International Scientific Journals
of Scientific Technical Union of Mechanical Engineering "Industry 4.0"

In nowadays, reducing emissions of the nitrogen oxide (NOx) in diesel engines become a principal goal for the future. The new technology Lean NOx Trap (LNT, is also known like NOx adsorber catalyst (NAC) or NOx Storage and Reduction (NSR) catalyst) can be applied on passenger cars, light and heavy-duty diesel engines to reduce NOx emissions substantially. The NOx emissions are absorbed onto a catalyst during lean engine operation. After the catalyst is saturated, the system is regenerated in short periods of fuel rich operation during which NOx is catalytically reduced. This paper presents a literature review about the function and importance of LNT as the new aftertreatment exhaust system for reducing the NOx emissions of the new generation of diesel engines.

One of the primary incentives for expanding the production and use of biofuels worldwide is the potential environmental benefit that can be obtained from replacing petroleum fuels with fuels derived from renewable biomass resources. The use of straight vegetable oil in diesel engines is one of the available alternatives, but its use in existing vehicles usually requires modification of engine or fuel system components. The increased viscosity, low volatility, and poor cold flow properties of vegetable oils lead to severe engine deposits, injector coking, and piston ring sticking. The paper presents a literature review on vegetable oils as alternative fuel for diesel engines.

The article presents a numerical study of pre-injection strategy in order to reduce the rate of heat release and pressure rise in a modern direct injection diesel engine, developed for passenger car. A model of the engine was built in advanced simulation code AVL BOOST. In order to determine the injection rate a supplementary model of the solenoid injector was built in AVL HYDSIM. A study of rate of heat release and pressure rise into combustion chamber was conducted at single operating point. The engine effective power was taken into consideration as well. The results revealed that pre-injection strategy is a promising approach for reducing the rate of heat released and the engine noise at low speed and load. However, a precise control of pre-injected mass and injection timing has to be realised by engine control system.