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Engine Boosting Systems, 2017

2017-03-28
The papers in this collection cover conceptual, modeling, and experimental studies relating to advanced turbochargers/superchargers and advanced boosting systems to achieve increased power density, better fuel economy, and reduced emissions.
Collection

Engine Boosting Systems, 2015

2015-04-14
This technical paper collection covers conceptual, modeling and experimental studies relating to advanced turbochargers/superchargers and advanced boosting systems to achieve increased power density, better fuel economy, and reduced emissions.
Collection

Engine Boosting Systems, 2018

2018-04-03
The papers in this collection cover conceptual, modeling, and experimental studies relating to advanced turbochargers/superchargers and advanced boosting systems to achieve increased power density, better fuel economy, and reduced emissions.
Journal Article

High Power-Density, High Efficiency, Mechanically Assisted, Turbocharged Direct-Injection Jet-Ignition Engines for Unmanned Aerial Vehicles

2019-05-02
Abstract More than a decade ago, we proposed combined use of direct injection (DI) and jet ignition (JI) to produce high efficiency, high power-density, positive-ignition (PI), lean burn stratified, internal combustion engines (ICEs). Adopting this concept, the latest FIA F1 engines, which are electrically assisted, turbocharged, directly injected, jet ignited, gasoline engines and work lean stratified in a highly boosted environment, have delivered peak power fuel conversion efficiencies well above 46%, with specific power densities more than 340 kW/liter. The concept, further evolved, is here presented for unmanned aerial vehicle (UAV) applications. Results of simulations for a new DI JI ICE with rotary valve, being super-turbocharged and having gasoline or methanol as working fuel, show the opportunity to achieve even larger power densities, up to 430 kW/liter, while delivering a near-constant torque and, consequently, a nearly linear power curve over a wide range of speeds.
Collection

Engine Boosting Systems, 2014

2014-04-01
This technical paper collection will cover conceptual, modeling and experimental studies relating to advanced turbochargers/superchargers and advanced boosting systems to achieve increased power density, better fuel economy, and reduced emissions.
Technical Paper

Customized and Market Specific Thermal Robust Clutch System Solution

2021-09-21
2021-01-1239
The goal of reducing fuel consumption and CO2-Emission is leading to turbo-charged combustion engines that deliver high torque at low speeds (down speeding). To meet NVH requirements damper technologies such as DMF (Dual Mass Flywheel) are established, leading to reduced space for the clutch system. Specific measures need to be considered if switching over from SMF (Single Mass Flywheel) to DMF [8]. Doing so has an impact on thermal behavior of the clutch system, for example due to reduced and different distribution of thermal masses and heat transfer to the surroundings. Taking these trends into account, clutch systems within vehicle powertrains are facing challenges to meet requirements e.g. clutch life, cost targets and space limitation. The clutch development process must also ensure delivery of a clutch system that meets requirements taking boundary conditions such as load cycles and driver behavior into account.
Technical Paper

Time to Boost Analysis of an Advanced Boosting System for Automotive Applications

2021-09-05
2021-24-0093
Fun to drive and drivability are important issues in modern vehicles, and the propulsion system plays a key role in achieving these goals. Today most engines are characterized by the presence of a turbocharging system to achieve a high level of specific power and efficiency. Unfortunately, turbocharged engines are characterized by a delay in the delivery of toque, especially at low load and low speed, a phenomenon commonly called turbo-lag. In this paper an innovative turbocharging system is studied with the aim of providing a solution to this annoying behavior; a hybrid boosting system consisting of a traditional turbocharger and an electrically assisted compressor is analyzed. This architecture, especially thanks to the good dynamic behavior of the e-compressor, achieves the goal of an important reduction in terms of time-to-boost, providing an important improvement in engine readiness.
Technical Paper

Simulation Study of a Turbocharged Two-Stroke Single Cylinder 425cc SI Engine

2021-09-05
2021-24-0003
An afterburner-assisted turbocharged single-cylinder 425 cc two-stroke SI-engine is described in this simulation study. This engine is intended as a Backup Range Extender (REX) application for heavy-duty battery electric vehicles (BEV) when external electric charging is unavailable. The 425 cc engine is an upscaled version of a 125 cc port-injected engine [26] which demonstrated that the selected technology could provide a specific power level of 400 kW/L and the desired 150 kW in a heavy duty BEV application. The 425 cc single cylinder two-stroke engine is an existing engine as one half of a 850 cc snowmobile engine. This simulation study includes upscaling of the swept volume, impact on engine speed and gas exchange properties. In the same way as for the 125cc engine [26], the exhaust gases reaches the turbine through a tuned exhaust pipe and an afterburner or oxidation catalyst.
Technical Paper

