Japanese automaker Toyota recently announced plans to develop a hydrogen-powered version of its iconic Land Cruiser SUV that will use a traditional combustion engine. This unconventional powertrain design has raised some eyebrows, as most hydrogen vehicles use fuel cell technology rather than direct hydrogen combustion. However, Toyota believes there are some potential advantages to this approach.
The Hydrogen Combustion Engine
The hydrogen Land Cruiser will use an adapted 5.7-liter V8 gasoline engine that can burn hydrogen fuel directly. The hydrogen is combined with air in the engine cylinders and ignited by spark plugs, just like a gasoline engine. The only byproduct from the reaction is water vapor.
Toyota has been experimenting with hydrogen combustion engines for over 25 years. In 2015, the company unveiled a hydrogen-burning Corolla that used many of the same concepts. The primary benefit of burning hydrogen directly is that it allows the engine to retain the performance and drivability qualities of a traditional gasoline engine. There is no loss of power or engine response when switching fuels.
The engine does need some modifications to reliably burn hydrogen. The fuel system must be adapted for hydrogen’s different properties and the engine timing and compression ratio may need adjustment. But Toyota says the engine architecture itself does not require an entire redesign. This makes adapting existing engine designs for hydrogen more straightforward.
Potential Benefits Over Fuel Cell Vehicles
The more common approach in hydrogen vehicles today is to use a fuel cell and electric powertrain. The fuel cell combines hydrogen and oxygen to generate electricity which powers the vehicle’s electric motor. However, Toyota sees some distinct advantages to the combustion engine approach instead:
- Lower costs – hydrogen fuel cells are still very expensive compared to combustion engines
- Greater range – fuel cell vehicles may only achieve 300-400 km of range, while the hydrogen Land Cruiser is targeting over 650 km.
- Faster refueling – hydrogen tanks can be refilled much quicker than recharging batteries
- Better performance – hydrogen combustion can provide comparable torque and power to gasoline engines
- Easier adaptation – the engine still uses familiar transmission, drivetrain and vehicle components
- Lower weight – a combustion engine avoids the heavy battery pack needed for a fuel cell/battery electric powertrain
While fuel cell cars offer some efficiency and emissions benefits, Toyota believes sticking with combustion technology makes the most sense for larger, performance-oriented vehicles like the Land Cruiser. It allows them to retain the capabilities expected from these types of SUVs without sacrificing range or refueling times.
The Case for Hydrogen Over Electrification
Toyota’s hydrogen combustion plans align with the company’s broader strategy of investing heavily in hydrogen rather than full electrification. Toyota argues that batteries do not make sense for all vehicles and that hydrogen has some inherent advantages over electricity:
- Quick refueling is important for many drivers, especially in markets like Australia where long distances are common.
- Hydrogen can be produced from a variety of sources, including fossil fuels, biomass, or renewable energy. This gives it more flexibility than batteries tied to the electric grid.
- Combustion engines meet performance demands better than electric powertrains in larger vehicles.
- Hydrogen storage tanks take up less space than large battery packs.
- Hydrogen has a higher energy density than batteries, providing greater range from less fuel.
Toyota sees hydrogen playing a crucial role in decarbonization, especially for applications not well suited to battery electric vehicles. With falling costs and improving infrastructure, they believe hydrogen will become a viable zero-emission option for a wide range of vehicles.
Challenges Remain for Hydrogen Infrastructure
While Toyota is bullish on hydrogen’s potential, there are still major obstacles to overcome, especially regarding infrastructure. There are only around 500 hydrogen stations worldwide today, almost all located in Japan, California, and parts of Europe.
Toyota and other automakers are working to rapidly expand the hydrogen refueling network. But it will require massive investments from both private companies and governments. Critics argue this money would be better spent on faster chargers and electric infrastructure that can service both BEVs and fuel cell vehicles.
There are also challenges around producing low-cost green hydrogen from renewable energy rather than fossil fuel sources. Most hydrogen today comes from steam reforming natural gas, which negates some of the environmental benefits.
Toyota believes these infrastructure limitations can be solved if enough automakers get behind hydrogen vehicles. They point to the speed at which gas stations proliferated in the early 20th century once demand was proven. But other experts say hydrogen may never be economically competitive with electricity for most passenger vehicle uses.
Uncertain Demand for the Hydrogen Land Cruiser
Perhaps the biggest question is whether Toyota’s hydrogen Land Cruiser will resonate with buyers given the extra costs and lack of fueling infrastructure. The limited-volume Mirai sedan has seen sluggish sales so far, and SUVs like the Land Cruiser tend to be sensitive to higher pricing.
Toyota maintains that the off-road and towing capabilities enabled by hydrogen combustion will allow the Land Cruiser to fill a unique niche. But if infrastructure remains limited, it may only appeal to a tiny group of early adopters willing to plan trips around hydrogen stations.
The hydrogen Land Cruiser is still in early development and not expected until around 2025. So Toyota has time to evaluate demand and expand the refueling network. However, if major progress doesn’t occur over the next few years, the viability of a hydrogen-powered Land Cruiser will remain uncertain.
Toyota’s overall hydrogen strategy is also banking heavily on commercial vehicles and industries like trucking, shipping, and aerospace leading the way. Passenger vehicles may only represent a small portion of the demand. Other automakers are still split on whether hydrogen or batteries will power the majority of consumer cars and trucks long-term.
