Sentences with phrase «low cam lobes»
It doesn't use direct injection, but the V - 6 does have a new version of iVTEC that can not only switch between high and low cam lobes, but on the rear bank of cylinders, can keep the valves closed completely.
http://www.automobilemag.com/ Not exact matches
Valve float is bad because the valve gets a running start at the valve seat instead of being gently lowered on to the valve seat by the cam lobe.
Because of this, at low RPM, when VTEC is not engaged, one of the two intake valves is allowed to open only a very small amount due to the mild cam lobe, forcing most of the intake charge through the other open intake valve with the normal cam lobe.
Using these inputs, the ECU is programmed to switch from the low lift to the high lift cam lobes when certain conditions are met.
In basic form, the single cam lobe and follower / rocker arm of a conventional engine is replaced with a locking multi-part rocker arm and two cam profiles: one optimized for low - RPM stability and fuel efficiency, and the other designed to maximize high - RPM power output.
Multi-valve engines tend to have smaller valves that have lower reciprocating mass, which can reduce wear on each cam lobe, and allow more power from higher RPM without the danger of valve bounce.
In order to achieve the optimum volumetric efficiency in the lower portion of the engine's operating range, rocker arms are programmed to follow cam lobes that provide low lift and reduced duration (shorter time open with less valve lift).
As the engine load changes, electromagnetic actuators allow a movable shaft containing different cam lobes to shift imperceptibly between high - lift and low - lift profiles.