초록 ▼

In a fuel cell system (100), the amount of fuel gas supplied through an fuel gas supply passage (24) and the amount of fuel gas consumed by a fuel cell (10) are detected. A difference between the amount of supplied fuel gas and the amount of consumed fuel gas is calculated by subtracting the amount

In a fuel cell system (100), the amount of fuel gas supplied through an fuel gas supply passage (24) and the amount of fuel gas consumed by a fuel cell (10) are detected. A difference between the amount of supplied fuel gas and the amount of consumed fuel gas is calculated by subtracting the amount of consumed fuel gas from the amount of supplied fuel gas. The pressure of the fuel gas in a leak detection passage (Cx), the change in the pressure of the detected fuel gas can be detected, and the change in the amount of fuel gas in the gas leak detection passage (Cx) due to the change in the pressure of the fuel gas can thus be detected. The difference is corrected by subtracting the change in the amount of fuel gas in the gas leak detection passage from the difference. When the corrected difference is equal to or greater than a predetermined value, a fuel gas leak is detected in the leak detection passage (Cx).

대표청구항 ▼

The invention claimed is: 1. A gas leak detection device that detects a gas leak in a fuel cell system including a fuel cell; a fuel gas supply source; a supply passage through which fuel gas is supplied from the fuel gas supply source to the fuel cell; a discharge passage through which fuel gas is

