Effects of a start-stop system for gasoline direct injection vehicles on fuel consumption and particulate emissions in hot and cold environments. (1st September 2022)

• Record Type: Journal Article
• Authors: Zhu, Rencheng; Fu, Yanan; Wang, Lulu; Hu, Jingnan; He, Liqiang; Wang, Menglei; Lai, Yitu; Su, Sheng
• Is Part Of: Environmental pollution. Volume 308(2022)
• Publication Date: 2022-09-01
• Subjects: Start-stop system -- Cold environment -- Particulate emissions -- Fuel consumption -- Gasoline direct injection (GDI) -- Worldwide-harmonized light-duty test cycle (WLTC); Pollution -- Periodicals; Pollution -- Environmental aspects -- Periodicals; Environmental Pollution -- Periodicals; Pollution -- Périodiques; Pollution -- Aspect de l'environnement -- Périodiques; Pollution -- Effets physiologiques -- Périodiques; Pollution; Pollution -- Environmental aspects; Periodicals; Electronic journals; 363.73
• DOI: 10.1016/j.envpol.2022.119689
• Languages: English
• ISSNs: 0269-7491

Abstract

Abstract: Engine start-stop (S&S) technology has been substantially incorporated into modern vehicles to save fuel during idling in congested urban areas because fuel economy regulations have become more stringent. However, the potential for increasing particle emissions after engine restarts, especially in cold environments, is of great concern. To investigate the effects of S&S systems on fuel consumption and tailpipe emissions, a chassis dynamometer was employed to measure the fuel consumption, particulate matter (PM), solid particle number (PN), particle number size distribution and black carbon (BC) for a typical gasoline direct injection vehicle when the S&S was on (S&S-on) and when the S&S was off (S&S-off) according to the worldwide harmonized light-duty test cycle in both hot (28 °C) and cold (5 °C) environments. S&S operation resulted in 3.1–4.3% fuel-savings at 28 °C but had a tendency to increase particulate emissions, especially of BC (21.8–31.8%) and PM (19.2–32.8%). Although PN emissions with S&S-on over the entire cycle were slightly lower than those with S&S-off, more particles were emitted during the engine restart moments. In a cold environment, the fuel-savings advantage of the S&S system was weakened, and the negative impacts on the particle emissions during the restart moment worsened. The S&S system resulted in higher abundances of accumulation mode particles, especially under cold ambient conditions. The relationship between the PN reduction rates and idling segments was determining to be exponential. Our results indicate that the S&S system, which may increase particle emissions during restarts, does save fuel, and that a comprehensive evaluation of the system in cold environments is needed to determine the serviceability of new engine technologies and after-treatments. Graphical abstract: Image 1 Highlights: The advantages of start-stop system (S&S) decrease in cold environments. S&S operation uses 3.1–4.3% less gasoline at 28 °C, but increases particle emissions. More large particles (>0.07 μm) are generated during engine restart moments. Engine restarts with S&S-on result in more particles at 5 °C than at 28 °C. Particles emitted during restart with S&S-on decrease as the idling time increases.