HONDA’S 2021 ENGINE SECRETS

Honda’s head of power unit development, Yasuaki Asaki, gave an unusually detailed insight into the development of its 2021 engine after Max Verstappen’s victory at Imola, describing it as the single biggest shift in architecture since moving to a split turbine/compressor layout during the Mclaren years.

“We’ve changed the camshaft layout to be much more compact, and also brought its position lower down so it’s closer to the ground,” Asaki explained in a Honda Racing F1 blog post. “We’ve also had to change the valve angle. The main point of what we’ve changed was to improve combustion efficiency. In order to do so we had to change the valve angle, and in order to do that we had to change the camshaft.

“We’ve also had to make the head cover lower and more compact, which means the way that air flows over it has become a lot better. And we’ve lowered the centre of gravity of the ICE [internal combustion engine]. Another thing we changed is the bore pitch, by reducing the distance between one bore and the next, we’ve made the engine itself shorter, smaller.

“In the old engine straddling the transmission we also had a bank offset whereby the left bank was slightly offset from the right bank. So, what we’ve done is reverse this offset on the new engine so that the right bank is forward, and the left bank is back.

“Another point we’ve had to think about is the fact that combustion efficiency has got better. And the camshaft output has got better. Due to the rules of physics the amount of energy that can be stored has changed, and it meant that the amount of exhaust energy has decreased.

“So, compared to the [MGU-H] recovery that we were getting last year, what we’re having to do is increase the amount of crankshaft output, and at the same time ensure that there’s a good level of exhaust output, exhaust temperature as well.”