![]() The PCM calculates and determines the desired camshaft position. Retaining a fixed camshaft position is accomplished by dithering (oscillating) the solenoid valve duty cycle. Duty cycles near 0% or 100% represent rapid movement of the camshaft. As the PCM controls the duty cycle of the solenoid valve, oil pressure/flow advances or retards the cam timing. ![]() The solenoid valve controls the flow of engine oil in the VCT actuator assembly. The VCT solenoid valve is an integral part of the VCT system. The CKP signal is used as a reference for CMP positioning. The VCT system is enabled by the PCM when the proper conditions are met. The VCT system will not operate until the engine is at normal operating temperature. During part and wide open throttle, camshaft position is determined by engine RPM, load and throttle position. At idle (low engine speeds and closed throttle) the PCM controls camshaft position based on air and coolant temperatures. The PCM receives input signals from the IAT (intake air temperature), ECT (engine coolant temperature), EOT (engine oil temperature), CMP, TP (throttle position), MAF (mass air flow) and CKP to determine the operating conditions of the engine. A CKP (crankshaft position sensor) provides the PCM with crankshaft positioning information in 10 degree increments (Figure 115). The extra tooth placed between the equally spaced teeth represents the CMP signal for that bank. V6 engines use a CMP 3+1 tooth trigger wheel. Four cylinder and V8 engines use a CMP 4+1 tooth trigger wheel. ![]() The CMP trigger wheel has a number of equally spaced teeth equal to the number of cylinders on a bank plus one extra tooth (n+1). The VCT (variable cam timing) system consists of an electric hydraulic positioning control solenoid, a CMP (camshaft position sensor) and trigger wheel. The IPS system is on Lincoln LS, Thunderbird and Focus SVT and the DEPS system is on the F150 5.4L 3V. ![]() The elimination of the EGR system is accomplished by controlling the overlap in valve opening between the intake valve opening and exhaust valve closing.Ĭurrently for the 2004 model year, Ford Motor Company uses the PS and DEPS systems. In addition, on some applications a VCT system can eliminated the need for an external Exhaust Gas Recirculation (EGR) system. IPS systems also have the added benefit of improve torque. VCT systems provide reduced emissions and enhanced engine power, fuel economy and idle quality. At part and wide open throttle the PCM controls cam timing based on engine RPM, load and throttle position. At idle and low engine speeds with closed throttle, the phase angle are controlled by air flow, engine oil temperature and engine coolant temperature. Intake Phase Shifting (IPS) system - the intake cam is the active cam being advanced.ĭual Equal Phase Shifting (DEPS) system - both intake and exhaust cams are phase shifted and equally advanced or retarded.ĭual Independent Phase Shifting (DIPS) system - where both the intake and exhaust cams are shifted independently.Īll systems have four operational modes idle, part throttle, wide open throttle and default mode. There are four types of VCT systems.Įxhaust Phase Shifting (EPS) system - the exhaust cam is the active cam being retarded. Variable Cam Timing (VCT) enables rotation of the camshaft(s) relative to the crankshaft (phase-shafting) as a function of engine operating conditions. Heres some information I have found on VVT for the SVTF Which #4 is also the worse reading of them all which is 60 PSI. Secondly I can see oil coming up on each of the cams lobes except for lightly on #4 intake. As far as oil goes I have not mechanically checked but was good up to it not starting. Although I would dought fuel pressure would cause low compression. I was going to test the fuel pressure but have the wrong fitting so i was not able to test tonight.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |