step 105, the actual high-pressure side fuel pressure Phigh read in step 103 is compared with the high-pressure side fuel pressure estimated value Phighexp, and the actual high-pressure side fuel pressure Phigh is obtained from the high-pressure side fuel pressure estimated value Phighexp. If it is lower than the predetermined value α, it is determined that there is a fuel leak (step 106). Otherwise, it is determined that there is no fuel leak (step 107). Here, the predetermined value α is set in consideration of an error between Phigh and Phighexp.

  Instead of the method of determining the presence or absence of fuel leakage based on the difference between the actual high-pressure side fuel pressure Phigh and the high-pressure side fuel pressure estimated value Phighexp, the ratio (Phigh / Phighexp) of both is a predetermined value β (β <1) Whether or not there is a fuel leak may be determined depending on whether or not it is the following. The processing in steps 101 to 107 functions as a fuel leakage determination means in the claims.

  As described above, after determining whether or not there is a fuel leak immediately before starting the engine, the routine proceeds to step 108, where it is determined whether or not the ignition switch 37 has been switched from the ON position to the OFF position, that is, whether or not the engine is stopped. If “No”, the program is terminated. If “Yes”, the process proceeds to Step 109, and the high pressure side fuel temperature Thighmem and the high pressure side fuel pressure Phighmem detected when the engine is stopped are stored in the backup RAM 36. And store the program. The data of the high pressure side fuel temperature Thighmem and the high pressure side fuel pressure Phighmem stored in the backup RAM 36 are stored and retained in the backup RAM 36 even when the engine is stopped, and the fuel leakage is detected at the next ON operation of the ignition switch 37. Used as data for diagnosis.

  In this program, the fuel supply system state change from the previous engine stop to immediately before the engine start is judged by the change in fuel pressure to determine the presence or absence of fuel leakage. For example, the fuel pressure and fuel temperature when the engine is stopped The fuel supply system calculated from the fuel pressure and the fuel temperature when the engine is stopped is compared with the ratio between the fuel pressure and the fuel temperature immediately before the engine is started. The fuel amount of the fuel supply system calculated from the fuel amount and the fuel pressure and fuel temperature immediately before starting the engine may be compared to determine the presence or absence of fuel leakage.

[Start permission / prohibition program]
The start permission / prohibition program shown in FIG. 4 is started every predetermined time, and when the ignition switch 37 is switched from the OFF position to the ON position, engine start is permitted / permitted according to the result of the fuel leakage diagnosis of the fuel supply system. This program is prohibited. When this program is started, it is first determined in step 201 whether or not the ignition switch 37 has been switched from the OFF position to the ON position. If “No”, the program is executed without performing the subsequent processing. finish.

  On the other hand, when the ignition switch 37 is switched from the OFF position to the ON position, the process proceeds from step 201 to step 202, where it is determined whether or not the fuel leak diagnosis program of FIG. If it is determined that there is, the process proceeds to step 203, the second starter relay 40 is held in the OFF state, the engine start is prohibited, and in the next step 205, the warning lamp 44 is turned on (or flashes). Warning the driver. This prevents the gas engine 11 from being operated in a state where fuel leakage has occurred. On the other hand, if it is determined in step 202 that there is no fuel leakage, the routine proceeds to step 204, where the second starter relay 40 is turned on to allow engine start.

[During fuel leakage diagnosis program]
The fuel leakage diagnosis program during operation shown in FIG. 5 is started at predetermined time intervals, and diagnoses the presence or absence of fuel leakage in the fuel supply system during engine operation as follows. First, in step 301, it is determined whether or not a fuel leakage diagnosis condition during engine operation is satisfied. Here, as the fuel leakage diagnosis condition during engine operation, for example, it is not in a high load region, is in a steady operation state, and a predetermined time (until the gas fuel filling state is stabilized) has elapsed since fuel replenishment. When the fuel pressure is within a predetermined range that can be accurately detected, the fuel temperature is not in a low temperature region where measurement is not possible, the sensor system and the control system are normal, etc. The fuel leakage diagnosis condition is satisfied, but if any one of the conditions is not satisfied, the fuel leakage diagnosis condition is not satisfied. Note that the fuel leakage diagnosis condition may be satisfied when the engine is idle, when the test terminal of the ECU 31 is ON, or when the fuel is being cut. If it is determined in step 301 that the fuel leakage diagnosis condition is not satisfied, the program is terminated without performing a fuel leakage diagnosis.

