In my previous article on the subject of con rods I asked, "Can we manage without big-end bearings?" and went on to look at the various attempts to do this and the possible future options. The article briefly mentioned the benefits of not having a bearing, and observed that there is one currently successful application of bearing-free technology being raced. In the application concerned - four-stroke, single-cylinder race engines with 'assembled' cranks, where the...
While the main purpose of a crank is obvious, it has many other demands placed upon it. Rotating constantly as it does, it is ideal for taking drives to other assemblies such as pumps. While it is possible to drive pumps electrically - and there are some advantages to doing this - it is banned in some forms of motorsport, and the vast majority of series-production engines drive their pumps mechanically. With very few exceptions, four-stroke engines use camshafts to open poppet valves, and...
I'm sure we've all been accused of it at some time - the compulsive desire to have things just the way we want them, with little or no compromise. Perfection is the goal, anything else is a poor second best and, except in the case of pure genius perhaps, it is often considered a major flaw in one's character. But in the world of engine dynamometers, control is everything. Many of you will no doubt be familiar with the large and unmistakable throttle lever alongside the console of...
One of the biggest changes to the engine ECU in recent years has been the rise of the drive-by-wire system. Generically known as 'x-by-wire' or sometimes (incorrectly) as 'fly-by-wire', such systems were introduced by vehicle OEMs in response to more punitive emissions legislation in recent years. Consisting of a throttle pedal device requesting a torque demand from the engine, the engine ECU calculates the ignition and fuelling necessary and requests the appropriate amount...
In the July 2010 issue of RET-Monitor, keyword: heads-blocks, I gave some insight into fracture splitting of the main bearing cap. The advantages of a fractured split line were discussed, including the design freedom that can be achieved using fracture splitting. What I did not mention though - and this is where this article connects to the previous one - is the fact that fracture splitting cannot be done with every type of cast iron. Based on the process-specific requirements, fracture...