Report by the Committee on Motor Vehicle Emissions (1973) / Chapter Skim
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7 Discussion
7 Discussion
Pages 113-127
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From page 113... ...
The current crash programs of the major manufacturers have turned out to be expensive and, in retrospect, not well planned. Nevertheless, the almost world-wide effort to achieve the federal emission standards set for the light-duty motor vehicles in the United States has produced a significant rate of progress toward meeting the requirements of the Clean Air Amendments of 1970.
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From page 114... ...
To achieve the further reductions called for by the 1975 and 1976 standards, most major manufacturers currently plan to use catalysts in the exhaust stream to promote both oxidation of carbon monoxide and hydrocarbons and chemical reduction of NOx. The CMVE believes that engines equipped with oxidation catalysts will be able to meet - 114
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From page 115... ...
Although American manufacturers and others evidently will be able to produce catalyst-equipped vehicles capable of certification for the 1975 model year, and even possibly capable of 1976 certif~cation, compliance with the certification procedure, of itself, may not constitute indication of satisfactory performance of catalyst-equipped vehicles in actual customer use. As discussed in Section 4.2, the diverse conditions to be undergone by the engine and control systems during 50,000 miles of customer use are far more strenuous than those undergone during certification.
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From page 116... ...
7.3.1 Carbureted Three-Valve Stratified-Charge Engine Prototype compact cars equipped with the carbureted threevalve stratified-charge engine have met the 1975 standards for 50,000 miles. Three tests on vehicles equipped with an advanced version of this system show average low-mileage emissions of 0.25 grams per mile HC, 2.50 grams per mile CO, and 0.43 grams per mile NO (see Table 3-11~.
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From page 117... ...
7.3.3 Wankel Engines As shown in Table 3-7, the Wankel engine with thermal reactor on a compact car has met the 1975 standards with NOx levels of about 1 g/mile for 50,000 miles, but with a fuel penalty of about 30 percent compared with a 1973 equivalent piston engine. The use of EAR and richer carburetion can probably further reduce NOx levels, but at the cost of even greater fuel consumption, and even so it is not yet certain that the 1976 standard for NO can be achieved.
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From page 118... ...
~5) of the Act." However, the considerate ons that must enter into the determination of optimal technologically feasible interim standards are so complex and carry so many implications that, as explained below, it is inadvisable and inappropriate for this Committee to recommend a specific set of interim levels at this time.
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From page 119... ...
Thus, at this time, the Committee finds it inadvisable to recommend a specific set of interim standards. 7.5 Effects of a Delay in Enforcement on Total Automobile Emissions To illustrate the ef fects of various delays in implementing the emissions standards, should this be found necessary, a computer model was used to calculate total automotive emissions in a typical metropolitan area for the years from 1960 to 2000.
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From page 120... ...
The Implementation of emissions controls since 1968 has already caused an appreciable reduction in annual emissions of HO and CO, but little reduction in NO . Federal standards for model year 1973 cars call for decreases of approximately 80 percent for hydrocarbons, - 120
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From page 122... ...
to to lo N Cat ret CO UJ cn X O Z ~ O Z m Z O ~ ~ Z A: _ C,0 U]
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From page 124... ...
Preponderantly, these ef fects ref lect the removal from service of older, uncontrolled, or less-well-controlled automobiles. 7.6 Implementation of 1975 and 1976 Standards and Related Matters Of two promising candidates for certification and production in 1975 and 1976 - the dual-catalyst system and the carbureted stratifiedcharge engine - only the forager is planned for manufacture on a scale commensurate with expected requirements in those years.
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From page 125... ...
. The circumstances recounted above - the probable certifiability of the carbureted stratified-charge engine under both 1975 and 1976 standards but its relatively limited planned production, particularly in 1975, and the considerable promise of other, as yet incompletely developed systems - make judgment concerning an optimal national approach to decision concerning the scheduled implementation of the 1975/1976 standards extraordinarily complex - precisely because the entire research and development aspect of this situation is very much in flux and changing rapidly.
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From page 126... ...
there is no assurance that the additional development time would not simply be employed by the major manufacturers for further development of the present systems; and (d) the presence on the market of even a small number of alternative control systems that are more reliable, cheaper, and accompanied by a lesser fuel penalty, if any, would constitute an effective market device, which, without other intervention, would assure changeover by the major manufacturers at an acceptable pace, particularly if the recall provisions of the Act are enforced as warranted.
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From page 127... ...
These matters are so complex and important that the Committee strongly urges an early and thorough reexamination by Congress, EPA, and the Academy of all aspects of motor vehicle pollution standards established in the Clean Air Amendments of 1970 -- their premises, underlying assumptions, the goals that were set, and the interplay among the three pollutants dealt with specifically in the Act. In the light of the material developed in its study, CMVE believes that such a reexamination would be extremely valuable in relating motor vehicle emission control to the many issues relevant to a sound national environmental policy.
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