Common Rail Direct Injection Essay Example for Free

general Rail Direct Injection EssayDirect injection means injecting the fuel directly into the cylinder sort of of premixing it with air in separate intake ports. That allows for controlling blow a fuseion and emissions more precisely, but demands in advance(p) locomotive management technologies. Unlike petrol engines, diesel motor engines dont need ignition dodging. due to the inherent property of diesel, combustion will be automatically effective under a received pressure and temperature combination during the compression phase of Otto cycle. Normally this requires a high compression ratio rough 22 1 for normally aspirated engines. A strong thus heavy block and head is call for to cope with the pressure. Therefore diesel engines are always much heavier than petrol equivalent. The lack of ignition system simplifies repair and maintenance, the absence of throttle also help. The output of a diesel engine is controlled simply by the amount of fuel injected. This makes t he injection system very decisive to fuel scrimping. Even without direct injection, diesel inherently delivers superior fuel economy because of leaner mixture of fuel and air. Unlike petrol, it can combust under very lean mixture.This inevitably reduces power output but under light level or partial load where power is not much an important consideration, its superior fuel economy shines. Another explanation for the inferior power output is the extra high compression ratio. On star occur the high pressure and the heavy pistons prevent it from revving as high as petrol engine (most diesel engine deliver peak power at lower than 4500 rpm. ), on the other hand the long stroke dimension required by high compression ratio favors tortuousness instead of power. This is why diesel engines always low on power but strong on torque.To enlighten this problem, diesel makers prefer to add turbocharger. It is a device to input extra air into the cylinder piece of music intake to boost up the power output of the engine. Turbochargers top end power suits the torque curve of diesel very much, unlike petrol. Therefore turbocharged diesel engines output similar power to a petrol engine with similar capacity, while delivering superior low end torque and fuel economy.