A major consideration of any engine designer right from the outset is that of the cooling system. Even in the most efficient of gasoline race engines, only 35% of the fuel energy available is converted into mechanical power. The rest, something like 850kW from an engine delivering 450kW, is converted into heat which will need to be dissipated into the surrounding atmosphere. Putting it into perspective that’s something like 280+, 3kW electric fires worth of heat, approximately half of which will go out through the exhaust system with the remainder - around 400kW rejected Read more…
Archive for January, 2010
The Cooling System
Thursday, January 21st, 2010Biobutanol
Thursday, January 21st, 2010
Mention the word bioethanol to most people, even the ones who have little interest in our industry, and the chances are they will at least know that you are talking about alternative fuels. Added to gasoline fuel in amounts up to 98% of the total, the process of adding ethanol derived from bio sources to spark ignition fuels can reduce the so-called ‘carbon footprint’ making our sport, or so we try to convince others, more politically acceptable to all. The real benefit to us performance types, as we all probably know by now, is that with higher detonation resistance and richer mixtures Read more…
Bespoke Nuts
Thursday, January 21st, 2010
There are a plethora of different kinds of nuts on the market, and many are aimed at the racing market. Most of these will have been designed originally for the aerospace sector, and here we benefit from the exceptional quality control that the aerospace industry demands. Despite this range of good quality proprietary parts being available to us, there are also a considerable number of racing engine manufacturers who have bespoke nuts manufactured to their own designs. These might be to fit into a particularly confined space, maybe to minimise the height of the nut, or perhaps to Read more…
Feeling the Heat (3)
Thursday, January 21st, 2010
In previous articles, we have looked at why we might choose to insulate the exhaust system of a racing vehicle, the various methods by which we might insulate the exhaust and what the consequences of doing so might be.
In light of this, we discussed exhaust coatings with a British company, one of whose specialities is the application of thermal barrier coatings to exhaust systems. Zircotec, who are based in the middle of an area rich in motorsport expertise, have a number of exhaust coatings which are made available on a Read more…
The Sleeping Beauty
Thursday, January 21st, 2010
Can you imagine waking up one day and not remembering where you are? I’m only too certain that this may have happened to many of you after the recent festivities but the experience is probably something you would prefer to forget. Perhaps then you might spare a thought for the feelings of an engine upon being cranked into life. Waking from its enforced slumber the camshaft will tell it when to open and close the intake and exhaust valves but who tells it when to fire the charge and more importantly on which cycle?
In times past the ignition was triggered from a mechanical Read more…
The Chassis Dyno
Thursday, January 21st, 2010
Believe it or not measuring the precise output from a reciprocating engine has always been a controversial and sometimes, difficult task. Even in the confines of the engine test cell, day-to day repeatability can often be onerous not to say expensive and so it is easy to understand why many competitors may prefer to test their engine while it remains in the vehicle - on a chassis dynamometer.
Engine dynamometers are generally the province of serious tuners and the OE engine business. Attaching the Read more…
Crankshafts: Stress-concentration mitigation
Thursday, January 21st, 2010
In previous articles on the subject of crankshafts, we have touched on the benefits of compressive residual stresses. Two methods by which this might be introduced have been discussed, these being nitride hardening (nitriding) and fillet rolling, although there are many others, some of which will be discussed at a later date. By imparting these residual stresses to the surface of the material, there is a large increase in fatigue strength, which gives a greater factor of safety against failure by fatigue.
Con Rods: Application of Shot-peening
Thursday, January 21st, 2010
In a number of previous articles, I have touched on the subject of residual compressive stress, and how this can be helpful to us in increasing the fatigue strength and hence life of components. This allows them to be smaller and lighter than would otherwise be possible for a given life requirement, and as designers and tuners of racing engines, this naturally appeals to us. Light components, most especially those that rotate are becoming more important than ever to the series production engine designer, as the push for fuel economy continues with haste. Very recently in fact, in Read more…
NICKEL PLATING
Thursday, January 21st, 2010
Nickel plating is a common process, but there are two main methods of producing a thin layer of nickel on the surface of a metallic object. The first is to use a traditional electroplating process whereby the parts to be plated are part of an electric circuit and form the cathodes. A rod of the plating metal is used as an anode. These are immersed into a bath of electrolyte commonly containing a salt of the metal to be plated. In the case of nickel plating, the salt used is Nickel Chloride. Quite often with electroplating, there are two or even three plating processes used for the best results, Read more…
CAMSHAFT DURATION
Thursday, January 21st, 2010
Invariably measured in crankshaft degrees, the duration of any camshaft is generally accepted to be the number of degrees the valve is lifted off its seat to the instant that it shuts again. Ideally it should open instantaneously to its maximum lift and then remain open until it would be closed again equally quickly. This would produce a square shaped valve motion diagram and cause the maximum amount of charge air or exhaust gas to flow. In real life however, the opening and closing are constrained by the laws of physics and valves have to be carefully lifted off their seat, accelerated to maximum Read more…
