By R. Bruce Striegler

The website of a newly established British company, Carnot Engines, says, “The off-grid energy and long-haul transport sectors, unregulated until the last decade, must become net-zero by 2050. Battery technology is unsuitable due to cost and weight. Hydrogen technology is considered the only viable solution to decarbonizing these sectors. Carnot power units will have greater efficiency, lower total cost of ownership and greater range, reliability and durability than fuel cells. They are the key to unlocking a hydrogen future while minimizing the impact to supply chains.” The website goes on to say, “We aim to reduce global CO2 Emissions by 13 per cent to accelerate the world’s transition to net-zero and bring clean, secure and affordable energy to all.”

Co-founded in 2019 by three young British entrepreneurs, Archie Watts-Farmer, Francis Lempp and Nadiur Rahman, Carnot Engines is developing game-changing power units with twice the efficiency, half the fuel consumption and zero CO2 emissions. For 130 years, internal combustion (IC) engines have wasted a third of fuel energy to cooling systems, which Carnot is eliminating by revolutionizing IC engine design. IC engine cooling systems prevent metal components from melting, reducing fuel efficiency to only 35 per cent. Carnot power units are designed with key components manufactured from ceramics which can withstand these high temperatures, eliminating the need for a cooling system. With fuel efficiencies of 70 percent, Carnot power units promise to offer a unique solution to unlocking a net zero hydrogen future for large/long-haul applications.

The basic IC engine was developed by French engineer Nicolas Léonard Sadi Carnot in 1824, during his research into designing a better steam engine. In thermodynamics and engineering, a heat engine is a system that converts heat or thermal energy to mechanical energy, which can then be used to do mechanical work. During the 1980’s there was a huge push to manufacture engine components out of ceramic materials, namely alumina and silicon nitride. Ceramics can operate at extremely high temperatures, which increases engine performance, decreases fuel consumption, and enables multi-fuel capability. Ford and Isuzu pioneered ceramics development applications. However, prototypes were unstable, and the projects were abandoned.

“Re-thinking, re-designing and revolutionizing the engine”

Enter Carnot Engines Ltd. Just like the fuel injectors and turbochargers, ceramics are already used widely in the aviation industry on aircraft turbines.

Francis Lempp, 24, obtained his MSc in Particle Physics from Royal Holloway University of London in 2018 and then pursued ceramic engine design. Since then, the young physicist has played a large role in delivering two government funded Innovate UK research projects on ceramic engine technology and co-founded Carnot. “I began to find the quantum realm a little too abstract. I wanted to put my skills to use and get involved in a project that had a more tangible impact. This is when I found ceramic engine research. My knowledge of physics was very transferable, and I began my career in engineering as a mathematical modeller. I still remain very close to my physics background, modelling the equations of gas flow and heat transfer in the Carnot engine.”

When asked what motivated him to start Carnot Engines, he replied, “I felt as though we could really make a difference. There is a huge ongoing transition to net-zero, but people’s expectations are slipping away from reality. As a result, many industries which play a significant role in global warming are being left in the dark ages. These industries can’t relate to the battery craze or rely on fuel cells for the near or distant future. These are expensive solutions and require rare metals. Who will pay for the infrastructure? Where will these metals come from? There is no silver bullet solution.” He goes on, saying, “Many people assume that this kind of technology comes out of a huge engineering firm. In fact, such firms are often too large to make significantly creative innovations. They play it safe. Smaller companies like us have a much more creative approach. We blend the perfect balance of experience and innovation, mixing industry experts with young creative thinkers and stripping down the pre-conceptions of how an engine must operate. We are re-thinking, re-designing and revolutionizing the engine, bringing it into the 21st century.”

Archie Watts-Farmer, Carnot’s CEO, spent 10 years as lead engineer / project manager on various Rolls-Royce engine programs including the Joint Strike Fighter LiftFan, the Harrier Pegasus engine, the A350 Trent XWB and also qualifying as a chartered engineer. Nadiur Rahman leads the physical modelling and design at Carnot. With a MEng in Mechanical Engineering from Queen Mary University of London, Nadiur’s previous experiences include using advanced engineering techniques to model complex gas flows, kinematics and create computer aided designs. Nadiur has a wide knowledge of modelling structural design concepts in uncooled ceramic engines, and has delivered two government funded Innovate UK projects.

Is the Carnot Engine the end of the IC engine?

In 2017, Volvo announced it would stop designing IC engines by 2019 and shortly after, the UK government said that all new cars must be zero-emission by 2040. This prompted The Economist to run an article-cum-obituary about the IC engine proclaiming “the end is in sight for the machine that changed the world”. A number of other automakers have since announced their intention to phase out the IC engine. So are we really witnessing the end of the internal combustion engine’s 130-year reign?

