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A Comprehensive Study on BSVI Turbocharger Selection and its Deterioration with Closed Crank-Case Ventilation in Heavy Commercial Vehicles

Automobile Industry-Juzer Jaliwala
Automotive-Aravind Mohan
  • Technical Paper
  • 2019-24-0061
To be published on 2019-08-15 by SAE International in United States
BSVI Norms getting implemented in India by April 2020 and every heavy commercial vehicle OEMs viewing it as one of the greatest challenge, there are many factors and trade off that should be considered at every step of the project. The newly developed engine in BSVI will be equipped with actuators like Intake Throttle Valve, Exhaust Throttle Valve and combination of these flap operations with turbocharger output plays a prominent role in controlling performance and emission. Turbocharger selection plays major role in engine and vehicle performance on road and testcell. Turbo charger plays an apex role in providing both required boost to the engine performance and set up a control on emissions. This study focusses on the use of different AVU (Air Valve Unit) controlled waste gate turbochargers from different suppliers and how it’s getting matched with the engine performance requirements. The fluctuations observed in boost pressure at higher loads due to the waste gate operational inconsistency and its solution is also explained. The legislation stresses on importance of positive crank case ventilation (connected to…
 

Optimal Engine Re-Start Strategy on a Mild Hybrid Powertrain by Means of Up-Front Modelling

Ford Werke GmbH-Harald Stoffels, Shan-An Kao, Michael Frenken
  • Technical Paper
  • 2019-24-0206
To be published on 2019-08-15 by SAE International in United States
The ability to switch off the internal combustion engine (ICE) during vehicle operation is a key functionality in hybrid powertrains to achieve low fuel economy. However, this can affect driveability, namely acceleration response when an ICE re-engagement due to a driver initiated torque demand is required. The ICE re-start as well as the speed and load synchronisation with the driveline and corresponding vehicle speed can lead to high response times. To avoid this issue, the operational range where the ICE can be switched off is often compromised, in turn sacrificing fuel economy. Based on a 48V off-axis P2 hybrid powertrain comprising a lay-shaft transmission we present an up-front simulation methodology that considers the relevant parameters of the ICE like air-path, turbocharger, friction, as well as the relevant mechanical and electrical parameters on the hybrid drive side, including a simplified multi-body approach to reflect the relevant vehicle and powertrain dynamics. Applying different ICE re-start strategies at different speeds and gears, the driveability of the ICE re-engagement was evaluated using a commercialized driveability evaluation tool. The objective…
 

Friction reduction by optimization of local oil temperatures

Universitat of Stuttgart-Michael Bargende
University of Kassel-Oemer Oezdemir, Adrian Rienäcker
  • Technical Paper
  • 2019-24-0177
To be published on 2019-08-15 by SAE International in United States
The reduction of engine-out emissions and increase of the total efficiency is a fundamental approach to reduce the fuel consumption and emissions of vehicles driven by combustion engines. Conventional passenger cars are operated mainly in lower partial loads most of their lifetime. Under these conditions, oil temperatures which are far below the maximum temperatures allowed, dominate inside the journal bearings. Therefore, the objective of this research project was to investigate possible potentials of friction reduction by optimization of the thermal management of the oil circuit of a combustion engine. Within the engine investigations, it was shown that especially the friction of the main and connecting rod bearings can be reduced with an increase of the oil supply temperature. For the investigations, the oil circuit of the test engine was modified to realize three separate oil circuits of main and connecting rod bearings, cylinder head and the piston jets with turbocharger, that were individually supplied with oil at different pressures and temperatures by an external system. Furthermore, on a journal bearing test rig it was shown…
 

