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In contrast to motorcycles with 4-stroke engines, 2-stroke engine motorcycles produce very high hydrocarbon and carbon monoxide emissions. Compared to a 1976 automobile, such motorcycles produce as much hydrocarbon emissions as ten to twenty passenger cars. Modified automobile catalyst technology with the addition of an air pump is shown to be effective in reducing the hydrocarbon and carbon monoxide emissions by 75 - 85% after mileage accumulation of 12,000 miles; these tests are in progress and are being continued. In spite of the fact that current 2-stroke engine motorcycles run rich (no excess air) hydrocarbon emissions can be reduced by 35% and higher with aged catalyst systems without the addition of air. The mechanical durability of the catalytic systems is completely satisfactory. Present data indicate that catalyst system technology has been developed to meet proposed interim EPA emission standards for 2-stroke motorcycle engines.

This paper discusses the results of studies of the exhaust HC emission of 2-stroke engines for motorcycles. The major factor producing HC emissions from 2-stroke engines is the short circuiting of fresh charge. Therefore, we made a study of the relation between the delivery ratio and the trapping efficiency by comparing the test results and the theoretical values of perfect mixing. We then verified the effects of engine speeds and irregular combustion to the trapping efficiency. Tests were conducted to clarify the relationship between the air/fuel ratio and HC concentration and mass HC emission, and the test results were compared with the theoretical values. In addition, a study was made on how to reduce the mass HC emission by optimizing air/fuel ratio. Next, we launched tests to study the effects of ignition timing on HC emissions as well as the ignition timing characteristics and throttle opening and engine speed.

This report describes a new type of simulation system - automatic operation equipment for motorcycles. In this system, all operations such as throttle, clutch and gear shifting are controlled automatically with command signals. This system could be used for the emission measurement standard modes and actual drive patterns. Therefore, this system could be used for various motorcycle simulation testing on a chassis dyanmometer. Further, durability tests for emission reduction devices could be performed with reliable and effective results using this system.

This report documents the investigation of the technical and economic feasibility of using a carbon canister on board the vehicle to retain displaced hydrocarbon vapors during refueling. Denoted by the API as an Interim Report of Project EF-14, this report is a sequel to the Project's Phase I Report of April 1973, “Cost Effectiveness of Methods to Control Vehicle Refueling Emissions.” To initiate the design of a prototype carbon canister system capable of handling refueling vapor losses, studies were undertaken on a bench-test system to define the total amount of refueling vapor to be handled, vapor retention capacity of activated carbon, and purge capacity over a range of refueling conditions and fuel system parameters. In addition, extensive exhaust and evaporative emission tests were performed on the baseline vehicle and the modified vehicle. Detailed cost and effectiveness analyses were performed.

This paper summarizes an investigation of reductions in exhaust emission levels attainable using various techniques appropriate to gasoline engines used in vehicles over 14,000 lbs GVW. Of the eight gasoline engines investigated, two were evaluated parametrically resulting in an oxidation and reduction catalyst “best combination” configuration. Four of the engines were evaluated in an EGR plus oxidation catalyst configuration, and two involved only baseline tests. Test procedures used in evaluating the six “best combination” configurations include: three engine emission test procedures using an engine dynamometer, a determination of vehicle driveability, and two vehicle emission test procedures using a chassis dynamometer. Dramatic reductions in emissions were attained with the catalyst “best combination” configurations. Engine durability, however, was not investigated.

This paper discusses the use of an oxidation type catalytic converter for medium and heavy-duty gasoline powered trucks. It offers the highest reductions of HC and CO; and it is the simplest, most durable, and most cost effective system for reducing air pollution from trucks without fuel or driveability penalties.

