Development of 2-Cylinder Diesel Engine for European Quadricycles to Achieve EURO 5+ Standard

The EURO 5+ standard (134/2014/EU) has been enforced in the year 2025 for quadricycle in Europe. The exhaust emission regulation under this standard has significantly tightened compared to the EURO4. Also, this standard limits vehicle weight, which remains unchanged from the EURO4 standard. We introduce the unique technologies to meet EURO5+ standard in this paper. Emission limit values of the EURO 5+ standard are more stringent, requiring an 84% reduction in NOx and a 94% reduction in PM compared to the previous standard. Diesel engines with mechanical injection control systems for the previous standard are required significant technological advancements to meet EURO 5+ standard of exhaust emission. The adoption of engine aftertreatment components such as SCR (Selective Catalytic Reduction) for NOx reduction and DPF (Diesel Particulate Filter) for PM reduction are common solution. However, to meet this new regulation, adding the weight of these after-treatment parts would cause the vehicle to exceed the weight limit. Therefore, we have improved our original IDI (Indirect Injection) technology to develop an electronic controlled fuel injection system for small diesel engines, thereby improving the exhaust emission. This electronic control system enables various control strategies. By combining it with the EGR (Exhaust Gas Recirculation) system and DOC (Diesel Oxidation Catalyst) for NOx and PM reduction, we have developed an engine that meets the Euro 5+ standard. This engine with these additional emission control devices also contributes the weight limit. This paper will focus on combustion improvement technologies that achieve low emissions with IDI combustion to comply with EURO 5+ standards, as well as technologies for compact additional emission control devices aimed at achieving low emissions that meet the requirements of targeted European quadricycles.