Browse Topic: Turbochargers

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Optimization of HEV Vehicle’s Engine Modulated Noise2025-01-008405/05/2023
One 1.5L Miller-cycle turbocharged four cylinder gasoline hybrid engine is installed on a certain hybrid vehicle. When accelerating at low to medium speeds with a small throttle, there is a "da da" knocking noise inside the car, which seriously affects the overall sound quality of the vehicle. By analyzing the vibration and noise data of the engine, it was found that the frequency of the abnormal knocking sound is 200-1000Hz, which presents a half order characteristic in the time domain, that is, one knocking occurs when the engine crankshaft rotates twice. Through Hilbert demodulation analysis of the vibration data in the problem frequency range, it was found that the knocking noise was modulated in the frequency domain, with a modulation frequency of half of the crankshaft rotation frequency. By building a fully flexible multi-body dynamic model of a hybrid powertrain and inputting the engine's cylinder pressure excitation, the combustion excitation is coupled with mechanical
dan, Kong
Improvement of Transient Response on a Downsized 4 Cylinder Engine for Automobile Application2021-28-028010/01/2021
The automobile industry is one among the fastest in terms of adapting the technological advancements and evolving based on changing customer requirements. Researchers are focusing on making the automobiles better by means of making the vehicles more efficient, powerful and less polluting. In this study, venues of improving low end torque via improvement in volumetric efficiency as well as proper selection of turbochargers. An in-depth analysis of gas dynamics with respect to valve timing is studied along with the AVL boost simulation. It was found that volumetric efficiency starts to improve when there is a reduction in exhaust – exhaust valve overlap. There is an improvement found in the fresh air ratio (lambda) as the residual gas content is reduced. After the selection of valve timing, turbocharger optimization is done with comparison between two turbine sizes. Along with turbocharger comparison, technology comparison is also done namely between normal electronic VGT (Variable
Jain, Praveer Kirtimohan, Chendil, Chellapandi, Asthana, Shivam, Sanjay, Nehal, Meda, Venkata Saikumar, R, Sivasubramamanian, Daithankar, Parag, Ramadandi, Padmavathi, RS, Ranganathan, A, Guru Sankar
Time to boost analysis of an advanced boosting system for automotive applications2021-24-009309/05/2021
Fun to drive and drivability are important issues in modern vehicles, and propulsion system plays a key role in achieving these goals. Nowadays, most engines are characterized by the presence of a turbocharging system in order to obtain a high level of specific power and efficiency. Unfortunately, turbocharged engines are characterized by a delay in toque delivery, especially at low load, 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 bosting 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. The experimental campaign is carried out entirely on the test bench for components of the propulsion system of
Usai, Vittorio, Marelli, Silvia
An Optimized Design of Multi-Chamber Perforated Resonators to Attenuate Turbocharged Intake System Noise2021-01-066904/06/2021
The turbocharger air intake noise during transient conditions like wide open throttle and tip-in/out affects the passenger ride comfort. This paper aims to study an optimized design of multi-chamber perforated resonators to attenuate this noise. The noise produced by a turbocharger in a test vehicle has been measured to find out the noise spectral characteristics which can be used to design the acoustic targets including the amplitude and frequency range of transmission loss (TL). The structural parameters of the resonators are optimized based on genetic algorithm (GA) and two-dimensional prediction theory of the resonator TL. The optimized resonators are installed on the test vehicle to verify the actual noise reduction effect. The results suggest that the broadband noise has been eliminated, and subjective feelings are greatly improved.
Guo, Rong, Luo, Rui
Driving Cycle Based Control and Calibration for a Turbocharged SI Engine with Low Pressure EGR System2020-01-201509/15/2020
Low pressure cooled EGR (LPEGR) for spark ignition (SI) engines is known to be one of the key technologies to benefit fuel consumption owing to lower pumping loss at part load, knock suppression capability and extended stoichiometric operating range thanks to combustion cooling effect. In order to implement this technology to industrialised application with the optimal performance efficiently and robustly, several challenges need to be solved, especially the EGR estimation accuracy and transport delay estimation accuracy during transient. And these challenges could be more complex on a turbocharged SI engine due to the much longer induction system, and more complex air path model due to the introduction of turbine, compressor and dump valve. This paper describes the control and calibration method for a turbocharged LPEGR engine, and the validation result in Worldwide harmonized Light vehicles Test Cycles (WLTC). The test result shows remarkable fuel benefit and accurate EGR estimation
Ma, He, Noguchi, Hidenori, Williams, Philip
The Potential of Exhaust Waste Heat Use in a Turbocharged Diesel Engine for Charge Air Cooling2020-01-208909/15/2020
Even a basic analysis of the use of fuel energy in a combustion engine would indicate that one-third of fuel energy is converted into exhaust waste, which is released into the environment. The scale of energy loss encourages scientists to try to consider the waste heat of exhaust gases as a potential source of useful energy. It is a standard today that waste heat is commonly used to power a turbocharger applied to internal combustion engines. Waste heat can also be used to drive an adsorption cooling system for air-conditioning inside the car. The drawback of that solution is complexity of the system and size of adsorption bed which make it not suitable for automotive industry use. The concept of increasing the capability of vehicles’ turbo engines can boost performance of turbo-charged engines through extra cooling of air being impelled into the combustion chamber of the engine. Cooling of the charge inside the intake manifold saves fuel and reduces nitric oxide emissions in exhaust
Danilecki, Krzysztof, Eliasz, Jacek
Parametric Study on Electric Turbocharging for Passenger Cars2020-01-222409/15/2020