This is a summary compilation and analysis of exhaust-emission results and operating parameters from forty-five heavy-duty gasoline and diesel-powered vehicles tested over a 7.24-mile road course known as the San Antonio Road Route (SARR); and, for correlative purposes, on a chassis dynamometer.(2) Exhaust samples were collected and analyzed using the Constant Volume Sampler (CVS) technique similar to that used in emission testing of light-duty vehicles. On the road course, all equipment and instrumentation were located on the vehicle while electrical power was supplied by a trailer-mounted generator. In addition to exhaust emissions, operating parameters such as vehicle speed, engine speed, manifold vacuum, and transmission gear were simultaneously measured and recorded on magnetic tape. The forty-five vehicles tested represent various model years, GVW ratings, and engine types and sizes.

To meet exhaust emission standards, nearly all 1975 model U. S. passenger cars use catalytic converters in conjunction with unleaded gasoline. While it has been established that lead and phosphorus from gasoline are deleterious to catalyst performance, much less is known about any similar effect of elements normally present in conventional engine oils. In addition, the ability to protect engines from excessive deposits and wear is essentially unproved for engine oils in which the phosphorus and metals contents have been either reduced (low ash oils) or eliminated (ashless oils). To obtain catalyst and engine performance information on such oils, tests were run using 95, 1972-1973 model passenger cars, operated with unleaded gasoline in several types of service. Forty cars were equipped with 1975 production-prototype underfloor catalytic converters containing pelleted oxidation catalysts.

The validity and appropriateness of the application of the Head Injury Criterion (HICm) concept to motorcycle helmet testing has been examined. Its derivation has been reviewed and its logic assessed. It is shown to be an inconsistent and unreliable criterion for helmet performance evaluation. This inconsistency stems primarily from its poor correlation with experimental data and from the basic assumption that the seriousness of a head impact can be ascertained by considering only a portion of the test headform acceleration pulse. Several alternative criteria which all are physically sound and mathematically consistent and which are more amenable to protective headgear design and testing are proposed. These criteria include force and loading time minimization; load distribution; minimization of loading rate and maximization of energy dissipation.

The results of a head injury model development program are presented. They include a description of the model's features and its capabilities for simulating direct and indirect impact forces. The model's validity is discussed in terms of level of confidence and verification. Skull bone response and brain response are presented for a variety of dynamic simulations. The scope and limitations imposed by the assumption of linearity are discussed. The results demonstrate that while some minor changes appear indicated, the model predictions yield useful insight into the mechanical causes of skull and brain injury.

A finite element model of the human brain is developed which provides badly needed new information and insight in brain dynamics. The model is based on fewer assumptions and has sufficient detail to permit correlation with experiments. It demonstrates a new approach to brain modeling and hopefully it will become a useful tool in future research.

This report defines humanlike quasi-static bending response characteristics of the lower torso. Six volunteers were subjected to a total of 72 tests to define response characteristics for sagittal flexion and extension bending. The effects of muscle tensing and knee bend on the response are evaluated. Sixteen loading corridors of moment of applied force about the H-point axis versus thorax-pelvis and pelvis-femur angles are suggested. The significant differences between the relaxed and tensed muscles results illustrate the need for a philosophical decision regarding which of these conditions should be adopted to define lower torso bending response for the human surrogate used in automotive safety studies.

Results from longitudinal impact tests on the knees of nine seated cadavers are reported. Typical impact velocities, impact force histories and femur strain histories are presented. The importance of femur bending is revealed by strain readings on the medial, lateral, anterior and posterior surfaces. The effects of impactor padding, leg tissue and oblique impacts are illustrated. The average fracture force level was found to be 10.04 kN and the impact energy to be 549J. The fracture patterns and possible mechanisms are discussed.

This paper presents the results of direct impact tests and driving point impedance tests on the legs of seated unembalmed human cadavers. Variables studied in the program included impactor energy and impact direction (axial and oblique). Multiple strain gage rosettes were applied to the bone to determine the strain distribution in the bone. The test results indicate that the unembalmed skeletal system of the lower extremities is capable of carrying significantly greater loads than those determined in tests with embalmed subjects (the only similar data reported in the present literature). The strain analysis indicated that significant bending moments are generated in the femur with axial knee impact. The results of the impedance tests are used to characterize the load transmission behavior of the knee-femur-pelvis complex, and the impact test results are combined with this information to produce suggested response characteristics for dummy simulation of knee impact response.

