A Comparison of Cold-Start Behavior and its Impact on Fuel Economy for Advanced Technology Vehicles

Air Pollution, Greenhouse Gas, and Traffic Externality Benefits and Costs of Shifting Private Vehicle Travel to Ridesourcing Services

“…For personal vehicles and for 1 nth of TNC vehicle shift distance (where n is the number of trips served in a shift), we modify vehicle efficiency by multiplying by a fuel economy penalty associated with cold-start operations. An Argonne National Laboratory report estimates this penalty at ϕ = 13 to 25%, 18 and we use a uniform distribution between these values in our analysis. As a result, personal vehicle CO 2 emissions, q CO 2 , are determined using the conversion k = 11.5 kg CO 2 per gallon of gasoline, where gasoline consumed is calculated as the distance traveled divided by the product of vehicle efficiency and cold-start penalty.…”

“…16 Cold starts have been estimated to decrease fuel economy by 13−25% (and 10−80% in more extreme cases) 17−19 during the first 5 to 20 min of operation; larger relative decreases are associated with lower ambient temperatures 17 and less aggressive driving behavior. 18 Similarly, cold starts increase PM2.5 emissions 18−30% per trip. 15,20 Figure 2 shows NO x , VOC, and PM 2.5 cold-start emissions from gasoline passenger cars for model years 1990 through 2020, estimated using EPA's MOVES model (version 2014b) 21 for vehicles operating in the calendar year 2020 (i.e., such that a MY2020 vehicle is new but a MY2010 vehicle and its emission control equipment have aged 10 years) and the associated monetized damages estimated by reduced-complexity integrated assessment models AP2 22 (an updated version of the Air Pollution Emission Experiments and Policy analysis model) and InMAP, 23 using the dose−response function reported in Pope et al (2019) 24 and the default value of reduced mortality risk (historically named the "value of statistical life") of $9.4 million in 2019 USD (as described in Moran and Monje, 2016 25 ).…”

“…For some VOC species, the emissions from one cold start are comparable to those from roughly 360 km of hot operation (i.e., after the engine and emission control systems reach the operating temperature) Second, when an engine starts cold, it operates less efficiently (due to higher friction, among other reasons) and starts fuel-rich, both of which contribute to elevated fuel consumption and emissions of fine particulate matter (PM 2.5 ) . Cold starts have been estimated to decrease fuel economy by 13–25% (and 10–80% in more extreme cases) − during the first 5 to 20 min of operation; larger relative decreases are associated with lower ambient temperatures and less aggressive driving behavior . Similarly, cold starts increase PM2.5 emissions 18–30% per trip. , …”

Comparative Analysis of Efficiency and Operating Characteristics of Automotive Powertrain Architectures Through Chassis Dynamometer Testing

“…Technology Vehicles" by Anderson et al, to be published in 2014 [16]. better understand the duration of these effects, the Prius' coolant and oil temperatures for the hot start and cold start US06 cycles are plotted in Figure 6.3.11.…”