A new turbocharged hybrid engine has been certified to keep running while fully submerged under more than three feet of water, a waterproofing benchmark aimed squarely at off-road trucks and SUVs that regularly ford rivers and flooded trails. The HORSE B20, built by the Renault-and-Geely-backed joint venture Horse Powertrain, carries an IPX8 rating for operation at depths up to 1.1 meters, or roughly 3.6 feet, according to The Drive.

Key Points

• The HORSE B20 is a 2.0-liter turbocharged four-cylinder engine built for hybrid, plug-in hybrid and range-extended electric powertrains, producing 140 to 185 kW (about 188 to 248 horsepower) and 300 to 380 Nm of torque, according to paultan.org.
• The engine carries an IPX8 waterproof rating and can keep operating fully submerged at depths up to 1.1 meters, sealed with torsional vibration dampers and dedicated engine-transmission sealing, per Electric & Hybrid Vehicle Technology International.
• IPX8-rated sensors monitor conditions while underwater, and the control system automatically limits power or adjusts throttle response based on that feedback, according to The Drive.
• The engine weighs about 130 kilograms (287 pounds) and is engineered for SUVs and pickup trucks built for extreme off-road terrain, including grades of up to 100%, according to Electric & Hybrid Vehicle Technology International.
• The B20 is already in production use in the Geely Galaxy Cruiser 700 plug-in hybrid sold in China, which is rated for a maximum wading depth of nearly 35 inches, per The Drive.

Built To Keep Running, Not Just Survive A Splash

Most off-road vehicles are rated for how deep they can wade before water reaches the air intake or floods the cabin, not for how the engine itself behaves once submerged. Horse Powertrain’s approach targets the engine directly, sealing the block, transmission interface and electrical components so combustion can continue rather than shutting down the moment water rises past the bumper, per Electric & Hybrid Vehicle Technology International. “[The B20] enables new opportunities across a range of vehicle categories,” Ingo Scholten, Horse Powertrain’s deputy chief technology officer, said in the company’s announcement of the engine.

Who Is Behind It

Horse Powertrain is a joint venture combining Renault’s and Geely’s combustion and hybrid engine businesses, formed to supply engines across both companies’ brands, according to The Drive. The B20 uses Miller-cycle combustion and direct injection, and Horse Powertrain says it reaches a brake thermal efficiency of 48.4%, among the highest published figures for a production gasoline engine, according to paultan.org. No U.S. market application has been announced; the engine’s first confirmed home is a Chinese-market PHEV, though its off-road-first design suggests wider ambitions for trucks and SUVs built to cross water without stalling out.