The motor generator unit installed on the turbocharger shaft (MGU-H) provides a fundamental contribution to the amazing performances and efficiency of the last Formula 1 power units. The excess of exhaust gas energy - normally dumped through the waste-gate - can be converted into electric energy and used to push the car, by means of a second motor generator unit installed on the engine crankshaft (MGU-K). The goal of this paper is to assess pros and cons of the MGU-H technology when applied to a family of engines of different displacement, installed on a typical passenger car. The influence of engine size and cylinders layout is investigated, under the same set of hypotheses, considering both transient and steady engine operations. The baseline engine is a commercial 2.0 L, SI, 4-cylinder in-line, rated at 200 HP at 4500-5000 rpm. The study considers the following other SI configurations: a) 1.5L, 3-cylinder in-line, 150 HP; b) 3.0L, V6, 300 HP; c) 4.0L, V8, 400 HP; d) 6.0L, V12, 600
Mattarelli, Enrico, Scrignoli, Francesco, Rinaldini, Carlo Alberto
Investigation of H2 Formation Characterization and its Contribution to Post- Oxidation Phenomenon in a Turbocharged DISI Engine2020-01-218809/15/2020
In this research, simulation and experimental investigation of H2 emission formation and its influence during the post-oxidation phenomenon were conducted on a turbo-charged spark ignition engine. During the post-oxidation phenomenon phase, rich air-fuel ratio (A/F) is used inside the cylinder. This rich excursion gives rise to the production of H2 emission by various reactions inside the cylinder. It is expected that the generation of this H2 emission can play a key role in the actuation of the post-oxidation and its reaction rate if enough temperature and mixing strength are attained. It is predicted that when rich combustion inside the cylinder will take place, more carbon monoxide (CO)/ Total Hydro Carbon (THC)/ Hydrogen (H2) contents will arrive in the exhaust manifold. This H2 content facilitates in the production of OH radical which contributes to the post-oxidation reaction and in-turn can aid towards increasing the enthalpy. Through simulations, it was also investigated that
KUMAR, Madan, Moeeni, Salaar, Kuboyama, Tatsuya, Moriyoshi, Yasuo, Przewlocki, Jan, Tromellini, Rodolfo, Grill, Michael, Chiodi, Marco, Bargende, Michael
Lean-Burn Stratified Alcohol Fuels Engines of Power Density up to 475 kW/Liter Featuring Super-Turbocharging, Rotary Valves, Direct Injection, and Jet Ignition2020-01-203609/15/2020
Direct injection (DI) and jet ignition (JI), plus assisted turbocharging, have been demonstrated to deliver high efficiency, high power density positive ignition (PI) internal combustion engines (ICEs) with gasoline. Peak efficiency above 50% and power density of 340 kW/liter at the 15,000 rpm revolution limiter working overall λ=1.45 have been report-ed. Here we explore the further improvement in power density that may be obtained by replacing gasoline with ethanol or methanol, thanks to the higher octane number and the larger latent heat of vaporization, which translates in an increased resistance to knock, and permits to have larger compression ratios. Results of simulations are proposed for a numerical engine that uses rotary valves rather than poppet valves, while also using mechanical, rather than electric, assisted turbocharging. While with gasoline, the power density is 410-420 kW/liter, the use of oxygenates permits to achieve up to 475 kW/liter working with methanol.
Boretti, Alberto
Analysis of the Boost System for a High Performance 2-Stroke Boosted Uniflow Scavenged Direct Injection Gasoline (BUSDIG) Engine2020-01-200709/15/2020
A 2-stroke boosted uniflow scavenged direct injection gasoline (BUSDIG) engine was researched and developed at Brunel University London to achieve higher power-to-mass ratio and thermal efficiency. In the BUSDIG engine concept, the intake scavenge ports are integrated to the cylinder liner and controlled by the movement of piston top while exhaust valves are placed in the cylinder head. Systematic studies on scavenging ports, intake plenum, piston design, valve opening profiles and fuel injection strategies have been performed to investigate and optimise the scavenging performance and in-cylinder fuel/air mixing process for optimised combustion process. In order to achieve superior power performance with higher thermal efficiency, the evaluation and optimisation of the boost system for a 1.0 L 2-cylinder 2-stroke BUSDIG engine were performed in this study using one dimensional (1D) engine simulations. The results show that the engine exhaust valve opening (EVO) timing and exhaust
Wang, Xinyan, Zhao, Hua
Experimental and Numerical Investigation of a Turbocharger Turbine Using Exergy Analysis at Non-Adiabatic Conditions2020-01-222509/15/2020
Heat transfer in a turbocharger plays a crucial role in the optimization of turbocharger-engine matching process. Due to high temperature gradients between the hot exhaust gas compared to the compressor as well as the environment, it is well-known, that the heat loss from a turbocharger turbine is significant. Investigations of turbocharger performance are commonly done by quantifying the performance parameters under adiabatic conditions, following the paradigm of the first law of thermodynamics, based on the energy balance method. It turns out that an adiabatic assumption and the energy balance method is insufficient to provide a deep understanding about the aerothermodynamic effects on the turbine performance due to heat transfer. Based on the current state-of-the-art, this study aims to improve the characterization methods for passenger car turbocharger turbines, considering the impacts of heat transfer. Firstly, the turbocharger is measured on a hot gas test bench. Based on this
Lim, Shyang Maw, Kazemi Bakhshmand, Sina, Biet, Clemens, Mihaescu, Mihai
The Influence of Reduxco Catalyst in the Diesel Fuel on Energy Parameters, Exhaust Gas Composition and Rate of Heat Release of a Diesel Engine2020-01-206109/15/2020
