Any technical discussion about engine vibration generally revolves around one of two areas, namely the cranktrain and the valvetrain. In terms of the crankshaft, torsional vibrations - or rather their avoidance or mitigation - are a major concern. In these days of computer simulation, we can run analyses to study this phenomenon. For many years, however, engineers had to rely on formulae and a lot of painstaking calculations, as laid down in books such as "A Handbook of Torsional...
The vast majority of race crankshafts that we see are made from one piece of material and are generally machined from either a billet of wrought steel, a forging or possibly a casting - certainly in the case of multi-cylinder engines this is the norm. For a substantial proportion of certain types of engine, however, it is typical to find a crankshaft assembled from a number of pieces. This is generally the case where needle-roller bearings are used for the big-end bearing. The types of...
Most of the time many of us are quite happy with just one injector per cylinder. The complexity of EFi arrangements and the software necessary to control an engine under the wide range of anticipated conditions are complex enough without going looking for problems. But there are occasions when the one injector is not enough, say when the turndown ratio of any single injector is simply not large enough to cover the anticipated fuelling requirements of the engine. A typical example of this...
It's widely known that Compacted Graphite Iron (CGI) has a number of material properties which in certain applications make it the material of choice for cylinder blocks. So does this also apply to race engine cylinder heads and, if so, why? First let's look at some of the key criteria of a cylinder head. It has a number of functions, such as keeping gas and coolant inside, and providing the structure for assembling or bolting on other components - valve seats and guides, for...
As engineers we all have a lot to learn, and no matter how long we have been in the business, I am sure there is no-one out there who will not claim to be learning still. Take this lesson from the history books for instance. For many years it has been accepted practice to locate wet liners via a recess in the cylinder block top deck and seal between the outer liner surface and the cylinder block casting at the base of the liner using a system of 'O' rings under compression. Clamped...