By YANG Shihan

BYD has responded to Great Wall Motor’s (GWM) accusations of cheating in emissions tests. The company claims the fuel tanks in some of its hybrids meet the required standards, even in extended electric-only running.

Earlier, BYD faces allegations that two models equipped with atmospheric pressure fuel tanks do not meet national standards for evaporative pollutant emissions. BYD responded that GWM’s testing did not adhere to standard test conditions.

There are two technical approaches to evaporative emission compliance in hybrid vehicles. One approach involves modifying traditional fuel vehicles, which require a high-pressure fuel tank. The other, designed specifically for EVs, complies with regulations used at atmospheric pressure.

BYD is not reliant on high-pressure fuel tanks and an intelligent system controls fuel vapor evaporation. BYD has applied for multiple patents related to vapor emissions.

The company also highlights that over 80 percent of countries use Chinese standards. BYD follows the same standards for domestic and international markets, employing both atmospheric pressure and high-pressure fuel tanks that comply with local regulations.

BYD did not explicitly mention compliance with “China VI” vehicle emission standards in their response. Reports suggest that BYD’s Xi’an factory is transitioning to high-pressure fuel tanks to meet the emission standards, effective nationwide from July onwards.