Goodbye ICE? Not so fast

Mark Twain’s infamous, flippant telegram – sent to multiple newspapers across the US following the erroneous publication of his obituary in 1897 – could just as easily reflect the status of today’s internal combustion engine.

“The reports of my death are greatly exaggerated.”  – Mark Twain

Written off by some as outdated dinosaurs in a world destined to be ruled by electric propulsion alone, internal combustion engines have evolved significantly in response to increasingly stringent regulations around greenhouse gas emissions. Sophisticated fuel management systems and scrubbing technology have cut GHG emissions to a fraction of what they were even a decade ago. Meanwhile, new fuels have further contributed to slicing emissions – to the point some manufacturers are touting internal combustion engines with virtually no emissions at all.

In the US, engine builder Cummins introduced its first natural gas engine in 1986. Today, the company is preparing to launch an all-new internal combustion engine powered by natural gas – its X15N, with CO2 and NOx levels said to be 90% below current EPA standards. Weighing in at a svelte 2,614 pounds, or about 500 pounds less than a comparable diesel – the 15-litre, inline six cylinder offers a power output of up to 500 horsepower and a whopping 1,850lb-ft of torque. Due to launch in 2024 in the North American heavy truck market, the engine’s size, weight and torque make it a natural for future use in leisure marine applications.

Also due for launch – and designed with the marine sector in mind – is Cummins’ new X10 internal combustion engine, expected to come to market by 2026. The first member of the company’s sustainable X engine family, the X10 is positioned to replace the existing L9 and the X12 diesels and will be with fully compliant with the EPA 2027 emission regulations one full year before they take effect. At launch, the 10-liter X10 will be offered in models from 320hp to 450 hp with NOx output 75% below current standards. Although it will be launched as a diesel product, the X platform is fully fuel agnostic, allowing the X10 and future X-series engines to run on other fuels like natural gas, dimethyl (DME) or hydrogen to further reduce or eliminate GHG output.

 In Germany, MAN announced the certification of its 175D high-speed engine for operation on biofuels earlier this year. The company says the engine, available in 12-, 16- and 20-cylinder variants, is approved for operation with all standard biofuels, including HVO (hydrotreated vegetable oil) and FAME (fatty acid methyl ester) products without requiring any mechanical adjustments, allowing their immediate use. The company has also invested significantly in emission-free hydrogen technology.

While some engine builders modify existing platforms to achieve emissions targets, others are adopting a clean sheet approach to figuratively re-invent the wheel. In the US, tech firm Astron Aerospace recently unveiled its unusual Omega 1 internal combustion engine, featuring a unique circular design with no crankshaft or reciprocating pistons. Described as the world’s first active linear power transfer engine, the engine can run on a wide range of sustainable fuels for ultra-low to no GHG emissions while delivering a supremely compact footprint; the company’s working prototype weighs just 35 pounds or 16 kg, while generating 160hp and 170 lb-ft of torque. Further, the Omega 1’s unique architecture allows multiple engine units to be stacked as required to increase output.

 While electric propulsion has clearly captured public interest, limitations in battery technology – including questions about the sustainability of battery construction technologies – remain. Internal combustion engines burning sustainable marine fuels continue to offer a viable alternative, making speculation over their demise both premature and greatly exaggerated.