Understanding how a hydrogen engine works

August 9, 2024
hydrogen engine

What happens under the bonnet of a hydrogen vehicle? Although many people use the term “hydrogen engine”, in reality, hydrogen vehicles use electric engines powered by hydrogen. Hydrogen trucks, cars, tractors and so on are indeed electric vehicles or more precisely Fuel Cell Electric Vehicles (FCEV).

However, unlike the “conventional” electric vehicle (which should really be referred to as a battery electric vehicle or BEV) – whose electricity is stored in the battery during charging – the “hydrogen electric vehicle” generates its own electricity using a hydrogen fuel cell.

To use a hydrogen vehicle, the user must fill the hydrogen tank rather than recharging the battery.

There are two types of hydrogen engine technology:

  • The FCEV: an electric vehicle with an electric engine powered by a fuel cell – most hydrogen vehicles available today use this technology,
  • The ICE: A vehicle with a hydrogen internal combustion engine. This technology, which is not yet on the market, is in the R&D phase and interests manufacturers such as Toyota, Porche, and MAN. This type of engine would keep much of the current engine’s operating system the same and would require minimum adjustments to vehicles.

What defines the power of a hydrogen engine?

FCEVs have several design parameters that define a vehicle’s power:

  • Battery capacity (in kWh)
  • Fuel cell power (in kW)
  • Hydrogen storage capacity (in kg)
  • Overall engine power in (kW)

Depending on the vehicle’s purpose, manufacturers design various configurations of these four elements.

Gas or liquid hydrogen?

These are the two means of storing hydrogen and each has its advantages and disadvantages, depending on the vehicle’s purpose. Liquid hydrogen allows you to store four times more hydrogen but liquefying hydrogen results in a lower energy yield due to the additional liquefaction operation. What’s more, once it is in the car, it must be used very quickly before it turns back into gas and expands. This means it must be used or evacuated ... and lost!

How exactly does a fuel cell work?

There are several types of fuel cells, which convert fuel into energy. The most common is the hydrogen fuel cell, which converts hydrogen (the fuel) into electricity (the energy), through the electrochemical reaction of hydrogen and oxygen.

This process, which occurs instantaneously, powers the electric engine while releasing only water.

Technically, the fuel cell uses a “redox” reaction to produce electricity. It comprises two electrodes: an oxidising anode (emitting electrons) and a reducing cathode (collecting electrons), separated by an electrolyte, which directly conducts the ions from one electrode to the other and blocks the electrons, forcing them to pass through the external circuit of the battery.

The tank continuously supplies the anode with hydrogen, while the cathode receives oxygen (from the air).

The anode causes the fuel to oxidise and release electrons, which are forced by the ion-charged electrolyte (which separates the two electrodes) to pass through an external circuit. This external circuit therefore provides a continuous electric current which powers the engine.

Once reunited in the cathode, the ions and electrons recombine with oxygen. This combination causes reduction, which – in addition to the electric current – generates heat and pure water vapour, which escapes in the form of gas through a small tube placed under the vehicle, either while driving or by pressing a button at the end of the trip.

  • The tank continuously supplies the anode with hydrogen, while the cathode receives oxygen (from the air).
  • The anode causes the fuel to oxidise and release electrons, which are forced by the ion-charged electrolyte (which separates the two electrodes) to pass through an external circuit. This external circuit therefore provides a continuous electric current which powers the engine.
  • Once reunited in the cathode, the ions and electrons recombine with oxygen. This combination causes reduction, which – in addition to the electric current – generates heat and pure water vapour, which escapes in the form of gas through a small tube placed under the vehicle, either while driving or by pressing a button at the end of the trip.

Running a hydrogen engine therefore emits only pure water and is completely clean, provided that a completely clean hydrogen fuel is used.


A guide to understanding hydrogen-powered technology
A guide to understanding hydrogen-powered technology

As global concerns about climate change and environmental pollution grow, the search for sustainable and eco-friendly energy sources has intensified. One such alternative is the hydrogen engine, which uses hydrogen as a clean fuel source for generating power. This article delves into the concept of hydrogen engines, their types, advantages, challenges, and applications.

Types of Hydrogen Engines

There are two primary types of hydrogen engines: hydrogen internal combustion engines (HICE) and hydrogen fuel cell engines. Each type has its unique characteristics and applications.

Hydrogen Internal Combustion Engines (HICE)

Hydrogen internal combustion engines operate similarly to traditional gasoline or diesel engines. However, instead of using fossil fuels, they combust hydrogen to generate power. These engines can be adapted from existing internal combustion engines, making them an attractive option for transitioning to a cleaner energy source.

Hydrogen Fuel Cell Engines

Hydrogen fuel cell engines use fuel cells to convert hydrogen and oxygen into electricity, which then powers an electric motor. Unlike HICE, fuel cell engines do not involve combustion, making them more efficient and environmentally friendly.

