Hondas challenge has been to match its rivals for power and fuel efficiencies. Starting from a long way back in 2015, the Honda PU is still behind on peak power, but not as far as it might appear. A key comment during a technical director press conference suggested the power units contribution to lap time varies only by 0.3 seconds. In F1 terms, this equates to 30hp. This isnt a huge deficit, nor one which cannot be bridged with a single update.
Nevertheless, there have been races this season where the McLaren-Honda still appears to lack far more than a few tenths of horsepower. This is where Honda are about to catch up. In a race, the Honda engine currently uses too much fuel relative to its rivals, who have applied highly advanced lean burn combustion solutions, which allows the limited fuel to produce maximum horsepower throughout the race.
With a conventional combustion set up, the Honda cannot match this from good engineering alone, so a step change is required in the combustion design. For Ferrari and Mercedes, this is a process known as pre-chamber ignition, whereby a small chamber is formed inside the cylinder head between the spark plug and the main combustion chamber. This gets filled with a rich fuel mixture. The main combustion chamber gets filled with only a very weak fuel air mix, which would be hard to ignite with a conventional spark plug. When the spark plug ignites the fuel in the pre-chamber, the resulting flame vents through small holes into the main combustion chamber, which then burns the weak fuel mix easily. This creates a long power stroke, despite the largely weak fuel mix.
Such technology requires a very different cylinder head architecture, along with special fuel injectors, spark plugs and critically special fuel, to be able to react to the unusual combustion process.
Honda have earmarked development tokens to be spent in Malaysia to allow a big upgrade to the engine. With the turbo, MGU and inlet system all now optimal, its expected that a lean burn technology will be the result of this development. This will ultimately bring Honda closer into line with its rivals, allowing them to push the engine for maximum power throughout the race, rather than having to curb its performance to manage the fuel available.
