不同进气定时和点火定时对燃烧的影响的英语演讲ppt.pptVIP

S/A = BTDC 10? S/A = TDC S/A = ATDC 5? Fig. 15 indicates the cylinder and intake pressure, cyclic THC and NOx emissions with fixed valve timing and various spark timings during the first 4 seconds of cold start. As the ignition time delay, the accumulated THC has been reduced but the maximum NOx value doubled. The catalyst light-off performance by spark retardation was determined by temperature traces of the catalyst bed with various ignition timings as shown in Fig. 16. This results show that ignition retardation logic has a positive effect on the enhancement of the catalyst performance as well as on the decrease of the engine-out hydrocarbons. Conclusions The results are summarized as follows. With the advancement of the intake openings to BTDC 10?from ATDC 10?, the engine-out THC emissions were reduced 7.7%, and NOx emission was reduced 22%. With spark retard to ATDC 5?from BTDC 20?, high conversion efficiency can be obtained quickly by shortening the catalyst light-off time. The engine-out THCs were reduced by about 66% with ignition retard. However, 73% more NOx was generated, because of the supplementary air to maintain the target engine speed. Therefore the intake valve timings and engine combustion characteristics should be considered when determining the amount of spark retardation. During cold start, the valve overlap has advantages in reducing cold-start THC and NOx emissions before catalyst activation. Make Presentation much more fun Thank you ! apparatus[??p??r?t?s] * Effects of various intake valve timings and spark timings on combustion, cyclic THC and NOx emissions during cold start phase with idle operation in CVVT engine Therefore, various factors of engine combustion, aftertreatment and engine control have been investigated for cold start emission reduction. More than 95% of total hydrocarbon (THC) emissions in test were exhausted within the first few cycles before catalyst activation ?Pie chart of THC Research background 1 An in-line