Axial Flow Turbine Concept for Conventional and E-Turbocharging

Brunel University-Apostolos Pesyridis
Universita di Napoli Federico II-Alessandro Cappiello, Raffaele Tuccillo, Maria Cristina Cameretti
  • Technical Paper
  • 2019-24-0185
To be published on 2019-08-15 by SAE International in United States
Engine downsizing has established itself as one of the most successful strategies to reduce fuel consumption and pollutant emissions in the automotive field. In this regard, a major role is played by the turbocharging, allowing to increase engine power density, and so reducing engine size and weight. However, the need for turbocharging imposes some issues to be solved. In the attempt of mitigating turbo lag and poor low-end torque, many solutions have been presented in the open literature so far, such as: low inertia turbine wheels and variable geometry turbines; or even more complex concepts such as twin turbo and electrically assisted turbochargers. None of them appears as definitive, though. As possible way of reducing turbine rotor inertia, and so the turbo lag, also the change of turbine layout has been investigated, and it revealed itself as viable option, leading to the use of mixed-flow turbines. Only recently, the use of axial-flow turbines, with the aim of reducing rotor inertia, has been proposed as well. The current paper documents a case study involving the design…
 

DEVELOPMENT AND APPLICATION OF A QUASI-3D MODEL FOR THE SIMULATION OF RADIAL COMPRESSORS OF TURBOCHARGERS FOR INTERNAL COMBUSTION ENGINES

Politecnico di Milano-Gianluca Montenegro, Augusto Della Torre, Matteo Tamborski, Angelo Onorati, Andrea Marinoni
Università degli Studi di Genova-Silvia Marelli
  • Technical Paper
  • 2019-24-0187
To be published on 2019-08-15 by SAE International in United States
Although the characterization of turbochargers group has been historically performed by means of experimental analysis, the development of processors and software, together with the necessity of reducing the prototyping costs, has lead computational fluid-dynamic to be a possible alternative for determining the engine-turbo matching without resorting to detailed maps. In this work 3Dcell method, a quasi3D approach, developed by the Internal Combustion Engine Group at Politecnico di Milano, has been customized and applied to for the fluid dynamic simulation of fluid machines with rotating components (compressor impellers or turbine rotors). The 3Dcell is based on a pseudo-staggered leapfrog method applied to the governing equation to a 1D problem arbitrarily oriented in space. As mention above, 3Dcell has been developed for acoustic simulation for simple and motionless geometries. The current thesis work has aimed to the adjustment and extension of the acoustic 3Dcell method to make it able to analyse the behaviour of a turbo-compressor. Therefore, they have been faced problems as the implementation of governing equations with their source terms, the development of three-dimensional unstructured…
 

Inverted Brayton cycle as an option for waste energy recovery in turbocharged diesel engine

Universita degli Studi dell Aquila-Davide Di Battista, Roberto Cipollone PhD, Roberto Carapellucci PhD
  • Technical Paper
  • 2019-24-0060
To be published on 2019-08-15 by SAE International in United States
Energy recovery in reciprocating internal combustion engines (ICE) is one of the most investigated options for the reduction of fuel consumption and GHG emissions saving in the transportation sector. In fact, the energy wasted in ICE is greater than that converted in mechanical form. The contribution associated to the exhaust gases is almost one third of the fuel energy, calling for an urgent need to be recovered into mechanical form. An extensive literature is oriented toward this opportunity, strongly oriented to ORC (Organic Rankine Cycle)-based power units. From a thermodynamic point of view, one option, not extensively explored, is certainly represented by the Inverted Brayton Cycle (IBC) concept and by the corresponding components which make possible this recovery. IBC is a thermodynamic (exhaust) gas cycle which considers an expansion (made by a turbine under the ambient pressure), an isobaric cooling and a compression in sequence which restores the pressure which is needed to evacuate the exhaust gases toward the atmosphere. Thanks to the expansion which decreases the pressure below the ambient pressure, mechanical work produced…
 

Driving Cycle and Elasticity Manoeuvre Simulation of a Small SUV Featuring an Electrically Boosted 1.0 L Gasoline Engine

Politecnico di Torino-Alessandro Zanelli, Federico Millo
Röchling Automotive-Marco Barbolini
  • Technical Paper
  • 2019-24-0070
To be published on 2019-08-15 by SAE International in United States
Nowadays, the increasing trend in low voltage electrification promotes the introduction of electrified powertrain. In this context, electric boosting systems are a promising solution to improve the driveability of heavily downsized gasoline engines. The aim of this work is therefore to evaluate, through numerical simulation, the impact of different (12 V or 48 V) electric superchargers (eSC) on an extremely downsized 1.0 L engine in terms of vehicle performance and fuel consumption over different driving cycles. The virtual test rig developed for the analysis integrates a vehicle model representative of a B-SUV segment car with a 1-D CFD fast-running engine model representative of a 1.0 L state-of-the-art gasoline engine, equipped with a dual boost charging system, featuring an eSC in series with the main turbocharger. Vehicle performances were evaluated in terms of vehicle elasticity manoeuvers and in terms of CO2 emissions for type approval and RDE driving cycles. Improvements in elasticity time up to 17 % for the 12 V eSC, and up to 25 % for the 48 V eSC were highlighted, while no…
 

