Classification of Piston Engines

1. Step of Work 2 Stroke Engine

               Charging cylinder followed by compression          Combustion continued exhaust and rinse out

Two stoke engine is engine that need 2 times the piston move (one round of the crankshaft) to generate one-time job.

2. Step or Work 4 Stroke Engine

                               Suction Step                      Compression step

                           Piston moves down                   Piston moves up 

                       from the TDC to the BDC         from BDC to the TDC

                               Step work                                   Step Exhaust

                        Piston moves down                            Piston moves up

                    from the TDC to the BDC                  from BDC to the TDC

 4 stroke engine is a engine that need 4 times the piston move (twice the crankshaft rotation) to produce once work step.

BDC : bottom death center

TDC : top death center