Showing papers in "Vehicle System Dynamics in 1973"
TL;DR: In this paper, an approximate method is presented which produces a handling diagram useful for the study of steady-state turning behavior at different values of steer angle, path radius and speed.
Abstract: SUMMARY An approximate method is presented which produces a handling diagram useful for the study of steady-state turning behaviour at different values of steer angle, path radius and speed In three successive parts the steady state response of simple and more elaborate vehicle models and the stability of the resulting motion are discussed.
67 citations
TL;DR: In this paper, a simplified analysis of the turning behavior of motor vehicles is presented, based on a simplified version of the Part 3: More Elaborate Systems (ELS) model.
Abstract: (1973). Simplified Analysis of Steady-State Turning Behaviour of Motor Vehicles Part 3: More Elaborate Systems. Vehicle System Dynamics: Vol. 2, No. 4, pp. 185-204.
65 citations
TL;DR: In this paper, a simplified analysis of the stability of the turning behavior of a vehicle is presented, based on a simple simplified version of the Steady State Turn Behavior of Vehicles.
Abstract: (1973). Simplified Analysis of Steady-State Turning Behaviour of Motor Vehicles Part 2: Stability of the Steady-State Turn∗. Vehicle System Dynamics: Vol. 2, No. 4, pp. 173-183.
37 citations
Journal Article•
TL;DR: The same theory for the STEADY-STATE RESPONSE to STEERing InPUT of the SIMPLE LINEAR TWO-DEGREE of FREEDOM VEHICLE can be applied to more COMPLEX LINEAR systems.
Abstract: AN APPROXIMATE METHOD IS PRESENTED WHICH PRODUCES A HANDLING DIAGRAM USEFUL FOR THE STUDY OF STEADY-STATE TURNING BEHAVIOR AT DIFFERENT VALUES OF STEER ANGLE, PATH RADIUS AND SPEED. THREE SUCCESSIVE PARTS DISCUSS HANDLING DIAGRAMS OF SIMPLE SYSTEMS; STABILITY OF THE STEADY-STATE TURN, AND THEORY APPLIED TO MORE ELABORATE SYSTEMS. ESSENTIALLY THE SAME THEORY FOR THE STEADY-STATE RESPONSE TO STEERING INPUT OF THE SIMPLE LINEAR TWO-DEGREE OF FREEDOM VEHICLE CAN BE APPLIED TO MORE COMPLEX LINEAR SYSTEMS. THE ONLY REAL DIFFERENCE IS THAT NEWLY INTRODUCED EFFECTIVE SLIP ANGLES AND EFFECTIVE CORNERING STIFFNESS OF FRONT AND REAR AXLES WILL REPLACE THE REAL SLIP ANGLES AND CORNERING STIFFNESSES OF THE TIRE PAIRS. /DOT/
25 citations
21 citations
TL;DR: In this article, an improved approximation of the theory of the dynamic frequency response of side force and aligning torque acting upon the rolling wheel when the latter is moved laterally and swivelled about the vertical axis, is presented.
Abstract: An improved approximation of the theory of the dynamic frequency response of side force and aligning torque acting upon the rolling wheel when the latter is moved laterally and swivelled about the vertical axis, is presented. The method is particularly suitable for application in vibration problems of steering and suspension systems of automobiles and aircraft where relatively high speed and high frequency phenomena play a role. The theoretical results show satisfactory agreement with experimental data. Calculations indicate that the inertia of the tire decreases the tendency to shimmy at higher frequencies and speeds of travel. For castered wheels however, tire inertia may have an adverse effect due to its unfavorable influence upon the side force response to swivel motions.
19 citations
TL;DR: In this article, the effects of vehicle weight increase and mission control on fuel economy and coal economy were investigated for an instantiate car and compared with a SUBCOMPACT and a Luxury VEHICLE.
