At a time when sustainability and efficiency are essential for cars, automakers and major automotive suppliers are devoting enormous resources to developing cleaner combustion engines, without even resorting to electrification solutions.
The different technologies applied to internal combustion engines have their advantages and disadvantages, which sometimes makes it impossible to combine one and the other to achieve maximum efficiency. However, the Americans from Avadi Engines have achieved what no one else had dared: an engine that combines the Otto cycle, typical of gasoline, with the Wankel principle.
Graphical animation of Avadi Engines’ combustion engine in action
An Otto cycle gasoline engine with the consumption of a diesel and without electricity
It’s called Avadi MA-25 and, for now, it’s designed as a range extender for cars, motorcycles, small scooters or small vans that need continuous performance at low, constant speeds , but not for large models, and even less for sports cars.
The particularity of this innovative engine lies in the fact that it is composed of a single cylinder and two connecting rods connected to a shaft which rotates 180 degrees like a crankshaft, but which is not mounted on the crankcase – as it This is usually the case – but on a fixed crown. In this way, the engine generates rotary movement directly despite the piston, connecting rod and crankshaft.
Furthermore, although it is a four-stroke engine, it does not have valves, although not entirely, because it uses the rotary valve principle. A perforated disc in the cylinder acts as a valve with an eccentric port that controls inlet or outlet depending on position.
The four-stroke engine without valves
Avadi reiterates that its new engine is not intended to provide high performance – its maximum power is only 15 hp and its torque is twice as high – but that it is capable of achieving an efficiency of 42% compared to a standard gasoline engine, which provides between 30 and 35%, while consuming much less fuel and weighing only 11 kg.
Efficiency comparable to that of a diesel engine while consuming gasoline, thanks to three essential characteristics: first, the piston and the cylinder rotate slightly out of sync with each other, so that the piston tilts much less despite its vertical position, which reduces friction in the cylinder. Second, it does without valves and camshafts, components that consume more energy, especially at low revs. Third, this engine requires neither water cooling nor an oil pump, eliminating more moving parts and lubricating itself through centrifugal force.
source: Anecdotes.fr