Low gear forces : even at peak combustion load
The load working on the eccentric gear is depending on 3 main factors.
1. The load on the piston. The higher the pressure on the piston crown the higher the load on the gear.
At low loads the peak combustion pressure on the piston is 40 to 60 bar (running with high CR), resulting in a peak force of 25.000 N is 2500 kg (twice the weight of a car).
At full load the peak combustion pressure is 100 bar (running with a CR of 7,5:1) and with 3 bar absolute boost pressure, resulting in a peak force of 50.000 N = about 5000 kg.
2. The ratio of the eccentrity and the eccentric gear radius.
The eccentricity we use on our prototype engines is about 3 mm. The radius of the eccentric gear is 35 mm. This means that 3/35 = 0,0857 thus only 8,57 % of the piston load is transmitted to the gears.
3. The angle of the eccentric in relation to the force direction (the conrod).
The position (the angle) of the eccentric also has a major influence on the gearload. When the eccentric position is horizontal and the conrod vertical the maximum of 8,57% of the piston load will be applied to the gear. But when the eccentric is in vertical position at high engine loads at the moment of peak combustion the load on the gears is zero at that moment.
Zero gearload at peak combustion load (100 bar)
In general we can say that the peak gear load will always be lower then 80 Nm, with average gearload just at about 25 Nm (under full load). The peak load on the actuation system is as low as 1 Nm under full load
