Most cars are designed to handle water depths of around 100 mm to 200 mm. This means that when driving in heavy rain or passing through a deep puddle or shallow ford, the vehicle can continue operating without any issues. However, in some instances, more substantial water resistance is required, with some off-road vehicles designed to tolerate depths of more than 800 mm.
But how is this water resistance achieved, and what technologies go into an engine to allow it to cope with these water levels?
For a vehicle to travel through deep water, it needs to overcome several challenges. First and foremost is that if water enters the engine, it can cause it to stop working or even result in permanent damage.
An engine’s cylinders are the key areas to protect from water ingress. Since water is denser than air, water within an engine cylinder can stop the piston within the engine cylinder from completing its stroke, stopping the engine completely. This is called hydrolock – along with bringing the engine to a halt, it can cause serious damage from the extra mechanical strain to blocked pistons.
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Another risk water poses to an engine lies in electronics, since water can quickly cause irrevocable damage to fragile circuit boards or wider damage through short-circuits. As electronic systems play a key role in modern engines – such as the timing of ignition systems, coordination with the transmission, and integration with hybrid powertrains – a failure of these electronics can cause permanent damage to an engine.
In addition, water also can cause long-term damage to an engine through encouraging corrosion or rust – leading to reduced efficiency and greater risk of breakdowns. The same also extends to dilution or contamination of lubricant, increasing friction and regular wear-and-tear.
Waterproofing vehicles is essential for preventing damage that water may cause
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For a vehicle to be capable of entering a body of water, a number of adaptations must be made. The first is ensuring that the engine can receive sufficient air without taking in water. This is achieved by positioning the air intake higher up in the vehicle, or by attaching an external snorkel to provide a continuous air supply.
In most cases, the vehicle's exhaust does not need to be relocated, as the air pressure generated by the engine is enough to prevent water from entering. However, at greater depths, modifications may include a raised exhaust outlet or the addition of water traps and drain points.
Waterproofing the engine itself is a more significant challenge, as it is not a closed system. However, at Horse Powertrain, some of our latest innovations have enabled us to develop an engine that can tackle this challenge.
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Recently, we revealed our waterproofed HORSE B20 engine that can operate at depths of up to 1.1 meters of water. Key to waterproofing engines like the HORSE B20 is the use of a fully sealed structure that prevents any water ingress, including dedicated engine-transmission sealing. This ensures that water can’t enter the engine through its connection to the wider powertrain or vehicle.
In addition, the engine is fitted with IPX8-rated electrical components and sensors that continuously monitor its operating environment. This allows it to change its behavior when submerged and make more efficient use of available air by limiting the engine’s power or modifying its throttle response.
At Horse Powertrain, we are champions of the combustion engine, focusing our expertise and investment on ensuring the engines of the future meet the demands and standards of the next stage of global mobility. Innovations such as the HORSE B20 waterproof engine are just one example of the technologies we develop.
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