The Electro-Hydraulic Valvetrain System EHVS - System and Potential

Denger, Dirk; Mischker, Karsten

doi:10.4271/2005-01-0774

Cited by 21 publications

(7 citation statements)

References 7 publications

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“…The magnet valve commands are subject to certain hardware-related constraints that form the borders for the set of admissible actuation commands lli£Hvs-For a detailed description of the EHVS, see Ref. [18]. Sections 3.2-3.6 describe the utilization of the CV for all additional engine modes.…”

Section: Charge Valve Actuationmentioning

confidence: 99%

Validation of the Fuel Saving Potential of Downsized and Supercharged Hybrid Pneumatic Engines Using Vehicle Emulation Experiments

Dönitz

Voser

Vasile

et al. 2011

Journal of Engineering for Gas Turbines and Power

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The pneumatic hybridization of power trains is especially effective when it is combined with stnmg downsizing and supercharging of spark ignited engines. This paper presents measurement results obtained from such an engine. Specifically, performance measurements for all additional engine modes are shown. The pneumatic motor mode and the pneumatic pump mode are individually optimized over their whole operating range for maximum recuperation efficiency. Jointly with the conventional combustion mode and the pneumatic supercharged mode, they are implemented in one engine control svstem, thereby enabling the switching between all modes. A dynamometer simulates the longitudinal dynamics of two series production vehicles for the modifled engine. This experimental setup, defltied as emulation, is used to accurately measure the engine's fuel ccmsumption in the MVEG-95 and federal test procedure (FTP) drive cycles. Causal and noncausal energy management strategies are presented and used for choosing the engine mode during a drive cycle. Fuel savings of up to 35% are measured when comparing the modifled engine to the vehicles' statidard engines with the same rated power. Hybrid pneumatic vehicles (HPVs) may prove to be a viable alternative to hybrid electric vehicles since fuel savings and driveability are cotnparable, while the added cost is expected to be substantially lower for HPVs.

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Section: Charge Valve Actuationmentioning

confidence: 99%

Validation of the Fuel Saving Potential of Downsized and Supercharged Hybrid Pneumatic Engines Using Vehicle Emulation Experiments

Dönitz

Voser

Vasile

et al. 2011

Journal of Engineering for Gas Turbines and Power

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“…A significant amount of research has been carried out in this area in the development of both laboratory systems [6]- [9] and production oriented systems [10]- [12]. These systems can be classified into the following broad categories based on the energy source used for actuation.…”

Section: Introductionmentioning

confidence: 99%

Modeling and control design of a camless valve actuation system

Gillella

Sun

2009

2009 American Control Conference

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This paper presents the modeling and control design of a new fully flexible engine valve actuation system which is an enabler for camless engines. Unlike existing electromechanical or servo actuated electro-hydraulic valve actuation systems, precise valve motion control is achieved with a hydromechanical internal feedback mechanism. This feedback mechanism can be turned on or off in real-time using simple two state valves which helps reduce the system cost and enables mass production. Since the external control only activates or deactivates the internal feedback mechanism, the trajectory of the entire closed-loop system is purely dependent on the design parameters of the internal feedback system. A mathematical model of the system is developed to evaluate the effect of each of the design parameters. The "Area-schedule" is identified as the key design feature which affects the trajectory of the closedloop system. It needs to be designed systematically to optimize the performance of the system as well as improve its robustness. By treating this feature as the feedback control variable, the design problem is transformed into a nonlinear optimal control problem which is later solved using the numerical dynamic programming method. The effectiveness of the designed areaschedules is verified with simulations.

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“…This flexibility allows cycle-to-cycle control of fuel intake and waste exhaust, which leads to benefits such as improved fuel economy and lower exhaust emissions. Additionally, at low-to-moderate engine speeds, the timing can be opti-mized to improve full load torque as discussed by Denger and Mischker [4].…”

Section: Introductionmentioning

confidence: 99%

Parameter Identification for Electrohydraulic Valvetrain Systems

Gray¹,

Krstić

Chaturvedi

2011

Journal of Dynamic Systems, Measurement, and Control

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We consider an electrohydraulic valve system (EHVS) model with uncertain parameters that may possibly vary with time. This is a nonlinear third order system consisting of two clearly separated subsystems, one for the piston position and the other for the chamber pressure. The nonlinearities involved are flow-pressure characteristics of the solenoid valves, the pressure dynamics of the chamber due to varying volume, and a variable damping nonlinearity. We develop a parametric model that is linear in the unknown parameters of the system using filtering. We deal with a nonlinear parameterization in the variable damping term using the Taylor approximation. We design a parameter identifier, which employs a continuous-time unnormalized least-squares update law with a forgetting factor. This update law exponentially converges to the true parameters under a persistence of excitation condition, which is satisfied due to the periodic regime of operation of EHVS. We present simulation results that show good following of unknown parameters even with the presence of sensor noise.

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The Electro-Hydraulic Valvetrain System EHVS - System and Potential

Cited by 21 publications

References 7 publications

Validation of the Fuel Saving Potential of Downsized and Supercharged Hybrid Pneumatic Engines Using Vehicle Emulation Experiments

Validation of the Fuel Saving Potential of Downsized and Supercharged Hybrid Pneumatic Engines Using Vehicle Emulation Experiments

Modeling and control design of a camless valve actuation system

Parameter Identification for Electrohydraulic Valvetrain Systems

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