How Hydrogen Engines Work

The functioning of hydrogen engines varies depending on the type of engine being used.

Hydrogen Combustion Process

In a hydrogen internal combustion engine, hydrogen is mixed with air and compressed in the engine's cylinders. A spark plug then ignites the mixture, causing a controlled explosion that generates mechanical power. This power is used to drive the engine's pistons and ultimately power the vehicle or device.

Hydrogen Fuel Cells Process

In a hydrogen fuel cell engine, hydrogen and oxygen are introduced into the fuel cell, where an electrochemical reaction occurs. This reaction produces electricity, water, and heat. The generated electricity powers the electric motor, while the water and heat are expelled as harmless byproducts.

Advantages of Hydrogen Engines

Hydrogen engines offer several benefits over conventional internal combustion engines, including:

  1. Reduced greenhouse gas emissions: Since hydrogen engines produce water and heat as their primary byproducts, they contribute far fewer greenhouse gas emissions than fossil fuel-based engines.
  2. Improved energy efficiency: Hydrogen engines, particularly fuel cell engines, have higher energy conversion efficiencies than internal combustion engines, resulting in better overall performance and lower fuel consumption.
  3. Renewable fuel source: Hydrogen can be produced from various renewable sources, such as water electrolysis, making it a sustainable energy option.

Challenges and Limitations

Despite their advantages, hydrogen engines face some challenges and limitations, including:

  1. High costs: Developing and producing hydrogen engines can be expensive, particularly for fuel cell engines, which require costly materials like platinum as catalysts.
  2. Limited infrastructure: Hydrogen refueling stations are scarce compared to gasoline stations, making widespread adoption of hydrogen engines more challenging.
  3. Storage and transportation: Hydrogen storage and transportation present significant obstacles due to its low energy density and the need for high-pressure containers or cryogenic storage.

Applications of Hydrogen Engines

Hydrogen engines are being implemented across various sectors, including:

Transportation

Automakers are increasingly exploring hydrogen engines for vehicles, such as passenger cars, buses, and trucks. Companies like Toyota, Hyundai, and Honda have introduced hydrogen-powered vehicles, while others continue to develop new models.

Stationary Power Generation

Hydrogen engines can also be used for stationary power generation, providing backup power to buildings or remote locations. They offer a clean, reliable, and efficient energy solution, particularly in areas with limited access to grid electricity.

Aerospace and Aviation

The aerospace and aviation industries are researching hydrogen engines as an alternative to conventional jet engines. Several companies are developing hydrogen-powered aircraft, aiming to reduce emissions and increase efficiency in air travel.

Future Prospects and Developments

The demand for clean and sustainable energy sources is expected to grow, and hydrogen engines will likely play a significant role. Ongoing research and development efforts aim to improve the efficiency, affordability, and infrastructure of hydrogen engines, making them more accessible and widespread.

Conclusion

Hydrogen engines offer a promising alternative to traditional internal combustion engines, with the potential to significantly reduce greenhouse gas emissions and reliance on fossil fuels. While challenges remain, continued advancements in hydrogen engine technology and infrastructure could pave the way for a more sustainable and eco-friendly future.

Read article
Advantages and Disadvantages of hydrogen cars
Advantages and Disadvantages of hydrogen cars

In the quest to combat climate change and reduce carbon footprints, hydrogen cars have emerged as a compelling solution. The allure of zero-emissions driving, coupled with exciting technological advancements, makes hydrogen cars a viable contender in the evolving automotive landscape. This comprehensive guide explores the key advantages and disadvantages of these innovative vehicles.

Hydrogen Cars: The Future of Sustainable Driving?

Hydrogen cars are powered by fuel cells, which use  hydrogen to generate electricity that powers the vehicle. The only by-product of this process is water, making these cars an eco-friendly alternative to conventional gasoline or diesel vehicles.

Hydrogen Cars Advantages

Emission-Free Operation

Undoubtedly, the most significant advantage of hydrogen cars is their zero-emission status when running. Unlike traditional vehicles that emit harmful pollutants, hydrogen vehicles emit only water vapor, contributing to cleaner air. They need to use green hydrogen to ensure a fully positive footprint. Hydrogen cars are really efficient to reduce carbon footprint when they are used with a high intensity (such as taxi operation for example).

Rapid Refuelling

Another significant advantage of hydrogen cars is their refuelling time. Unlike electric cars that need hours to charge, hydrogen cars can be refueled in just a few minutes, similar to conventional cars.

Excellent Range

When it comes to travel range, hydrogen cars are hard to beat. They can typically cover 300-400 miles on a single tank, making them an excellent option for long-distance travel.

Hydrogen Cars Disadvantages

Infrastructure Limitations

Despite their potential, hydrogen cars face significant infrastructure challenges. The number of hydrogen refuelling stations is currently limited, particularly compared to gasoline stations or electric charging points.