Development of a PN Surrogate Model Based on Mixture Quality in a GDI Engine

2021-09-05
2021-24-0013
A novel surrogate model is presented, which predicts the engine-out Particle Number (PN) emissions of a light-duty, spray-guided, turbo-charged, GDI engine. The model is developed through extensive CFD analysis, carried out using the Siemens Simcenter STAR-CD, and considers a range of part-load operating conditions and single-variable sweeps where control parameters such as start of injection and injection pressure are varied in isolation. The work is attached to the Ford-led APC6 DYNAMO project, which aims to improve efficiency and reduce harmful emissions from the next generation of gasoline engines. The CFD work focused on the air exchange, fuel spray and mixture preparation stages of the engine cycle. A combined Rosin-Rammler and Reitz-Diwakar model, calibrated over a wide range of injection pressure, is used to model fuel atomization and secondary droplets break-up.
Technical Paper

Potentials of the Oversizing and H2-Supported Lean Combustion of a VVA SI Gasoline Engine Towards Efficiency Improvement

2021-09-05
2021-24-0007
In recent years, internal combustion engine (ICE) downsizing coupled with turbocharging was considered the most effective path to improve engine efficiency at low load, without penalizing rated power/torque performance at full load. On the other side, issues related to knocking combustion and excessive exhaust gas temperatures obliged adopting countermeasures that highly affect the efficiency, such as fuel enrichment and delayed combustion. Powertrain electrification allows operating the ICE mostly at medium/high loads, shifting design needs and constraints towards targeting high efficiency under those operating conditions. Conversely, engine efficiency at low loads becomes a less important issue. In this track, the aim of this work is the investigation of the potential of the oversizing of a small Variable Valve ActuationSpark Ignition gasoline engine towards efficiency increase and tailpipe emission reduction.
Technical Paper

Experimental and Numerical Analyses of Direct and Port Water Injection in a Turbocharged Spark-Ignition Engine

2021-09-05
2021-24-0035
Water injection represents a promising tool to improve performance of spark-ignition engines. It allows reducing in-cylinder temperature, preventing knock risks. Optimizing the spark advance, water injection allows obtaining an increase of both efficiency and power output, particularly at medium and high loads. Water can be injected into the intake port or directly into the combustion chamber. In this paper, the authors investigated the effects of both direct and port water injection in a downsized PFI spark-ignition engine at high load operation. Different water-to-fuel ratios have been analyzed for both configurations. For the experimental analysis, low-pressure water injectors have been installed in the intake ports of the engine under study, upstream of the fuel injectors. Experimental tests have been carried out at various operating points. Furthermore, engine operation with port water injection has been simulated by means of the AVL Fire 3-D code.
Technical Paper

Machine Learning Application to Predict Turbocharger Performance under Steady-State and Transient Conditions

2021-09-05
2021-24-0029
Performance predictions of advanced turbocharged engines are becoming difficult because conventional engine models are built using performance map data of turbochargers with a proportional integral derivative (PID) controller. Improving prediction capabilities under transient test cycles or real driving conditions is a challenging task. This study applies a machine learning technique to predict turbocharger performances with high accuracy under steady-state and transient conditions. The manipulated signals of engine speed and torque created based on Compressed High-Intensity Radiated Pulse (Chirp signal) and Amplitude-modulated Pseudo-Random Binary Signal (APRBS) are used as inputs to the engine testbed. Data from the engine experiments are used as training data for the AI-based turbocharger model. High prediction accuracy of the AI turbocharger model is achieved with the co-efficient of determination in the model, and cross-validation results are higher than 0.8.
Technical Paper

A Novel Experimental Approach to Increase Shell Stiffness of Double Layered Critically Shaped Automotive Muffler for Optimizing Shell Radiation Noise in a Cost Effective Way

2021-09-22
2021-26-0288
Short development cycles, less packaging space and stringent noise emission rules have increased the need of CAE usage and first time right design approach. Engine exhaust noise is the main contributor of automotive noise when vehicle speed is low to moderate. Exhaust noise contains tailpipe noise and shell radiation noise. As vehicle speed increases, contribution of flow noise and tire noise is comparatively at higher side. The cold end development engineer is responsible to design a muffler to meet tailpipe and shell radiation noise targets. Muffler shell stiffness is a key characteristic for deciding shell radiation noise. High intensity pulses of exhaust gas passes through the exhaust pipe and hits cold end from inside which causes shell vibration and respectively shell noise. There are several conventional methods available to improve shell stiffness, but all of them are not applicable for ‘double layered critically shaped mufflers’ and all of them are not cost-effective.
Journal Article

