Horse Powertrain has unveiled a new 2.0-liter hybrid engine designed to keep working in conditions that would stop most powertrains in their tracks. The new HORSE B20 is fully waterproof to IPX8 standards and can operate while submerged in up to 1.1 meters (42 inches) of water, opening new possibilities for hybrid SUVs and pickup trucks designed for serious off-road use.
Unlike conventional gasoline engines that can suffer major problems during deep-water crossings, the B20 uses a fully sealed structure, waterproof electrical components and dedicated engine-to-transmission sealing. The result is a combustion engine engineered specifically for extreme terrain, including deep-water wading and sustained high-load operation.
A Waterproof Engine for Hybrid SUVs and Trucks
The HORSE B20 is a four-cylinder, 2.0-liter turbocharged gasoline engine developed for hybrid electric vehicles (HEVs), plug-in hybrids (PHEVs) and range-extended electric vehicles (REEVs).
Depending on the configuration, it produces between 140 and 185 kW (188-248 hp) and delivers 300-380 Nm (221-280 lb-ft) of torque. At just 130 kg (287 lbs), the engine is also relatively lightweight for its capabilities.
Its most unusual feature is the IPX8 waterproof rating. When the engine detects that it has entered deep water, its control system can automatically adjust throttle response or limit power based on sensor feedback. This allows the powertrain to maintain stable operation while submerged rather than simply relying on conventional engine protection systems.
The engine uses IPX8-rated electrical components and sensors, along with a sealed waterproof architecture and dedicated torsional vibration dampers. These measures are intended to protect critical components during demanding water crossings.
Designed to Climb a 100% Grade
Waterproofing isn’t the only extreme capability of the B20. Horse Powertrain says the engine can maintain continuous, stable power output while tackling a 100% grade.
A 100% grade represents a 45-degree incline, equivalent to climbing one meter vertically for every meter traveled horizontally. Such terrain is beyond the capability of most ordinary SUVs and is generally reserved for highly capable off-road vehicles.
The B20 is designed to maintain its performance during prolonged high-load situations, including continuous steep climbs and extended operation in high temperatures.
An active dual-cooling system helps keep the engine within its optimal operating temperature range during these conditions. The system is designed to manage heat during sustained climbing and other scenarios where the powertrain is subjected to extreme loads for extended periods.
48.4% Thermal Efficiency
Despite being developed for extreme off-road applications, the B20 also focuses heavily on fuel efficiency.
The engine uses an advanced Miller cycle, direct fuel injection and high-tumble intake ports to improve the combustion process. Horse Powertrain claims a brake thermal efficiency of 48.4%, an impressive figure for a gasoline combustion engine.
Specially designed pistons make greater use of the “squish” effect near the top of the compression stroke, helping improve air-fuel mixing and create a faster, cleaner combustion event. High-pressure fuel injectors and optimized intake ports further contribute to combustion efficiency.
The engine also incorporates a gantry-style aluminum block with an integrated exhaust manifold, a simplified balance-shaft system and a variable-displacement oil pump. Together, these technologies are designed to improve efficiency, durability, noise and vibration performance.
The result is an engine that combines the high-load capability required for extreme off-roading with efficiency more commonly associated with modern electrified powertrains.
Already Tested in a Production Vehicle
The HORSE B20 isn’t simply a technology demonstrator. The engine was first showcased at the Beijing Auto Show 2026 and has already been used in a plug-in hybrid vehicle.
The Chinese-market Geely Galaxy Cruiser 700 uses the B20 as part of its PHEV powertrain, paired with Horse Powertrain’s 3DHT230 three-speed intelligent hybrid transmission.
That application provides an early look at how the waterproof engine could be integrated into future hybrid off-road vehicles. Rather than replacing electric motors, the B20 is designed to work as part of an electrified powertrain, giving automakers another option for combining electric propulsion with a highly capable combustion engine.
Could Waterproof Hybrid Powertrains Become More Common?
The B20 highlights a potentially important direction for off-road electrification. Electric vehicles already offer strong low-speed torque and sophisticated traction control, but extreme water crossings and prolonged high-load operation present unique engineering challenges.
Horse Powertrain’s approach combines electric propulsion with a combustion engine specifically designed to survive conditions that conventional powertrains may struggle with. Its support for HEV, PHEV and REEV architectures also gives automakers flexibility across different vehicle platforms.
For extreme off-road SUVs and pickups, that could make hybrid powertrains more attractive without sacrificing deep-water capability or sustained climbing performance.
The B20 demonstrates that electrification does not necessarily mean giving up traditional off-road capability. Instead, a carefully engineered hybrid system could combine electric torque, combustion-engine range and the ability to tackle some remarkably hostile terrain.
As hybrid and range-extender technology continues to evolve, engines such as the HORSE B20 could help push electrified vehicles further beyond paved roads.