According to the information provided by the catalyst producer, the catalyst with the trade name Reduxco, which was used in the research, is a reaction product of acetic acid, iron, n-butanol, n-propanol and isopropanol. According to Customer data, Reduxco catalyst in a fuel causes a decrease of the energy of activation of the hydrocarbon fuel oxidation reaction, introduces additional OH groups allowing to increase the burning rate, facilitates the combustion of already formed solid particles in the engine cylinder. To confirm this information, comparative tests were carried out (in the Internal Combustion Engines laboratory of the Cracow University of Technology); the analysis included not only the energy parameters and exhaust gas composition of the diesel engine powered by standard diesel oil and Reduxco-containing fuel, but also the indicator charts and rate of heat release in the engine cylinder. What was used in the tests was a turbocharged VW 1.9 TDI diesel engine, which was
Cisek, Jerzy, Lesniak, Szymon, Mokretskyy, Vitaliy, Przybylski, Włodzimierz
Unsteady Simulation of Six-Inlet Pulsed-Flow Turbocharger Turbine2020-01-223709/15/2020
The turbochargers are driven by unsteady, pulsating flow. Such flow is generated by the exhaust phase of an internal combustion engine (ICE). A lot of turbocharger simulations are done during steady-state operation. Such simulations are favorable for turbocharger optimization at a certain operating point. However, the frequency and amplitude of exhaust pulses can heavily influence turbine performance. This paper presents the results of the three-dimensional (3-D) simulations of the six-inlet turbocharger turbine, under pulsating operation with a moving mesh approach. One of the key points of interest was the separation of the pressure pulses from the six-exhaust pipes during engine operation. The leakage between the exhaust pipes was analyzed at each time step at the different turbine speed. Another key point was the turbine response during pulsating flow at the different rotor speed. Parameter such as the turbine total-static efficiency under the single-pressure pulse was investigated
Kozak, Dariusz, Mazuro, Paweł
Mercedes-AMG ready with electrically-assisted turbocharger20AUTP08_0807/01/2020
In announcement signaling automakers continue significant R&D for internal-combustion propulsion, Mercedes-AMG said it is preparing to launch a new, electrically-assisted turbocharger for engines to power its next vehicle generation. Confirming that the new turbocharger design will soon be fitted in a “series production” model line, the company said the electrically augmented turbocharger delivers enhanced driving dynamics while also improving efficiency. Mercedes-Benz and other automakers already have launched auxiliary electric compressors to augment conventional turbochargers, but this design integrates the strategy by using the electric machine to act directly on shaft connecting the turbine and compressor wheels: the 1.6-inch (41-mm)-wide motor sits between the exhaust-driven turbine and the impeller that compresses the intake air directed into the engine. It can spin to a conventional turbocharger rate of up to 170,000 rpm.
Visnic, Bill
Experimental Evaluation of Steady State Performance of an Automotive Electric Supercharger2020-37-000806/23/2020
Nowadays, the electric supercharger for turbocharged downsized automotive engines is mainly used to improve torque at low engine speeds in order to obtain an improvement of the time to boost. These components are usually designed to fill the gap in terms of torque in transient operation caused by the main turbocharger with reference to the typical turbo lag issues. An advanced solution of the engine boosting system was taken into account, considering the adoption of an e-booster system coupled to a waste-gated turbocharger, typically adopted alone in order to provide a reduced turbo-lag, i.e. an optimized transient response of the system. In the experimental activity described in this work, the maximum speed of the e-booster used is about 70000 rpm, the maximum pressure ratio is 1.5 and the maximum power required on the shaft is less than 4 kW. The compressor unit have to be maintained in the idle condition in order to avoid excessive electric consumption and overheating problem when
Marelli, Silvia, Usai, Vittorio
Prediction of Broadband Noise in an Automotive Centrifugal Compressor with Three-Dimensional Computational Fluid Dynamics Detached Eddy Simulations2019-01-148706/05/2019
Centrifugal compressors for automotive turbochargers must operate over wide speed and flow ranges to provide the required air pressure and mass flow rate to the intake manifold of the internal combustion engines. At a fixed rotational speed, the flow field near the inducer of the impeller becomes increasingly unstable with decreasing flow rate, as the incidence angle grows between the air flow approaching the impeller, relative to the tangent of the main impeller blades at the leading edge. Flow field measurements conducted earlier have revealed that once the incidence angle exceeds a critical value (nearly independent of rotational speed) of approximately 15°, reversed flow near the periphery (blade tips) starts penetrating upstream of the impeller, with a high tangential velocity in the direction of impeller rotation. As the incidence angle is increased towards this critical value, whoosh noise elevates, where it remains high for a significant portion of the mid-flow operating range
Dehner, Rick, Selamet, Ahmet
On the Measurement and Simulation of Flow-Acoustic Sound Propagation in Turbochargers2019-01-148806/05/2019
Most of today’s internal combustion engines are turbocharged by combined radial compressors and turbines for downsizing. This mostly leads to reduced orifice noise of both intake and exhaust systems, but the detailed damping mechanisms remain yet unknown. Intake and exhaust systems are developed with 1D-CFD simulations, but validated acoustic sub-models for turbochargers are not yet available. Therefore the aim of this publication is studying the turbocharger’s silencing capabilities and subsequently develop new acoustic turbocharger models. The acoustic properties of the turbocharger can be well described by transmission loss. In addition to thermodynamic variations, parameter variations with wastegate and VTG systems were also performed. A total of four turbochargers of very different sizes were investigated. Low frequency attenuation is dominated by impedance discontinuities, increasing considerably with mass flow and pressure ratio. High frequency transmission loss is generated by
Ruppert, Hendrik, Falke, Felix, Pischinger, Stefan, Günther, Marco, Stienen, Ralf
Surge Prediction in a Single Sequential Turbocharger (SST) Compressor Using Computational Fluid Dynamics2019-01-149006/05/2019
