Chapter 2 Crank-connecting rod mechanism and parts Section 2 Piston connecting rod group Two-stroke gasoline engines mostly use convex top piston. Four-stroke gasoline engines mostly use flat top piston,and also with concave top piston. Regular four-stroke diesel engine piston is designed into a variety of pits. (a】 (b】 (d) (e) (f) Figure 2.7 Piston top shape schematic diagram (a)flat top (b)concave top (c)convex top (d)(e)(f)concave pit 机被与电子工程学聚 Automobile and Tractor Northwest A&F UniversityAutomobile and Tractor Northwest A&F University Chapter 2 Crank-connecting rod mechanism and parts Two-stroke gasoline engines mostly use convex top piston． Four-stroke gasoline engines mostly use flat top piston, and also with concave top piston． Regular four-stroke diesel engine piston is designed into a variety of pits． Figure 2.7 Piston top shape schematic diagram (a) flat top (b) concave top (c) convex top (d) (e) (f) concave pit Section 2 Piston & connecting rod group