The invention claimed is: 1. A gas leak detection device that detects a gas leak in a fuel cell system including a fuel cell; a fuel gas supply source; a supply passage through which fuel gas is supplied from the fuel gas supply source to the fuel cell; a discharge passage through which fuel gas is discharged from the fuel cell; and a purge valve provided in the discharge passage, which adjusts an amount of fuel gas discharged from the fuel cell, the gas leak detection device comprising: a supply-amount detector provided in the supply passage, which detects an amount of supplied fuel gas, wherein the supply passage includes a first passage positioned downstream of the supply-amount detector, the fuel cell includes a second passage through which the fuel gas flows, the discharge passage includes a third passage positioned upstream of the purge valve, the gas leak detection device further comprising: a consumption-amount calculator programmed to calculate an amount of fuel gas consumed by the fuel cell; a pressure detector that detects a pressure of the fuel gas in a gas leak detection passage including the first passage, the second passage, and the third passage; a change-amount calculator that obtains a change in the pressure of the fuel gas using the detected pressure, and is programmed to calculate a change in an amount of fuel gas in the gas leak detection passage due to the change in the pressure of the fuel gas; a difference-amount calculator programmed to calculate a difference between the detected amount of supplied fuel gas and a sum of the amount of consumed fuel gas and the change in the amount of fuel gas in the gas leak detection passage by subtracting the amount of consumed fuel gas and the change in the amount of fuel gas in the gas leak detection passage from the amount of supplied fuel gas; and a fuel-gas leak detector that determines that a fuel gas leak is present in the gas leak detection passage when the difference is equal to or greater than a first predetermined value. 2. The gas leak detection device according to claim 1, wherein the gas leak detection passage includes a circulation passage, one end of which is connected to the supply passage at a position downstream of the supply-amount detector, and the other end of which is connected to the discharge passage, whereby the fuel gas flows to the supply passage from the discharge passage through the circulation passage so that the fuel gas can be reused. 3. The gas leak detection device according to claim 2, wherein the fuel cell system includes a circulation pump provided in the circulation passage, which delivers the fuel gas from the discharge passage to the supply passage, the gas leak detection device includes a correction portion that corrects the amount of supplied fuel gas detected by the supply-amount detector so as to reduce an influence of pulsation generated by the circulation pump, and the difference-amount programmed to calculate the difference by subtracting the amount of consumed fuel gas and the change in the amount of fuel gas in the gas leak detection passage from the corrected amount of supplied fuel gas. 4. The gas leak detection device according to claim 2, wherein the fuel cell system includes a circulation pump provided in the circulation passage, which delivers the fuel gas from the discharge passage to the supply passage, and the supply-amount detector detects the amount of supplied fuel gas when the circulation pump is not in operation. 5. The gas leak detection device according to claim 1, wherein the gas leak detection passage includes a plurality of sections, the pressure detector detects a pressure of the fuel gas in each of the plurality of sections in the gas leak detection passage, the change-amount calculator obtains a change in the detected pressure of the fuel gas in each of the sections; the change-amount calculator obtains the change in the amount of fuel gas in each of the sections due to the change in the pressure of the fuel gas in the corresponding section; and the change-amount calculator programmed to calculate the change in the amount of fuel gas in the gas leak detection passage, by summing the changes in the amounts of fuel gas in all the sections. 6. The gas leak detection device according to claim 1, wherein the fuel cell system includes a pressure-release valve provided in the supply passage, which reduces the pressure of the fuel gas, and the gas leak detection device includes an amount detector that detects the amount of fuel gas, and that is provided in the supply passage such that the pressure-release valve is positioned between the amount detector and the supply-amount detector; and a leak determination permission portion that permits the fuel-gas leak detector to determine whether a fuel gas leak is present, in a case where a difference between the amount of supplied fuel gas detected by the supply-amount detector and the amount of fuel gas detected by the amount detector is in a predetermined range. 7. The gas leak detection device according to claim 6, wherein the fuel-gas leak detector determines that a fuel gas leak is present between the supply-amount detector and the amount detector in the supply passage, when both the amount of supplied fuel gas detected by the supply-amount detector and the amount of fuel gas detected by the amount detector are constant, but the difference between the amounts is not within the predetermined range. 8. The gas leak detection device according to claim 1, wherein the fuel cell system includes a cut-off valve provided in the supply passage at a position upstream of the supply-amount detector, which cuts off supply of the fuel gas when closed, and the fuel-gas leak detector determines that a fuel gas leak is present in the supply passage at a position upstream of the supply-amount detector and downstream of the cut-off valve, in a case where the supply-amount detector detects a greater amount of fuel gas flowing in a direction opposite to a direction where the fuel gas is supplied than a predetermined amount when the supply of the fuel gas is cut off by closing the cut-off valve. 9. The gas leak detection device according to claim 1, wherein the fuel cell system includes a cut-off valve provided in the supply passage at a position upstream of the supply-amount detector, which cuts off supply of the fuel gas when closed, and the fuel-gas leak detector determines that a fuel gas leak is present in the gas leak detection passage, in a case where the supply-amount detector detects a greater amount of fuel gas flowing in a direction where the fuel gas is supplied than a predetermined amount when the cut-off valve is closed and the fuel cell is not generating electric power. 10. The gas leak detection device according to claim 1, further comprising: a first pressure difference detector which detects an upstream pressure in the supply passage at a position upstream of the supply-amount detector and a downstream pressure in the supply passage at a position downstream of the supply-amount detector, and obtains a pressure difference between the upstream pressure and the downstream pressure by subtracting the downstream pressure from the upstream pressure; and a first amount estimation portion which estimates an amount of fuel gas flowing in the supply-amount detector, based on the pressure difference, wherein the fuel-gas leak detector determines that an abnormality is present in the supply-amount detector, in a case where an absolute value of a difference between the amount of fuel gas estimated by the first amount estimation portion and the amount of supplied fuel gas detected by the supply-amount detector is equal to or greater than a second predetermined value. 11. The gas leak detection device according to claim 1, wherein the fuel cell system includes a regulator which is provided in the supply passage at a position upstream or downstream of the supply-amount detector, the gas leak detection device includes a second pressure difference detector which detects an upstream pressure in the supply passage at a position upstream of the regulator and a downstream pressure in the supply passage at a position downstream of the regulator, and obtains a pressure difference between the upstream pressure and the downstream pressure by subtracting the downstream pressure from the upstream pressure; and a second amount estimation portion which estimates an amount of fuel gas flowing in the regulator in the supply passage, based on the pressure difference obtained by the second pressure difference detector, and the fuel-gas leak detector determines that an abnormality is present in the supply-amount detector, in a case where an absolute value of a difference between the amount of fuel gas estimated by the second amount estimation portion and the fuel gas supply amount detected by the supply-amount detector is equal to or greater than a third predetermined value. 12. A fuel cell system comprising: a fuel cell; a fuel gas supply source; a supply passage through which fuel gas is supplied from the fuel gas supply source to the fuel cell; a discharge passage through which fuel gas is discharged from the fuel cell; a purge valve provided in the discharge passage, which adjusts an amount of fuel gas discharged from the fuel cell; and a supply-amount detector provided in the supply passage, which detects a fuel gas supply amount that is an amount of supplied fuel gas, wherein the supply passage includes a first passage downstream of the supply-amount detector in a supply direction in which the fuel gas is supplied from the fuel gas supply source, the fuel cell includes a second passage through which the fuel gas flows, the discharge passage includes a third passage upstream of the purge valve in a discharge direction in which the fuel gas is discharged from the fuel cell, and the fuel cell system further includes a pressure detector that detects a pressure of the fuel gas in a gas leak detection passage including the first passage, the second passage, and the third passage; a consumption-amount calculator programmed to calculate an amount of fuel gas consumed by the fuel cell; a change-amount calculator that obtains a change in the pressure of the fuel gas using the detected pressure, and is programmed to calculate a change in an amount of fuel gas in the gas leak detection passage due to the change in the pressure of the fuel gas; a difference- amount calculator programmed to calculate a difference between the detected amount of supplied fuel gas and a sum of the amount of consumed fuel gas and the change in the amount of fuel gas in the gas leak detection passage by subtracting the amount of consumed fuel gas and the change in the amount of fuel gas in the gas leak detection passage from the detected amount of supplied fuel gas; and a fuel-gas leak detector that determines that a fuel gas leak is present in the gas leak detection passage when the difference is equal to or greater than a predetermined value. 13. A method for detecting a gas leak in a fuel cell system that includes a fuel cell; a fuel gas supply source; a supply passage through which fuel gas is supplied from the fuel gas supply source to the fuel cell; a discharge passage through which fuel gas is discharged from the fuel cell; and a purge valve provided in the discharge passage, which adjusts an amount of fuel gas discharged from the fuel cell; comprising detecting, at a predetermined first position within the supply passage, an amount of supplied fuel gas; calculating an amount of fuel gas consumed by the fuel cell; detecting a pressure of the fuel gas in a gas leak detection passage that includes a first passage downstream of the predetermined first portion in the supply passage; a second passage through which the fuel gas flows in the fuel cell; and a third passage upstream of the purge valve in the discharge passage; obtaining a change in the pressure of the fuel gas using the detected pressure; calculating a change in an amount of fuel gas in the gas leak detection passage due to the change in the pressure of the fuel gas; calculating a difference between the detected amount of supplied fuel gas and a sum of the amount of consumed fuel gas and the change in the amount of fuel gas in the gas leak detection passage by subtracting the amount of consumed fuel gas and the change in the amount of fuel gas in the gas leak detection passage from the detected amount of supplied fuel gas; and determining that a fuel gas leak is present in the gas leak detection passage when the difference is equal to or greater than a predetermined value.