Inner-Insulated Turbocharger Technology to Reduce Emissions and Fuel Consumption from Modern Engines

BorgWarner Turbo Systems-Jürgen Werner
Ricardo UK Ltd-Joshua Dalby
  • Technical Paper
  • 2019-24-0184
To be published on 2019-08-15 by SAE International in United States
With more focus on real world emissions from light-duty vehicles, the interactions between engine and after-treatment are critical. For modern engines, most emissions are generated during the warm-up phase following a cold start. For Diesel engines this is exaggerated due to colder exhaust temperatures and larger aftertreatment systems. The De-NOx aftertreatment can be particularly problematic. Engine manufacturers are required to take measures to address these temperature issues which often result in higher fuel consumption (retarding combustion, increasing engine load or reducing the Diesel Air-fuel-ratio). In this paper we consider an inner-insulated turbocharger as an alternative, passive technology which aims to reduce the exhaust heat losses between the engine and the aftertreatment. Firstly, the concept and design of the inner-insulated turbocharger is presented. A transient 3D CFD/FEM simulation is conducted and predicts that external heat losses will be reduced by 70% compared to a standard turbocharger. A 1-D modelling methodology is then presented for capturing the behavior of the inner-insulated turbocharger. This is important as conventional models based on isentropic efficiency maps cannot accurately predict turbine…
 

Incipient surge detection in automotive turbocharger compressors

Università degli Studi di Genova-Silvia Marelli, Paolo Silvestri, Vittorio Usai, Massimo Capobianco
  • Technical Paper
  • 2019-24-0186
To be published on 2019-08-15 by SAE International in United States
Nowadays, turbocharging is a technique widely used to improve fuel consumption and exhaust emissions in automotive engines. Centrifugal compressors are typically adopted, even if an efficient engine integration is often restricted by surge phenomena. The focus of the present work is to describe an experimental analysis developed with the aim at characterizing and identifying compressor behavior in incipient surge conditions. The acoustic and vibrational operative response of two automotive centrifugal compressors has been experimentally analyzed on the test facility operating at the University of Genoa. Each compressor is characterized by a classical architecture and one of them is equipped with a “ported shroud”, which enlarges stable zone. Compressors characteristic curves have been measured under steady flow conditions for different levels of corrected rotational speed from the choking region to the surge line. Moreover, transient operations have been taken into account where, starting from a stable condition, surge phenomenon was generated progressively closing a valve positioned downstream the compressor or increasing rotational speed keeping fixed the circuit characteristics. Accelerometer and microphone signals have been acquired and…
 

Evaluation of Hybrid Electric Turbocharging for Medium Speed Engines

Delft University of Technology-Klaas Visser
Royal IHC-Benny Mestemaker, Jan Westhoeve
  • Technical Paper
  • 2019-24-0188
To be published on 2019-08-15 by SAE International in United States
This paper investigates the effects of hybrid electric turbocharging on the total system efficiency, the transient loading capability and the operational range of maritime engines, including the effects of the air control valves (cylinder bypass & charge air blow-off valve). An existing and validated mean-value first principle engine model has been adapted to simulate the operating principle of a combustion engine with a hybrid electric turbocharger system. The simulation of power take off/in together with an air excess ratio control strategy is included by means of torque addition to/removal from the turbocharger shaft and limiting it with eight boundary controllers. The analysis of the simulation results illustrates a trade-off between the increase of the system efficiency on one side and the transient loading capability of the engine on the other side. With turbocompounding, the system efficiency can be increased at the expense of a deteriorated gas exchange process and an increased thermal loading of the engine. And assisting the turbocharger for steady state operation leads to a smaller operating envelope due to the limitation of…