Abstract
This paper presents a propagation model of pressure reflection waves in the exhaust pipe of 2 stroke-cycle engine and a design method of the energy saving type exhaust pipe (ESTEP) by the model simulation.
The following two kinds of pressure reflection waves at the exhaust port are effective for ESTEP.
1) The positive pressure reflection wave in the stroke from scavenging port closing to exhaust port closing (SC∼EC)
2) The negative pressure reflection wave in the scavenging port (SO∼SC)
The positive pressure reflection wave is useful for preventing a flux of fuel gas and the negative pressure reflection wave for activating a flux of exhaust gas.
It has been experimentally confirmed that the model which was decided after the consideration of effects on composition of exhaust gas, temperature and bias pressure, gave a good prediction on behaviours of the pressure deflection waves.
According to the model simulation, the ESTEP having the both reflection waves has been designed and the fuel consumption experiments have been successfully done. The result shows 22% saving of fuel consumption in comparison with an exhaust pipe on market.
