BMW Motorrad seems to be applying the ShiftCam system with variable camshaft in its entry-level family. The Germans have applied for a patent for a single-cylinder with variable camshaft.
As a result of increasingly stringent emission regulations, variable camshaft systems are becoming more and more commonplace in the motor industry to create optimum combustion throughout the farming area. The knife cuts both ways, on the one hand the cleanest possible exhaust gases and on the other hand optimum performance.
This is also the case at BMW Motorrad, which developed the ShiftCam system for this purpose, a relatively simple construction that is now used in the R 1250 Boxer family and the S 1000 RR. According to leaked patents, the G family, which consists of the G 310 R and G 310 GS in Europe, seems to be the next to use ShiftCam.
Unlike many brands, which work with complicated hydraulic constructions that only adjust the timing of the camshaft, BMW’s ShiftCam system does exactly what the name suggests: shift the camshaft.
By providing the camshaft with dual cam profiles for each valve, sliding the camshaft brings one of the two profiles into contact with the valve. This has the advantage that not only the timing, but also the valve lift can be adjusted. You don’t get more variable than this.
The big advantage of having two different camshaft profiles is that you can run a conservative profile at low rpm, with less lift (how far the valve opens) to increase gas velocity in the combustion chamber. In addition, you can reduce the valve overlap (the time that the intake and exhaust valves are both open), which makes the block run more efficiently and reduces emissions.
The BMW ShiftCam patent drawing shows a solenoid in the center of the intake camshaft, which switches between the low-rpm profile and the high-rpm profile via the spiral grooves. At high speeds, you need a larger valve lift, because with a lower lift you do not get enough air / fuel mixture into the combustion chamber.
Now the patent is not discussed on the cylinder capacity, but the only single-cylinder that really matters at BMW is the 310 in the G 310 GS, G 310 R and G 310 RR, although the latter is only available in Asia for now. In addition, BMW also has a single-cylinder in the C 400 scooter family, but the G family seems a more logical choice to us.
However, it could also be that BMW is developing a completely new single-cylinder, with more displacement and more power to close the gap with the competition in the popular A2 segment.
– Thanks for information from Motorfreaks.