A review of the existing mathematical models of a car occupant in a rear-end crash reveals that existing models inadequately describe the kinematics of the occupant and cannot demonstrate the injury mechanisms involved. Most models concentrate on head and neck motion and have neglected to study the interaction of the occupant with the seat back, seat cushion, and restraint systems. Major deficiencies are the inability to simulate the torso sliding up the seat back and the absence of the thoracic and lumbar spine as deformable, load transmitting members. The paper shows the results of a 78 degree-of-freedom model of the spine, head, and pelvis which has already been validated in +Gz and -Gx acceleration directions. It considers automotive-type restraint systems, seat back, and seat cushions, and the torso is free to slide up the seat back.

The overall objective of this experimental investigation of pedestrian/vehicle impacts was to conduct representative impacts of unembalmed cadavers in order to (1) pioneer the establishment of impact tolerance levels for the pelvis and legs of a standing pedestrian and (2) explore the ability of a few selected geometry and compliance modifications to the impacting vehicle to increase the impact velocities that can be tolerated. A series of 15 experimental impacts were conducted which covered a speed range from 10 to 30 mph. Dynamic data obtained included high-speed films and time histories of (1) bumper and hood edge forces, (2) horizontal and vertical ground reaction forces, and (3) pelvic acceleration. The resulting injuries were determined from examination of pre- and post-impact X-rays and detailed pathological dissections, and were assessed as to probable temporary total and permanent partial disabilities.

Pedestrian-vehicle accidents have become a peculiar urban problem that has to be solved in the future. This demands a better knowledge about the performance of pedestrian accidents. Tests using dummies to simulate real world accidents are very important to study the mechanism of impacts. Since only the dummy has been fitted with measuring devices like accelerometers, it is highly difficult to estimate the interaction between the dummy and the car to a fair degree of accuracy. Therefore, it is necessary to measure the body forces in addition to the dummy accelerations in order to explain the impact mechanism more precisely. For this purpose, a body force measuring test vehicle has been developed at the Institute of Automotive Engineering, Berlin. A deformable unit which simulates the stiffness and geometrical measurements of a vehicle front is supported by load cells.

Several types of energy absorbers were tested on a sled simulating a crash deceleration using instrumented, seated erect dummies and cadavers. The energy absorbers were mechanical load limiting devices which attenuated the impact by yielding or tearing of metal. Their principal effects were to reduce the peak deceleration sustained by the occupant with the expected reduction in restraint forces. Constant load level energy absorbers were found to be unattractive because they can easily “bottom out” causing forces and body strains which could be much higher than those without absorbers. Head accelerations were significantly reduced by the energy absorbers as well as some body strain. However, spinal strains in the cadaver were not significantly reduced. They appear to be not only a function of the peak deceleration level but also of the duration of the pulse.

Collisions between vehicles and pedestrians are analyzed, in conjunction with a bidisciplinary “pedestrian” investigation, by simulating accidents using adult and child dummies. A series of experimental collisions were carried out at varying impact speeds with a sample of vehicles representative of the various front-end profiles of vehicles at present running on the roads, the purpose being to study how these profiles affect the kinematics of the adult and child and to define the risks of injury during the different phases of the accident. The degrees of severity of the impact against the vehicle and the ground are compared and head impact speeds analyzed. Countermeasures are proposed and an initial evaluation made using a cadaver.

The use of a high efficiency, continuously variable transmission (CVT) with a wide ratio range is required in order to operate an automotive engine at minimum brake specific fuel consumption (bsfc). Such operation will increase fuel economy from 20-40% over conventional practice. This paper describes a 12:1 ratio range CVT, and shows a simplified control system capable of allowing a vehicle to operate with the engine at or very near minimum bsfc under all demand power conditions for optimized fuel economy. Also described is the effect such a transmission has on vehicle performance and raises the possibility of reducing engine size to maintain normal performance, and further increase fuel economy.