By ATN Editorial Team
Summary: Horse Powertrain has revealed the HORSE B20 engine, a 130 kg 2.0-litre four-cylinder turbocharged petrol unit sealed to IPX8 and rated for wading to depths of 1.1 metres. It is aimed at off-road SUVs and pick-up trucks in HEV, PHEV and REEV configurations, and has already run inside a plug-in hybrid powertrain in the Geely Galaxy Cruiser 700 for the Chinese market.
Key engineering takeaway: Output is 140 to 185 kW and 300 to 380 Nm, and Horse Powertrain says an advanced Miller cycle takes brake thermal efficiency to 48.4%. Combustion hardware includes high-pressure injectors, high-tumble intake ports and pistons shaped to exploit the squish effect at the top of the compression stroke. The more interesting part of the HORSE B20 engine is the wading strategy rather than the seals: IPX8-rated electrical components and sensors monitor the operating environment continuously, and when the engine is submerged the control system limits power or alters throttle response on that sensor feedback.
Why it matters: Waterproofing a combustion engine to a wading depth is normally solved around the engine, in body sealing and intake routing, so pulling it into the engine’s own structure, its transmission interface and its control strategy moves the boundary between what the OEM owns and what the supplier owns. The HORSE B20 engine also shows the shape of the market Horse Powertrain is building for, where one combustion unit has to serve hybrid, plug-in and range-extender layouts, and where a claimed 48.4% brake thermal efficiency is what makes keeping the engine worthwhile against simply fitting a larger battery.
- HORSE B20 engine is a four-cylinder 2.0-liter turbocharged unit capable of 140-185kW power and 300-380Nm of torque
- Designed for hybrid vehicles that tackle extreme off-road terrains and deep-water wading
- Powertrain is fully waterproofed for depths up to 1.1 meters at IPX8 standard
Horse Powertrain, a global leader in innovative, low-emission hybrid and combustion powertrain solutions, has revealed its fully waterproof engine, the HORSE B20.
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 meters. It is also capable of maintaining continuous and stable power output under extreme off-road high-load conditions including 100% grade climbing.
Weighing just 130kg, 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 140-185kW of power and 300-380Nm of torque. The engine is powered by an advanced Miller cycle, enabling a brake thermal efficiency of 48.4%.
Combustion And Cooling Hardware In The HORSE B20 Engine
The HORSE B20 features a range of innovations to encourage leaner, cleaner combustion and to maximise 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 – this enables 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 aluminium 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.
IPX8 Sealing And Submerged Engine Control
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. 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.
Ingo Scholten, Deputy Chief Technology Officer of Horse Powertrain
First Application In The Geely Galaxy Cruiser 700
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 vehicle (China only), paired with a HORSE 3DHT230, a 3-speed intelligent hybrid transmission.
HORSE B20 Engine: Frequently Asked Questions
What is the HORSE B20 engine?
The HORSE B20 engine is a 130 kg, 2.0-litre four-cylinder inline turbocharged petrol engine from Horse Powertrain, built for hybrid, plug-in hybrid and range-extender applications in off-road SUVs and pick-up trucks. Its distinguishing feature is a fully sealed structure rated to IPX8, allowing operation in water up to 1.1 metres deep.
What does an IPX8 rating mean for an engine?
IP codes describe how well an enclosure resists solids and liquids. The X means solid-particle protection has not been rated, and the 8 is the highest standard water rating, covering continuous immersion beyond one metre at a depth the manufacturer specifies. Horse Powertrain specifies 1.1 metres for the B20. On an engine the rating covers the sealed structure, torsional vibration dampers, the engine-to-transmission sealing joint, and the electrical components and sensors.
What happens when the engine is submerged?
It does not simply rely on seals. Horse Powertrain says IPX8-rated sensors continuously monitor the environment around the engine, and when submersion is detected the control system automatically limits power or adjusts throttle response using that sensor feedback, to hold stable operation through a deep wade.
What is the Miller cycle and why does it raise efficiency?
The Miller cycle closes the intake valve away from bottom dead centre, usually early, so the effective compression stroke is shorter than the expansion stroke. Extracting more work on expansion than is spent on compression raises thermal efficiency and reduces the tendency to knock, which is why it pairs naturally with turbocharging to recover the lost charge mass. Horse Powertrain states an advanced Miller cycle takes the B20 to 48.4% brake thermal efficiency.
Which vehicle uses the HORSE B20?
It was first shown at the Beijing Auto Show 2026 and has since been used in a plug-in hybrid powertrain in the Geely Galaxy Cruiser 700 off-road vehicle, sold in China only, paired with the HORSE 3DHT230 three-speed hybrid transmission.
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