An Initial Study of Variable Valve Timing Implemented with a Secondary Valve in the Intake Runner

Vogel, Olivier; Roussopoulos, Kimon; Guzzella, Lino; Czekaj, James

doi:10.4271/960590

Cited by 5 publications

(2 citation statements)

References 10 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Several methods to close off the intake have been investigated. An additional rotary [26] or poppet [27] valve can be installed in each intake runner and shut to cut off intake air. This has the advantage of allowing a conventional cam strategy for the engine's existing intake valves, and allows more flexibility in actuation for the secondary valves vis-à-vis controlling the load with the existing intake valves.…”

Section: Ntelc Via Intake Regulationmentioning

confidence: 99%

See 1 more Smart Citation

Iterative learning control of a fully flexible valve actuation system for non-throttled engine load control

Heinzen

Gillella

Sun

2011

Control Engineering Practice

View full text Add to dashboard Cite

This thesis presents the iterative learning control of a fully flexible valve actuation system for non-throttled load control of an internal combustion engine. First, a description is given of a novel camless valve actuation system with a unique hydro-mechanical internal feedback mechanism which simplifies the external control design. All the critical parameters describing the engine valve event, i.e. lift, timing, duration and seating velocity can be continuously varied by controlling the triggering timings of three two-state valves. Initial testing of a prototype experimental setup reveals that the performance of the system (transient tracking and steady-state variability) is influenced purely by the state of the system when the internal feedback mechanism is activated. This feature motivates the development of a cycle-to-cycle learning-based external control for activating the internal feedback mechanism based on the desired valve profile characteristics and the system state. To verify the proposed control methodology, it is implemented on the experimental system to track reference trajectories for the various valve event parameters corresponding to the non-throttled load control of an engine during the U.S. Federal Test Procedure (FTP) urban driving cycle. Vehicle load demand analysis is used to compute the desired engine speed and torque requirements. Detailed dynamic valve flow simulations assuming full flexibility of the engine valve event parameters are used to calculate the required trajectory of all these parameters to satisfy the speed and torque requirements without the use of a throttle. The experimental results show that the proposed framework, i.e., the valve actuation system and the external control methodology, is able to provide excellent performance even during aggressive transient operation. Over the 19 145 valve events of the FTP cycle, 99% of cycles had lift errors of 0.203 mm or less, and 99% of cycles had duration errors of 4.87 crank-angle degrees or less. Furthermore, only 11.99% of cycles had seating velocities higher than the desired bound; 99% of cycles had seating velocities 0.0429 m/s or less over the desired bound.

show abstract

Section: Ntelc Via Intake Regulationmentioning

confidence: 99%

“…The volume of air trapped between the secondary and primary valves causes a reduction in efficiency of, in one example, 20-45%. Even so, fuel savings of around 5% at part load and 15% at idle are projected [27].…”

Section: Ntelc Via Intake Regulationmentioning

confidence: 99%

Iterative learning control of a fully flexible valve actuation system for non-throttled engine load control

Heinzen

Gillella

Sun

2011

Control Engineering Practice

View full text Add to dashboard Cite

show abstract

Control of Camless Intake Process—Part II1

Ashhab

Stefanopoulou

Cook

et al. 1998

Journal of Dynamic Systems, Measurement, and Control

View full text Add to dashboard Cite

A model-based control scheme is designed to regulate the cylinder air charge of a camless multicylinder engine for unthrottled operation. The controller consists of a feedforward and an adaptive feedback scheme based on a control-oriented model of the breathing process of an engine equipped with electro-hydraulic springless valvetrain. The nonlinear control scheme is designed to achieve cylinder-to-cylinder balancing, fast cycle-to-cycle response, and minimization of pumping losses. The algorithm uses conventional sensor measurements of intake manifold pressure and mass air flow to the intake manifold, and intake valve duration measurement. Closed-loop simulation results are shown for a four-cylinder engine. [S0022-0434(00)03001-X]

show abstract