Copyright © 2016 by Pearson Education, Inc. All Rights Reserved Advanced Engine Performance Diagnosis, 6e James D. Halderman CHAPTER Variable Valve Timing

Copyright © 2016 by Pearson Education, Inc.All Rights Reserved

Advanced Engine Performance Diagnosis, 6eJames D. Halderman

CHAPTER

Variable Valve Timing Systems

3


ADVANCED ENGINE PERFORMANCE ADVANCED ENGINE PERFORMANCE DIAGNOSISDIAGNOSIS




Figure 3.1 Figure 3.1 Camshaft rotation during advance and Camshaft rotation during advance and retard.retard.



Figure 3.2 Figure 3.2 The camshaft is rotated in relation to the The camshaft is rotated in relation to the camshaft by the PCM to provide changes in valve timing.camshaft by the PCM to provide changes in valve timing.



Figure 3.3 Figure 3.3 Spline cam phaser assembly.Spline cam phaser assembly.



Figure 3.4 Figure 3.4 A spline phaser.A spline phaser.



Figure 3.5 Figure 3.5 The screen(s) protect the solenoid valve The screen(s) protect the solenoid valve from dirt and debris that can cause the valve to stick. from dirt and debris that can cause the valve to stick.

This fault can set a P0017 diagnostic trouble code This fault can set a P0017 diagnostic trouble code (crankshaft position–camshaft position correlation error).(crankshaft position–camshaft position correlation error).



Figure 3.6 Figure 3.6 A vane phaser is used to move the camshaft A vane phaser is used to move the camshaft using changes of oil pressure from the oil control valve.using changes of oil pressure from the oil control valve.



Figure 3.7 Figure 3.7 A magnetically controlled vane phaser.A magnetically controlled vane phaser.



Figure 3.8 Figure 3.8 When the PCM commands 50% duty cycle, When the PCM commands 50% duty cycle, the oil flow through the phaser drops to zero.the oil flow through the phaser drops to zero.



Figure 3.9 Figure 3.9 A camshaft position actuator used in a A camshaft position actuator used in a cam-in-block engine.cam-in-block engine.



Figure 3.10 Figure 3.10 A plastic mock-up of a Honda VTEC system A plastic mock-up of a Honda VTEC system that uses two different camshaft profiles: one for that uses two different camshaft profiles: one for

low-speed engine operation and the other for high speed.low-speed engine operation and the other for high speed.



Figure 3.11 Figure 3.11 Engine oil pressure is used to switch Engine oil pressure is used to switch cam lobes on a VTEC system.cam lobes on a VTEC system.



Figure 3.12 Figure 3.12 A typical variable cam timing control valve. A typical variable cam timing control valve. The solenoid is controlled by the engine computer and The solenoid is controlled by the engine computer and

directs engine oil pressure to move a helical gear, which directs engine oil pressure to move a helical gear, which rotates the camshaft relative to the timing chain sprocket.rotates the camshaft relative to the timing chain sprocket.



Figure 3.13 Figure 3.13 The schematic of a variable valve timing The schematic of a variable valve timing control circuit, showing that battery power (+) is being control circuit, showing that battery power (+) is being applied to the variable valve timing (VVT) solenoid and applied to the variable valve timing (VVT) solenoid and

pulsed to ground by the PCM.pulsed to ground by the PCM.



Figure 3.14 Figure 3.14 A variable valve timing solenoid being A variable valve timing solenoid being controlled by applying voltage from the PCM.controlled by applying voltage from the PCM.



Figure 3.15 Figure 3.15 Oil pressure applied to the locking pin Oil pressure applied to the locking pin causes the inside of the lifter to freely move inside the causes the inside of the lifter to freely move inside the

outer shell of the lifter, thereby keeping the valve closed.outer shell of the lifter, thereby keeping the valve closed.



Figure 3.16 Figure 3.16 Active fuel management includes many Active fuel management includes many different components and changes to the oiling system, different components and changes to the oiling system,

which makes routine oil changes even more important on which makes routine oil changes even more important on engines equipped with this system.engines equipped with this system.



Figure 3.17 Figure 3.17 The driver information display on a The driver information display on a Chevrolet Impala with a 5.3 liter V-8 equipped with Chevrolet Impala with a 5.3 liter V-8 equipped with

active fuel management.active fuel management.

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Copyright © 2016 by Pearson Education, Inc. All Rights Reserved Advanced Engine Performance Diagnosis, 6e James D. Halderman CHAPTER Variable Valve Timing