Volvo Workshop Manuals
XC90 2.5T AWD L5-2.5L Turbo VIN 59 B5254T2 (2003)
Relays and Modules > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Description and Operation > System Overview > Page 1010
The combustion of the fuel film on the cylinder walls is improved by retarding the ignition.
By opening the exhaust valve late, combustion takes place over a relatively long period. The film of fuel on the cylinder walls combusts, reducing the
By opening/closing the intake valve late:
so that there is little or no overlap, a predetermined pressure difference is maintained between the intake manifold and the combustion
maintains a high and stable pressure in the intake manifold (due to the upwards movement of the piston). Stable high pressure means that the
Double continuous variable valve timing (CVVT)
CVVT on both the intake camshaft and the exhaust camshaft means that the valve overlap can be changed to a greater degree than on engines where only
during cold starting and during the warm-up phaseswhen the intake camshaft and exhaust camshaft are set late. This reduces the emissions
during idle and when the engine is at operating temperaturewhen the exhaust camshaft is set to early and the intake camshaft is set to late.
at part loadwhen both the exhaust and intake camshaft are set to relatively late, with greater valve overlap. Greater valve overlap results in
Turbocharger (TC) control system
|[PREV PAGE] [NEXT PAGE]|