STUTTGART: German engineering company Mahle Powertrain is heading an innovative project to replace air-polluting diesel with ammonia in heavy duty combustion engines.
Ammonia as a fuel has not played a major role in the scramble to decarbonise engines so far but Mahle says it is ideal to replace diesel fuel in large marine engines and in off-highway sectors such as mining, quarrying and construction.
"Off-highway industries such as mining, quarrying and construction remain a significant challenge in the transition towards a more sustainable transport sector," said Jonathan Hall, Mahle Powertrain's Head of Research & Advanced Engineering Projects.
The project is funded through the British government's Net Zero Innovation Portfolio as part of the Red Diesel Replacement project.
Red diesel fuel is used for engines that power off-road vehicles and railway locomotives, as well as machines like tractors and bulldozers that are used on farms and at construction sites.
In Britain and most western European countries, red diesel accounts for 15% of all diesel usage, with 56% of it used by the construction industry alone.
Red diesel, which isn't different from ordinary diesel except that it's dyed red, is taxed at a lower rate and is much cheaper to buy than diesel at forecourt service station pumps.
"Although not often discussed, the production and transportation infrastructure of ammonia is well developed and a prime candidate for decarbonisation using renewable energy," said Mahle.
This makes it a readily available, zero-carbon fuel for sectors which have energy demands that a pure-electric approach will struggle to meet, the company added.
The research focuses on two approaches. The first is a retro-fit, dual-fuel arrangement being tested on a six-cylinder turbo-diesel engine. Additional injectors added to the air intake introduce ammonia as the main source of energy.
The second approach is being developed using Mahle's own single-cylinder engine and the company's trademarked Jet Ignition – a highly innovative form of pre-chamber ignition – replacing the traditional spark plug to ignite the ammonia. This eliminates the need for a fossil-fuel ignition source.
