The New 4-Cylinder Turbocharged GDI Engine from SAIC Motor 2020-01-0836
SAIC Motor Corporation Limited (SAIC Motor) has developed a new 1.5 L 4-cylinder turbocharged gasoline direct injection engine to meet the market demand and increasingly stringent requirement of CAFE and tail-pipe emission regulations. A series of advanced technologies for improving engine fuel economy, engine-out emission, torque and power output specially low end torque performance have been employed, such as: central gasoline direct injection, integrated exhaust manifold, high tumble combustion system, Miller Cycle, cooled external EGR, 35MPa fuel injection system, multi-hole injector with variable hole size design, efficient turbo charging with electric wastegate (EWG), etc. As a result, the engine is able to achieve over 39% brake thermal efficiency (BTE), as well as substantial fuel consumption reduction in vehicle driving cycle. It delivers 275 Nm maximum torque and 127kW rated power, with fast low end torque response. By integrating the 35MPa high pressure fuel injection system and optimized multi-hole fuel spray, the engine-out particulate numbers (PN) emission is reduced by more than 70% over a previous base engine with 20Mpa fuel injection system. The vehicle equipped with this new engine is capable of meeting China VI b standard emission regulatory requirement without gasoline particulate filter (GPF).
In this paper, the engine layout and design/optimization of the combustion system will be described. The detailed investigations with simulations and dyno testing of effects of the core technologies will also be presented: effect of high tumble port and masking design, effect of fuel spray pattern optimization, Miller cycle vs. Otto cycle, 35MPa vs. 20MPa fuel injection system, electric wastegate (EWG) vs. pneumatic wastegate control, cooled LP-EGR vs. HP-EGR.