  On the other hand, if it is determined in step 301 that the fuel leakage diagnosis condition is satisfied, the process proceeds to step 302 where the high-pressure fuel temperature Thigh and the high-pressure fuel pressure detected by the high-pressure fuel temperature sensor 28 and the high-pressure fuel pressure sensor 27 are detected. Read Phigh. Thereafter, in step 303, the amount of fuel in the fuel supply system from the fuel tank 23 to the fuel pressure regulator 25 (high-pressure side fuel) is calculated based on the high-pressure side fuel temperature Thigh and the high-pressure side fuel pressure Phigh using the gas state equation. Amount) Mhigh is calculated. The processing in step 303 functions as high-pressure side fuel amount calculation means in the claims.

  Thereafter, in step 304, the low pressure side fuel temperature Tiow and the low pressure side fuel pressure Plow detected by the low pressure side fuel temperature sensor 30 and the low pressure side fuel pressure sensor 29 are read. In the next step 305, the amount of fuel in the fuel supply system from the fuel pressure regulator 25 to the fuel injection valve 19 (low pressure side fuel) is calculated based on the low pressure side fuel temperature Tlow and the low pressure side fuel pressure Plow using the gas state equation. Amount) Mlow is calculated. The processing in step 305 functions as a low-pressure side fuel amount calculation means in the claims.

  In the next step 306, the high-pressure side fuel amount Mhigh and the low-pressure side fuel amount Mlow are added together to obtain the fuel amount (hereinafter referred to as “total fuel amount”) Mtotal of the entire fuel supply system. Thereafter, in step 307, it is determined whether or not a predetermined time for determining the amount of decrease in the total fuel amount Mtotal has elapsed. If the predetermined time has not elapsed, the process proceeds to step 308 and fuel injection of each cylinder is performed. The injection pulse tinj for driving the valve 19 is integrated for all cylinders to obtain an all-cylinder injection pulse integrated value Tinj (corresponding to fuel consumption). Thereafter, the processing of steps 301 to 308 described above is repeated until a predetermined time elapses, and an all-cylinder injection pulse integrated value Tinj within the predetermined time is calculated.

  Then, when a predetermined time has elapsed, the process proceeds from step 307 to step 309, the total fuel amount Mtotal at that time is stored in the RAM 34 as Mnew, and then the process proceeds to step 310, where the total fuel amount Mtotal is decreased by a predetermined time. DM (hereinafter referred to as “total fuel reduction amount”) is calculated by the following equation.

DM = Mold -Mnew
Here, Mold is a total fuel amount Mtotal a predetermined time before the present time, and uses data stored in the RAM 34 in step 315 described later. The processing in step 310 functions as fuel reduction amount calculation means in the claims. It should be noted that the amount of decrease in the high-pressure side fuel amount Mhigh and the amount of decrease in the low-pressure side fuel amount Mlow within a predetermined time are respectively calculated and summed together to obtain the total fuel decrease amount DM within the predetermined time. It may be calculated.

  Thereafter, in step 311, the total cylinder injection pulse integrated value Tinj within a predetermined time is converted into a fuel amount by the following equation, and the amount of fuel injected from the fuel injection valve 19 within the predetermined time (hereinafter referred to as “consumed fuel amount”). ) Find Minj.

Minj = K × Tinj
Here, K is a conversion coefficient for converting the total cylinder injection pulse integrated value Tinj into the fuel consumption amount Minj. The processing in steps 308 and 310 functions as fuel consumption calculation means in the claims.

  Then, in the next step 312, the total fuel decrease amount DM within a predetermined time is compared with the consumed fuel amount Minj within the predetermined time, and if the total fuel decrease amount DM is greater than the consumed fuel amount Minj by a predetermined value γ or more, It is determined that there is a leak (step 313). Otherwise, it is determined that there is no fuel leak (step 314). Here, the predetermined value γ is set in consideration of errors of DM and Minj. If it is determined that there is a fuel leak, the process proceeds to step 315, where the warning lamp 44 is turned on (or flashes) to warn the driver.

