Horse Powertrain reveals waterproof hybrid engine suitable for off-road vehicles

UK-based Horse Powertrain, a global leader in innovative, low-emission hybrid and combustion powertrain solutions, has revealed its fully waterproof engine, the HORSE B20.

The Horse Powertrain B20 engine is a four-cylinder 2.0-liter turbocharged unit designed for hybrid vehicles that tackle extreme off-road terrains and deep-water wading. [Credit: Image courtesy of Horse Powertrain]

Designed for extreme off-road vehicles and deep-water wading, the HORSE B20 brings all-terrain capabilities to hybrid vehicles, including applications for SUVs and pick-up trucks. Fully compliant with IPX8 waterproofing standards, the HORSE B20 can operate up to depths of 1.1 m -- that's 3 ft 7.3 in. It is also capable of maintaining continuous and stable power output under extreme off-road high-load conditions including 100% grade climbing, which translates to a 45-degree continuous slope.

Weighing just 130 kg (287 lb), the HORSE B20 is a four-cylinder, 2-liter inline gasoline engine designed for HEV, PHEV, and REEV applications. Featuring a turbocharger and direct injection technology, it can output up to 140 (187.75 HP) to 185 kW (248.10 HP) of power and 300 (221.27 FtLb) to 380 Nm (280.27 FtLb) of torque. The engine is powered by an advanced Miller cycle, enabling a brake thermal efficiency of 48.4%.

The HORSE B20 features a range of innovations to encourage leaner, cleaner combustion and to maximize fuel economy and range. These include high-pressure injectors and high-tumble intake ports, which promote superior air-fuel mixing and more efficient combustion. Additionally, the engine features pistons designed to make full use of the "squish" effect to promote air-fuel mixing at the peak of the compression cycle, enabling the spark plug to ignite a cleaner and faster combustion event.

Outside the engine cylinders, the HORSE B20 uses a number of innovative technologies. These include a gantry-type aluminum block with integrated exhaust manifold and a simplified balance shaft system, which improve NVH, durability, and overall efficiency. It also features a variable displacement oil pump ensuring optimal oil flow and pressure throughout the engine.

To improve the cooling efficiency, an exclusive, fully active dual-cooling system ensures the unit remains in the optimal operating temperature, even under extreme conditions such as continuous slope climbing and long-duration, high-temperature scenarios.

To achieve an IPX8 waterproof rating, the engine uses a fully sealed, waterproof structure equipped with torsional vibration dampers and dedicated engine-transmission sealing. Fitted with IPX8-rated electrical components and sensors, it continuously monitors the surrounding operating environment of the engine. When the engine is submerged in water, the control system makes automatic adjustments such as limiting power or adjusting the throttle response, based on feedback signals from the sensors. This ensures the stable operation of the engine under deep wading conditions.

"The HORSE B20 demonstrates how we are meeting the full range of market needs, delivering flexible engine and powertrain solutions designed for multiple use cases and applications," said Ingo Scholten, deputy chief technology officer of Horse Powertrain. "Supporting HEV, PHEV, and REEV platforms, the HORSE B20 enables new opportunities across a range of vehicle categories -- particularly off-road applications, due to the engine's waterproofing and climbing capabilities. This engine is another step forward in advancing modern powertrain technology and a further example of how Horse Powertrain is pushing our industry forward."

First showcased at the Beijing Auto Show 2026, the HORSE B20 was recently used within a PHEV powertrain in the Geely Galaxy Cruiser 700 off-road SUV (China only), paired with a HORSE 3DHT230, a 3-speed intelligent hybrid transmission.

In another innovation, Horse Powertrain introduced a small add-on gas engine last year that extends EV range for OEMs. The C15 engine unit turned out to be right on trend to make it easy for battery electric vehicle (BEV) makers to build in extra mileage and turn their vehicles into hybrids by providing an add-on, briefcase-sized internal combustion engine (ICE) that could extend range by hundreds of miles -- and be more acceptable to customers.

Two views of the Horse C15 engine unit, which measures just 500 x 550 x 275 mm. [Credit: Photos courtesy of Horse Powertrain]

Just this month, Horse Powertrain opened its new North American office in Detroit, MI. This is a significant milestone for the company. The new North American office is strategically positioned in the heartland of the US automotive industry, predominantly catering to US clients. The office will house 32 new roles across a range of business functions, adding to the company's regional facilities across Europe, China, and South America.

The company currently supplies the M252 2.0-liter turbocharged four-cylinder engine in the third-generation Mercedes-Benz CLA and is an independent 50-50 joint venture equally owned by Geely and the Renault Group.

Learn more at horse-powertrain.com.

Source: Horse Powertrain

Published September 2026