Can hydrogen save the internal combustion engine?

As the automotive sector transitions to an electrified future, the phasing out of the internal combustion engine (ICE) seems set. Recent developments with hydrogen, however, indicate that ICE may have a longer lifespan than originally thought.


The use of hydrogen ICEs is largely motivated by the absence of CO2 as a by-product of combustion. The idea was born, however, in 1806 with the demonstration of a Rivaz engine powering an automobile and operating with a mixture of hydrogen and oxygen.

The relative technological maturity of the internal combustion engine is also seen as an advantage for hydrogen ICEs as a clean technology solution. In particular, adapting an existing engine technology may have fewer technical (and/or less difficult) hurdles to overcome than developing an entirely new engine technology and its supporting infrastructure.

In addition to its green credentials, modern interest in hydrogen ICE stems from differing views as to which technology can decarbonize the automotive and transportation sectors, as well as the recognition that a single technology may not to be able to meet all the demands of the sector.


Although hydrogen is a cleaner fuel than diesel, for example, hydrogen-powered ICEs are not free of pollutants. The combustion of hydrogen with air produces nitrogen oxides (NOx) whose emissions are widely regulated.

In light of this, Ford was recently granted US patent no. US11248542B2 (US ‘542), the description of which generally relates to a hydrogen combustion engine which can operate efficiently with low emissions of nitrogen oxides in its environment.

By way of background, US ‘542 teaches that the combustion air ratio λ corresponds to the engine load, so that a change in the engine load can result in an alteration in the quality of the mixture. air-fuel.

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To overcome this problem, US ‘542 teaches a method of operating a hydrogen combustion engine with a first combustion air ratio with λA≤1 under conditions of higher torque demand, by operating the hydrogen combustion engine with a second combustion air ratio with a λB≥ 2 during low torque demand conditions, and switching from the second combustion air ratio to the first combustion air ratio in response to an increase in torque demand. The switching step includes advancing an intake valve opening to increase exhaust gas recirculation (EGR) flow to the combustion chamber when a fuel injection amount is increased.

In this way, higher NOx output conditions can be avoided – recirculated exhaust gases among others moves oxygen into the combustion chamber – and overall NOx production is reduced.

US ‘542 engineering input can also provide desired torque with reduced noise, vibration and harshness:

“The technical effect of adjusting valve operation is to increase EGR flow as the engine transitions from lean to rich operation is to change a NOX formation point to lower lambda values ​​closer to operation rich so that the switch decreases or avoids NOX formation.At the transition point from the second to the first operating state, the EGR is increased to dilute the load so that the engine delivers the same torque as at the lean lambda operating point. By doing this, the valve train can transition from the first operating state to the second operating state or vice versa smoothly.


Besides Ford, a group of Japanese companies – Denso, Kawasaki Heavy Industries, Subaru, Toyota, Mazda and Yamaha – are working to expand fuel options for ICEs. The goals of this group include exploring the use of hydrogen engines in two-wheeled and other vehicles (eg, land or sea) and pursuing racing using hydrogen engines.

Such initiatives highlight the potential limitations (at least in the short term) of electric vehicles, for example those powered by batteries or fuel cells.

For example, batteries can experience charging and reliability issues when heavy equipment is used in remote, often harsh locations. The added weight of a battery array on a vehicle can also reduce vehicle performance.


Although we have focused on hydrogen ICEs so far, a November 2021 UKIPO study found a substantial increase in global hydrogen patenting activity between 2001 and 2018, with Toyota being the most prolific applicant. As such, internal combustion engines – fueled by hydrogen – might be here to stay.

The opportunity for the UK to make its mark on the global hydrogen stage was recently pleaded for by Ian Constance, CEO of the Advanced Propulsion Center (APC) [1]. Although against the UK’s leadership in battery cell research in the 1980s and 1990s, the following observation is relevant to this article:

“[Most] Vehicles made in the UK are SUVs and 4x4s or utility vehicles, off-road vehicles, light utility vans and premium brands – all types of vehicles where the power, utility, Range and off-road capabilities are significant and could benefit from a hydrogen powertrain. “,

Ian Constance adds:

“But heavy-duty applications – public transport, sea, rail and air – will need a different solution. Hydrogen will play a role, the UK could have a key role – and that means jobs and economic growth.

In our view, another element of hydrogen leadership is innovation.

To give hydrogen innovators the best chance of securing a leadership position, a strong intellectual property rights portfolio is likely vital. These rights can not only help to provide competitive advantage over competitors through their enforcement, but also help to attract new investment, through which the leadership position can be maintained.

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