The Single Sequential Turbocharger (SST) used in Ford’s 6.7L Scorpion Diesel is analyzed using Computational Fluid Dynamics (CFD) to draw conclusions about the compressor stability at low mass flows. The SST compressor concept consists of a double-sided wheel which flows in parallel fed by two separate inlets (front and rear), followed by a single vane-less diffuser, and a volute. CFD simulations for the full stage are performed at low mass flow rates Both, front and rear, sides have ported shroud casing-treatment (CT) in the inlet region. An objective of the analysis is to determine which side of the SST unit compressor (front or rear on the double-sided wheel) suffers flow break down first as the mass flow is reduced, and its impact on the overall stability of the SST compressor. Another objective is to better understand the interactions between the compressor inlet flow and the flow through the casing-treatment. It has been observed that these interactions reduce the effectiveness
Karim, Ahsanul, Wade, Robert, Morelli, Anthony, Miazgowicz, Keith, Lizotte, Brian
New Psychoacoustic Criteria for Turbocharger Aero Noise2019-01-148906/05/2019
With ever more stringent regulations related to air pollution and CO2 emissions, there is a growing trend to address this through the downsizing of automotive engines. Turbochargers are used to improve engine power by using exhaust gas energy to provide boosted air pressure for better efficiency. They are a key element in powertrains of today and in the future. During real operating conditions, the rotational speed of a turbo varies greatly making this rotating machinery run in “continuous transient” phases and produces unwanted noises as a result. Recently, we identified a new source of aero noise while developing a new type of turbocharger. Our typical in-house procedure for characterizing usual aero broad band noise source was to use the 3-microphone methodology for measuring the acoustic intensity. However, this methodology is not well adapted if the noise source is tonal, not constant over time and includes high frequency content, which is the case with the new type of
Rigault, Alexandre, Kihm, Fred, Baron, Nicolas
FSI - MRF Coupling Approach For Faster Turbocharger 3D Simulation2019-01-000701/15/2019
Fluid-Structure Interaction (FSI) simulation approach can be used to simulate a turbocharger. However, this predictive 3D simulation encounters the challenge of a long computational time. The impeller speed can be above 100,000 rpm, and generally a CFD solver limits the maximum movement of the impeller surface per time step. The maximum movement must be a fraction (~0.3) of the cell length, thus the time step will be very small. A Multiple Reference Frame (MRF) approach can reduce computational time by eliminating the need to regenerate the mesh at each time-step to accommodate the moving geometry. A static local reference zone encompassing the impeller is created and the impact of the impeller movement is modeled via a momentum source. However, the MRF approach is not a predictive simulation because the impeller speed must be given by the User. A new simulation approach was introduced that coupled the FSI and MRF approach. Like in the FSI approach, the total moment of the impeller was
Abidin, Zainal, Morris, Andrew, Miwa, Jason, Sadique, Jasim, Wang, Yunliang
2-Stroke Engine Options for Automotive Use: A Fundamental Comparison of Different Potential Scavenging Arrangements for Medium-Duty Truck Applications2019-01-007101/15/2019
The work presented here seeks to compare different means of providing scavenging systems for an automotive 2-stroke engine. It follows on from previous work solely investigating uniflow scavenging systems, and aims to provide context for the results discovered there as well as to assess the benefits of a new scavenging system: the reverse-uniflow sleeve-valve. For the study the general performance of the engine was taken to be suitable to power a medium-duty truck, and all of the concepts discussed here were compared in terms of indicated fuel consumption for the same cylinder swept volume using a one-dimensional engine simulation package. In order to investigate the sleeve-valve designs layout drawings and analysis of the Rolls-Royce Crecy-type sleeve had to be undertaken. A new methodology for optimization was developed and the analysis process also took into account work done by the charging system, this being assumed to be a combination of supercharger and turbocharger to permit
Turner, James W. G., Head, Robert A., Chang, Junseok, Engineer, Nayan, Wijetunge, Roshan, Blundell, David W., Burke, Paul
Agglomeration and Nucleation of Non-Volatile Particles in a Particle Grouping Exhaust Pipe of a Euro VI Heavy-Duty Diesel Engine2019-01-004401/15/2019
The possibility of non-volatile particle agglomeration in engine exhaust was experimentally examined in a Euro VI heavy duty engine using a variable cross section agglomeration pipe, insulated and double walled for minimal thermophoresis. The agglomeration pipe was located between the turbocharger and the exhaust treatment devices. Sampling was made across the pipe and along the centre-line of the agglomeration pipe. The performance of the agglomeration pipe was compared with an equivalent insulated straight pipe. The non-volatile total particle number and size distribution were investigated. Particle number measurements were conducted according to the guidelines from the Particle Measurement Programme. The Engine was fuelled with commercially available low sulphur S10 diesel. Experiments conducted in heavy duty engine relevant operating points were done to sweep the effect of (i) Mass flow rate in the exhaust (ii) Temperature in the exhaust and (iii) Engine speed and thus exhaust
K, Arun Prasath, Stenlaas, Ola, Bernemyr, Hanna, Erlandsson, Anders
Cadillac pulls the wraps off two new V-Series sedans19AUTP08_1901/01/2019
Cadillac has added two more sedans to its V-Series performance lineup, the 2020 CT4-V and CT5-V. The CT4-V will square off against established C-segment players such as the BMW 3-Series and Mercedes-Benz C-Class, along with Hyundai's new Genesis G70. The CT5-V will compete with the BMW 5-Series and Audi A6. The two new 4-door sedans join the larger 2019 CT6-V sedan in the V-Series stable, though the company noted that the series is evolving to be less focused on hard-core, track-worthy machines, and more about sporty and comfortable daily drivers. “We are inviting even more customers into the V-Series family,” said Brandon Vivian, Cadillac executive chief engineer, “by adding a new level of elevated performance between our Sport models and the ultimate, high-performance track capability that the V-Series has grown to represent.”
