How Do Hydrogen Engines Work?

Reviewed by

Richard McCuistian, ASE Certified Master Automobile Technician

Technical Reviewer at CarParts.com

Written by CarParts.com Research Team - Updated on September 30th, 2024

Reading Time: 4 minutes
Summary
  • As its name suggests, a hydrogen engine is a type of engine that uses hydrogen as a clean fuel source. It produces zero carbon emissions, making it an eco-friendly alternative to traditional engines.
  • There are two types of hydrogen engines: hydrogen internal combustion engines (HICE) and hydrogen fuel cell engines.
  • Some of the advantages of hydrogen-powered cars are that they’re environmentally friendly, provide instant torque and power, and offer improved energy efficiency.

Over the years, the call for eco-friendly energy sources has only gotten louder. As people demand more sustainable options to combat climate change, automakers are looking for other solutions. One popular solution that shows a lot of promise is the switch from traditional internal combustion engines to hydrogen engines.

What Is a Hydrogen Engine?

As its name suggests, a hydrogen engine is a type of engine that uses hydrogen as a clean fuel source. It produces zero carbon emissions, making it an eco-friendly alternative to traditional engines. There are two types of hydrogen engines, hydrogen internal combustion engines (HICE) and hydrogen fuel cell engines.

How Does a Hydrogen Engine Work?

While both HICE and hydrogen fuel cell engines use hydrogen, they operate a little differently.

Hydrogen Internal Combustion Engines

In a HICE-powered vehicle, the combustion process is similar to a traditional internal combustion engine. Instead of fossil fuels, hydrogen is mixed with air and compressed in the cylinders, where a spark plug ignites the mixture. This explosion generates mechanical power that drives the engine’s pistons, powering the car.

Hydrogen Fuel Cell Engines

Unlike HICE, hydrogen fuel cell engines don’t need combustion to work. Instead, they use fuel cells that convert hydrogen and oxygen into electricity, water, and heat. The electricity powers the electric motor, while water and heat are expelled from the engine as harmless byproducts.

Hydrogen Engine of a Toyota Mirai. A hydrogen engine uses hydrogen as a clean fuel source, resulting in zero carbon emissions, and making it an eco-friendly alternative to traditional engines.

What Are the Advantages of Hydro-Powered Cars?

Upgrading to a HICE or switching to a fuel cell electric vehicle (FCEV) will take a lot of time and money, so it’s best to know for certain what you’re getting into. Consider the advantages of hydrogen-powered cars:

Environmentally Friendly

Unlike fossil fuel-based engines, hydrogen engines only produce water and heat as byproducts, making them an eco-friendly alternative to traditional engines.

Instant Torque and Smooth Power

Driving a hydrogen car feels similar to driving an electric vehicle. It offers smooth power and virtually silent acceleration, thanks to the electric motors providing you with full torque even at low speeds.to

Improved Energy Efficiency

Compared to traditional internal combustion engines, fuel cell engines have higher energy conversion. They consume less fuel while providing a better overall performance.

Fast Refueling

Charging an EV can sometimes take a long time. With a hydrogen-powered car, however, you don’t have to worry about any of that. Some hydrogen cars only take around three to four minutes to refill the hydrogen tank.

High Range

Similar to EVs, hydrogen vehicles have a high range with large battery storage. A single top-up of hydrogen can last around 310 miles. This range isn’t affected by the outside temperature, so you can expect the same range even if it’s winter. However, keep in mind that this can vary depending on your car’s year, make, and model.

Incentives

Hydrogen cars aren’t cheap, but most manufacturers offer leasing packages that can make up for the initial cost. Some leasing packages include complimentary fuel, service, and maintenance. In California, you might even be eligible for a $4,500 rebate, thanks to their Clean Vehicle Rebate Project.

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What Are the Disadvantages of Hydrogen Cars?

Despite their many advantages, hydrogen cars are still far from being mainstream. This is likely due to the challenges and limitations that come with producing hydrogen engines. Here are a few disadvantages of hydrogen cars:

High Costs

Hydrogen engines are pricey for a reason. Developing and producing hydrogen engines can be expensive, especially those that need platinum and other costly materials.

Limited Refueling Stations

Compared to gasoline stations, hydrogen refueling stations can be hard to come by. This can be a hassle, especially if you don’t live near one. You’ll have to schedule your refueling sessions to make sure you don’t run out of hydrogen before you can drive to the nearest station.

Hydrogen Storage and Transportation

Storing and transporting hydrogen is far from easy. Hydrogen is a gaseous substance that needs high-pressure containers or cryogenic storage to stay in good condition.

Hydrogen Engine vs. Diesel Engine vs. Natural Gas Engine

HICE might seem like a foreign concept, but they’re actually a lot more similar to diesel and natural gas engines than you’d expect.

Similarities

HICE and natural gas engines operate similarly, and this is because they have almost the same components, namely the engine block, crank, cylinder heads, and ignition system.

HICE and diesel engines aren’t too different either. They also have similar engine blocks, cranks, mounts, and flywheel housings.

Having similar engine components can make it easier to produce hydrogen engines and install them in more types of vehicles.

Differences

HICE uses direct injection systems that introduce hydrogen directly into the cylinders. Because hydrogen ignites much easier than gasoline, pre-ignition issues can occur if hydrogen is injected into the intake manifold or ports.

Unlike traditional combustion engines, hydrogen engines are also tuned to run lean. Hydrogen needs twice as much air as fuel does in order to produce less carbon emissions.

Can Hydrogen Engines Work in Medium and Heavy-Duty Trucks?

Yes, they can. Hydrogen engines look, sound, and work like internal combustion engines, so they’re more than capable of powering medium and heavy-duty trucks. Several fuel cell buses are already operating in different US states, thanks to the continued efforts of the US Department of Energy (DOE) and Department of Transportation (DOT) alongside nongovernment organizations.

Reviewed By Richard McCuistian, ASE Certified Master Automobile Technician

Technical Reviewer at CarParts.com

Richard McCuistian has worked for nearly 50 years in the automotive field as a professional technician, an instructor, and a freelance automotive writer for Motor Age, ACtion magazine, Power Stroke Registry, and others. Richard is ASE certified for more than 30 years in 10 categories, including L1 Advanced Engine Performance and Light Vehicle Diesel.

Written By CarParts.com Research Team

Automotive and Tech Writers

The CarParts.com Research Team is composed of experienced automotive and tech writers working with (ASE)-certified automobile technicians and automotive journalists to bring up-to-date, helpful information to car owners in the US. Guided by CarParts.com's thorough editorial process, our team strives to produce guides and resources DIYers and casual car owners can trust.

Any information provided on this Website is for informational purposes only and is not intended to replace consultation with a professional mechanic. The accuracy and timeliness of the information may change from the time of publication.

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Published by
CarParts.com Research Team and Richard McCuistian, ASE Certified Master Automobile Technician