Computational Fluid Dynamics Calculations of Turbocharger's Bearing Losses

2010-05-05
2010-01-1537
Fuel consumption in internal combustion engines and their associated CO2 emissions have become one of the major issues facing car manufacturers everyday for various reasons: the Kyoto protocol, the upcoming European regulation concerning CO2 emissions requiring emissions of less than 130g CO2/km before 2012, and customer demand. One of the most efficient solutions to reduce fuel consumption is to downsize the engine and increase its specific power and torque by using turbochargers. The engine and the turbocharger have to be chosen carefully and be finely tuned. It is essential to understand and characterise the turbocharger's behaviour precisely and on its whole operating range, especially at low engine speeds. The characteristics at low speed are not provided by manufacturers of turbochargers because compressor maps cannot be achieve on usual test bench.
Journal Article

3D-CFD-Study of Aerodynamic Losses in Compressor Impellers

2018-07-05
Abstract Due to the increasing requirements for efficiency, the wide range of characteristics and the improved possibilities of modern development and production processes, compressors in turbochargers have become more individualized in order to adapt to the requirements of internal combustion engines. An understanding of the working mechanisms as well as an understanding of the way that losses occur in the flow allows a reduced development effort during the optimization process. This article presents three-dimensional (3D) Computational Fluid Dynamics (CFD) investigations of the loss mechanisms and quantitative calculations of individual losses. The 3D-CFD method used in this article will reduce the drawbacks of one-dimensional calculation as far as possible. For example, the twist of the blades is taken into account and the “discrete” method is used for loss calculation instead of the “average” method.
Technical Paper

Aggressive Catalyst Heating Strategy Using Advanced Mixture Formation and Combustion Timing Techniques in a GDI Engine

2021-09-22
2021-26-0185
Precise control over mixture formation withhigh fuel pressure and multiple injections allows Gasoline Direct Injection (GDI) engines to be operated satisfactorily at extreme conditions wherePort Fuel Injection (PFI) engines wouldnormally struggle due to combustion instability issues. Catalyst heating phase is one such important condition which is initiated after a cold engine start to improve the effectiveness of the three-way catalyst (TWC). For a given TWC specification, fast light-offof TWC is achieved in the catalyst heating phase by increasing the exhaust gas temperature with higher exhaust mass flow. The duration of this phase must be as short as possible, as it is a trade-off between achieving sufficient TWC light off performance and fuel efficiency.
Technical Paper

A Case Study of Compressor Surge Related Noise on Turbocharged 2.0-L Gasoline Engine

2021-09-22
2021-26-0282
Till recently supercharging was the most accepted technique for boost solution in gasoline engines. Recent advents in turbochargers introduced turbocharging technology into gasoline engines. Turbocharging of gasoline engines has helped in powertrains with higher power density and less overall weight. Along with the advantages in performance, new challenges arise, both in terms of thermal management as well as overall acoustic performance of powertrains. The study focuses mainly on NVH aspects of turbocharging of gasoline engines. Compressor surge is a most common phenomenon in turbochargers. As the operating point on the compressor map moves closer to the surge line, the compressor starts to generate noise. The amplitude and frequency of the noise depends on the proximity of the operating point to the surge line. The severity of noise can be reduced by selecting a turbocharger with enough compressor surge margin.
Journal Article

48V Exhaust Gas Recirculation Pump: Reducing Carbon Dioxide with High-Efficiency Turbochargers without Increasing Engine-Out NOx

2021-08-23
Abstract Regulations limiting GreenHouse Gases (GHG) from Heavy-Duty (HD) commercial vehicles in the United States (US) and European Union will phase in between the 2024 and 2030 model years. These mandates require efficiency improvements at both the engine and vehicle levels, with the most stringent reductions required in the heaviest vehicles used for long-haul applications. At the same time, a 90% reduction in oxides of nitrogen (NOx) will be required as part of new regulations from the California Air Resources Board. Any technologies applied to improve engine efficiency must therefore not come at the expense of increased NOx emissions. Research into advanced engine architectures and components has identified improved turbomachine efficiency as one of the largest potential contributors to engine efficiency improvement. However this comes at the cost of a reduced capability to drive high-pressure Exhaust Gas Recirculation (EGR).
Journal Article

Applying a Driven Turbocharger with Turbine Bypass to Improve Aftertreatment Warm-Up and Diesel Nitrous Oxides Conversion

2021-09-23
Abstract As emissions regulations continue to tighten, both from lower imposed limits of pollutants, such as nitrous oxides (NOx), and in-use and real-world testing, the importance of quickly heating the aftertreatment to operating temperature during a cold start, as well as maintaining this temperature during periods of low engine load, is of increasing importance. Perhaps the best method of providing the necessary heating of the aftertreatment is to direct hot exhaust gasses to it directly from the engine. For heavy-duty diesel engines that utilize turbochargers, this is achieved by fully bypassing the exhaust flow around the turbine directly to the aftertreatment. However, this disables a conventional turbocharger, limiting engine operation to near-idle conditions during the bypass period.
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