Seredynski, Paul
WHAT WE'RE DRIVING19AUTP08_1201/01/2019
Toyota sought to channel its 2000 GT and Supra sportscar heritage with the introduction of the 2020 Supra, but in the process the company also forecast the future. Acknowledging the SUV-centric product-development investment reality of 2019, Toyota partnered with BMW, which was in position to supply a six-cylinder engine with the Supra's traditional inline configuration, while contracting assembly to Austria's Magna Styr.
Porsche reveals eighth-generation of fabled 91119AUTP01_1501/01/2019
Regularly updating and evolving the Porsche 911's aesthetic signature might seem an impossible task. But more than half a century after its birth, the unveiling of the eighth-generation at the 2018 L.A. Auto Show demonstrated that it is in fact still a totally possible art-with design boss Michael Mauer the chief artist. Designated in-house as the 992 series and slightly larger than the outgoing 991, it is launched in rear-wheel-drive and all-wheel-drive forms-Carrera S and Carrera 4S-and now only in the wide-body width previously used for the Carrera 4 GT3 and GTS, instead of two body widths. Across the nose, the new 911 is 45 mm (1.8 in) wider than the outgoing version, a figure some 911 purists may look at askance, as growth in recent years has already been considerable.
Birch, Stuart
Effective Suppression of Surge Instabilities in Turbocharger Compression Systems through a Close-Coupled Compressor Inlet Restriction2018-01-171409/10/2018
The current work demonstrates effective suppression of compression system surge instabilities by installing a variable cross-sectional flow area restriction within the inlet duct of a turbocharger centrifugal compressor operating on a bench-top facility. This restriction couples with the compressor, similar to stages in a multi-stage turbomachine, where the effective pressure ratio is the product of those for the restriction and compressor. During experiments at constant compressor rotational speed, the compressor is stable over the negatively sloped portion of the pressure ratio vs. flow rate characteristics, so the restriction is eliminated within this operating region to preserve compressor performance. At low flow rates, the slope of the compressor alone characteristics reaches a positive value, and the unrestricted compression system enters mild surge. Further reduction of flow rate with the unrestricted compressor inlet results in a sudden transition to deep surge instabilities
Dehner, Rick, Selamet, Ahmet, Miazgowicz, Keith
Development of a New 1.8L Down-Speeding Turbocharged Gasoline Engine with Miller Cycle2018-01-171209/10/2018
Upcoming China 4th stage of fuel consumption regulation and China 6a emission legislation require improvement of many existing engines. This paper summarizes an upgrade of combustion system and mechanical layout for a four-cylinder engine family. Based on an existing production process for a naturally aspirated 2.0-liter gasoline engine, a 1.8-liter down-speeded and turbocharged gasoline engine is derived. Starting development by analysis of engine base geometry, a layout for a Miller-Cycle gas exchange with early closing of intake valves is chosen. Requirements on turbocharger configuration are investigated with one-dimensional gas exchange simulation and combustion process will be analyzed by means of 3D-CFD simulation. Challenging boundary conditions of a very moderate long-stroke layout with a stroke/bore-ratio of only 1.037 in combination with a cost efficient port fuel injection system and fixed valve lift profiles are considered. To compensate reduced in-cylinder charge motion
Ye, Yisu, Xu, Libing, Wang, Jinshi, Yao, Kefu, Zhao, Mingxiang, Dieterich, Carsten, Souren, Mike, Morcinkowski, Bastian
Effect of Mesh Size in Numerical Simulation of Turbine Housing in Turbocharger2018-01-171509/10/2018
Numerical method is popular in analyzing turbine housing in turbocharger with an early and rapid risk assessment. However, complex casting and extreme thermal loading from exhaust gas temperature and flow variation under engine duty cycle lead to big thermal stress and this makes material serviced in the plastic zone. Previous numerical simulations show that a mesh size is insensitive to the elastic finite element analysis (FEA), but might not be proper for elastic-plastic FEA, even that other boundary conditions keep same, which indicating simulation results are changeable with mesh size and a simple numerical mesh size convergence might not be enough to guarantee accurate numerical results as well. Therefore, several different mesh sizes are used in elastic-plastic analysis of turbine housing to investigate the influence on numerical results. Based on the numerical results and their comparison, we conclude that theoretical results exist under smaller finite element size but it is
Guo, Henry, Long, Haiyang
Divided Exhaust Period Implementation in a Light-Duty Turbocharged Dual-Fuel RCCI Engine for Improved Fuel Economy and Aftertreatment Thermal Management: A Simulation Study2018-01-025604/03/2018
Although turbocharging can extend the high load limit of low temperature combustion (LTC) strategies such as reactivity controlled compression ignition (RCCI), the low exhaust enthalpy prevalent in these strategies necessitates the use of high exhaust pressures for improving turbocharger efficiency, causing high pumping losses and poor fuel economy. To mitigate these pumping losses, the divided exhaust period (DEP) concept is proposed. In this concept, the exhaust gas is directed to two separate manifolds: the blowdown manifold which is connected to the turbocharger and the scavenging manifold that bypasses the turbocharger. By separately actuating the exhaust valves using variable valve actuation, the exhaust flow is split between two manifolds, thereby reducing the overall engine backpressure and lowering pumping losses. In this paper, results from zero-dimensional and one-dimensional simulations of a multicylinder RCCI light-duty engine equipped with DEP are presented. It is shown
Bharath, Anand Nageswaran, Reitz, Rolf, Rutland, Christopher
Virtual Full Engine Development: 3D-CFD Simulations of Turbocharged Engines under Transient Load Conditions2018-01-017004/03/2018
