The applications of copper alloys in engines are generally those where we might expect to see relative movement or where a combination of strength, wear resistance and thermal conductivity is required. A favourite type for many of these applications are the copper-beryllium alloys. Beryllium is a very lightweight element, and has some attractive mechanical and physical properties. However, there are health considerations regarding its use. Copper-beryllium alloys are not felt to be a...
In the recent Alternative Energy Focus article in Race Engine Technology magazine (issue 53, March/April 2011), the subject of KERS and its different strategies were discussed. The car manufacturers - thus far at least - have opted to use a purely electrical system. A large combined motor/generator converts kinetic energy recovered under braking into chemical energy stored in a battery, and then the stored energy is re-used at will once the vehicle is no longer traction limited. The...
Making a comeback from earlier times, the ball-race bearing system may be a preferred solution in some turbocharger applications, but for reasons of cost the more usual approach for the vast majority of units is still the fully floating design. Consisting essentially of two bushes, one at either end of the bearing housing through which the shaft passes, unusually these bushes themselves are allowed to rotate in their housing, creating in effect a 'bearing within a bearing'....
High lifts or long durations are common features in high-performance camshafts, and when optimised can produce high engine torques over a useful but often limited range of engine speeds. The introduction of variable valve timing can widen this range of useful speeds, but at part load against a partially closed throttle, large valve lifts introduce pumping inefficiencies that are increasingly unacceptable in performance roadcar engines. Over the past decade, therefore, a multitude of...
The contribution of the piston assembly to overall engine frictional losses is well documented and has been the subject of a lot of research over a number of decades. In SAE paper 911230, for example, the authors Tsuchida and Tsuzuku study the effects of various design features on piston friction losses for high-speed engines (up to 16,000 rpm). At the time - the late 1980s and early '90s - the Japanese were selling production motorcycles with engine speeds higher than even Formula One...