Research On Turbocharging Of A FSAE Engine

Small-displacement turbocharging was a significant approach to improve the performance of a Formula SAE(FSAE for short)racing car.Research on FSAE downsizing single-cylinder engine turbocharge matching could provide reference and experience for energy saving and emission reduction of automobile industry.This paper researched on the single-cylinder engine of HRT15 C racing car.With the purpose to enhance the power density of the racing car,the parameters of the intake air was calculated to select appropriate turbochargers.Some simulations and matching calculations were done with GT-POWER software.The results showed that turbocharging was an effective way to enhance the power of a downsizing single-cylinder engine.However,there were very limited types of turbocharger could match with a downsizing single-cylinder engine.The MGT1328 turbocharger and RHF25 turbocharger which were selected in this paper,both have advantages and disadvantages.Base on the simulations,this paper designed the bench test system of the downsizing turbocharged single-cylinder engine,including intake and exhaust system,cooling system,lubrication system,boost control system,etc.The RHF25 turbocharger and MGT1238 turbocharger were compared through experiment with the bench test system.The experimental results revealed that the engine which was matched with RHF25 turbocharger had an obvious increase in intake air mass flow rate compared to the original engine.However,when the throttle position reached 40%,the turbine caused steep exhaust resistance,as a result,the power did not reach expected target.Matched with MGT1238 turbocharger,the power of aimed engine achieved obviously improvement in partial load,the maximum increase rate was 20.7%.At the same time,the engine with MGT1238 turbocharger had some weaknesses in high intake air temperature rise rate,low volumetric efficiency in high speed,etc.The experiment which had been accomplished showed that a downsizing single-cylinder engine could be more powerful if it was matched with a turbocharger which was bought in the market.However,there will be some limitation and it was hard to achieve the power target if an existent turbocharger was directly installed on the engine.According to the previous research results,this paper made further analysis on the reason why the engine did not reach target power after matched with RHF25&MGT1238 turbocharger.In conclusion,the main reason was that the exhaust flow rate of a single-cylinder engine was more fluctuant than the exhaust flow rate of a multi-cylinder engine,so the turbine which was selected according to average exhaust flow rate could not achieve the desired boost effect.To solve the problem,this paper put forward two solutions.Firstly,the paper added an exhaust stabilizer before turbine to stabilize the fluctuation of exhaust pressure and flow rate.Secondly,the paper combined the compressor of RHF25 turbocharger with the turbine of MGT1238 turbocharger to produce a new turbocharger(named R-M turbocharger)and applied the new turbocharger to the aimed engine.Then,the R-M turbocharger was optimized further.The simulation results showed that,matched with RHF25 turbocharger,the engine’s power increased 12.7% and achieved the matching aim after the engine was equipped with a 160 mm diameter exhaust stabilize.The R-M turbocharger matched well with the aimed engine and the efficiency of compressor could be enhanced 1.3% by optimizing the size of turbocharger.