  In place of the method for determining the presence or absence of fuel leakage based on the difference between the consumed fuel amount Minj and the total fuel decrease amount DM, whether the ratio (Minj / DM) of the two is a predetermined value δ (δ <1) or less. However, the presence or absence of fuel leakage may be determined. The processing in steps 312 to 314 functions as an in-operation fuel leakage determination means in the claims.

  As described above, after determining the presence or absence of fuel leakage during engine operation, the routine proceeds to step 316 and the current total fuel amount Mtotal is stored in the RAM 34 as Mold in preparation for the next fuel leakage diagnosis. Thereafter, in step 317, the all-cylinder injection pulse integrated value Tinj is reset and the program is terminated.

  According to this program, both the high pressure side fuel amount Mhigh and the low pressure side fuel amount Mlow are calculated to calculate the fuel decrease amount DM of the entire fuel supply system. Therefore, the reliability of fuel leak detection can be improved.

  The present invention is not limited to the configuration that executes all the three programs shown in FIGS. 3 to 5 described above, and may be configured to execute only one or two programs.

  In the second embodiment, the fuel pressure regulator 25 is constituted by an electrically controlled pressure control valve, and this fuel pressure regulator 25 is feedback-controlled so that the low pressure side fuel pressure Plow matches the low pressure side target fuel pressure Ptarget, and the fuel pressure regulator 25 Based on the control amount C (i) of 25, it is determined whether or not there is a fuel leak in the fuel supply system.

  The control of the fuel pressure regulator 25 and the fuel leakage diagnosis are executed as follows by the fuel pressure control / fuel leakage diagnosis program of FIG. This program is started every predetermined time. First, in step 401, after reading the signals of various sensors for detecting the engine operating state such as the intake air temperature, the intake pipe pressure, the coolant temperature, the engine speed and the air-fuel ratio, the step is executed. In 402, the reference control amount Cbase and the low pressure side target fuel pressure Ptarget of the fuel pressure regulator 25 are calculated according to the engine operating state.

  Thereafter, in step 403, the low pressure side fuel pressure Plow detected by the low pressure side fuel pressure sensor 29 is read. In step 404, the low pressure side target fuel pressure Ptarget is compared with the low pressure side fuel pressure Plow, and Ptarget> Plow. If so, the process proceeds to step 405, where a predetermined correction amount a is added to the previous control amount C (i-1) of the fuel pressure regulator 25 to obtain the current control amount C (i). If Ptarget = Plow, the process proceeds to step 406, where the previous control amount C (i-1) is directly used as the current control amount C (i). If Ptarget <Plow, the routine proceeds to step 407, where the predetermined control amount b is subtracted from the previous control amount C (i-1) of the fuel pressure regulator 25 to obtain the current control amount C (i).

  After correcting the current control amount C (i) of the fuel pressure regulator 25 as described above, the process proceeds to step 408, and whether or not the fuel leakage diagnosis condition is satisfied in the same manner as in step 301 in FIG. If the fuel leak diagnosis condition is not satisfied, the program is terminated without making a fuel leak diagnosis.

  On the other hand, if it is determined in step 408 that the fuel leakage diagnosis condition is satisfied, the process proceeds to step 409, where the current control amount C (i) is compared with the reference control amount Cbase, and the current control amount is determined. If the amount C (i) is larger than the reference control amount Cbase by a predetermined value ε or more, it is determined that there is a fuel leak (step 410). Otherwise, it is determined that there is no fuel leak (step 411). Here, the predetermined value ε is set in consideration of errors of C (i) and Cbase. If it is determined that there is a fuel leak, the process proceeds to step 412 where the warning lamp 44 is turned on (or flashes) to warn the driver, and at step 413, the high-pressure side electromagnetic provided in the high-pressure side fuel pipe 24 Close the valve (not shown) and end the program. When the high pressure side solenoid valve is closed, a small amount of fuel is supplied to the fuel injection valve 19 side so that the vehicle can be evacuated to a safe place.

Instead of the method of determining the presence or absence of fuel leakage based on the difference between the current control amount C (i) and the reference control amount Cbase, the ratio (C (i) / Cbase) of both is a predetermined value ζ (ζ> 1). ) Whether or not there is a fuel leak may be determined based on whether or not it is above.
In the second embodiment described above, the high-pressure side fuel temperature sensor 28 and the high-pressure side fuel pressure sensor 27 are not necessary.

