What is the difference between a conventional diesel engine and common rail diesel engine.How does the common rail diesel engine work?

Answer 1

Common rail diesel basic description:

A common rail diesel engine differs from a conventional diesel engine in several important respects. A conventional diesel engine works via a mechanical injection system, which relies on the engine's diesel injection pump to deliver the required fuel pressure, at the correct time, to the diesel injector in order to allow the injector to operate. Each individual injector on a conventional diesel engine has its own pipe or "rail" connecting the injector to the mechanical pump, allowing the delivery of fuel to the injector. Common rail diesel injection systems work on a much different principle. In this system the mechanical controls are replaced by electronic controls to allow for more precise metering and timing of the fuel delivery into the engine, and therefore the injection pump is no longer solely responsible for the operation of the injection system. Also, the individual injector rails are replaced by 1 (or 2) "common rail" which operates under a constant high pressure. There is no injection pump associated with this system, yet a high pressure pump is still required to deliver the high pressure fuel to the common rail. The high pressure pump is capable of producing (depending on the system used) approximately 29000 psi of pressure into the common rail. At the correct time the electronic injector is operated and the fuel is injected into the engine allowing ignition to occur. The timing and fuel quantity is controlled by an advanced engine management system which gathers data on the engine conditions via a collection of sensors. All of these sensors measure different system parameters to calculate the correct fueling for the engine at any given moment.