How The Horse B20 Four Cylinder Engine Can Survive Up To A Meter Underwater

Car engines aren't meant to be dunked in water, but a Geely-backed company called Horse Powertrain has now built one that's apparently waterproof. Horse Powertrain is a joint venture between Renault and Chinese auto giant Geely, providing parts to Renault Alliance-mates Nissan and Mitsubishi, and Geely-owned Volvo. Horse brought out the waterproof B20 engine at this year's Beijing Auto Show, and it's called the B20 (no Honda relation). 

It's a 2.0-liter turbocharged four-cylinder engine that's IPX8 waterproof, meaning it can run temporarily submerged in up to 3.6 feet of water (that's 1.1 meters or 43 inches). The B20 is able to do this thanks to a fully sealed structure rocking "torsional vibration dampers" and "dedicated engine-transmission sealing." Electrical components and sensors are themselves IPX8-rated and constantly monitor the environment in which the engine is running. When the systems detect submersion, power is limited, and throttle response is adjusted to make sure the engine remains stable.

Naturally, Horse's waterproof engine was designed for "extreme" off-road SUVs and trucks, but specifically those with hybrid powertrains. Think electrified versions of rigs like the Jeep Wrangler or the Toyota Land Cruiser. Or, another vehicle you might be less familiar with, the Geely Galaxy Cruiser 700, which uses this very engine.

Judging by the figures, it isn't some technically-works sewing machine, either. It's said to make anywhere from 188 to 248 hp and 221 to 280 lb-ft of torque. It's also been engineered to maintain power when subjected to "extreme off-road high-load conditions" such as grades of up to 100% — that's a 45-degree slope.

The B20 weighs 287 pounds and uses high-pressure injectors and high-tumble intake ports. For better durability and NVH, it uses a "gantry-type aluminum block with integrated exhaust manifold and a simplified balance shaft system." There's also a variable-displacement oil pump and a fully active dual-cooling system.

All that said, these are all manufacturer claims, and we've yet to find a third-party test of the B20's waterproof...ness. But if the technology actually works and makes for more capable off-roaders, waterproof engines might be the next big engineering goal of every other automaker that builds one.