No abstract

No abstract

Rear tire separation or delamination events affect the rear wheel adhesion and thus the vehicle stability. Maintenance of the lateral force of the tires on the rear axle of a vehicle is paramount to vehicle control. Tire tread separation events are, unfortunately, a foreseeable event for which allowance in the design of the vehicle must be made. Testing of vehicles illustrates how loss of control of a vehicle can occur if, during the process of delamination, the excitation of the rear wheel due to the delaminating tread causes tramp on the rear axle of the vehicle. This tramp occurs if the excitation is at the natural frequency of the rear axle. For solid rear axle vehicles, this natural frequency coincides with the rotational frequency of the wheel when traveling at highway speed. The tramp motion can be so severe to cause the tires to alternately leave the ground. Testing of the vehicle with excitation within the natural frequency of the axle/tire combination during an SAE J266 circle test, showed an oversteer gradient of 12 to 19 degrees per g, resulting in a critical speed of approximately 28 mph (45 kph), a highly unstable situation while traveling at highway speed. This paper reports from testing results how the vehicle may, be designed to eliminate the dangerous tramp mode by proper installation of the shock absorbers and proper shock damping characteristics. The test results show that the vehicle can maintain a continuous understeer characteristic during the rear wheel excitation at the natural frequency.

Radial and mixed-flow turbine stages are an important component of turbochargers in automotive engines. The aerodynamic design of such turbines is generally compromised by the severe mechanical and manufacturing constraints to withstand the harsh motor environment with high stresses, high temperatures and unsteady operation. Conventionally, the designer deals with these constraints in the preliminary design stage by using a high degree of empiricism. This is then followed in the detailed design by extensive and time-consuming 3D CFD analysis and geometry optimisation. This paper describes a new approach to the preliminary design of radial turbine impellers using a quasi-3D throughflow method, which allows a more rapid consideration of the design issues before moving on to a full 3D CFD analysis. The paper describes the development of deviation models suitable for radial and mixed-flow turbines out of a range of CFD solutions in which a number of important features have been varied: aerodynamic loading, tip clearance and blade root thickness. The features of the deviation model are related to predicted features of the flow. The results of throughflow calculations including the deviation model are compared against the CFD predictions.

Crash tests conducted by Ford, General Motors, and other automakers have shown that localized accelerations on various objects, including seatbelt buckles, can experience many multiples of the center of gravity acceleration (sometimes exceeding 500 g's) due to contact with other objects within the vehicle or from elastic and plastic deflections of the vehicle structure. In March of 1959, the Cummings [18] pivoting cover buckle patent recognized that the moving parts should be so balanced that "the buckle will not open under the influence of inertia." This paper follows the development of the modern lock for the latch buckle design concept through its evolution. After a discussion of the realization of the inertial potential for unlatching of the buckle from numerous patents and testing, seatbelt locking mechanisms will be discussed by category, followed by a short summary of the inertial blocking mechanisms. These designs will be described, patents for each listed, examples given of vehicles where they have been installed, and the inertial capability of each buckle type catalogued. From this discussion, the reader should have a clear understanding of the capabilities of the modern lock for the latch seatbelt buckle and the roots from whence it has been developed.