17 Mike Bassett | In conversation E-Mobility Engineering | May/June 2025 cycle fuel economy analysis into exploring the impact of the company’s engines on vehicle efficiency. This proved to be very valuable in 2010, when the company began research on EV range extenders and formed a hybrid product group. Bassett was placed in charge, and he and his team were tasked to develop a fully functioning C-segment passenger car as a demonstrator vehicle. “That was a career highlight for me,” he reflects. “It involved developing a range extender unit, putting it in a vehicle and developing the strategy for running it for the best efficiency, while also maintaining good noise, vibration and harshness (NVH) levels. I still look back on that project with fond memories. “We received a lot of interest from vehicle manufacturers who were considering range extenders. So, we developed the engine in 2010, created the vehicle in 2012 and for the next five years we were still getting regular inquiries about the possibility of buying that engine, but we struggled to turn that into a commercial reality. “Recently, though, we saw interest rekindled with a Chinese engine manufacturer, and we have literally just finished developing a high-efficiency range extender for them. I was surprised that it didn’t get more traction originally, so it’s good to finally see market pull for that. Sometimes, it just takes time for some of these things to come through.” The design that MAHLE Powertrain has developed for the Chinese market is a 60 kW, two-cylinder, turbocharged engine weighing around 80 kg, plus its generator. Very high efficiency is achieved through use of a high compression ratio, low-pressure exhaust gas recirculation and a prechamber-based combustion system. Bassett says with that amount of power, the electric car it is supporting can cruise at motorway speeds without depleting the battery, creating a seamless approach to hybridisation. “The vehicle characteristics are always the same whatever it is doing,” explains Bassett. “You are always driving with the electric motor and because the engine is totally decoupled from the wheels, that enables a more extreme approach to optimising engine efficiency. The extra range capability simply depends on the size of the fuel tank you put in the vehicle. “The engine achieves a brake thermal efficiency of around 40% with quite a low technology package designed to run on local fuels. So, in terms of CO2 intensity in grammes per kilowatt-hour, it is probably achieving something similar to the Chinese electricity grid. On that basis, it’s not an unreasonable approach, certainly for the time being.” Exploring innovation Bassett’s career progression at MAHLE Powertrain led him to become head of research in 2016, a post that he held for six years before moving into his current role as engineering director. During that period, he continued to lead on many innovative projects including traditional hybrids, fast-charging batteries and even fuel cells. One of the most interesting battery innovation projects was the application of a unique fast-charging lithium-carbon drivetrain and evaluated how best to use the electrical energy. The lessons he learned then still serve to this day, because the efficiency of the entire vehicle remains one of the many impactors on the performance and range of all hybrid and electric vehicles, and he explains: “Whole drive cycle analysis gives you an understanding of total vehicle efficiency and how any parasitic losses will really cost you over that cycle. “Of course, it also varies depending on use case. If you’re driving at high speed, the dominating factor is aerodynamic drag; at low speeds, auxiliary systems, the power of pumps, fans and air conditioning systems really make a big difference to the range. Understanding those different trade-offs is hugely relevant to EVs.” The move to MAHLE Powertrain When financial instability led to uncertainty over the future of his role at Lotus Engineering, Bassett made “a sideways move” to join MAHLE Powertrain, working on engine thermodynamic analysis for various customer projects. Shortly after his move to MAHLE Powertrain, the parent company (MAHLE) instigated a project to develop a Stirling engine for solar power generation. Sitting at the focal point of an 11 m mirror, it used a solar collector to generate 30 kW of power. The project made it to running hardware and was tested using a gas burner on one of MAHLE’s engine test cells before market forces brought it to an end. “Applying my thermodynamics knowledge to that engine was really quite interesting,” Bassett recalls. “We achieved 42% thermal efficiency, which as far as we know makes it one of the most efficient Stirling engines ever built – but at the time we were developing it, the price of photovoltaics dropped and it became financially less attractive.” During his first few years, he also began to instil his experience of fullMike Bassett
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