Effect of Fuel Injection Timing on the Mixture Preparation in a Small Gasoline Direct-Injection Engine
30 Oct 2018-
About: The article was published on 2018-10-30. It has received 6 citations till now. The article focuses on the topics: Gasoline direct injection & Fuel injection.
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TL;DR: A review of the latest research topics, sorting them as if we are following the ideal fuel droplet life, beginning from the injection and ending after the combustion reaction is provided in this paper.
49 citations
TL;DR: In this article , the impact of engine technology, emission standards, engine-start conditions and engine load on vehicle PN emissions were quantified via real driving emission (RDE) and chassis dynamometer tests.
Abstract: Vehicle particle number (PN) emissions have attracted increasing public attention due to their severe influence on human health. In this study, we selected 35 light-duty gasoline vehicles (LDGVs) with gasoline direct injection (GDI) and multi-port fuel injection (MPFI) engines to elucidate the main factors influencing PN emissions. Via real driving emission (RDE) and chassis dynamometer tests, we quantified the impact of engine technology, emission standards, engine-start conditions and engine load on vehicle PN emissions. The RDE test results indicated that GDI vehicles generated higher PN emissions than those of MPFI vehicles under hot-running conditions. MPFI vehicle PN emissions were greatly affected by rapidly changing driving conditions, especially vehicles equipped with automatic start-stop systems. In regard to China 6 GDI vehicles equipped with a gasoline particle filter (GPF), their PN emissions were usually low, and peak PN emissions could mainly be attributed to GPF regeneration. Engine manufacturers should optimize GPF regeneration conditions to further reduce particulate emissions. Furthermore, the analysis results of PN emissions for different road types indicated that PN emissions were related to vehicle driving conditions. The vehicle specific power (VSP) could be used as an important explanatory variable to characterize the PN emission rate when distinguishing different engine technologies and emission standards. A real-world LDGV VSP-based PN emission rate was suggested based on the RDE test dataset. The VSP-based emission rate could be considered to more accurately quantify vehicle PN emissions and support the formulation of urban vehicle particle emission control policies.
3 citations
3 citations
TL;DR: The effect of fuel injection timing on cycle-to-cycle spray variations and macroscopic spray characteristics is quantitatively analyzed at wide-open throttle condition with stoichiometric air–fuel ratio and results showed that spray variations were slightly higher at injection timing of 240° BTDC compared to injection timings at 210°BTDC and 180° BT DC.
Abstract: Fuel injection timing for early injection mode at higher loads in a gasoline direct-injection engine is critical for mixture formation, combustion process and emissions. In the present work, the effect of fuel injection timing on cycle-to-cycle spray variations and macroscopic spray characteristics is quantitatively analyzed at wide-open throttle condition with stoichiometric air–fuel ratio. A Mie scattering technique was employed to visualize the liquid phase of the fuel dispersion with early injection timings at 180° before top dead center (BTDC), 210° BTDC and 240° BTDC of compression with fuel pressure of 5 MPa. A quantitative analysis using proper orthogonal decomposition revealed that cycle-to-cycle spray variations were not significant. Comparing different injection timings, results, however, showed that spray variations were slightly higher at injection timing of 240° BTDC compared to injection timings at 210° BTDC and 180° BTDC. Concerning macroscopic characteristics, it was found that the spray tip penetration length was longer at 210° BTDC compared to injection timings at 240° BTDC and 180° BTDC. It was also observed that the spray areas were comparable for different injection timings until about 0.9 ms after the start of injection, but it was enhanced at later time stamps for injection at 240° BTDC compared to injections at 210° BTDC and 180° BTDC.
2 citations
TL;DR: In this paper , the combustion chamber geometry for spray-guided, wall-guided and air-guided combustion strategies were fabricated by fixing the fuel injector and spark plug at proper positions to obtain swirl, turbulence, and squish effects for better mixing of fuel with air and superior combustion of the mixture.
Abstract: In this study, the combustion chamber geometry for spray-guided, wall-guided, and air-guided combustion strategies were fabricated. The piston crown shape and the cylinder head in each combustion chamber geometry was machined by fixing the fuel injector and spark plug at proper positions to obtain swirl, turbulence, and squish effects for better mixing of fuel with air and superior combustion of the mixture. Conducted tests on all the three modified gasoline direct injection engines with optimized exhaust gas recirculation and electronic control towards fuel injection timing, the fuel injection pressure, and the ignition timing for better the performance and emissions control. It is clear from the results that NOx emissions from all three combustion modes were reduced by 4.9% up to 50% of loads and it increase for higher loads due to increase of in-cylinder pressure. The fuel consumption and emissions showed better at 150 bar fuel injection pressure for wall-guided combustion chamber geometry. Reduced HC emissions by 3.7% and 4.7%, reduced CO emissions by 2% and 3.3%, reduced soot emissions by 6.12% and 10.6%. Reduces specific fuel consumption by about 10.3% and 13.3% in wall-guided combustion strategy compare with spray-guided and air-guided combustion modes respectively
1 citations