scholarly journals Quantifying the Effects of Idle-Stop Systems on Fuel Economy in Light-Duty Passenger Vehicles

2012 ◽  
Author(s):  
Jeffrey Wishart ◽  
Matthew Shirk ◽  
Tyler Gray ◽  
Nicholas Fengler
Keyword(s):  
Fuel Economy ◽  
Passenger Vehicles ◽  
Light Duty

scholarly journals Drive cycle simulation of high efficiency combustions on fuel economy and exhaust properties in light-duty vehicles

2015 ◽  
Vol 157 ◽  
pp. 762-776 ◽  
Author(s):  
Zhiming Gao ◽  
Scott J. Curran ◽  
James E. Parks ◽  
David E. Smith ◽  
Robert M. Wagner ◽  
...  
Keyword(s):  
Fuel Economy ◽  
High Efficiency ◽  
Drive Cycle ◽  
Cycle Simulation ◽  
Light Duty ◽  
Light Duty Vehicles

Diesel Emission Test Stand for Advanced SCR Control

2015 ◽  
Author(s):  
Joe Noto ◽  
Athul Radhakrishnan ◽  
Ye Sun ◽  
Josh Ferreira ◽  
Marc Compere
Keyword(s):  
Control Systems ◽  
Fuel Economy ◽  
Nox Reduction ◽  
Test Stand ◽  
Diesel Emissions ◽  
Diesel Generator ◽  
Light Duty ◽  
Nox Sensor ◽  
Diesel Emission ◽  
Tier 3

The combination of increasingly challenging emissions regulations and impending Corporate Average Fuel Economy (CAFE) standards of 54.5 mpg by 2025 presents auto makers with a challenge over the next 10 years. The most promising technologies currently available for meeting high fuel economy and low emissions regulations are increased hybridization, turbo downsizing, and increased Diesel engine implementation. Combining these into a hybrid turbo Diesel is an ideal transition technology for the very near future as battery and other alternative fuels become viable for widespread automotive use. This paper presents a Diesel emission test stand to improve Selective Catalytic Reduction (SCR) systems for light duty Diesel vehicles, particularly hybrid power systems that experience many start-stop events. Advanced modeling and control systems for SCR systems will further reduce tailpipe emissions below existing Tier structures and will prepare manufacturers to meet increasingly stringent Tier 3 standards beginning in 2017. SCR reduces oxides of Nitrogen, NO, and NO2, from otherwise untreated Diesel emissions. Scientific study has proved that inhaling this harmful exhaust gas is directly responsible for some forms of lung cancer and a variety of other respiratory diseases. In addition to EPA Tier emissions levels and CAFÉ standards, the On-Board Diagnostics (OBD) regulations require every vehicle’s emission control systems to actively report their status during all engine-on vehicle operation. Testing and development with production NOx sensors and production SCR components is critical to improving NOx reduction and for OEMs to meeting strict Tier 3 light duty emission standards. The test stand was designed for straightforward access to the NOx sensors, injector, pump and all exhaust components. A Diesel Particulate Filter (DPF) followed by a Diesel Oxidizing Catalyst (DOC) precedes the Selective Catalytic Reducer (SCR) injector, mixing pipe and catalyst. An upstream NOx sensor reads engine-out NOx and the downstream NOx sensor reports the post catalyst NOx levels. Custom fabrication work was required to integrate the SCR mechanical components into a simple system with exhaust components easily accessible in a repeatable, controlled laboratory environment. A Diesel generator was used in combination with a custom designed resistive load bank to provide variable NOx emissions according to the EPA drive cycles. A production exhaust temperature sensor was calibrated and integrated into the software test manager. Production automotive NOx sensors and SCR injector, pump and heaters were mounted on a production light duty vehicle exhaust system. The normalized nature of NOx concentration in parts per million (ppm) allows the small Diesel generator to adequately represent larger Diesels for controls development purposes. Both signal level and power electronics were designed and tested to operate the SCR pump, injector, and three Diesel Exhaust Fluid (DEF) heating elements. An Arduino-based Controller Area Network (CAN) communications network read the NOx Diesel emissions messages from the upstream and downstream sensors. The pump, injector, solenoid, and line heaters all functioned properly during DEF fluid injection. CAN and standard serial communications were used for Arduino and Matlab/Simulink based control and data logging software. Initial testing demonstrated partial and full NOx reduction. Overspray saturated the catalyst and demonstrated the production NOx sensor’s cross-sensitivity to ammonia. The ammonia was indistinguishable from NOx during saturation and motivates incorporation of a separate ammonia sensor.

Corrigendum to “Air quality impacts from the electrification of light-duty passenger vehicles in the United States” [Atmos. Environ. 208 (2019) 95–102]

2020 ◽  
Vol 229 ◽  
pp. 117487
Author(s):  
Jordan L. Schnell ◽  
Vaishali Naik ◽  
Larry W. Horowitz ◽  
Fabien Paulot ◽  
Paul Ginoux ◽  
...  
Keyword(s):  
United States ◽  
Air Quality ◽  
The United States ◽  
Atmos Environ ◽  
Passenger Vehicles ◽  
Light Duty

Effect of Fuel Economy on Automobile Safety

2005 ◽  
Vol 1941 (1) ◽  
pp. 1-7 ◽  
Author(s):  
Sanjana Ahmad ◽  
David L. Greene
Keyword(s):  
Fuel Economy ◽  
Negative Relationship ◽  
Cointegration Analysis ◽  
Corporate Average Fuel Economy ◽  
Traffic Fatalities ◽  
Passenger Cars ◽  
Light Duty ◽  
Light Trucks ◽  
Short Period ◽  
Light Duty Vehicle

Since 1975, the fuel economy of passenger cars and light trucks has been regulated by the corporate average fuel economy (CAFE) standards, established during the energy crises of the 1970s. Calls to increase fuel economy are usually met by a fierce debate on the effectiveness of the CAFE standards and their impact on highway safety. A seminal study of the link between CAFE and traffic fatalities was published by R. W. Crandall and J. D. Graham in 1989. They linked higher fuel economy levels to decreases in vehicle weight and correlated the decline in new car weight with about a 20% increase in occupant fatalities. The time series available to them, 1947–1981, includes only the first 4 years of fuel economy regulation, but any statistical relationship estimated over such a short period is questionable. This paper reexamines the relationship between U.S. light-duty vehicle fuel economy and highway fatalities from 1966 to 2002. Cointegration analysis reveals that the stationary linear relationships between the average fuel economy of passenger cars and light trucks and highway fatalities are negative: higher miles per gallon is significantly correlated with fewer fatalities. Log–log models are not stable and tend to produce statistically insignificant (negative) relationships between fuel economy and traffic fatalities. These results do not definitively establish a negative relationship between light-duty vehicle fuel economy and highway fatalities; instead they demonstrate that national aggregate statistics cannot support the assertion that increased fuel economy has led to increased traffic fatalities.

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