When considering a bolted joint, and when explaining how it works under load to a novice engineer, it is often helpful to consider the components as springs. The joint and the bolt ‘share’ any imposed loads depending on coefficients that are functions of the components’ stiffness, as is the case with nested helical springs. It does not take a huge leap of imagination to look at the actual applications of helical springs as fasteners. There are applications where the imposed...
In the search for engine performance – whether it is more power, better fuel economy or cleaner exhaust gases – the overriding direction irrespective of fuel type is one of higher fuel injection pressures. In a typical gasoline direct injected engine, the rail pressure will be around 200 bar or more; in a diesel engine with the latest of common rail injection, the pressure in the injectors will be well beyond this, with figures of up to 3500 bar currently quoted. From a technical...
Little did Swiss inventor Alfred Buchi realise at the time that his patent application to pressure charge the internal combustion engine using what amounted to ‘waste’ exhaust gas would fundamentally change the landscape in the automotive performance some 100 or so years later. His idea of powering an axial flow compressor using an axial flow turbine was indeed inspirational, but was essentially brought about by the poor engine volumetric efficiencies of the period. Since then of...
Electric and hybrid electric/internal combustion technology is finally starting to make headway in the racing world. Such powertrain solutions present a host of challenges relating to electrical energy storage and motor technology, and they also require a reassessment of lubrication and cooling systems. Electric motors and energy stores need both lubrication and cooling, with the two tasks increasingly being combined through the use of shared lubricating oil/coolant. While not yet common...
There has been a great deal of evolution in piston design over the years, in which a large number of usually small development steps have given us some really beautiful components. If we are to describe a modern racing piston, we would probably be safe to say it is an aluminium component with a ‘slipper’ skirt, having ribs joining the piston pin bosses to each other and then to the relatively unsupported lateral areas of the crown. This is pretty much the state of the art at the...