Common Rail Direct Injection (CRDI)

The most important contributor to its effectiveness remains with the common rail. Which basically means same fuel line. That is, when fuel gets injected into say cylinder 1; there is virtually no pressure loss at the rest of the rail. This in turn means that there is always adequate pressure available for the injection. Common rail technology makes use of 2 pumps in order to bring the fuel up to high pressures of up to 1350 bar. During the first stage, an electronic pump draws required amount of fuel from the fuel tank; this low-pressure pump is governed by the engine management system. The speed of the pump is determined by driver inputs and other information obtained from sensors. This has allowed Common rail systems to reduced emissions due to absence of unburnt fuel. The second stage of pumping is done with the help of a mechanical pump that is coupled with the crankshaft and geared in order that it may rotate at half engine speed. The fuel now goes to an accumulating duct (rail), where these pressures maybe maintained. This tank allows for the maintaining of this constant pressure even during the injection. The injection maybe carried out using electromagnetic valves, which govern the exact amount of fuel for injection. Leaks occurring at the pump, leaks for opening the valves etc are returned back to the fuel tank. Which in turn results in zero wastage of fuel. When common rail technology is integrated with turbo chargers or superchargers the power delivered by a diesel engine may well exceed that attained by a similar sized petrol engine. Today's manufacturers are embracing this technology due to all the advantages it holds. At the rate with which this technology is catching up, Diesel definitely holds the key as far as development in efficiency is concerned.