Abstract: SINCE 1968, VEHICLE WEIGHT INCREASES AND EMISSIONS CONTROLS HAVE REDUCED FUEL ECONOMY SUBSTANTIALLY. ADDITIONAL LOSSES IN ECONOMY AND ACCELERATION WILL BE EXPERIENCED THROUGH 1976. RECOMMENDATIONS ARE MADE TO LESSEN THE IMPACT OF THE PREDICTED LOSSES. FACTORS INFLUENCING FUEL ECONOMY AND ACCELERATION ARE EXAMINED FOR AN INTERMEDIATE CAR. CHANGES IN ENGINE EFFICIENCY AND DISPLACEMENT, COMPRESSION RATIO, TORQUE CONVERTER, TRANSMISSION, AXLE RATIO, AERODYNAMIC DRAG, TIRES, ACCESSORIES, VEHICLE WEIGHT, AND EMISSIONS CONTROLS ARE EXAMINED. WHEN PRACTICAL, THE EFFECTS OF 10 PERCENT CHANGES ARE ANALYZED. COMPARISONS ARE ALSO MADE WITH A SUBCOMPACT AND A LUXURY VEHICLE. /AUTHOR/
12 citations
TL;DR: In this paper, the random vertical vibration of two linear models of a sprung mass with a passenger on seat is numerically solved and the acceleration of the passenger is frequency-weighted according to two various criteria.
Abstract: SUMMARY The random vertical vibration of two linear models of a sprung mass with a passenger on seat is numerically solved. The input signal has a power spectrum of a real road. The acceleration of the passenger is frequency-weighted according to two various criteria. The gain in comfort obtained by lowering the natural frequency of the sprung mass is calculated along with the dynamic and static spring deflections. In addition, a solution of the vibration of the unsprung mass with evaluation of a possible improvement is presented.
9 citations
TL;DR: In this article, the effects of anti-skid braking on the handling behavior and braking performance of a tractor-semitrailer truck were investigated in a cornering maneuver that involves braking and driver steering.
Abstract: This paper describes a study of anti-skid braking and the effects of such braking on the handling behavior and braking performance of a tractor-semitrailer truck. The truck, represented by a digital computer model having fourteen degrees of freedom, is taken to be in a cornering maneuver that involves braking and driver steering. Conventional braking or one of three types of anti-skid braking is used in the maneuver. The results show that the effects of anti-skid braking on the handling behavior and braking performance of the truck are beneficial. The results also show that the behavior of the wheels and the handling behavior and braking performance of the truck depend on the type of anti-skid braking used.
6 citations
TL;DR: In this article, the authors used the conservation laws of linear momentum, angular momentum, and energy to predict initial speeds and impact locations for two inelastic vehicles on a collision course.
Abstract: Methods are presented for predicting either initial speeds or impact locations for two inelastic vehicles on a collision course. Forty system parameters are distinguished, of which up to 35 can be deduced with varying degrees of accuracy from post-collision data. The remaining parameters are calculated using the conservation laws of linear momentum, angular momentum, and energy. Essential ingredients of this analysis are the plastic impact deformation energies and the friction work along the post impact trajectories. Examples of central impact and computer-aided studies for oblique impact illustrate how vehicle speed predictions vary within the bounds of uncertain accident data. /Author/
3 citations
TL;DR: In this article, the random vibration of a nonuniform cantilever beam with a concentrated mass at its end is modeled as a simple model of the suspension spring of a motor vehicle.
Abstract: SUMMARY The random vibration of a nonuniform cantilever beam with a concentrated mass at its end, is studied as a simple model of the suspension spring of a motor vehicle. The spectral response of the displacement of the concentrated mass is obtained when the beam is subjected to the random motion of the support. The conditions for the validity of the single degree approximation is also discussed.
Journal Article•
TL;DR: A PRACTICAL, MULTIPURPOSE URBAN DIFFUSION MODEL (APRAC-1A) has been developed and evaluated for predicting the presence of InERT, VEHICLE-GENERATED POLLUTANTS.