[Other Examples]
In the first and second embodiments, at least one of the temperature and pressure near the fuel injection valve 19, the temperature near the fuel tank 23, the pressure, the fuel property, the engine speed, the load, the coolant temperature, and the engine temperature, The determination values α to ζ of leakage may be determined and the detected values of fuel pressure and fuel temperature may be corrected. Alternatively, the gas engine 11 may be stopped by forcibly turning off the second starter relay 40 while the fuel tank 23 is being refueled.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic block diagram of the whole system which shows Example 1 of this invention. It is a circuit diagram which shows the structure of an engine starting control circuit. It is a flowchart which shows the flow of a process of a fuel leak diagnostic program. It is a flowchart which shows the flow of a process of a start permission / inhibition program. It is a flowchart which shows the flow of a process of the fuel leak diagnostic program during a driving | operation. 10 is a flowchart showing a flow of processing of a fuel pressure control / fuel leakage diagnosis program executed in a second embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 11 ... Gas engine, 19 ... Fuel injection valve, 23 ... Fuel tank, 24 ... High pressure side fuel piping, 25 ... Fuel pressure regulator, 26 ... Low pressure side fuel piping, 27 ... High pressure side fuel pressure sensor (high pressure side fuel pressure detection means) 28 ... High pressure side fuel temperature sensor (high pressure side fuel temperature detection means) 29 ... Low pressure side fuel pressure sensor (low pressure side fuel pressure detection means), 30 ... Low pressure side fuel temperature sensor (low pressure side fuel temperature detection means), 31 ... ECU (high pressure side fuel amount calculation means, low pressure side fuel amount calculation means, fuel decrease amount calculation means, fuel consumption amount calculation means, fuel leakage judgment means during operation), 35 ... battery, 36 ... backup RAM (storage means), 37 ... Ignition switch, 39 ... First starter relay, 40 ... Second starter relay, 44 ... Warning lamp.

Claims (1)

In a gas engine having a fuel supply system for reducing the pressure of gas fuel charged in a fuel tank through a fuel pressure regulator and supplying the fuel to a fuel injection valve,
High pressure fuel temperature detecting means for detecting the fuel temperature on the high pressure side of the fuel supply system;
High pressure fuel pressure detection means for detecting fuel pressure on the high pressure side of the fuel supply system;
Low pressure side fuel temperature detecting means for detecting the fuel temperature on the low pressure side of the fuel supply system;
Low pressure side fuel pressure detecting means for detecting fuel pressure on the low pressure side of the fuel supply system;
The amount of fuel in the fuel supply system from the fuel tank to the fuel pressure regulator (hereinafter referred to as “high pressure side”) based on the fuel temperature and fuel pressure on the high pressure side detected by the high pressure side fuel temperature detecting means and the high pressure side fuel pressure detecting means. High pressure side fuel amount calculating means for calculating the fuel amount)
The amount of fuel in the fuel supply system from the fuel pressure regulator to the fuel injection valve (hereinafter referred to as “low pressure”) based on the fuel temperature and fuel pressure on the low pressure side detected by the low pressure side fuel temperature detecting means and the low pressure side fuel pressure detecting means. Low-pressure side fuel amount calculating means for calculating "side fuel amount"),
A reduction amount within a predetermined period of a total value of both high-pressure side and low-pressure side fuel amounts calculated by the high-pressure side and low-pressure side fuel amount calculation means, or a reduction within a predetermined period of both high-pressure side and low-pressure side fuel amounts. A fuel decrease amount calculating means for obtaining a fuel decrease amount of the entire fuel supply system within a predetermined period from a total value of the amounts;
Fuel consumption calculating means for calculating the fuel consumption within a predetermined period by integrating the injection pulses for driving the fuel injection valve for a predetermined period for all cylinders;
The fuel supply system is compared by comparing the fuel decrease amount of the entire fuel supply system within the predetermined period calculated by the fuel decrease amount calculation means with the fuel consumption amount within the predetermined period calculated by the fuel consumption calculation means. A fuel leak detection device for a gas engine, comprising: an in-operation fuel leak determination means for determining whether or not there is a fuel leak.

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