While journal bearings currently reign supreme for applications such as crankshafts, other areas of the powertrain use different types. There is a host of different applications, but those intended for use in turbochargers are some of the most interesting. Providing a low-friction bearing capable of operating at the very high speeds a turbocharger sees – more than 150,000 rpm – and which can also survive the high temperatures experienced within a turbine housing is no easy...
Whether you are racing a go-kart or a Formula One car, the bearings that allow the reciprocating parts to rotate are of vital importance to both durability and performance. The sphere of Formula One engine development, while not unique, provides one of the sternest tests for bearing design, notably thanks to the ever-present battle to find a compromise between strength and frictional efficiency. For example, the development of ever-lower viscosity lubricants to reduce parasitic losses...
The intense competition to win, be it on the racetrack or in car dealer showrooms, is pushing the design of the internal combustion engine to even greater extremes. To save weight, engines are kept short, crankshaft journals need to be narrower and, together with the increased engine output required, engine bearings are under more stress than ever before. Increased bearing load results in higher bearing surface temperatures which, after all the analysis has been undertaken and the tests...
In recent years the push towards more fuel-efficient, direct injected engines has led to increased peak cylinder pressures and higher bearing loads. In order to support this higher level of performance, therefore, plain metal shell bearings have had to offer better fatigue resistance alongside improved conformability. Although aluminium-tin-silicon (Al-Sn-Si) bearings have been around for many years, and give good conformability in applications requiring lesser performance, in the search...
Throughout the 20th century, lead made a significant contribution to the development of the internal combustion engine. Initially this was in the form of Babbit-type materials (a mixture of tin, antimony, copper and lead) that were used in engine bearings. Later, lead played a more significant role in the development of ‘anti-knock’ compounds when added to gasoline fuels. In the former case, the softness of lead helped the lubrication in the bearings, whereas as an additive in...