Production and Storage Challenges

Hydrogen production and storage present challenges. Although hydrogen is abundant, producing it in a usable form requires energy, potentially negating some of its environmental benefits. Similarly, storing hydrogen requires special considerations due to its low density and high flammability.

High Costs

The cost of hydrogen cars and hydrogen fuel is currently high, partly due to limited demand and partly due to the complex technology involved. However, costs are expected to decrease as technology improves and adoption increases.

Comparing Hydrogen Cars to Other Green Vehicles

Comparing hydrogen cars to other green vehicles like electric cars is essential to understand where they stand in the broader context of sustainable transportation. While both options offer emission-free driving, each has its pros and cons.

The Role of Renewable Hydrogen in Advancing Hydrogen Cars

Renewable hydrogen can significantly enhance the eco-credentials of hydrogen cars. By producing hydrogen using renewable energy sources, the entire life cycle of hydrogen fuel can be made sustainable.

The Future of Hydrogen Cars

Despite current challenges, the future of hydrogen cars looks promising. With the ongoing commitment to developing renewable hydrogen and enhancing fuel cell technology, hydrogen cars may soon become a common sight on our roads.

Read article
Hydrogen Cars vs Electric Cars: Which is the Better Choice?
Hydrogen Cars vs Electric Cars: Which is the Better Choice?

As the world moves towards greener, more sustainable transportation options, hydrogen cars and electric cars have emerged as viable alternatives to traditional gasoline-powered vehicles. This article will delve into the workings of both hydrogen and electric cars, discussing their advantages and disadvantages, and exploring their potential impact on the environment and the future of transportation.

How Hydrogen Cars Work

Hydrogen cars are powered by hydrogen fuel cells, which generate electricity through an electrochemical reaction between hydrogen and oxygen. The electricity produced is used to power an electric motor, which drives the car. The only byproduct of this process is water, making hydrogen cars a zero-emission vehicle.

How Electric Cars Work

Electric cars are powered by rechargeable batteries that store electricity. These batteries provide power to an electric motor, which drives the car. Electric cars produce no tailpipe emissions, making them an environmentally friendly option.

Advantages of Hydrogen Cars

  1. Zero tailpipe emissions
  2. Fast refueling times
  3. Longer driving range compared to electric cars
  4. Lighter weight due to smaller battery packs

Advantages of Electric Cars

  1. Zero tailpipe emissions
  2. Lower operating costs due to fewer moving parts and lower energy costs
  3. Quieter operation
  4. Widespread charging infrastructure

Disadvantages of Hydrogen Cars

  1. Limited refueling infrastructure
  2. Higher vehicle costs due to expensive fuel cell technology
  3. Limited vehicle availability

Disadvantages of Electric Cars

  1. Longer charging times
  2. Limited driving range compared to hydrogen cars
  3. Heavy batteries can affect vehicle performance

Environmental Impact

Both hydrogen and electric cars offer significant environmental benefits compared to traditional gasoline-powered vehicles. While electric cars have a smaller carbon footprint due to their reliance on electricity, hydrogen cars also contribute to a cleaner environment by producing only water as a byproduct.

Charging and Refueling Infrastructure

While electric vehicle charging stations have become more prevalent, hydrogen refueling infrastructure remains limited. This could change in the future as more investments are made in hydrogen technology and infrastructure.

Range and Performance

Hydrogen cars generally offer a longer driving range than electric cars, making them a more suitable option for long-distance travel. However, electric cars provide better acceleration and torque, leading to a more responsive driving experience.

Car Availability and Pricing

As of now, electric cars are more widely available and affordable than hydrogen cars. This is due to the higher production costs associated with hydrogen fuel cell technology. However, as technology advances and economies of scale are achieved, hydrogen car prices could decrease.

Government Incentives and Regulations

Governments worldwide are increasingly offering incentives and implementing regulations to encourage the adoption of hydrogen and electric cars. These incentives can include tax breaks, rebates, and other financial benefits, making the transition to cleaner transportation more accessible.

The Future of Hydrogen and Electric Cars

Both hydrogen and electric cars will play an essential role in the future of transportation as the world moves towards more sustainable options. While electric cars currently have the edge in terms of availability and infrastructure, hydrogen cars have the potential to become a more prominent player in the market as technology advances and infrastructure expands.

Conclusion

Hydrogen cars and electric cars both offer viable alternatives to traditional gasoline-powered vehicles in the pursuit of more sustainable transportation. While electric cars currently enjoy greater availability, lower costs, and more established charging infrastructure, hydrogen cars have the advantage of longer driving ranges and faster refueling times. As technology progresses and infrastructure develops, the competition between hydrogen and electric cars will continue to evolve, ultimately benefiting consumers and the environment alike.

View all hydrogen cars on Lhyfe Heroes

Read article
Back to all hydrogen insights