Horse Powertrain has developed an unusual new gasoline engine designed for hybrid vehicles that may have to deal with one of the biggest challenges in serious off-road driving: deep water. The new Horse B20 is a 2.0-liter four-cylinder engine with an IPX8 water-resistance rating, allowing it to continue operating when the vehicle is submerged in water up to 1.1 meters deep.
While electric motors and water are generally a problematic combination, conventional internal combustion engines are not immune to the dangers of deep-water crossings either. Water entering an engine’s intake, electrical components or drivetrain can quickly turn an ambitious off-road adventure into an expensive recovery operation. Horse Powertrain believes the B20 could offer hybrid SUVs a significant advantage in exactly those conditions.
Horse B20 Was Designed Specifically for Hybrid Vehicles
Unlike many gasoline engines that are adapted for electrified applications, the B20 was developed specifically for hybrid powertrains. Horse says the engine is suitable for hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs) and range-extending electric vehicles (EREVs).
Depending on its configuration, the 2.0-liter turbocharged four-cylinder gasoline engine produces between 190 and 252 horsepower, while torque output ranges from 300 to 380 Nm.
Despite its capabilities, the B20 weighs approximately 130 kilograms, giving manufacturers a relatively compact and lightweight combustion engine for electrified off-road applications.
But horsepower and torque are not the most interesting aspects of the B20.
Its most unusual feature is its ability to operate underwater.
IPX8 Water Resistance Makes the B20 Different
Horse Powertrain has engineered the B20 around an IPX8 water-resistance rating. According to the company, the engine can continue operating when submerged in water as deep as 1.1 meters.
That capability is particularly relevant to off-road hybrid SUVs, where river crossings, flooded trails and deep water can present serious challenges.
To achieve the required level of protection, Horse has sealed critical electrical components and sensors. The company has also developed a dedicated sealing solution between the engine and transmission, helping prevent water intrusion into areas that are essential to the powertrain’s operation.
The result is an internal combustion engine designed to tolerate conditions that would be extremely challenging for a conventional powertrain.
The Engine Can Adapt When It Detects Deep Water
The B20’s waterproof construction is only part of the system. Horse has also designed its engine-management software to respond when the engine detects that the vehicle is operating underwater.
The control system can automatically adjust throttle response or reduce engine power depending on the conditions.
That approach is intended to help maintain stable engine operation during a water crossing. Rather than simply relying on mechanical protection, the B20 combines sealed components with electronic controls designed to adapt the engine’s behavior.
For drivers tackling difficult terrain, that could make the difference between successfully crossing a flooded section of trail and being forced into an expensive recovery.
Horse B20 Is Built for Extreme Off-Road Gradients
The B20 isn’t designed exclusively to survive deep water. Horse also says the engine is capable of operating on a 100 percent grade.
A 100 percent grade means the vehicle gains one meter of elevation for every meter traveled horizontally. In geometric terms, that corresponds to an incline of approximately 45 degrees.
A 45-degree climb is an extreme challenge for any production vehicle and is normally associated with highly capable off-road SUVs and specialized terrain vehicles.
The B20’s ability to support this type of application highlights the fact that Horse is targeting demanding hybrid vehicles rather than conventional road-going passenger cars.
48.4 Percent Thermal Efficiency Could Be the B20’s Biggest Advantage
Water resistance may be the B20’s most unusual feature, but its efficiency figures are arguably even more significant for the broader hybrid market.
Horse claims the engine achieves a thermal efficiency of 48.4 percent.
For a gasoline internal combustion engine, that is an impressive figure. Conventional gasoline engines typically operate with thermal efficiencies substantially below this level, while some of the most efficient modern hybrid engines have pushed beyond 40 percent.
The B20 achieves its claimed efficiency using a Miller-cycle combustion strategy combined with direct fuel injection, specially designed pistons and intake ports engineered to generate strong swirl within the air-fuel mixture.
The objective is to extract as much useful energy as possible from every combustion cycle while reducing energy lost as heat.
For hybrid vehicles, high thermal efficiency is especially valuable because the gasoline engine can be operated closer to its most efficient operating range while electric motors handle additional power demands.
Dual Cooling Helps the Engine Survive High Loads
Extreme off-road driving can place enormous thermal demands on a powertrain.
Long climbs, low vehicle speeds and heavy loads can leave an engine working hard for extended periods, making effective cooling particularly important.
Horse has therefore equipped the B20 with an active dual-cooling system designed to regulate temperatures during sustained high-load operation.
The system is intended to maintain appropriate operating temperatures during demanding situations such as steep climbs and difficult terrain, complementing the engine’s water-resistant construction.
The Horse B20 Is Already Entering Production
Perhaps the most interesting part of the B20 story is that this is not simply a technology demonstrator or an engineering project that may take years to reach production.
Horse Powertrain first presented the B20 at the Beijing Auto Show, and the engine has already entered application in the Chinese market.
The Geely Galaxy Cruiser 700 is among the first vehicles to use the new engine. In that application, the B20 forms part of a plug-in hybrid powertrain and is paired with Horse’s three-speed hybrid transmission.
That gives the technology an immediate real-world application rather than leaving it as a concept designed only to demonstrate what might be possible in the future.
Horse Powertrain Is Targeting the Next Generation of Hybrid Powertrains
Horse Powertrain was established in 2024 through a partnership between Renault and Geely, with the company focusing on internal combustion engines and hybrid powertrain technology.
The B20 illustrates the direction in which the company sees the internal combustion engine evolving.
Rather than attempting to compete with electric motors purely on their own terms, the engine is designed to complement electric propulsion. High thermal efficiency can reduce fuel consumption, while its sealed construction gives hybrid vehicles additional capability in extreme environments.
For off-road vehicles, that combination could be particularly compelling.
A hybrid SUV equipped with a highly efficient gasoline engine, electric propulsion and a waterproof powertrain could potentially deliver strong low-speed electric performance while retaining the range and refueling convenience of an internal combustion engine.
What the Waterproof Engine Means for Off-Road Hybrids
Deep-water capability has traditionally been associated with rugged body-on-frame SUVs and specialized off-road vehicles. Hybridization introduces additional engineering challenges because electric motors, high-voltage components, sensors and control systems must all be protected against water intrusion.
Horse’s B20 addresses one important part of that equation by creating a combustion engine specifically designed to tolerate deep-water operation.
Its claimed 1.1-meter submerged operating capability, 48.4-percent thermal efficiency, 190-to-252-horsepower output and ability to handle a 100-percent grade make it an unusual combination of efficiency and extreme-terrain capability.
The B20 also demonstrates that the internal combustion engine still has room for significant development in the hybrid era.
Horse B20 Could Give Hybrid SUVs a New Off-Road Advantage
The Horse B20 is not revolutionary simply because it is a new 2.0-liter gasoline engine. Its significance comes from the combination of technologies packed into one powertrain.
It is designed specifically for hybrids, offers up to 252 horsepower and 380 Nm of torque, claims an impressive 48.4-percent thermal efficiency, incorporates active dual cooling and, most unusually, is engineered to continue operating when submerged in water up to 1.1 meters deep.
With the engine already finding its way into production vehicles such as the Geely Galaxy Cruiser 700, the B20 provides a glimpse at how combustion engines could remain relevant in increasingly electrified off-road vehicles.
For drivers who want the efficiency and instant response of hybrid propulsion without giving up serious off-road capability, a waterproof gasoline engine could prove to be a surprisingly important piece of the puzzle.
Source: Horse Powertrain