Copper materials in bearings
Plain bearings come in a huge range of sizes, and in dealing with engines we will be familiar with a number of different types. The simplest are the cylindrical bush types which we see in various guises, most notably as con rod bushes and valve guides. Con rod bushes and valve guides are most commonly alloys of copper. In the case of the small-end bush, these see relatively little sliding but high loads. The valve guide experiences little load but intermittent sliding. Read more…
RET Focus: Advanced Materials, view the latest magazine article here.
KERS: power electronics
Whenever we hear about Formula One KERS systems, or the much-vaunted hybrid systems as used at Le Mans and in a growing number of roadcars, many of us imagine a large alternator being used to change mechanical energy into electrical energy (or vice versa) and a battery for converting the electrical energy into chemical energy and provide short-term storage Read more…
RET Focus: Alternative Energy, view the latest magazine article here.
A bit of a crush
To those who travel regularly on a mass transit rail network like the London Underground or New York Subway, the term ‘crush’ will have its own and possibly unpleasant associations. Packed tightly into a carriage just as one more person squeezes in before the doors close, the experience (particularly at peak travelling times) is not quickly forgotten. But when applied to the technology of shell bearings, ‘crush’ is not just nice to have, it is absolutely essential Read more…
RET Focus: Bearings, view the latest magazine article here.
Follower friction
In these days of soaring fuel prices the top priority for any engine manufacturer is the responsible use of scarce resources. Specific fuel consumption or the amount of fuel used per unit power output per hour is the measure of the task, and a major enemy of this is friction. But when it comes to low-friction engines the experts in this field are not, as you might expect, from the race engine industry No, the real experts in this area, in my opinion, are the OE engine manufacturers, whose search for that extra 0.1% fuel saving (wherever it comes from) is both inexorable and painstaking.
Read more…
RET Focus: Camshafts, view the latest magazine article here.
Piston skirt coatings
If you attend a motorsport trade show and look at the pistons on offer, you will see that a number of them have a coating (or sometimes more than one coating). More often than not, where a single coating is applied to a piston, it will be a skirt coating. Piston skirt coatings are very commonly used, and the practice is not just a recent phenomenon Read more…
RET Focus: Coatings, view the latest magazine article here.
Fasteners for con rods
Bespoke race engines are festooned with purpose-designed fasteners, each of which carries out a specific task. We need specially designed fasteners for many reasons; every engineer has his preferences, so all engines are different and fastener designs reflect this. In general, bespoke fasteners are designed to higher standards than commercial parts. In minimising stress concentration and selecting high-quality materials, we seek to make parts that will prove more durable than a commercial-grade component. Commercial fasteners are, for their price, of excellent quality, but we often want something better than a general-purpose component that has been designed to a price Read more…
RET Focus: Con Rods, view the latest magazine article here.
Taking the heat
That the average gasoline-fuelled race engine is no more than about 28% efficient is a source of great angst to many power unit engineers. But while the best will claim 37-38% and the worst nearer 20%, the inescapable fact still remains that the vast majority of energy available from the fuel is lost in the form of heat.
Split evenly between heat in the exhaust gas and that delivered up to the cooling water jacket, that means for a 450 kW race engine Read more…
RET Focus: Coolant System, view the latest magazine article here.
Splitting crank pins
Opinion is divided on the need to have even firing intervals for engines. With very few exceptions, road vehicle engines fire at equal intervals, while many two-cylinder engines fire at unequal intervals, and some three-cylinder engines in the past have also had some very odd firing orders.
The current Yamaha R1 is a four-cylinder engine that has made use of a cruciform crankshaft to give an uneven firing order Read more…
RET Focus: Crankshafts, view the latest magazine article here.
Rotary sense
I’m sure you’ll agree when I say the environment alongside a race engine isn’t the most electronics-friendly of places. Heat and high levels of vibration are traditionally the enemies of anything electronic, and consequently the technology of producing robust sensors for engine management systems must be a particular challenge. Because of its critical function therefore, a prime example here is the engine speed/timing sensor Read more…
RET Focus: Electronics, view the latest magazine article here.
No pain, no gain…
As I described in my previous article, there were (and are) many enthusiasts out there creating their own race engines. Historically, the racing series with the most open regulatory books have been those based on these DIY race engines. One such series with lots of birth certificates for engines originated in the late 1980s, and was the Sound of Singles Series, later called Supermono. This motorcycle series mandated single-cylinder four-stroke engines without forced induction. Later the additional boundary of an 800 cc maximum displacement was added Read more…
RET Focus: Engine Structure, view the latest magazine article here.
