Once again, it all looks very complicated and yet we want to try to put it back on simple foundations. However, we are omitting Honda's original 1974 patent, not least because it is based on carburettor technology. At that time the technology of the G-Kat was not yet ready. It was therefore already common practice to feed an engine around partial load with a comparatively lean mixture.

If wanted, one could accelerate accordingly and achieve the maximum performance beyond a stoichiometric mixture (14.7 : 1) by further enrichment. The Honda patent then went a step further by offering a perhaps even slightly rich mixture to ensure reliable ignition of the spark plug at all times, but the rest of the combustion chamber was running low on fuel. The stratified charging was born.

Before we go on, here is a restriction: Today's petrol engines have an extensive relationship with their three-way cat. They take this into account with a stoichiometric mixture that is always strictly regulated. As a reward, the entire system then delivers relatively good exhaust emission values, much more cheaply than, for example, a Diesel engine. So a deviation of 14.7 : 1 usually makes the additional aftertreatment of the exhaust gas complicated.

This is not the only hurdle, albeit a rather large one, that a stratified charge has to overcome nowadays. The second one is the exact allocation of the areas with a slightly fatty and quite lean mixture, especially considering the different loads and temperatures. Too easily the finely thought-out order gets mixed up. Just imagine that the lean mixture would end up at the spark plug and the slightly richer one in the combustion chamber. Misfirings would be the consequences.

And this is exactly where a design is used that has been around in the Diesel engine for a very long time, the prechamber. But be careful, at that time the objective was almost the opposite, because a combustion triggered in the prechamber should hit the main combustion chamber with a certain amount of delay. Today it is exactly the opposite. The full force with simultaneous ignition in all parts of the main combustion chamber is required.

The first realisation obviously comes from the Formula 1 of Mercedes or Mahle in 2014, the other participants followed. Since that time, there have been restrictions on fuel consumption and they were looking for every gram of fuel that could be effectively converted into power. However, nowhere we have seen a close-to-production system where the spark plug is placed in a prechamber together with an injector.

This would then be a so-called active system of a prechamber. In Formula 1 it was out of the question anyway, because only one injection device was allowed there. But you understand, it is not enough to let the lean mixture be pushed into the prechamber by the piston, which strives for TDC.

. Nevertheless, the patent for Formula 1 is based on a single direct-injection injector and a prechamber which encloses the spark plug relatively tightly, with admittedly not very small openings to the main combustion chamber. And now comes the speciality, namely in the form of an injector with a multi-hole nozzle, where the blind holes do not all have the same diameter.

They must be custom-made with an injector that is precisely adjusted during assembly. One of its blind holes should therefore send the jet, which in turn hits the prechamber through an opening. This sounds like a challenge in itself, but all the more so because a normal F1 spark plug, for example, has a thread with a diameter of only 10 mm.

Nothing is ever certain about news from Formula 1, unless the news is more than 10 years old. Supposedly there are also supposed to be possibilities to change the mixture distribution and also between main and secondary combustion chamber, depending on whether performance or special economy is required. In addition, each team is obviously mixing its own fuel.

The Maserati MC 20 is a newcomer, whose makers have apparently built the car from scratch within 2 years. A new generation of engines is also supposed to have been developed. As so often, we do not really believe in the version with the white sheet, but rather in extensive support from Ferrari, which is probably still 90 per cent owned by this company despite its IPO. As proof we first of all mention the 90° cylinder angle, unusual for a V6, and the similarity of the whole construction of the drive unit to Ferrari.

A V8 lacks two cylinders, but can soon come back with the technology developed for Maserati. Why not in a Ferrari, possibly even as a V12? Anyway, if the pre-chamber is now almost universally used in Formula 1, then this supports our assumption that the development of the 'new' engine was very much influenced by Ferrari. But how was the principle implemented in this engine, named 'Nettuno' (Neptune)?

First of all, there is the narrow prechamber as an extension in the shaft of the main spark plug and an injector (passive prechamber) mounted on the side. Strangely enough, when looking at its position one has difficulties to imagine that one of its jets could hit one of the openings in the prechamber, but this could also be due to the drawing (picture above).

Strongly differing from Formula 1, there is both an intake manifold and direct injection. This is not uncommon in other engines, because the former are associated with the effects of better mixing and less energy to build up fuel pressure. Additionally here a second spark plug, right at the edge of the combustion chamber.

Double ignition and two injection systems are now admittedly very rare. There is reason to suspect that this is not a true double ignition at all, but rather that the ignition is ensured in certain critical operating ranges. It is noticeable that not a word is said about a possibly more complex exhaust aftertreatment.

The comparison with a smaller, but also very powerful engine from AMG may be interesting. With a displacement of two litres, it has 310 kW at 6,750 rpm, i.e. almost exactly the same output per litre, but at 750 rpm earlier than the Maserati. Its specific torque of 250 Nm/litre is almost 17 Nm/litre higher.

Exciting CO₂ emissions from 190-192 g/km to compare to 262 g/km at the Maserati. Of course, this cannot be two thirds, because then a one-litre engine with 103 kW (140 PS) would have to have 87 g/km, which is probably seems impossible. The AMG engine can therefore keep up very well in terms of fuel consumption.