Valve-Event Modulated Boost System

Roth, David B.; Keller, Philip; Sisson, James C.

doi:10.4271/2010-01-1222

Cited by 22 publications

(14 citation statements)

References 4 publications

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“…This ratio between the speed of the blade tip and the speed of the flow is commonly used as an adimensional parameter in turbochargers analysis [8]. The efficiency values of this turbine were only supplied by the manufacturer for shaft displacements of 2, 4, 6, and 8 mm and for different blade to jet speed ratios, so as to complete the efficiency-displacement plot, the data was interpolated between the shaft displacements of 2 to 8 mm.…”

Section: Sine Wave Controlmentioning

confidence: 99%

“…For the calculation of the power delivered by the turbine, the authors follow the method proposed by Watson and Janota [8].…”

Section: The Id Gas-dynamic Modelmentioning

confidence: 99%

“…Unfortunately, as just explained, the use of an ACT will cancel these pulses, as the inlet effective area will be constantly varying and adapting to the pressure pulse; consequently cancelling the pulses. This continuous opening and closing of the turbine's nozzle Viiill probably also affect the exhaust backpressure and could therefore increase the pumping losses [8]. The effect of the ACT on the overall engine performance is unknown and this is what will be tried to be unveiled in this research.…”

Section: Introductionmentioning

confidence: 97%

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Numerical Study of the Implementation of an Active Control Turbocharger on Automotive Diesel Engines

Galindo¹,

Dolz²,

Tiseira³

et al. 2013

Journal of Engineering for Gas Turbines and Power

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Active control turbocharger (ACT) has been proposed as a way to improve turbocharger performance under highly pulsating exhaust flows. This technique implies that the variable geometry mechanism in the turbine is used to optimize its position as a function of the instantaneous mass flow during the engine cycle. Tests presented in the literature showed promi,úng results in a pulsating gas-stand. In this work, a modeling study has been conducted at different engine conditions aimed to quantify the gain in on-engine conditions and to develop a strategy to integrate the ACT system within the engine. Different ways of changing the displacement of the variable mechanism have been analyzed by means of a one-dimensional gas dynamic model. The simulations have been carried out at constant engine operating points defined by fixed air-to-fuel ratio for different mechanism displacement functions around an average position that guarantees the desired amount of intake air. The benefits in overall engine efficiency are lower to those predicted in the literature. It can be concluded that it is not possible to use the ACT system to optimize the turbine operating point and at the same time to control the engine operating point, [

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Section: Sine Wave Controlmentioning

confidence: 99%

“…For the calculation of the power delivered by the turbine, the authors follow the method proposed by Watson and Janota [8].…”

Section: The Id Gas-dynamic Modelmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 97%

See 1 more Smart Citation

Numerical Study of the Implementation of an Active Control Turbocharger on Automotive Diesel Engines

Galindo¹,

Dolz²,

Tiseira³

et al. 2013

Journal of Engineering for Gas Turbines and Power

View full text Add to dashboard Cite

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“…Furthermore, combined super-and turbocharging systems have also been in production for some time, allowing positive pressure to be applied to the intake all the time and desensitizing the engine to the pulse overlap effects (particularly an issue in four or more cylinder groups) [10]. Other interesting downsizing approaches such as Divided Exhaust Period or Valve-Event Modulated Boost hold promise in improving the efficiency of the Otto cycle through pumping work reduction, scavenging and related combustion improvement [11,12,13].…”

Section: Commercial Viewmentioning

confidence: 99%

Ultra Boost for Economy: Extending the Limits of Extreme Engine Downsizing

Turner

Popplewell

Patel

et al. 2014

SAE Int. J. Engines

145

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The paper discusses the concept, design and final results from the 'Ultra Boost for Economy' collaborative project, which was part-funded by the Technology Strategy Board, the UK's innovation agency. The project comprised industry-and academiawide expertise to demonstrate that it is possible to reduce engine capacity by 60% and still achieve the torque curve of a modern, large-capacity naturally-aspirated engine, while encompassing the attributes necessary to employ such a concept in premium vehicles.In addition to achieving the torque curve of the Jaguar Land Rover naturally-aspirated 5.0 litre V8 engine (which included generating 25 bar BMEP at 1000 rpm), the main project target was to show that such a downsized engine could, in itself, provide a major proportion of a route towards a 35% reduction in vehicle tailpipe CO 2 on the New European Drive Cycle, together with some vehicle-based modifications and the assumption of stop-start technology being used instead of hybridization. In order to do this vehicle modelling was employed to set part-load operating points representative of a target vehicle and to provide weighting factors for those points. The engine was sized by using the fuel consumption improvement targets and a series of specification steps designed to ensure that the required full-load performance and driveability could be achieved.The engine was designed in parallel with 1-D modelling which helped to combine the various technology packages of the project, including the specification of an advanced charging system and the provision of the necessary variability in the valvetrain system. An advanced intake port was designed in order to ensure the necessary flow rate and the charge motion to provide fuel mixing and help suppress knock, and was subjected to a full transient CFD analysis. A new engine management system was provided which necessarily had to be capable of controlling many functions, including a supercharger engagement clutch and full bypass system, direct injection system, port-fuel injection system, separately-switchable cam profiles for the intake and exhaust valves and wide-range fast-acting camshaft phasing devices.