MotoGP exhausts
This year, for the first time in many decades, we find ourselves without a two-stroke engine in the Grand Prix classes of motorcycle road racing. For lovers of diversity in engineering in general and engines in particular, the class of 2012 Grand Prix bikes are perhaps a disappointment. Having seen the two-stroke bikes regulated out of existence with the demise of the 500 cc and 250 cc World Championships, 250 cc four-stroke single-cylinder engines have come to replace the 125 cc two-stroke engines that had been ubiquitous in the smallest Grand Prix class for many years. Limited to an 81 mm bore, they have thankfully Read more…
RET Focus: Exhausts, view the latest magazine article here.
Tensioning using turn-of nut methods
In the previous article on the subject of fasteners, the most commonly used method for the controlled tightening of fasteners was discussed. There are a couple of well-known equations that link tightening torque to fastener tension, and the more reliable of these was discussed. However, there is a great deal of variation of tension for a given torque, even for fasteners of exactly the same design. In terms of the equation itself, differences in the coefficient of friction and the dimensional tolerances of the fasteners in question have significant effects on the torque-tension relationship Read more…
RET Focus: Fasteners, view the latest magazine article here.
E10 - the fuel of the devil?
There are few issues likely to get owners of classic and vintage vehicles in the UK hot under the collar than changes to the composition of the fuels. Fifteen or maybe more years ago, the furore was all about lead. Added to petrol at 0.15 g/litre, not only did it supply cheap octane to the fuel by improving combustion by avoiding detonation but the tetraethyl lead compounds used also coated valve seats, reducing wear and helping to minimise valve seat recession Read more…
RET Focus: Fuel System, view the latest magazine article here.
The Roots supercharger
At a time when turbochargers are increasingly being touted along with engine downsizing for future road vehicle business, spare a thought for the old-fashioned supercharger. Driven directly or indirectly off the crankshaft, the air delivery characteristics of a positive-displacement, Roots-type supercharger are generally much more aligned with those of the reciprocating internal combustion engine Read more…
RET Focus: Induction System, view the latest magazine article here.
Slosh simulation
In the highest echelons of motorsport every system on a car is optimised to the greatest possible extent. For example, the volume of lubricant carried is pared to the minimum in order to reduce overall vehicle weight and the packaging requirements of ancillaries such as oil tanks. These packaging requirements also mean that the shape and structure of oil tanks will not always be the dictated solely by the need for consistent oil supply. Extensive work is therefore undertaken to simulate the movement of oil within a tank under high g-loadings in order to ensure pick-ups and returns are correctly located Read more…
RET Focus: Oil System, view the latest magazine article here.
Offsetting pin bores
When laying out a new race engine, the engineer (or team of engineers) will normally never consider anything other than having the cylinder bore axes intersecting the crankshaft axis. Indeed, this is also the layout of most production engines, and has certainly been the norm since the inception of the internal combustion engine.
There are reasons why designers of new engines might wish to have the cylinder axis not intersect the crankshaft axis Read more…
RET Focus: Pistons Rings, view the latest magazine article here.
Polishing
There are many components in the internal combustion engine which are subject to sliding contact, and which have to transmit substantial forces through that sliding contact. Some contacts are conformal - that is, the contacting pieces have similar and mating geometry - and hence have low levels of contact stress. A crankshaft operating within its bearings is a good example of this. Other contacts will have no such conformal aspects, and these non-conformal contacts are subject to high levels of contact stress Read more…
RET Focus: Surface Treatments, view the latest magazine article here.
Combustion analysis
In high-performance race engines, understanding the processes taking place during each combustion cycle is of great importance to development, be it with the intention of gaining more power, reliability or efficiency. Being able to measure and then analyse the combustion process effectively is a vital tool in allowing engineers to optimise an engine’s design.
It is often thought that this sort of analysis is the preserve of manufacturers building clean-sheet engine designs Read more…
RET Focus: Test Equipment, view the latest magazine article here.
Composite prop shafts
GT racing is one of the most challenging motorsport disciplines in terms of the demands it places on components, especially transmissions. These need to be able to deal with a wide range of conditions, from those experienced during short sprint races to full endurance epics such as the Le Mans 24 Hours. One area that is often overlooked though is the means for transmitting drive from the engine to the gearbox, specifically in front-engined, rear-wheel-drive cars. The generally accepted way of achieving this transfer is through the use of a prop shaft, a solution that dates from pretty much the dawn of the automobile.
Read more…
RET Focus: Transmission, view the latest magazine article here.
Curved-top tappets
For those familiar with the design of overhead cam engines, the most common type of cam follower used in bespoke race engines of this type is the solid ‘bucket’ tappet. These are akin to the flat-faced followers used in pushrod engines, except that the load path is directly from the cam lobe to the lash-cap. They have much to recommend them - they are a geometrically simple part, and lots of people understand how to design and make them. So few people outside Formula One use finger-follower valvetrains that not many companies offer finger followers on a commercial basis Read more…
RET Focus: Valvetrain, view the latest magazine article here.
