A method for reducing exhaust pressure of vehicle compressed air powered engine
Compressed air powered engine is a type of zero-pollution engine, but its conversion efficiency is very low for its high pressure exhaust which causes much exergy loss. In this study, a control system was developed to reduce the exhaust pressure of vehicle compressed air powered engine. The control system is made up of a controller, a pressure sensor, a photoelectric encoder, an inlet solenoid valve, and an exhaust solenoid valve. The controller receives the pressure signal of compressed air in cylinder from the pressure sensor and receives crank angle signal from photoelectric encoder, calculates when the solenoid valves should be opened or closed, and passes control signals to the solenoid valves. The simulation results indicate that the exhaust pressure can be controlled to be near to surrounding pressure by using this control system, and the exergy loss in exhaust stage can be avoided.
Dynamic characteristics of in-cylinder flow field in air-powered engine
The working process of air-powered engine was simulated using renormalization group(RNG) k-e turbulence model to give a view of energy distribution of inlet compressed air.Simulation represented the change of in-cylinder flow field and the behaviors of major parameters changing with crank angle,e.g.,cylinder pressure,turbulence kinetic energy and work output.Calculation results show that the perplexing turbulence around the inlet valve during the inlet process and exhaust are two primary factors resulting in energy losses,corresponding to 15.39% and 27.21% of the total energy when the engine speed is 1 500 r/min.Optimizing the structure of cylinder and inlet port and reasonably organizing inlet flow are far more important to air-powered engine,which can obviously improve the dynamic and economic characteristics of the engine.
White-Collar Crime in Modern England: Financial Fraud and Business Morality, 1845-1929.
List of tables Acknowledgments Introduction 1. The new economy: transformation of finance and opportunities for crime 2. The railway mania 3. Banking and credit fraud 4. Stock fraud 5. Company fraud: promotion 6. Company fraud: management 7. Company law and the courts 8. Business ethics and professionalization Conclusion Notes Bibliography Index.