German GP Honda preview

For the last time before the circuit undergoes significant change, Formula One will visit the Hockenheim-ring, one of the venues on the Grand Prix calendar that carries the reputation of a 'power circuit'. It is the prolonged high speeds at which the Formula One cars travel which give the German track its unique character, together with the famous stadium complex. In fact, in engine terms, Hockenheim compares to the A1-Ring in Austria and Monza in Italy, as an F1 engine spends about 60% of the lap at full throttle opening.

Just as the teams spend hour upon hour in the wind tunnel fine-tuning the aerodynamic performance of their packages, or on the chassis dynamics test rigs, so engine manufacturers spend as much time as possible 'on the dyno', in the constant search for power and how to harness it effectively. So, in their search for the holy grail of greater power, what are the considerations for engine designers and engineers?

In very simple terms, the challenge for the engine designers and engineers is to achieve the highest possible power output. This is best achieved by raising the engine speed as much as possible but additionally important are the abilities to induce the maximum amount of fuel and air and then to burn this mixture efficiently. However, the engine's power will still not increase with the revs unless the engine's internal losses can be contained as the engine speed rises.

To increase the ability to rev, over the years there have been several key technological advances. Since the demise of the V8 format, pneumatic valve gear has superseded mechanical springs to permit higher engine speeds and the growing sophistication of electronics has opened the door to computer-controlled fuel injection, along with more accurate mapping of ignition. It has also provided the ability to run the engine much closer to its mechanical rev limit by software disallowance of over-rev down-changes. The fuel-mapping quality in particular has enabled engine manufacturers to refine their management of the fuel-air ratio, which is critical in helping an engine to produce more power.

With fuel injection, the challenge is in delivering the correct amount of fuel into the inlet ports and making sure it arrives there always correctly matched to the amount of air induced into the cylinder at full and part-throttle. This is why the design of the airbox and of the air intake which feeds it is so critical to an engine manufacturer.

The amount of air forced into the cylinders is further increased by use of two things: the inducted air's inertia, and pressure waves created in the inlet and exhaust manifolds. The beneficial effect of these pressure waves is maximised by the accurate timing of valve functioning and by designing the inlet and exhaust manifolds to optimum lengths.

Apart from seeking to create power, engine manufacturers such as Honda face the ever-present challenge of stemming the natural losses of it through the engine's normal operation. There are two core reasons that an engine loses power: mechanical and heat. Mechanical losses occur from the friction of moving parts such as pistons, piston rings, crankshaft bearings, conrods, and the oil feed and scavenging pumps. The heat losses take place when some of the energy produced by the engine is transferred in to the water and oil of the cooling and lubrication systems. Manufacturers aim to minimise these losses with smaller and, more importantly, lighter parts and through careful design of the water jacket, engine cylinder head and block, always with a careful eye to maintaining the same level of endurance.

-Honda