Artigo Completo:

Due to the evolution of legislation on pollutant emission levels, engine designs are facing new challenges, requiring the introduction of new technologies capable of reducing emissions with the minimum possible impact on engine efficiency, such as performance and fuel consumption. At the same time, the product competitiveness must be considered. It's no use having a product with a complex level of technology, if the cost to have this technology is prohibitive for the consumer. The EGR technology (Exhaust Gas Recirculation) is one of the most widely used and could be applied separately or used in conjunction with other technologies depending on the level of emissions to be achieved. This technology can be presented in different ways, being classified in internal EGR and external EGR. The external EGR is not yet suitable for small diesel engines in off-road applications due to the cost of the components used. The internal EGR is more feasible for this type of application, because it has great efficiency and does not add increment of components to the engine. Basically, internal EGR operation is achieved by modifying the valve train system, in this way, an event can be added to the intake valve during the exhaust cycle to increase the level of exhaust residue in the cylinder. This increase in the quantity of gases with reduced concentration of O2 and reduction of the concentration of CO2 contribute to reduce the average temperature of the combustion chamber, resulting in the reduction of NOx formation rates, among other benefits. But the internal EGR can also add value to other engine needs. For this reason, this article aims to describe the benefits found in the engine after the application of the EGR technology, but specifically in the first start engine results under conditions of low temperature. The application of this technology has simplified all the injection system calibration job with a significant gain in the start-up time and start-up smoke. The gains of Start-up time and start-up smoke in low-temperature conditions exceed 50%, eliminating the need to apply cold start auxiliary systems in some cases.