Abstract: A PRACTICAL, MULTIPURPOSE URBAN DIFFUSION MODEL (APRAC-1A) HAS BEEN DEVELOPED AND EVALUATED FOR PREDICTING CONCENTRATIONS OF INERT, VEHICLE-GENERATED POLLUTANTS. THE MODEL REQUIRES ONLY ROUTINELY AVAILABLE METEOROLOGICAL AND TRAFFIC DATA TO GIVE THE FOLLOWING OUTPUTS: AERIAL CONCENTRATION ISOPLETHS, SEQUENTIAL HOURLY POINT VALUES, AND FREQUENCY DISTRIBUTIONS. AN EXTENSIVE FIELD EXPERIMENT WAS CONDUCTED IN SAN JOSE TO EVALUATE AND REFINE ALL COMPONENTS OF THE MODEL. A STREET EFFECTS SUBMODEL WAS DEVELOPED TO ACCOUNT FOR THE HIGH CONCENTRATIONS AND LARGE GRADIENTS OBSERVED IN URBAN STREET CANYONS. /AUTHOR/
Journal Article•
TL;DR: In this paper, a review is made of aVAILABLE data on FUEL ECONOMIES of the current INTERNAL COMBUSTION ENGINE-Powered AUTOMOBILES and of those with ALTERNATIVE POWERPLANTS.
Abstract: A REVIEW IS MADE OF AVAILABLE DATA ON FUEL ECONOMIES OF THE CURRENT INTERNAL COMBUSTION ENGINE-POWERED AUTOMOBILES AND OF THOSE WITH ALTERNATIVE POWERPLANTS. COMPARISONS OF FUEL ECONOMIES OF ALL THESE ENGINE SYSTEMS ARE MADE ON THE BASIS OF THE VEHICLE WEIGHT/ENGINE DISPLACEMENT, AND THE VEHICLE WEIGHT ALONE. THE THERMAL EFFICIENCIES ARE ALSO COMPARED. IT IS SHOWN THAT SEVERAL VERSIONS OF THE DIESEL ENGINE WHICH MEET THE 1975 CLEAN AIR ACT STANDARDS AND WHICH ARE ON THE ROAD TODAY ARE MORE EFFICIENT THAN THE CONVENTIONAL INTERNAL COMBUSTION ENGINE OF 1973. MOREOVER, PROTOTYPES OF OTHER ALTERNATIVE SYSTEMS, USING OTHER CYCLES (BRYTON, RANKINE, STIRLING) UNDER DEVELOPMENT ARE ALSO PROJECTED TO PROVIDE HIGHER EFFICIENCIES THAN THE CONVENTIONAL INTERNAL COMBUSTION ENGINE OF 1973. ALL COMPARISONS ARE MADE USING THE FEDERAL DRIVING CYCLE AS A COMMON REFERENCE. /AUTHOR/
TL;DR: In this paper, a general approach is taken to look at the automotive industry's efforts to solve the energy and mission challenges from the viewpoint of a state GOVERNMENT this paper.
Abstract: A GENERALIZED APPROACH IS TAKEN LOOKING AT AUTOMOBILE EMISSIONS AND ENERGY PROBLEMS FROM THE VANTAGEPOINT OF A STATE GOVERNMENT REGULATORY AGENCY. THE AUTO INDUSTRY'S VAST CAPABILITY FOR TECHNOLOGY, MASS PRODUCTION, QUALITY CONTROL, AND MARKETING ABILITY CULMINATES AT THE DEALERSHIP. THEREAFTER,THE VEHICLE IS OFTEN VIEWED BY THE USER MUCH DIFFERENTLY. INITIALLY,THIS PAPER ATTEMPTS TO OVERLAY MANY OF THE DIFFERENT DISCIPLINES THAT FORMULATE THE FINAL PRODUCT. BY EXAMINING A WIDE RANGE OF ENVIRONMENTAL ILLS,IN PART CREATED BY THE AUTOMOBILE,AND BY ANALYZING HOW THE AUTOMOTIVE INDUSTRY HAS ADAPTED TO PAST CRISES,THE IMPENDING EMISSION AND ENERGY QUESTIONS ARE EXPLORED BY USING VARIOUS ECONOMIC,REGULATORY,AND ENGINE DESIGN TREND INDICATORS. PROSPECTIVES FOR ANALYZING THESE PROBLEMS ARE DEMONSTRATED. SUBSEQUENTLY,BY NARROWING THE PAPER'S OBJECTIVES,SOME PREVIOUS TECHNICAL STUDIES ARE USED TO SHOW POTENTIAL BENEFITS IN EMISSIONS AND FUEL SAVINGS BY THE INSPECTION/MAINTENANCE CONTROL STRATEGY. FIRSTHAND EMISSION SURVEILLANCE AND SERVICE DATA ARE SUPPLIED,ILLUSTRATING THE EFFECT OF NEW JERSEY'S INSPECTION PROGRAM WITH EMPHASIS ON MINIMIZING THE IMPACT TO THE MOTORING PUBLIC. MAXIMUM EMISSION REDUCTION YIELDS OF 10-12 PERCENT ARE EXPECTED FOR CARBON MONOXIDE AND HYDROCARBON EMISSIONS. ALSO,AN ADDITIONAL 0.33 PERCENT FUEL SAVING