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“…Lower residual gas fraction also enables ignition timing to be advanced hence reducing the cylinder pressure and temperature. Reducing 15% of residual gas fraction when knock intensity is constant at 30kPa allows the ignition timing to be advanced up to 5 CAD, which improves the efficiency of combustion.Exhaust valve modulation concepts such as Divided Exhaust Period (DEP) [14][15][16][17] and Valve-Event Modulated Boost (VEMB) [18,19] direct the highest energy exhaust flow from the cylinder into a blow down manifold, which is connected to the turbocharger turbine, and the lower energy exhaust flow into a scavenging manifold, which bypasses the turbine. This arrangement helps to reduce the back pressure experienced by the piston during scavenging, with the pumping work reduced as a consequence.…”

mentioning

confidence: 99%

Turbocharger Matching Method for Reducing Residual Concentration in a Turbocharged Gasoline Engine

Ismail¹,

Costall²,

Martinez-Botas³

et al. 2015

SAE Technical Paper Series

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In a turbocharged engine, preserving the maximum amount of exhaust pulse energy for turbine operation will result in improved low end torque and engine transient response. However, the exhaust flow entering the turbine is highly unsteady, and the presence of the turbine as a restriction in the exhaust flow results in a higher pressure at the cylinder exhaust ports and consequently poor scavenging. This leads to an increase in the amount of residual gas in the combustion chamber, compared to the naturally-aspirated equivalent, thereby increasing the tendency for engine knock. If the level of residual gas can be reduced and controlled, it should enable the engine to operate at a higher compression ratio, improving its thermal efficiency. This paper presents a method of turbocharger matching for reducing residual gas content in a turbocharged engine. The turbine is first scaled to a larger size as a preliminary step towards reducing back pressure and thus the residual gas concentration in-cylinder. However a larger turbine causes a torque deficit at low engine speeds. So in a following step, pulse separation is used. In optimal pulse separation, the gas exchange process in one cylinder is completely unimpeded by pressure pulses emanating from other cylinders, thereby preserving the exhaust pulse energy entering the turbine. A pulse-divided exhaust manifold enables this by isolating the manifold runners emanating from certain cylinder groups, even as far as the junction with the turbine housing.This combination of appropriate turbine sizing and pulse-divided exhaust manifold design is applied to a Proton 1.6-litre CamPro CFE turbocharged gasoline engine model. The use of a pulse-divided exhaust manifold allows the turbine to be increased in size by 2.5 times (on a mass flow rate basis) while maintaining the same torque and power performance. As a consequence, lower back pressure and improved scavenging reduces the residual concentration by up to 43%, while the brake specific fuel consumption improves by approx. 1%, before any modification to the compression ratio is made. IntroductionMany efforts have been made globally to reduce greenhouse gasses, particularly the CO 2 emissions produced by motor vehicles. Based on a study of global atmospheric trace gases by the Carbon Dioxide Information Analysis Center (CDIAC), CO 2 has increased from 280ppm pre-1750 to 386ppm in 2009, an increase of 106ppm. Modern road vehicles are required to meet stringent emission and fuel economy requirements, and several emission standards for passenger cars are already established or are currently being proposed to tackle climate change, and some are in the process of revision. For example, the European Commission aims to reduce CO 2 emissions from light-duty vehicles to a level of 95g/km by 2020 [1]. As a consequence, researchers and manufacturers have been investigating advanced technologies to meet these demands. One method that can be viewed as a viable short-to-medium term solution [2] is to use a smaller capacity engine that...

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Valve-Event Modulated Boost System

Cited by 22 publications

References 4 publications

Numerical Study of the Implementation of an Active Control Turbocharger on Automotive Diesel Engines

Numerical Study of the Implementation of an Active Control Turbocharger on Automotive Diesel Engines

Ultra Boost for Economy: Extending the Limits of Extreme Engine Downsizing

Turbocharger Matching Method for Reducing Residual Concentration in a Turbocharged Gasoline Engine

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