NOX Emission Controls for Heavy-Duty Vehicles Toward Meeting a 1986 Standard (1981) / Chapter Skim
Currently Skimming:
'CONTROL COSTS AND OTHER REGULATORY QUESTIONS'
'CONTROL COSTS AND OTHER REGULATORY QUESTIONS'
Pages 79-96
The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.
From page 79... ...
These numbers were based on particular assumptions about fuel economy and annual mileage, but other reasonable assumptions would show the same general relation between initial cost and fuel penalty. For diesel engines the fuel cost of a l-percent increase in fuel consumption is roughly equal to the initial capital cost increase.
|
From page 80... ...
^Control technology: turbocharging, charge cooling, electronic injection timing controls, and exhaust gas recirculation. GUndiscounted costs for hardware, R&D, and certification testing.
|
From page 81... ...
This requires a detailed analysis that is beyond the scope of the committee's charge. To illustrate the relative cost-effectiveness of various controlled emissions levels for diesel and gasoline engines we have calculated the increase in fuel costs for assumed fuel penalties and assumed emissions levels.
|
From page 82... ...
127 247 126 247 137 503 Fuel economy in 1986b 6.84 10.88 6.03 9.77 3.49 5.90 Lifetime fuel use (thousands of gallons) 18.4 22.7 20.9 25.3 39.3 85.3 Assumed fuel cost (dollars per gallon)
|
From page 84... ...
200 g/bhp-h for diesel engines, 300 g/bhp-h for gasoline engines o Current NOX emissions (Ej) 8 g/bhp-h for diesel engines, 6 g/bhp-h for gasoline engines o Fuel costs (Cf)
|
From page 85... ...
From an emission control standpoint, the diesel engine has lower emissions of hydrocarbons and carbon monoxide, while the gasoline engine has lower NOX and particulate emissions. Catalytic emission control systems are widely used on light-duty gasoline engines, but their durability under the more severe operating conditions of heavy-duty engines remains to be proven.
|
From page 86... ...
On the other hand, because diesel engines are the largest fuel users of the heavy-duty engine fleet, any emission standard that imposes a fuel consumption penalty will have a greater effect on diesel users than on gasoline engine users. From a regulatory perspective, the cost of the increased fuel use required to reduce a unit amount of NOX emissions from diesels appears to be less than the comparable cost for gasoline engines.
|
From page 87... ...
Under the corporate average emissions standard concept, a manufacturer could produce an engine family whose entire production exceeded the emissions standard provided that the same manufacturer also produced another engine family with emissions correspondingly below the standard. In concept, emissions averaging in heavy-duty engines could be applied as follows: Production of diesel engines would be used to meet the hydrocarbon and carbon monoxide standards and production of gasoline engines to meet the NOX and particulate standards, in recognition of the differences between the two engine types in terms of the difficulty of controlling emissions of each type.
|
From page 88... ...
A fleet-average emissions standard that accomplished this could have a significant positive effect on the development of technology. Test Procedures Emissions reductions achieved in practice depend on the laboratory test procedures used to measure engine emissions.
|
From page 89... ...
The ability of the test procedures to represent actual emissions performance should be subjected to an ongoing review. Regulations and Technological Feasibility Some recent environmental regulations have set standards, to take effect some time after promulgation, that could not be met by the existing technology.
|
From page 90... ...
The establishment of such regulations is a clear signal to other companies that a market is present if they can develop the necessary technology. In the specific subject considered here, the control of NOX emissions from heavy-duty engines, two clear problems would be raised by the establishment of a technology-forcing regulation: the durability of catalysts for control of NOX from gasoline engines and the effects of exhaust gas recirculation on diesel engines' performance and durability.
|
From page 91... ...
Catalyst Technology The durability of catalysts for NOX emission control in heavy-duty gasoline engines has also been noted as a source of uncertainty. These catalysts have been shown to be effective when fresh.
|
From page 92... ...
Particulate Traps It has been observed in this report that with current control technology a decrease in NOX emissions from diesel engines generally implies an increase in emissions of particulates. However, it would be possible to reduce emissions of both types simultaneously if exhaust particulate traps were available.
|
From page 93... ...
Previous versions of the Texaco stratified charge engine, in light-duty vehicles, have shown good fuel economy with moderate emissions, but stringent emission controls sharply increased its fuel consumption (Tierney et al., l975)
|
From page 94... ...
Issues that should be considered during the regulatory processes include: o The differences between gasoline and diesel engines o The different size ranges in heavy-duty engines o Emissions averaging concepts o The amount of research and development that would be promoted by a specific standard o The ability of the industry to respond to the regulation.
|
From page 95... ...
l98lb. "Control of Air Pollution from New Motor Vehicles and New Motor Vehicle Engines: Particulate Regulation for Heavy-Duty Diesel Engines." (Proposed rule.)
|
From page 96... ...
96 l98lc. "Control of Air Pollution From New Motor Vehicle Engines: Gaseous Emission Regulations for l985 and Later Model Year Light-Duty Trucks and l986 and Later Model Year Heavy-Duty Engines." (Advance notice of proposed rulemaking.)
|
Key Terms
This material may be derived from roughly machine-read images, and so is provided only to facilitate research.
More
information on Chapter Skim is available.