2002 · INTAKE AND EXHAUST [15] · страница 3 из 9 · Открыть оригинал PDF ↗
At starting and driving at low speed, the duty control
valueofthevariablegeometrysolenoidvalveis
increasedtoapplythevacuumpressureofthe
vacuumpumptothevariablegeometryactuator.
Applyingthevacuumpressuretothevariable
geometryactuatorpullstheactuatorrodsothat
itcanmovetowardsthedirectionofclosingthe
variablenozzleofthevariablegeometry
turbocharger.Asclosingthenozzlereducesthe
exhaustgasmass,thespeedofexhaustgasflow
willbeincreasedandefficiencywillbeimproved.
Since the characteristic of boost pressure becomes
alowspeedtype,boostpressurewillsuddenly
risefromlowspeed.
Atdrivingathighspeed,thedutycontrolvalue
ofthevariablegeometrysolenoidvalveis
decreasedtoreducethevacuumpressurefrom
thevacuumpumpsothattheactuatorrodcan
returntothedeactivatedstatusandmovetowards
thedirectionofopeningthenozzleofthevariable
geometryturbocharger.
Openingthenozzleallowsthecharacteristicof
boostpressuretobecomeahighspeedtypeso
thattheappropriateboostpressurecanbe
maintained.
Therefore,boostpressurecanbecontrolledby
appropriatedutycontrolofthevariablegeometry
solenoidvalve.Theengine-ECUcalculatesthe
correctboostpressurebasedontheenginespeed
andfuelinjectionamount.Furthermore,theduty
controlofthevariablegeometrysolenoidvalveis
givenfeedbackofthesignalsfromthevariable
geometrycontrolpressuresensorandtheboost
pressure sensor so that the variable nozzle opening
angleofthevariablegeometryturbochargercan
bequicklyadjustedtoobtainthedesiredboost
pressure.
SERVICE SPECIFICATIONS <4D5-Step III>
| Items | Standard value |
|---|---|
| Variable geometry actuator activation vacuum (Approximately 1 mm stroke) kPa | Approximately 10.5 - 12.5 |
| Variable geometry solenoid valve coil resistance (at 20°C) Ω | 29 - 35 |
Таблица в оригинале
SEALANT<4D5-StepIII>
| Item | Specified sealant | Remarks |
|---|---|---|
| Thread of the intake manifold mounting bolts | 3M Stud Locking No.4170 or equivalent | Anaerobic sealant |
Таблица в оригинале
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