The simulation of transient engine behavior has gained importance mainly due to stringent emission limits, measured under real driving conditions and the concurrently demanded vehicle performance. This is especially true for turbocharged engines, as the coupling of the combustion engine and the turbocharger forms a complex system in which the components influence each other remarkably causing, for example, the well-known turbo lag. Because of this strong interaction, during a transient load case, the components should not be analyzed separately since they mutually determine their boundary conditions. Three-dimensional computational fluid dynamics (3D-CFD) simulations of full engines in stationary operating points have become practicable several years ago and will remain a valuable tool in virtual engine development; however, the next logical step is to extend this approach into the transient domain. This article evaluates the potential of different turbocharger models being included in
Kaechele, Andreas, Chiodi, Marco, Bargende, Michael
Numerical and Experimental Investigation of Effect of Tongue Shape on Turbine Reliability2018-01-048304/03/2018
Turbine housing in turbocharger is a critical part which must withstand severe cyclic mechanical and thermal load throughout its service life. The combination of thermal transients with mechanical load cycles results in a complex evolution of damage, leading to thermal mechanical fatigue (TMF) of the material and, after a certain number of loading cycles, to failure of the component. The volute tongue at radial turbine housing is a key feature which is frequently the first location subject to thermal crack failure due to turbine design. Design of tongue is of importance to improve system's TMF performance. In this work, two tongues including square and elliptic shape on radial turbine fatigue are studied. TMF performance is evaluated by finite element analysis (FEA). In particular, experimental method is carried out in order to validate the simulation model. The good agreement is found between numerical and experimental results. Based on both numerical and experimental investigation we
Guo, Henry, Jia, Wenchuan, Li, Na
Experimental Investigation on Surge Phenomena in an Automotive Turbocharger Compressor2018-01-097604/03/2018
Downsizing and turbocharging are today considered an effective way to reduce CO2 emissions in automotive gasoline engines, especially for the European and US markets. In the broad field of research and development for engine boosting systems, the instability phenomenon of surge has gathered considerable interest in recent years, as the main limiting factor to high performance boosting and boost pressure control. To this extent, developing an in-depth knowledge of the surge dynamics and on the phenomena governing the transition from stable to unstable operation can provide very valuable information for the design of the intake system and boost pressure control algorithms, allowing optimal boost pressure without compromising the transient response. This paper describes an experimental study that aims at better understanding the phenomena leading to the inception of surge, and exploring the effects of the downstream circuit geometry on the compressor dynamic behavior in surge and prior to
Marelli, Silvia, Misley, Anna, Silviestri, Paolo, Capobianco, Massimo, Taylor, Alexandra, Canova, Marcello
Turbocharger Impact on Diesel Electric Powertrain Performance2018-01-096504/03/2018
When electrifying the powertrain, there arises an opportunity to revise the traditional turbocharging trade-off between fuel-economy and transient performance. With the help of electrification, it might be possible to make the trade-off in favor of fuel economy, since transient response can be improved by the electric machine. The paper investigates this trade-off by looking at three turbocharger selections. A conventionally dimensioned turbocharger, an efficiency optimized turbocharger with maintained flow capacity, and an efficiency optimized turbocharger with increased flow capacity. The concepts are evaluated on the following cases: stationary operation, engine tip-in performance, vehicle acceleration performance, and on road fuel economy performance. The investigation is based on a validated mean value engine model of a six cylinder inline CI engine, and on a validated driveline and vehicle model of a heavy-duty truck. The evaluations are made with the help of simulations and
Leek, Alf Erik Viktor, Eriksson, Lars
Development of a New 2L Gasoline VC-Turbo Engine with the World’s First Variable Compression Ratio Technology2018-01-037104/03/2018
A new 2L gasoline turbo engine, named KR20DDET was developed with the world’s first mass-producible variable compression turbo (VC-Turbo) technology using a multi-link variable compression ratio (VCR) mechanism. It is well known that increasing the compression ratio improves gasoline engine thermal efficiency. However, there has always been a compromise for engine designers because of the trade-off between increasing the compression ratio and knocking. At Nissan we have been working on VCR technology for more than 20 years and have now successfully applied this technology to a mass production engine. This technology uses a multi-link mechanism to change the top and bottom dead center positions, thereby allowing the compression ratio to be continuously changed. The VC-Turbo engine with this technology can vary the compression ratio from 14:1 for obtaining high thermal efficiency to 8:1 for delivering high torque by taking advantage of the strong synergy with turbocharging. This enables
Kojima, Shuji, Kiga, Shinichi, Moteki, Katsuya, Takahashi, Eiji, Matsuoka, Kazuya
The Development of a New V6 3.5L Turbocharged Gasoline Engine2018-01-036604/03/2018
For the launch of the redesigned Lexus LS, a new 3.5 L V6 twin turbo engine has been developed aiming at unparalleled performance on four axes, “driving pleasure”, “power-performance”, “quietness” and “fuel economy”. To achieve outstanding power-performance and high thermal efficiency, the specifications have been optimized for high speed combustion. The maximum torque of 600 Nm, power of 310 kW (yielding specific power of 90 kW/L), and the maximum thermal efficiency of 37% have been achieved using several new technologies including a high efficiency turbocharger. A prototype vehicle equipped with this engine and Direct-Shift 10AT achieved a 0-60 mph acceleration time of 4.6 sec, with extremely good CAFE combined fuel economy of 23 mpg and power-performance aligned with V8 turbocharged offerings from competing OEM’s.
