Scientists Moots Hybrid Lorries Without Diesel Engines

Scientists Moots Hybrid Lorries Without Diesel Engines

Researchers at MIT are proposing plug-in hybrid vehicles for long-distance heavy transport

The truck would be primarily powered by batteries, but a non-diesel spark-ignition engine would extend range to that of today’s vehicles, according to MIT, avoiding the 10 to 15 tonnes of batteries required in an all-electric truck.

The engine would be ‘flex-fuel’, able to use any combination of petrol, ethanol or methanol. And the series hybrid (=’plug-in’) allows the fuel engine to always operate at its optimum speed, maximising its efficiency – as has happened for decades in ‘diesel-electric’ trains.

“We’ve been working for a number of years on ways to make engines for cars and trucks cleaner and more efficient, and we’ve been particularly interested in what you can do with spark ignition, because it’s intrinsically much cleaner,” said Daniel Cohn of MIT’s ‘Energy initiative and plasma fusion and science center’.

MIT’s ultimate goal remains entirely batter-powered vehicles, but the flex-fuel hybrid is a possible early route into the marketplace by overcoming concerns about limited range, cost, or the need for excessive battery weight to achieve longer range.

The proposed flex-fuel engine is one Cohn and engineer Leslie Bromberg have been working on for years, which is claimed to have the potential to emit far less greenhouse gas than a pure petrol engine, at only a small incremental cost, according to the researchers.

If run on methanol or ethanol from renewable sources, net greenhouse gas emissions could be zero.

“It’s a way of making use of a low-greenhouse-gas fuel, but always having the option of running it with gasoline,” said Cohn.

“Computer modelling of a whole range of desired engine characteristics, combined with screening of the results using an artificial intelligence system, yielded clear indications of the most promising pathways and showed that such substitutions are indeed practically and financially feasible,” said MIT.

Part of the financial equation, according to Bromberg, is that petrol engines have become more efficient and clean over the years, and the relative cost of diesel fuel has gone up, so that the cost advantages that led to the near-universal adoption of diesels for heavy trucking no longer prevail. “Over time, gas engines have become more and more efficient, and they have an inherent advantage in producing less air pollution,” he said.

The concept will be presented at the annual SAE International conference this week.

Source: electronicsweekly