| For solving the problem of global warming caused by the CO2 emissions from the combustion of fossil fuel, a large number of studies have done at home and abroad, the oxygen combustion technology(also known as O2/CO2 combustion technology) is recognized the most effective method for CO2 capture, this method has been applied in the power generation industry successfully. However, the research on how to solve the CO2 emissions from vehicle engines is less and less. In order to study how to capture the CO2 emissions from vehicle engines effectively, in this article, through the method of combing the simulation and experimental on a four cylinder four stroke gasoline engines for the test of using liquid oxygen to solidify carbon and closed inlet and exhaust system.Firstly, KIVA-3V was used to simulate the combustion characteristics of gasoline engine in O2/CO2 environment and analyzed the influence of the different O2/CO2 concentration ratio on the temperature, pressure, heat release rate and CO2 concentration in cylinder, the best inlet concentration of O2/CO2 ration was concluded. Secondly in order to study the influence of the different conditions on the test of using liquid oxygen to solidify carbon, the conditions of the gasoline engine was divided into 13 types based on the different rotating speed and load with European steady state cycle. Using KIVA-3V to simulate the influence of the different speed and load on the combustion characteristics in cylinder and summarized the change rule of temperature, pressure, heat release rate and the concentration of CO2 in the cylinder with the speed and load. Through the theoretical calculation the production of CO2 in the exhaust and the consumption of oxygen were obtained and the experiment of using liquid oxygen to solidify carbon was finished under the 13 conditions. The differences of the production of CO2 in the exhaust and the consumption of oxygen with the theoretical calculation were analyzed. Observation the influence of different conditions on the condensation process of CO2.The simulation results show that: the appropriate concentration of CO2 is helpful for combustion revert to the standard combustion conditions in the oxygen enriched conditions.When the O2/CO2 concentration ratio is 42% for optimal, at this time the temperature was relatively moderate, the rate of pressure rise was relatively smooth in cylinder, the performance and fuel economy of engine was better, so it proved using the O2/CO2 inlet under the condition of the inlet and exhaust closed was feasible in theory. With the increased of engine speed, the vortex was strong, the quality of mixture was good, the ignition delay period of engine was shorten. The rise of temperature and pressure in cylinder was smooth relatively, which made the work of engine stability. With the increased of engine load, the quality of mixture was increased, the combustion temperature and the pressure in cylinder was high. But too much load made the condition of engine become unstable.The experiment results show that: because the capture device and exhaust devices exist a certain amount of leakage, the amount of CO2 capture during the test was lower thanthe theoretical calculation values; when opened the liquid oxygen valve and sprayed the liquid oxygen into device, low temperature and high pressure liquid oxygen occurred boiling evaporation immediately after contacted with the high temperature exhaust gas and produced "Flash" phenomenon. So the consumption of oxygen during the test was more than the theoretical calculation values. With the increased of engine speed and load, the amount of CO2 generated in the exhaust gas increased, the amount of oxygen consumed also increased during the test. The flocculent floater of CO2 was captured in the collecting box increased with the increase of speed and load obviously and verified the feasibility of using liquid oxygen to solidify carbon of internal combustion engine. |
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