COULD BE REALIZED. IN ADDITION,DUE TO THE CAUSAL EFFECTS OF THIS STRATEGY,OTHER CONSERVATION-ORIENTED INCENTIVES BECOME APPARENT. FINALLY, IN A FURTHER NARROWING OF SCOPE,CONCEPTS FOR ESTIMATING THE INDIVIDUAL MOTORIST'S RATIONAL BEHIND HIS VALUE JUDGMENTS THROUGH ENERGY BALANCING ARE ATTEMPTED. ONLY BY VIEWING THE INDIVIDUAL MOTORIST AND THE MECHANISM IN WHICH HE PERCEIVES HIS ENVIRONMENT AND AUTOMOBILE CAN A MORE SYSTEMATIC ANALYSIS OF FUTURE AUTOMOTIVE IMPACTS BE UNDERTAKEN. /AUTHOR/
TL;DR: In this article, the authors discuss fuel economy in present automotive technologies and show that as vehicle weight has increased and EMISSION control has become more steely, fuel economy has degraded and will continue to degrade.
Abstract: THIS PAPER DISCUSSES FUEL ECONOMY IN PRESENT AUTOMOBILES AND SHOWS THAT AS VEHICLE WEIGHT HAS INCREASED AND EMISSION CONTROLS HAVE BECOME MORE STRINGENT, FUEL ECONOMY HAS DETERIORATED AND WILL PROBABLY CONTINUE TO DO SO. WEIGHT IS SEEN AS THE SIGNIFICANT FACTOR IN REDUCTION OF FUEL ECONOMY AND PERFORMANCE, AND SMALLER CARS ARE SEEN AS A POSSIBLE SOLUTION TO THE PROBLEM. /AUTHOR/
TL;DR: In this paper, the influence of the steering system on the general plane and dissipative motion of an unbraked vehicle is analyzed by using a mechanically equivalent system and the results show that such influence increases as the skidding path becomes longer.
Abstract: SUMMARY (Title: The Influence of the Steering System upon the General Plane and Dissipative Motions of a Motor Vehicle.) The basic equations describing the plane and horizontal skidding motions of an unbraked vehicle are derived by use of a mechanically equivalent system. They may be written as a system of nonlinear differential equations which in general allows numerical solutions only. A particular numerical solution is given in the paper, showing the influence of having an entirely free or fully blocked steering system. The results show that such influence increases as the skidding path becomes longer. The application of the above results being evident in connection with collision analyses.
Journal Article•
TL;DR: In this article, the authors consider the effect of wind on the performance of the highway air pollution and show that over a wide range of wind directions, the effect is only light and, for many PRACTICAL PURPOSES, could be disregarded.
Abstract: CONCENTRATIONS PRODUCED BY AN EXTENDED NEAR-GROUND LINE- SOURCE OF VEHICULARLY-GENERATED HIGHWAY AIR POLLUTION ARE CONSIDERED, WITH SPECIAL EMPHASIS ON THE INFLUENCE OF THE OBLIQUITY OF THE WIND. AN EARLIER MATHEMATICAL NOTATION WHICH HAS LED TO RECENT MISINTERPRETATION IN APPLICATIONS IS CLARIFIED, AND IT IS SHOWN THAT OVER A WIDE RANGE OF WIND DIRECTIONS THE CONCENTRATION DISTRIBUTION CAN BE CALCULATED BY A SIMPLE APPROXIMATE FORMULA. ALTHOUGH THE CONCENTRATIONS INCREASE AS THE WIND MORE CLOSELY PARALLELS THE DIRECTION OF THE HIGHWAY, THE INCREASE IS ONLY SLIGHT AND, FOR MANY PRACTICAL PURPOSES, COULD BE DISREGARDED. /AUTHOR/
TL;DR: In this paper, the authors discuss the present automotive industry situation in the United States, in terms of environmental damage, excess weight, and low fuel efficiency, and how the public is forced to deal with traffic.