Yamazaki, Daichi, Mori, Akio, Murase, Eiji
Divided-Exhaust Turbocharger System with Boost-Valve2018-01-089504/03/2018
In a divided-exhaust turbocharging system, 1 exhaust valve and port from each cylinder can be directed to the turbocharger turbine (referred to as the Blowdown Path) and the other can bypass the turbocharger (referred to as the Scavenge Path). The Blowdown and Scavenge valve events are determined based on the functions of the blowdown and displacement phases of the exhaust process. In our previous publications of another version of Divided Exhaust Period Turbocharging, the Valve Event Modulated Boost system (VEMB), we demonstrated significant engine efficiency and performance improvements over the base turbocharged engine. Reductions in pumping work and high-load Residual Gas Fraction are the primary reasons for efficiency and performance improvements. In this project we have evaluated through simulation and engine testing, the further advantages of the Divided-Exhaust-Boost (DEB) system version of Divided Exhaust Boosting; a version that does not require a concentric-camshaft for
Roth, David B., Chen, Wei, Ciaravino, Joseph
Evaluation of Engine-Related Restrictions for the Global Efficiency by Using a Rankine Cycle-Based Waste Heat Recovery System on Heavy Duty Truck by Means of 1D-Simulation2018-01-145104/03/2018
As a promising concept to improve fuel efficiency of a long-haul heavy duty truck with diesel engine, organic Rankine cycle (ORC) based waste heat recovery system (WHR) by utilizing the exhaust gas from internal combustion engine has continuously drawn attention from industry in recent years. The greatest achievable global efficiency may be, however, restricted by the engine. On one hand, engine operating conditions have direct impact on the temperature and the mass flow of exhaust gas, which is the waste heat source, on the other hand, the engine cooling system limits the heat rejection from the condenser of the WHR system. This paper aims to evaluate the impacts of the varied engine applications considering the effects of the WHR system on the global efficiency and engine emissions. A complex 0D/1D-simulation model for a turbocharged production heavy duty engine with low-/high-temperature cooling circuit and a WHR system with ethanol as working fluid have been established in GT-Suite
Yang, Kangyi, Bargende, Michael, Grill, Michael
Thermodynamic and Practical Benefits of Waste Energy Recovery Using an Electric Turbo-Generator Under Different Boosting Methods2018-01-085104/03/2018
This paper provides insight into the tradeoffs between exhaust energy recovery and increased pumping losses from the flow restriction of the electric turbo-generator (eTG) assessed using thermodynamic principles and with a detailed GT-Power engine model. The GT-Power engine model with a positive displacement expander model was used to predict the influence of back pressure on in-cylinder residuals and combustion. The eTG is assessed for two boosting arrangements: a conventional turbocharger (TC) and an electrically assisted variable speed (EAVS) supercharger (SC). Both a low pressure (post-turbine) and high pressure (pre-turbine) eTG are considered for the turbocharged configuration. The reduction in fuel consumption (FC) possible over various drive cycles is estimated based on the steady-state efficiency of frequently visited operating points assuming all recovered energy can be reused at an engine efficiency of 30% with 10% losses in the electrical path. On the city FTP and US06
Kiwan, Rani, Middleton, Robert, Stefanopoulou, Anna
Steady-State Experimental and Meanline Study of an Asymmetric Twin-Scroll Turbine at Full and Unequal and Partial Admission Conditions2018-01-097104/03/2018
The use of twin-scroll turbocharger turbines has gained popularity in recent years. The main reason is its capability of isolating and preserving pulsating exhaust flow from engine cylinders of adjacent firing order, hence enabling more efficient pulse turbocharging. Asymmetrical twin-scroll turbines have been used to realize high pressure exhaust gas recirculation (EGR) using only one scroll while designing the other scroll for optimal scavenging. This research is based on a production asymmetrical turbocharger turbine designed for a heavy duty truck engine of Daimler AG. Even though there are number of studies on symmetrical twin entry scroll performance, a comprehensive modeling tool for asymmetrical twin-scroll turbines is yet to be found. This is particularly true for a meanline model, which is often used during the turbine preliminary design stage. This study presents the development of a generalized meanline model for a twin-scroll turbine, which can be used in the early design
Palenschat, Torsten, Mueller, Markus, Rajoo, Srithar, Chiong, Meng Soon, Newton, Peter, Martinez-Botas, Ricardo, Tan, Feng Xian
Testing and Implementation of a Turbocharged Formula SAE Vehicle2018-01-096704/03/2018
Research on turbocharging for FSAE at the University of Malta, has been ongoing for a number of years. 1D simulations were done to determine best design configuration and determine a lowered compression ratio. A decompression plate was installed on the Kawasaki 600 cc engine. Calibration of the engine was performed on the engine dynamometer. A hot-gas test stand for testing of the turbocharger was developed. The turbocharger speed was measured by a custom built hall-effect sensing setup that is compact enough to be implemented also in the FSAE vehicle. Bespoke camshafts with optimized valve timing determined through WAVE 1D simulations and designed with Valdyn® were machined. The turbocharged setup was used on the University of Malta FSAE vehicle in the FSAE Italy 2017 competition. Knock was investigated through in-cylinder pressure measurements and use of commercial knock sensor on the 600 cc engine. Benchmarking in-cylinder pressure measurement tests were carried out on a 1.4 liter
Azzopardi, Jean Paul, Farrugia, Jean-Paul, Caruana, Carl, Grech, Nicholas, Farrugia, Nicholas, Chircop, Marlon, Farrugia, Mario, Farrugia, Michael
