DocumentCode :
397688
Title :
Synchronized phase shifting of multiple variable cam actuators
Author :
Magner, Stephen ; Jankovic, Mrdjan ; Cooper, Stephen
Author_Institution :
Ford Res. Lab., Dearborn, MI, USA
Volume :
4
fYear :
2003
fDate :
4-6 June 2003
Firstpage :
3130
Abstract :
Modern automotive engines often employ additional devices or systems, such as variable cam timing (VCT), that improve fuel economy, emissions, and/or peak torque and power. Every additional degree of freedom introduced by a new actuator increases mapping, calibration, and control design complexity. In addition, in VCT engine configurations with two banks of cylinders such as "V" engines or horizontally opposed engines, VCT creates control issues that arise due to requirements that multiple VCT devices shift synchronously. Non-synchronous VCT actuator movement may be caused by oil pressure differences between the banks (asymmetric oil supply), actuator sticking (cold starts), other mechanical imbalances, or improperly calibrated actuator control loops. Forcing the actuators to move together provides sufficient mitigation so that emission control and torque response are not compromised due to incorrect airflow estimation or spark timing. There are several approaches one can take to synchronize actuators. In this paper, we describe a system that modifies the reference cam phase command sent to the local VCT control loops in the two banks in order to slow down the faster actuator to match the response rate of the slower one. In this way we can prevent the difference between the banks from exceeding a set of threshold. The control algorithm accomplishes this without a-priori knowledge of which is the slow actuator and at what rate it is moving. The system automatically adjusts if actuators characteristics alter further, which may happen due to ageing or other factors.
Keywords :
actuators; automotive engineering; internal combustion engines; mechanical variables control; synchronisation; V engine; VCT engine configurations; actuator movement; airflow estimation; automotive engines; calibrated actuated control loops; calibration; control algorithm; control design complexity; emission control; fuel economy; mapping; multiple variable cam actuators; nonsynchronous VCT; oil pressure differences; peak torque; synchronized phase shifting; synchronous VCT; variable cam timing; Actuators; Automotive engineering; Calibration; Control design; Engine cylinders; Fuel economy; Petroleum; Pressure control; Timing; Torque;
fLanguage :
English
Publisher :
ieee
Conference_Titel :
American Control Conference, 2003. Proceedings of the 2003
ISSN :
0743-1619
Print_ISBN :
0-7803-7896-2
Type :
conf
DOI :
10.1109/ACC.2003.1244010
Filename :
1244010
Link To Document :
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