Exhaust hydrogen dilution device

An exhaust hydrogen dilution device to be mounted on a fuel cell system, the exhaust hydrogen dilution device comprising:

• a purge receiving chamber configured to temporarily store hydrogen that is to be purged intermittently from a fuel cell of the fuel cell system;
• an air passage chamber through which diluter gas is to flow, the air passage chamber adjoining the purge receiving chamber;
• and a purge nozzle coupled to the purge receiving chamber, and comprising a distal end configured to discharge the hydrogen into the purge receiving chamber, wherein
• an interface region between the purge receiving chamber and the air passage chamber comprises an interface member having a first vent on an upstream side and a second vent on a downstream side,
• a pressure loss at the first vent is greater than or equal to a pressure loss at the second vent,
• some of the diluter gas flows from the air passage chamber into the purge receiving chamber through the first vent and is mixed with the hydrogen stored in the purge receiving chamber into a mixed gas that flows toward the second vent,
• the pressure loss at the first vent and the pressure loss at the second vent are adjusted such that a ratio of the hydrogen flowing into the air passage chamber through the second vent is 4% or lower with respect to a total amount of gases that flow through the air passage chamber,
• the mixed gas in the purge receiving chamber flows into the air passage chamber through the second vent and is diluted with the diluter gas,
• the interface member inclines up to the second vent with the second vent residing at a lowest position in the purge receiving chamber,
• the interface member includes a first portion between the first vent and the second vent, and a second portion between the second vent and a side wall of the purge receiving chamber at the downstream side,
• the distal end of the purge nozzle is at a space within the purge receiving chamber above the first portion, and
• the interface member is configured to rectify a flow of the hydrogen from the purge nozzle toward the second vent by a structure including:
• (i) the purge receiving chamber providing for an unobstructed flow path between the purge nozzle and the second vent;
• and
• (ii) the first portion inclining at a first angle with respect to the second vent, and the second portion inclines at a second angle greater than the first angle with respect to the second vent.