DUAL - FUEL INJECTION • Dual-fuel refers to the engine's ability to
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operate on a combination of gas and diesel fuel simultaneously. Unlike gas-only engines, which need spark plugs, this is a compression-ignition unit. In most operations the gas will account for 80% of the total with the diesel acting as on agent for combustion. In high-load applications the proportion of gas can rise to as much as 92%.
The diesel compression ratio is retained—along with its fuel economy, says Caterpillar—while the gas offers potential benefits in terms of reduced noise and particulate emissions.
The fuel combination is delivered via Servojet Technologies' multipoint, port-injected delivery valves working with Cat's own electronically controlled diesel-injection system. The whole system is managed by Cat's Advanced Diesel Engine Management system (ADEM) and Servo jet's Eagle ECU, Engine start-up is handled by ADEM on diesel. When the engine is warm the Eagle ECU tells ADEM to switch to gas.
If there is any problem with the gas injectors ADEM will take over and fuel the engine on diesel. if the operator has trouble with gas refuelling he can simply run the engine like a conventional diesel. This avoids the potential infrastructure problems with gas power, although there is a payload penalty from the weight of the diesel tanks and gas cylinders.
says a spokesman. "If they keep putting up the price of diesel we should see these engines becoming more and more popular."
Power ratings are available from 190hp to 425hp, and a 500hp version is in the pipeline.