Toyota’s plan to develop a hydrogen-powered Land Cruiser with a combustion engine highlights the competing visions around alternative fuels. While many in the auto industry are all-in on battery electrics, Toyota believes hydrogen will play a vital role as well. With their extensive experience in hydrogen combustion research, Toyota sees an opportunity to leapfrog fuel cells and deliver a capable, zero-emission SUV that retains the benefits of traditional engines.
But successfully launching a hydrogen Land Cruiser still depends on solving major infrastructure limitations and building consumer demand. Toyota’s unconventional approach could pay off if they can make the economics work and expand the hydrogen station network in the next few years. If not, their hydrogen combustion strategy may fail to resonate beyond a tiny niche of enthusiasts. The path forward for hydrogen vehicles remains filled with uncertainty regardless of Toyota’s confidence in combustion technology.
What is the disadvantage of hydrogen combustion engine?
Some key disadvantages of using a hydrogen combustion engine compared to a fuel cell electric vehicle include:
- Lower efficiency – Fuel cells can convert hydrogen to electricity at higher efficiencies (50-60%) than a combustion engine (around 30%). This means more of the potential energy in hydrogen is wasted as heat in a combustion engine.
- NOx emissions – Burning hydrogen in an internal combustion engine still produces nitrous oxides (NOx) due to high temperatures in the engine. Fuel cell vehicles have no tailpipe emissions.
- Cost – Hydrogen combustion engines require spark plugs, fuel injectors, and exhaust systems that fuel cells do not need, adding cost and complexity.
- Onboard storage – Hydrogen takes up more space than batteries for a given amount of energy stored on board, reducing cargo/passenger capacity.
- Safety – Storing high-pressure hydrogen gas for a combustion engine introduces potential safety risks if tanks are damaged. Batteries don’t have the same risks.
- Fuel flexibility – Combustion engines lock you into hydrogen as the only fuel. Fuel cells can potentially use hydrogen derived from other sources like ammonia or methanol.
- Maintenance – Hydrogen combustion engines still require oil changes, engine tune-ups, and other maintenance that fuel cell EVs avoid.
So in summary, while hydrogen combustion can utilize existing engine designs, it is ultimately less efficient, still produces emissions, costs more, reduces cargo space, and lacks some of the flexibility of fuel cell vehicles. But Toyota believes the performance benefits outweigh these disadvantages for larger vehicles.
Why is Toyota pushing for hydrogen cars?
There are a few key reasons why Toyota is aggressively pursuing hydrogen fuel cell vehicles rather than solely focusing on battery-electric cars:
- Hedging their bets – Toyota doesn’t want to be left behind if hydrogen gains momentum. So they are investing in FCVs as a “Plan B” to batteries.
- Japanese government support – Japan has provided substantial subsidies and infrastructure investment for hydrogen fuels. This makes FCVs more viable in their home market.
- Refueling time – Hydrogen pumps can refuel cars much faster than recharging batteries. This better fits Toyota’s vision for a future with quicker refueling.
- Range – FCVs can achieve longer range than comparably sized battery-electric cars. Long range is still important in many non-urban markets.
- Resource limitations – Building millions of long-range BEVs strains supplies of rare earth metals for batteries. Hydrogen provides an alternative.
- Existing capabilities – Toyota has over 25 years experience developing hydrogen combustion engines. Leveraging this knowledge base is easier than starting from scratch with BEVs.
- Renewable potential – Hydrogen can be produced from renewable electricity via electrolysis. This provides a sustainable path as renewable electricity grows.
- Japan’s energy challenges – With few domestic fossil fuel resources, hydrogen allows Japan to rely more on renewable energy instead of imported oil/gas.
So in summary, Toyota sees hydrogen providing a strategic advantage and hedge compared to only focusing on battery-electrics. But it remains to be seen whether their significant investments in hydrogen will pay off in the long run.
How does Toyota’s hydrogen engine work?
Here’s a quick overview of how Toyota’s hydrogen combustion engine works:
- Fuel Storage – The hydrogen fuel is stored on the vehicle in high-pressure tanks at 70 MPa (10,000 psi). These tanks are usually made from carbon fiber for lightness and strength.
- Fuel Delivery – The pressurized hydrogen is regulated down to about 10 MPa (1,500 psi) and injected into the engine intake manifold. Special injectors are designed to handle gaseous hydrogen.
- Combustion – Inside the cylinders, the hydrogen mixes with air and is ignited by spark plugs, just like a gasoline engine. The combustion of hydrogen and oxygen produces water vapor as the exhaust.
- Engine Modifications – Compared to gasoline, hydrogen’s faster burning properties require some engine changes like lower compression ratios, retarded ignition timing, and hardened exhaust valves. The fuel system also needs to handle much higher pressures.
- Turbocharging – Most hydrogen engines are turbocharged to increase power density. The high octane rating of hydrogen allows for greater compression by the turbo without pre-ignition issues.
- Lubrication – Engine oil is still required for lubrication. But special low-friction coatings help reduce hydrogen leakage between moving surfaces.
So in essence, Toyota repurposes a traditional gasoline engine design but modifies it specifically for hydrogen’s unique properties and injection requirements. This allows them to achieve hydrogen combustion without a completely new engine architecture.
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