Horse Powertrain has revealed the HORSE B20, a waterproof 2.0-liter turbocharged four-cylinder engine for off-road HEV, PHEV and REEV vehicles. Rated IPX8 for wading up to 1.1 meters, it produces 140-185kW and 300-380Nm, with 48.4% thermal efficiency. It’s already used in China’s Geely Galaxy Cruiser 700.
Horse Powertrain, London, UK, has revealed the HORSE B20, a fully waterproof engine designed for hybrid vehicles operating in extreme off-road conditions and deep-water wading.
The four-cylinder, 2.0-liter turbocharged gasoline engine is built for hybrid electric vehicle (HEV), plug-in hybrid electric vehicle (PHEV) and range-extended electric vehicle (REEV) applications, including SUVs and pick-up trucks. It outputs 140-185kW of power and 300-380Nm of torque, and weighs 130kg.
The engine meets the IPX8 waterproofing standard, allowing operation at depths of up to 1.1 meters. Horse Powertrain says it can also maintain continuous, stable power output under extreme off-road high-load conditions, including 100% grade climbing.
To achieve the IPX8 rating, the HORSE B20 uses a fully sealed waterproof structure with torsional vibration dampers and dedicated engine-transmission sealing, along with IPX8-rated electrical components and sensors that monitor the engine’s operating environment. When submerged, the control system automatically adjusts power output and throttle response based on sensor feedback to maintain stable operation.
The engine uses a Miller cycle combustion process, with a brake thermal efficiency of 48.4%. Direct injection, high-pressure injectors and high-tumble intake ports are used to improve air-fuel mixing, alongside pistons designed to use the “squish effect” to promote mixing at peak compression, which the company says allows for a cleaner, faster combustion event.
Other features include a gantry-type aluminum block with an integrated exhaust manifold, a simplified balance shaft system, and a variable displacement oil pump. A fully active dual-cooling system is designed to keep the engine within its optimal operating temperature range during extended high-load use, such as continuous slope climbing.
According to Ingo Scholten, deputy chief technology officer at Horse Powertrain, the HORSE B20 supports HEV, PHEV and REEV platforms and “enables new opportunities across a range of vehicle categories – particularly off-road applications, due to the engine’s waterproofing and climbing capabilities.”
The HORSE B20 was first shown at the Beijing Auto Show 2026. It has since been used in a PHEV powertrain in the Geely Galaxy Cruiser 700 off-road vehicle, available in China only, paired with the HORSE 3DHT230, a three-speed intelligent hybrid transmission.
