A STUDY OF DEGRADED COMPONENTS AFFECTING IN-USE VEHICLE HANDLING

THE DEGRADATION OF AUTOMOBILE STEERING SYSTEM COMPONENTS WERE STUDIED AS THEY AFFECT THE SAFE HANDLING OF THE VEHICLE. VEHICLE STEERING PERFORMANCE IS A COMPLEX FUNCTION, INCLUDING THE CONDITION OF SEVERAL CHASSIS SYSTEMS AND COMPONENTS. THE STUDY NOT ONLY INVESTIGATED THE STEERING SYSTEM, BUT ALSO THE OTHER CHASSIS SYSTEMS AND COMPONENTS WHICH INFLUENCE STABILITY AND CONTROLLABILITY. THESE INCLUDE THE SUSPENSION, SHOCK ABSORBERS, BRAKE BALANCE BETWEEN WHEELS, ETC. EXISTING TEST FACILITIES WERE REVIEWED TO PLAN A TESTING SYSTEM TO EVALUATE THE AFFECTS OF DEGRADED CHASSIS COMPONENTS ON VEHICLE HANDLING. THE DEVELOPED TESTING SYSTEM INCLUDES: (1) INSTRUMENTATION SUITABLE FOR INSTALLATION IN A VARIETY OF VEHICLES, (2) A TEST COURSE, INCLUDING A REPRESENTATIVE VARIETY OF ORDINARY ROADWAY HAZARDS, TO PROVIDE A REPEATABLE DYNAMIC ENVIRONMENT FOR VEHICLES UNDER TEST, (3) PHYSICAL FACILITIES NEAR THE TEST COURSE FOR HOUSING SUPPORT EQUIPMENT AND TO PERMIT MECHANICAL ADJUSTMENTS TO BE MADE, (4) METHODS AND PHYSICAL CAPABILITIES FOR INDUCING CONTROLLABLE MALFUNCTIONS AND MALADJUSTMENTS INTO THE VEHICLE CHASSIS AREA, (5) ACCURATE MEASURING EQUIPMENT TO FACILITATE MONITORING OF VEHICLE CHASSIS ADJUSTMENTS, AND (6) EFFICIENT AND INCLUSIVE TESTING TECHNIQUES, PROCEDURES, TEST REPORTS AND DATA PROCESSING. STRONG EVIDENCE APPEARED THAT THE DELETERIOUS EFFECTS OF LOOSENESS IN THE STEERING SYSTEM COULD BE CHECKED BY TOTAL STEERING WHEEL MOTION WHILE THE CAR WAS PARKED. DURING THE BRAKING TEST, THE ADDITION OF LOOSE STEERING DROPPED THE TRANSFER FUNCTION TO A VALUE WHICH INDICATED THAT THE DRIVER, TO HOLD THE SAME COURSE AS THE OEM VEHICLE, WOULD HAVE TO TRIPLE HIS STEERING INPUT. IT IS RECOMMENDED THAT STEERING LOOSENESS SHOULD BE INCLUDED IN A PERIODIC MOTOR VEHICLE INSPECTION PROGRAM. LOOSE BALL JOINTS WERE SIGNIFICANT FACTORS IN VEHICLE HANDLING. THEY WERE AN OUTSTANDING CONTRIBUTOR TO PASS DEVIATION WHILE BRAKING CONTRIBUTED TO THE MAXIMUM YAW RATE. WEAKENED SHOCK ASBORBERS SHOWED A DECREASE IN THE HANDLING ABILITIES OF THE TEST CAR. ALIGNMENT PARAMETERS DETRACTED IN VARYING AMOUNTS FROM THE STABILITY OF THE VEHICLE. IT IS RECOMMENDED THAT MASS INSPECTION SYSTEMS INVESTIGATE THE THREE ALIGNMENT PARAMETERS OF TOE, CAMBER, AND CASTER. A PERIODIC MOTOR VEHICLE INSPECTION BRAKE EQUIPMENT MUST BE HIGH SPEED, FAST RESPONSE, AND HAVE THE ABILITY TO PRODUCE REALISTIC ON-ROAD BRAKE HEATING RATES AND TEMPERATURES.

• Corporate Authors:

  Clayton Manufacturing Company

  ,    
• Publication Date: 0

Subject/Index Terms

• TRT Terms: Automobiles; Brakes; Chassis; Curvature; Dynamic tests; Handling characteristics; Inspection; Measuring instruments; Motor vehicles; Shock absorbers; Steering; Suspensions; Temperature; Test procedures; Vehicle performance; Wheels
• Uncontrolled Terms: Handling
• Old TRIS Terms: Caster /of automobile wheels/
• Subject Areas: Highways; Safety and Human Factors; Vehicles and Equipment;

Filing Info

• Accession Number: 00223122
• Record Type: Publication
• Source Agency: Highway Safety Literature
• Files: TRIS
• Created Date: Mar 19 1971 12:00AM