Passenger cars represent just over 40 per cent of the global IC engine market but 45 per cent of transport greenhouse gas emissions (GHG) in the European Union. The rest is made up of mini-vans, commercial vehicles, marine propulsion, generator sets, agricultural, industrial, construction machinery and locomotives. With the introduction of lithium-ion battery packs in cars, pioneered by Tesla founders Eberhard and Tarpenning, the performance of electric cars has been revolutionized due to the battery’s vastly superior energy density to that of the previous incumbent, the lead-acid battery. With its 100-kWh battery, a Tesla Model S can achieve a range of 370 miles.

The young engineers point out that it seems we are reaching the limit of Li-ion battery technology energy density (thought to be ~300 kWh/kg). Next-generation battery technology is needed to achieve the leap required to bring competitive payloads. Li-air currently looks the most promising but is still in early-stage research and development. Based on the Li-ion development cycle (first used commercially by Sony in 1991), scaling up to mass production of Li-air batteries is many years away.

The viability of electrification is less compelling for larger transport applications, particularly long-haul. State-of-the-art Class 8 heavy duty trucks have a range of 900 miles, and can carry payloads of 23.5 tonnes. The maximum laden weight of the vehicle is limited by law, so the heavier the vehicle’s powertrain, chassis and frame, the less payload it can carry. With the weight of a battery pack required to achieve a 900-mile range of 26.6 tonnes, the payload of an all-electric class 8 heavy duty truck would be reduced to 1.4 tonnes, which is clearly not economic. The weight and cost of batteries would have to fall by an order of magnitude for the total cost of ownership of a battery-electric class 8 truck to compete with current diesel-powered units. Another serious problem would be the inability of electricity grids to deliver the power needed to charge batteries once commercial trucks operating on battery electric power become part of the transportation network. Extrapolating to even larger applications such as long-haul marine, it is clearly evident that battery-electric solutions cannot form plausible parts of future roadmaps in these sectors.

Potential problems for mass adoption of electric vehicles

For a highly developed small country such as Norway, it is entirely feasible that the grid reinforcement and charging infrastructure could be rolled out to support mass-adoption of Electric Vehicles (EVs). However, providing a charging network for the 420 million who live in rural areas in Sub-Saharan Africa without access to electricity is an entirely different proposition. Simply providing access to electricity in these regions is an impossible task as they are too remote and the communities too dispersed to be electrified through grid extension. Government initiatives are therefore focused on rolling out mini-grids. Security of supply, affordability and clean energy are the “energy trilemma” pillars required in any energy solution.

This raises the question of whether mass adoption of EVs is the optimum route to reducing transport CO2 emissions. An independent review carried out by Ricardo plc , a global engineering, environmental and strategic consultancy, (“Impact Analysis of Mass EV Adoption and Low Carbon Intensity Fuels Scenarios –Summary Report”) compared two scenarios for the European Union passenger car market in terms of achieving GHG emissions reductions — a mass electric vehicle adoption scenario versus a low-carbon fuel scenario. In the latter, a 45 percent EV market penetration was assumed with the remaining GHG emissions reductions achieved through the use of biofuel and eFuels. The analysis found both scenarios achieved an 85 percent reduction in total life cycle GHG emissions to 2050.

So there is apparently no silver bullet to transitioning to a sustainable future.  A diverse array of technological solutions is required, in which both electrification and improving engines’ sustainability must play crucial roles. IC engines must be made more sustainable through improved efficiency and the use of low-carbon or zero-carbon fuels.

The Carnot team believes that after 130 years of incremental gains, it’s time to revolutionize the IC engine, which is notoriously inefficient and produces unsustainable volumes of CO2. With key components manufactured from advanced ceramics able to withstand combustion temperatures, Carnot intends to halve fuel consumption and CO2 emissions.

How Carnot technology can change the future

While electric vehicles are increasing their market share around the world, there are still a variety of problems associated with their adoption, one of which is how and where the electricity is generated in the first place. Electric vehicles are simply shifting the problem from cities to non-urban areas, while increasing the strain on the grid. Another issue is the large amount of capital investment required to build the infrastructure needed to support the switch to electric.

The electric power technologies being developed today will provide economically viable and environmentally sustainable alternatives to conventional IC engine power. However, both battery power and fuel cell power units have weaknesses that will limit their rates of adoption. Carnot is one of a few companies worldwide that are in the process of developing sustainable solutions for applications which have no practical current alternatives. If its solutions based on ceramic internal combustion engines allow limitations in electric power technology to be bridged for the benefit of all, that would be a great contribution to mankind.