Engine Design: Art or Science?

by: Justin Rhoads

I hear a lot of opinions on this topic whenever I research products on the Internet. From what I have read most people land somewhere in the middle feeling that it’s a bit of both art and science. Having a little bit of an engineering background I tend to feel that it’s all science; in my opinion, the art is a little hit and miss….

When looking at engine design, building, or root cause analysis I find that everything comes back to science. Whether I’m looking into wave tuning on the intake tract, the engineering mechanics involved with the connecting rod in motion, to the thermal dynamics of what’s happening to the exhaust valve during the race. All of the above are quantified by some very powerful and complex mathematics. For many years an engine builder worked primarily by trial and error; grind on an intake port and then put it on the flow bench. Follow that up with some dyno time….do you think Renault does this with their F1 engine designs?

The answer is no; the same processes and knowledge that allows Lockheed Martin to determine that the F 35 will be able to fly before actually putting models into the wind tunnel apply to motorsports. Top level teams now employ engineers to perform analysis of connecting rod stresses instead of running an engine to determine mean time to failure. This goes far beyond the nuts and bolts aspect of engine building….

The same engineering methodology used to solve complex problems has also found it’s way into motorsports. No longer are engines built to simply have class leading power, the best brake specific fuel consumption, or the lightest rotating mass. Instead the process had evolved into an optimization exersize; the process has brought new considerations into the role of engine design. A 100ft view looks a little like this; 1^st determine the operational environment, 2^nd make concessions to optimize the engine characteristics for that environment with input from the driver and chassis guys, 3^rd test and refine the package to exploit the advantages produced by the driver/chassis.

What one finds when using this method is that the final result is what the application requires, what it needs, not what anyone “feels” is the best. If the application can not benefit from a 6 stage dry sump oiling system it will not have a 6 stage dry sump oiling system; even though that is the ultimate in oil control and a dream for many racers. This discipline ensures that only what is best for the application is used, nothing more, nothing less; keeping cost where they need to be and also cutting out any added features.

Remember, an engine is not a cell phone; if the driver, chassis, and application cannot utilize features of the engine, they should not be used.