Effects of Two Stage Injection on Particulate Matter Emissions in a Turbocharged Gasoline Direct Injection Engine

In order to study the potential of two stage injection strategy in reducing particulate emissions, the single injection strategy and the two stage injection strategy were adopted in a turbocharged direct injection engine respectively. The DMS500 particle analyzer was used to measure the particle number and particle size distribution. Particle number, size distribution and engine economy were compared between the two injection strategies under different operating conditions. Results show that, when the two stage injection is applied to the direct injection engine, the optimized secondary injection ratio and injection phase can effectively reduce the fuel consumption and particulate emissions. Compared the single injection and the two stage injection, both particle size distributions show the bimodal distribution of the nucleation and the accumulation. When the engine speed is less than 3 000 r/min and the torque is more than 105 N•m, the two stage injection can reduce the fuel consumption and particle number effectively. The increased proportion of nuclear particles leads to a decrease of the particles average size. In other operating conditions, the single injection engine has better economy and emission performance. © 2019, Editorial Office of the Transaction of CSICE. All right reserved.