Causes of Failure in High Emitting Cars

Heirigs, Philip L.; Austin, Thomas

doi:10.4271/961280

Cited by 5 publications

(1 citation statement)

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“…7,[25][26][27] Two important examples of malfunctioning emissions controls are improper fuel metering and failure of the oxygen sensor, which provides feedback for control of the fuel-air ratio. 28 There appear to be at least five possible causes of failure of such components: (1) extensive high power driving of a vehicle; (2) outright tampering of the ECS (by owner or mechanic); (3) inadequate maintenance (by owner); (4) improper repairs (by owner or mechanic); and (5) poor initial ECS design or manufacture. Component failures can also result from a combination of two or more of these causes.…”

Section: Malfunctioning Exhaust Emissions Controlsmentioning

confidence: 99%

Real-World Emissions from Conventional Passenger Cars

Ross

Goodwin

Watkins

et al. 1998

Journal of the Air & Waste Management Association

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It has long been recognized that vehicles emit more pollutants than allowed under the new car emission standards. Further tightening of the certification standards based on existing test procedures does not directly address the largest sources of emissions. This study attempts to quantify vehicle emissions by source, in order to prioritize future policymaking. Several new sets of data are used in conjunction with regulatory emission models to characterize the lifetime emissions from the average Model Year (MY)93 vehicle. Special attention is paid to two of the largest sources of real-world emissions: (1) high-power driving by cars with properly functioning emissions controls, and (2) cars with malfunctioning emissions controls. Emissions are projected to MY2000 and 2010, based on estimates of the effectiveness of recently adopted and proposed regulatory policies. These new policies are projected to reduce total emissions substantially.

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Section: Malfunctioning Exhaust Emissions Controlsmentioning

confidence: 99%

Real-World Emissions from Conventional Passenger Cars

Ross

Goodwin

Watkins

et al. 1998

Journal of the Air & Waste Management Association

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The development of a prescreening model to identify failed and gross polluting vehicles

Choo

Shafizadeh

Niemeier

2007

Transportation Research Part D: Transport and Environment

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The California State Bureau of Automotive Repair uses a high-emitter profile model to direct, or screen a fraction of the vehicle fleet in for inspection and maintenance testing at test-only facilities. Reviews by the California Inspection/Maintenance Review Committee showed the high-emitter profile to be inefficient and in need of improvement. In this study, using in-use vehicle emissions data from California's statewide smog check program, we specified a new multinomial logit model designed to improve the screening efficiency for targeting potential failed and gross polluting vehicles. Modeling results show that factors such as odometer reading, model year, vehicle make, as well as the presence of emissions control systems are significant factors in predicting the likelihood that a screened vehicle will test as a failed or a gross polluting vehicle. Comparisons indicate that the new multinomial logit model specification can predict various inspection/maintenance test outcomes more accurately than the existing high-emitter profile model.

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