Abstract: THIS PAPER DISCUSSES THE PRESENT AUTOMOBILE SITUATION IN THE UNITED STATES, IN TERMS OF ENVIRONMENTAL DAMAGE, EXCESS WEIGHT AND LOW FUEL ECONOMY,AND HOW THE PUBLIC IS FORCED TO DEAL WITH TRAFFIC. THE PAPER STRESSES THAT THE AUTOMOTIVE ENGINEERING INDUSTRY CAN ALLEVIATE SOME OF THE PROBLEMS BY DESIGNING AND MARKETING SMALLER, MORE EFFICIENT CARS AND BY BEING ATTUNED TO THE EFFECTS OF PRESENT-DAY AUTOMOBILES. SEVERAL SUGGESTIONS ARE MADE, INCLUDING A MILES-PER-GALLON TAX AND ENVIRONMENTAL STICKERS ON NEW CARS, NEXT TO PRICE STICKERS. /AUTHOR/
Journal Article•
TL;DR: In this article, the authors present preliminary data on the COST and EFFTIVENESS of an ANNUAL AUTOMOBILE EMISSION INSPECTION system and show that SEVERAL RETROFIT DEVICES are more efficient than InSP as a control strategy.
Abstract: PRELIMINARY DATA ARE PRESENTED ON THE COST AND EFFTIVENESS OF AN ANNUAL AUTOMOBILE EMISSION INSPECTION SYSTEM. USING A LEAST COST LINEAR PROGRAMMING MODEL IT IS SHOWN THAT SEVERAL RETROFIT DEVICES ARE MORE ECONOMICALLY EFFICIENT THAN INSPECTION AS A CONTROL STRATEGY. IT IS THEN ARGUED THAT THE ANNUAL EMISSION INSPECTION IS NOT A VERY GOOD ENFORCEMENT STRATEGY EITHER. A SIDE-OF-THE-ROAD INSPECTION SYSTEM IS SHOWN TO BE THEORETICALLY PREFERRED. /AUTHOR/
TL;DR: In this article, several dynamical models of fluid suspensions for tracked air cushion vehicles are analyzed and compared and it is shown that the general behavior resulting from linear analysis is in many respects similar to that obtained from the nonlinear analysis.
Abstract: In this paper several dynamical models of fluid suspensions for tracked air cushion vehicles are analyzed and compared. Specifically, the models considered conform to: a fifth-order linear suspension, a nonlinear configuration with a constant supply pressure, a nonlinear model with compressor characteristics, and a sixth-order nonlinear model with a supply duct connecting the compressor to the cushion chamber. Nonlinearities included in the analysis are the flexible-skirted cushion capacitance, cushion entrance and exit orifice restrictions, feeding system duct fluid capacitance, and compressor pressure-flow characteristics. Temporal responses are obtained for guideway and external force inputs. Back flow conditions under which the supply compressor can stall are examined. It is shown that the general behavior resulting from linear analysis is in many respects similar to that obtained from the nonlinear analysis. Thus, a linear model could provide a good initial basis for a preliminary design and...
TL;DR: In this paper, the authors investigated the sensitivity of station throughput to randomness in dwell times, i.e., vehicle dwell times are perhaps the most unpredictable parameters of station operations because of occasional passenger intervention.
Abstract: SUMMARY Vehicle dwell times are perhaps the most unpredictable parameters of station operations because of occasional passenger intervention. This paper reports on an investigation involving theoretical and Monte Carlo techniques to ascertain the sensitivity of station throughput to randomness in dwell times. Alternative configurations of vehicle loading positions, e.g., loading positions in parallel, in series, or in a series-parallel combination, are considered in an effort to rank the configurations by their associated performance levels.