Development of a Switching Roller Finger Follower for Cylinder Deactivation in Gasoline Engine Applications

Radulescu, Andrei; McCarthy, James E.; Brownell, Scott

doi:10.4271/2013-01-0589

Cited by 18 publications

(11 citation statements)

References 17 publications

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“…Cylinder deactivation (CDA) involves deactivating the fuel injection and valve motion for a sub-set of cylinders (Archer and McCarthy, 2018). CDA is a well studied and implemented strategy in the gasoline market, for which fuel benefits are realized by enabling stoichiometric combustion with reduced intake air throttling (Leone and Pozar, 2001;Radulescu et al, 2013). Production diesel engines do not currently implement CDA.…”

Section: Introductionmentioning

confidence: 99%

Impact of Cylinder Deactivation and Cylinder Cutout via Flexible Valve Actuation on Fuel Efficient Aftertreatment Thermal Management at Curb Idle

et al. 2019

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Cylinder deactivation (CDA) and cylinder cutout are different operating strategies for diesel engines. CDA includes the deactivation of both the valve motions and the fuel injection of select cylinders, while cylinder cutout incorporates only fuel injection deactivation in select cylinders. This study compares diesel engine aftertreatment thermal management improvements possible via CDA and cylinder cutout at curb idle operation (800 RPM and 1.3 bar BMEP). Experiments and analysis demonstrated that both CDA and cylinder cutout enable improved fuel efficient "stay warm" thermal management compared to a stock thermal calibration on a Clean Idle Certified engine. At curb idle, this stock calibration depends on elevated exhaust manifold pressure to increase the required fueling (for thermal management) and to drive EGR. The study described here demonstrates that CDA does not require an elevated exhaust manifold pressure for thermal management or EGR delivery control, whereas cylinder cutout does. In addition to achieving engine-out NOx levels no higher than the stock thermal calibration, both cylinder cutout and CDA enable up to 55 and 80% reductions in particulate matter (PM), respectively. Cylinder cutout demonstrates 17% fuel savings, while CDA demonstrates 40% fuel savings, over the stock six-cylinder thermal calibration. These fuel efficiency improvements primarily result from reductions in pumping work via reduced air flow through the engine. Cylinder cutout reduces the air flow rate via elevated amounts of recirculated gases which are also required to regulate engine-out NOx, resulting in a larger delta pressure across the engine and consequently more pumping work than CDA. CDA reduces the air flow rate by deactivating cylinders, which reduces the charge flow rate and enables a small delta pressure between the intake and exhaust manifolds, resulting in less pumping work by the cylinders. As a result, CDA is more efficient than cylinder cutout. Furthermore, the thermal merits of cylinder cutout require high exhaust manifold pressures, and are subject to the configuration of the exhaust manifold and the exhaust gas recirculation (EGR) path.

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Section: Introductionmentioning

confidence: 99%

Impact of Cylinder Deactivation and Cylinder Cutout via Flexible Valve Actuation on Fuel Efficient Aftertreatment Thermal Management at Curb Idle

et al. 2019

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“…CDA reduces airflow without incurring increased pumping losses, thereby reducing the amount of throttling required to maintain stoichiometric operation. 2 Firing in fewer cylinders also means less surface area for heat loss, which improves efficiency. 3 Fuel consumption improvements between 5% and 14% have also been demonstrated.…”

Section: Introductionmentioning

confidence: 99%

“…CDA can be implemented by trapping combusted exhaust gas. 2 CDA can also be implemented by trapping fresh gas. Both trapping strategies will result in the gas spring pressure decaying due to blow-by across the piston rings and heat loss through the cylinder and piston.…”

Section: Introductionmentioning

confidence: 99%

Comparative study of diesel engine cylinder deactivation transition strategies

Allen

Gosala

Shaver

et al. 2018

International Journal of Engine Research

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Cylinder deactivation is an effective strategy to improve diesel engine fuel efficiency and aftertreatment thermal management when implemented through deactivation of both fueling and valve motion for a set of cylinders. Brake power is maintained by injecting additional fuel into the remaining activated cylinders. The initial deactivation of cylinders can be accomplished in various ways, the two most common options being to trap freshly inducted charge in the deactivated cylinders or to trap combusted gases in the deactivated cylinders. The choice of trapping strategy dictates the in-cylinder pressure characteristics of the deactivated cylinders and has potential to affect torque, oil consumption, and emissions upon reactivation. The effort described here compares these trapping strategies through examination of in-cylinder pressures following deactivation. Proponents of each trapping strategy exist; however, the results discussed here suggest no significant performance differences. As an example, the in-cylinder pressures of both trapping strategies converge as quickly as seven cycles, less than 1 s, after deactivation at curb idle conditions.

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“…Normally, this additional valve lift is absorbed such that the motion is hidden from the valve event to enable nominal operation. Examples of lost motion enabled hardware include but are not limited to the valvetrain assemblies described in the studies by Schwoerer et al (2010); Zurface et al (2012); Radulescu et al (2013).…”

Section: Introductionmentioning

confidence: 99%

“…In addition, implementing a lost motion enabled boot profile minimizes the impact of potential critical shifts. Radulescu et al (2013) defines a critical shift for an EIVC SRFF to be the undesired event that results in a valve being partially lifted and dropped back to the valve seat due to improper latching (Radulescu et al, 2013). This critical shift leads to unintended impact on the system from a momentary loss of control of both the rocker arm and the valve movement.…”

Section: Introductionmentioning

confidence: 99%

Utilizing Production Viable Valve Strategies at Elevated Speeds and Loads to Improve Volumetric Efficiency via Intake Valve Modulation

et al. 2018

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Development of a Switching Roller Finger Follower for Cylinder Deactivation in Gasoline Engine Applications

Cited by 18 publications

References 17 publications

Impact of Cylinder Deactivation and Cylinder Cutout via Flexible Valve Actuation on Fuel Efficient Aftertreatment Thermal Management at Curb Idle

Impact of Cylinder Deactivation and Cylinder Cutout via Flexible Valve Actuation on Fuel Efficient Aftertreatment Thermal Management at Curb Idle

Comparative study of diesel engine cylinder deactivation transition strategies

Utilizing Production Viable Valve Strategies at Elevated Speeds and Loads to Improve Volumetric Efficiency via Intake Valve Modulation

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