Report by the Committee on Motor Vehicle Emissions (1973) / Chapter Skim
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4 Potential of Spark-Ignition Internal-Combustion Engines for Meeting Standards in Use
4 Potential of Spark-Ignition Internal-Combustion Engines for Meeting Standards in Use
Pages 69-86
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From page 69... ...
There are some not included, such as sustained operation at high engine power and long decelerations, that will provide severe tests for emission-control systems, especially those using catalytic converters. Ford believes the certification test 69
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From page 70... ...
Sufficient data are not available to fully assess the effects of low-t~perature operation on catalyst durability. However, increased loading on the catalysts due to low ambient temperatures, as well as occasional bouts of freezing and thawing, appear to offer inuse conditions that would lead to the necessity for more frequent catalyst replacement than during the certification procedure.
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From page 71... ...
1971 model year cars, with an average mileage accumulation of only 13,000 miles, exceeded the applicable standards for at least one of the pollutants. Cars for these model years contain neither catalysts nor much of the other complex hardware proposed by most manufacturers for 1975-76 model years.
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From page 72... ...
Spark plug misfire, sustained operation at high engine power, and descent down long hi Its are examples of situations that would result in catalyst overheating and pos sible failure. Such vehicle operation and driving modes would not occur in the mileage accumulation specified for the certification test.
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From page 73... ...
If they continue to do this when manufacturers' specifications are for low-emission adjustments, the cars will emit above the standards. The principal variations in the second method are related to how much of the work is done in state-owned and how much in privately owned facilities, the testing procedure used, testing frequency, pass/ fail standards, provision for retesting after repair/adjustment, and disposition of vehicles that cannot meet the standards.
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From page 74... ...
Repair at the time of failure of any important emissioncontrol device based on the manufacture of control systems that noticeably degrade the vehicle performance when an important component fails. Prescribed maintenance at predetermined intervals.
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From page 75... ...
The amount of training will vary slightly with the degree of state control on mechanics, but will generally have to be extensive. 4.4.2 Number of Mechanics The number of mechanics required to maintain 1975-76 emissioncontrol systems will depend upon the interpretation of the 50, 000-mile warranty provision of the 1970 Clean Air Amendments.
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From page 76... ...
However, the state inspection system that would significantly reduce serviceindustry equipment requirements would be one in which the state would perform the complete diagnosis and instruct mechanics on what parts to replace. r 4.5 State Action 4.5.1 Inspection and Maintenance Systems State governments have been interested in inspection and maintenance of motor vehicles as a means of reducing exhaust omissions for many years.
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From page 77... ...
The Clean Air Act generally preempted motor vehicle emission control for the federal government. This raised several problems connected with the design of state systems.
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From page 78... ...
This approach would require no special inspection facilities owned by the state, but it would require careful surveillance of privately Owned garages and additional equipment in these garages. Requiring the garages to adjust each car to manufacturer's specifications when performing any maintenance also does not require state-owned facilities but does require close supervision.
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From page 79... ...
Inspection lanes select the vehicles needing adjustment or repair but otherwise do nothing to reduce emissions unless the results assist or control the mechanics making the repairs. Inspection lanes can assist and control the mechanics in one or more of the following ways: Detect vehicles with excessive emissions (needing repairs)
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From page 80... ...
1975-1976 cars will require a much more thorough diagnosis of the complete emission control system. Diagnostic tests could be useful in inspects on lanes if they provided complete information on engine and control-system failures and operation.
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From page 81... ...
With practical and cost considerations thus limiting the number of cars sent for adjustment and repair, the maximum emissions reduction is to be achieved by adjusting only those cars whose emissions are clearly high and leaving alone those below or near the satisfactory level. The percentage of cars sent for adjustment/repair must be considered with great care also because it increases the load on both the service industry and the inspection lanes and because a high percentage of re-rejections will destroy public support, which is so important.
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From page 82... ...
No meaningful estimate of operating or capital costs chargeable to the emissions testing is possible because of shared costs. Time and cost would both increase if the testing were also intended to enforce the federal individual car warranty.
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From page 83... ...
The land, structure, and equipment will cost from $23, 000 to $60, 000 per inspection lane, with a major portion of the difference in cost caused by the presence or absence of dynamometer equipment. These numbers are approximately confirmed by the TRW study which estimated $44,000 to $52,000 per lane for dynamometer-equipped facilities.
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From page 84... ...
The three-valve carbureted stratified-charge engine and the Wankel engine with thermal reactor show potential for low emissions without the use of catalysts. HC and CO deterioration factors for the former, at 1975 levels and as measured on the federal driving cycle, are considerably less than those from catalyst-equipped vehicles.
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From page 85... ...
Since such a feedback loop makes the engine essentially selftuning, this approach should also eliminate a large fraction of the inherent variability between individual vehicles that results from manufacturing tolerances. Possibly also, operational variabilities that result fray variations in driving habits, fuel consumption, atmospheric parameters, and induction-system deterioration would be largely eliminated.
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From page 86... ...
The three-valve carbureted stratified-charge engine, Wankel with thermal reactor, and catalytic system with exhaust sensors and feedback control seem to have far more potential for achieving low emissions in use than the dual-catalyst system currently being proposed by most manufacturers for the 1976 model year.
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