A Cost-Efficient EGR Technology for Off-road Diesel Engines with Mechanical Fuel Injection Equipment to Satisfy Advanced Emissions Standards 2010-01-1958
A robust and cost-effective off-road engine that is economical for backhoe application is developed to meet the Indian BS-III CEV (construction equipment vehicle) standards equivalent to the US Tier-3 emissions regulation for markets where (a) advanced maintenance facilities are not available in remote areas of operation, (b) availability of the right fuel is not fully assured, (c) the initial cost of the engine is under tight control and (d) the legendary fuel economy of direct-injection diesel engines is not traded off when migrating to higher emissions standards. The highlights of the layout of the 4-cylinder 3.8-liter 56 kW diesel engine are the use of a high-pressure exhaust gas recirculation (EGR) and a proven inline mechanical fuel injection equipment that is easy to maintain and tolerant to inferior quality of fuels used inadvertently in remote areas of operation. Use of 25% EGR reduces oxides of nitrogen (NOx) formation inside the combustion chamber by 30%. The EGR flow is controlled by a calibrated orifice instead of the usual electronically controlled module. With the induction of the EGR gases, fuel injection timing is relatively advanced and the specific fuel consumption (SFC) of the engine is superior to the competing engines that satisfy similar emissions standards. The soot in the EGR is abrasive. To protect the engine parts like the piston, the rings, the liner and the bearings from the abrasive wear, the EGR gases are passed through a wall-flow filter for removing 99% of the soot.