14-09-2017, 02:16 PM
A non-cam or free-valve piston engine has stem valves actuated by means of electromagnetic, hydraulic or pneumatic actuators instead of cams. The actuators can be used both for opening and closing valves, and for opening valves closed by springs or other means.
As a camshaft normally only has one lobe per valve, the valve life and lift are fixed. The camshaft rotates at half the speed of the crankshaft. Although many modern engines use the camshaft phase, adjusting the lift and the length of the valve in a working engine is more difficult. Some manufacturers use systems with more than one cam lobe, but this remains a compromise since only a few profiles can be in operation at the same time. This is not the case with the tubeless motor, where the lift and synchronism of the valve can be freely adjusted from the valve to the valve and from cycle to cycle. It also allows multiple lifting events per cycle and, in fact, there are no events per cycle, completely disconnecting the cylinder.
As a camshaft normally only has one lobe per valve, the valve life and lift are fixed. The camshaft rotates at half the speed of the crankshaft. Although many modern engines use the camshaft phase, adjusting the lift and the length of the valve in a working engine is more difficult. Some manufacturers use systems with more than one cam lobe, but this remains a compromise since only a few profiles can be in operation at the same time. This is not the case with the tubeless motor, where the lift and synchronism of the valve can be freely adjusted from the valve to the valve and from cycle to cycle. It also allows multiple lifting events per cycle and, in fact, there are no events per cycle, completely disconnecting the cylinder.