Test results on a novel ethanol-assisted engine by the Ford Motor Company have indicated that alcohol can make automobiles
more climate-friendly. According to a report in New Scientist, the unit, called a direct-injection ethanol engine, runs primarily on petrol. When it needs to deliver maximum power, like climb a hill or overtake, the engine management computer adds a little ethanol to the fuel injected into the combustion chambers. This arrangement allows the engine to operate at a much higher compression ratio - a measure of the amount by which the fuel-air mixture is compressed before being ignited - than normal. “As a result, an average car engine can be “downsized” to one that should have around 23 percent better fuel efficiency,” officials at Ford said. Normally, the downside of a high compression ratio is that it encourages premature ignition or “knocking”, which drastically cuts down the power output. Adding ethanol to the fuel suppresses knocking. “We’re trying to get the best of both worlds,” said Paul Whitaker of AVL Powertrain Engineering of Plymouth, Michigan, which is developing the technology with Ford. “It’s like knock suppression on demand,” he added. Test results on a pickup truck fitted with the new engine were recently presented at the US Department of Energy’s annual vehicle technology review meeting in Arlington, Virginia. They showed a 23 percent improvement in fuel efficiency for the same performance levels. The ethanol from a 40-litre auxiliary tank would last about 30,000 kilometres, according to Ford. Whitaker said that the next step is to road test the engine in a variety of vehicles and to ensure that the engine does not become unusable if the ethanol tank runs dry. Ford said that its ethanol-assisted engine would cost 1100 to 1500 dollars more than a conventional engine. This is just one-third of the extra cost of a hybrid petrol-electric engine over a normal petrol engine. Hybrids typically deliver 25 to 35 per cent better fuel economy than a conventional engine.
more climate-friendly. According to a report in New Scientist, the unit, called a direct-injection ethanol engine, runs primarily on petrol. When it needs to deliver maximum power, like climb a hill or overtake, the engine management computer adds a little ethanol to the fuel injected into the combustion chambers. This arrangement allows the engine to operate at a much higher compression ratio - a measure of the amount by which the fuel-air mixture is compressed before being ignited - than normal. “As a result, an average car engine can be “downsized” to one that should have around 23 percent better fuel efficiency,” officials at Ford said. Normally, the downside of a high compression ratio is that it encourages premature ignition or “knocking”, which drastically cuts down the power output. Adding ethanol to the fuel suppresses knocking. “We’re trying to get the best of both worlds,” said Paul Whitaker of AVL Powertrain Engineering of Plymouth, Michigan, which is developing the technology with Ford. “It’s like knock suppression on demand,” he added. Test results on a pickup truck fitted with the new engine were recently presented at the US Department of Energy’s annual vehicle technology review meeting in Arlington, Virginia. They showed a 23 percent improvement in fuel efficiency for the same performance levels. The ethanol from a 40-litre auxiliary tank would last about 30,000 kilometres, according to Ford. Whitaker said that the next step is to road test the engine in a variety of vehicles and to ensure that the engine does not become unusable if the ethanol tank runs dry. Ford said that its ethanol-assisted engine would cost 1100 to 1500 dollars more than a conventional engine. This is just one-third of the extra cost of a hybrid petrol-electric engine over a normal petrol engine. Hybrids typically deliver 25 to 35 per cent better fuel economy than a conventional engine.
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