Search results
Results from the WOW.Com Content Network
The lobe separation angle (LSA, also called lobe centreline angle) is the angle between the centreline of the intake lobes and the centreline of the exhaust lobes. [23] A higher LSA reduces overlap, which improves idle quality and intake vacuum, [22] however using a wider LSA to compensate for excessive duration can reduce power and torque ...
The cam can be seen as a device that converts rotational motion to reciprocating (or sometimes oscillating) motion. [clarification needed] [3] A common example is the camshaft of an automobile, which takes the rotary motion of the engine and converts it into the reciprocating motion necessary to operate the intake and exhaust valves of the cylinders.
For twin-cam or DOHC engines, VCT was used on either the intake or exhaust camshaft. (Engines that have VCT on both camshafts are now designated as Ti-VCT.↓) The use of variable camshaft timing on the exhaust camshaft is for improved emissions, and vehicles with VCT on the exhaust camshaft do not require exhaust gas recirculation (EGR) as retarding the exhaust cam timing achieves the same ...
The mechanism is a coaxial shaft arrangement where the outer shaft carries the main body of the cam lobe. The main body of the cam lobe is in its maximum duration form. Typically the main lobe body would have a duration of about 450°. The lobe is very long axially, about 45 mm (1.8 in), and its profile consists of conventional opening and ...
The inner lifter is actuated by a small cam lobe, while the outer ring element is moved by a pair of larger-profile lobes. The timing of each valve is seamlessly adjusted by means of an electro-hydraulically operated rotary vane adjuster at the head of each intake camshaft.
By shifting area of the cam lobe which is in contact with the follower, the lift and duration can be continuously altered. This is achieved by moving the camshaft axially (sliding it across the engine) so a stationary follower is exposed to a varying lobe profile to produce different amounts of lift and duration.
Two versions of the Honda i-VTEC system can be found on a K-series engine, and both versions can come with variable timing control (VTC) on the intake cam. The VTEC system on engines like the K20A3 only operate on the intake cam; at low rpm only one intake valve is fully opened, the other opening just slightly to create a swirl effect in the ...
Camshafts normally have one lobe per valve, with a fixed valve duration and lift. Although many modern engines use camshaft phasing, adjusting the lift and valve duration in a working engine is more difficult. Some manufacturers use systems with more than one cam lobe, but this is still a compromise as only a few profiles can be in operation at ...