Equation-Based Compressor and Turbine Modeling for Variable Geometry Turbochargers2018-01-096604/03/2018
As modern engines are being downsized, turbochargers are becoming increasingly common. The operation of turbochargers is usually captured by a map provided by the manufacturer. However, the complexity of these maps makes them difficult to use for turbocharger estimation and control strategies. This work focuses on a method that is able to reduce the compressor and turbine maps from a cloud of points into a set of equations. This is accomplished by defining a series of non-dimensional and normalized variables that define a plane transformation. In this new plane, all the points of the map converge approximately into a line and the equation for this line can be found using a least square regression. While this strategy has been used previously, this work includes additional variables as well as an optimization process, which proved to be better at replicating the original maps than existing methods. The new technique is shown to accurately replicate the data contained in the maps and
Pulpeiro Gonzalez, Jorge, Hall, Carrie
Use of Water-Butanol Blends in a Turbocharged Common Rail Dual Fuel Engine for Enhanced Performance and Reduce Smoke Levels2018-01-025104/03/2018
Experiments were conducted on a turbocharged three cylinder automotive common rail diesel engine with port injection of butanol. This dual fuel engine was run with neat butanol and blends of water and butanol (up to 20% water by mass). Experiments were performed at a constant speed of 1800 rpm and a brake mean effective pressure of 11.8 bar (full load) at varying butanol to diesel energy share values while diesel was either injected as a single pulse or as twin pulses (Main plus Post). Open engine controllers were used for varying the injection parameters of diesel and butanol. Water butanol blends improved the brake thermal efficiency by a small extent because of better combustion phasing as compared to butanol without water. When the butanol to diesel energy share was high, auto-ignition of butanol occurred before the injection of diesel. This lowered the ignition delay of diesel and hence elevated the smoke level. Two separated heat release phases along with high rates of pressure
Yadav, Jaykumar, Ramesh, A
Adaptive Turbo Matching: Radial Turbine Design Optimization through 1D Engine Simulations with Meanline Model in-the-Loop2018-01-097404/03/2018
Turbocharging has become the favored approach for downsizing internal combustion engines to reduce fuel consumption and CO2 emissions, without sacrificing performance. Matching a turbocharger to an engine requires a balance of various design variables in order to meet the desired performance. Once an initial selection of potential compressor and turbine options is made, corresponding performance maps are evaluated in 1D engine cycle simulations to down-select the best combination. This is the conventional matching procedure used in industry and is ‘passive’ since it relies on measured maps, thus only existing designs may be evaluated. In other words, turbine characteristics cannot be changed during matching so as to explore the effect of design adjustments. Instead, this paper presents an ‘adaptive’ matching methodology for the turbocharger turbine. By coupling an engine cycle simulation to a turbine meanline model (‘in-the-loop’), adjustments in turbine geometry are reflected in both
Kapoor, Prakhar, Costall, Aaron W., Sakellaridis, Nikolaos, Hooijer, Jochem, Lammers, Rogier, Tartoussi, Hadi, Guilain, Stéphane
Diesel Engine Cylinder Deactivation for Improved System Performance over Transient Real-World Drive Cycles2018-01-088004/03/2018
Effective control of exhaust emissions from modern diesel engines requires the use of aftertreatment systems. Elevated aftertreatment component temperatures are required for engine-out emissions reductions to acceptable tailpipe limits. Maintaining elevated aftertreatment components temperatures is particularly problematic during prolonged low speed, low load operation of the engine (i.e. idle, creep, stop and go traffic), on account of low engine-outlet temperatures during these operating conditions. Conventional techniques to achieve elevated aftertreatment component temperatures include delayed fuel injections and over-squeezing the turbocharger, both of which result in a significant fuel consumption penalty. Cylinder deactivation (CDA) has been studied as a candidate strategy to maintain favorable aftertreatment temperatures, in a fuel efficient manner, via reduced airflow through the engine. This work focuses on prediction and demonstration of fuel economy benefits of CDA when
Joshi, Mrunal, Gosala, Dheeraj, Allen, Cody, Srinivasan, Sirish, Ramesh, Aswin, VanVoorhis, Matthew, Taylor, Alexander, Vos, Kalen, Shaver, Gregory, McCarthy Jr, James, Farrell, Lisa, Koeberlein, Edward D.
Drivecycle Benefits of Controlling Airflow with the SuperTurbo™2018-01-097004/03/2018
The SuperTurbo™ is a driven turbocharger that uses a high-speed traction drive combined with a CVT (Continuously Variable Transmission) or electric motor to provide additional power to or from the turbo shaft. The CVT can be shifted to a ratio that provides a turbo speed that generates a desired boost pressure and air flow rate to the engine. Unlike a conventional turbocharger, where the turbine and compressor powers must be balanced, the a driven turbocharger can provide additional power to the turbo shaft through supercharging when the turbine is not collecting sufficient power to drive the compressor to the desired boost pressure, and during other operating conditions can absorb excess turbine power through turbo-compounding to improve engine efficiency. This direct control of air flow to the engine enables greater flexibility in engine operation. The topics presented focus on heavy-duty diesel engines, but the concepts can be applied to all engine types. Transient response is
Brown, Jared W., Waldron, Thomas
Ultra-High Fuel Injection Pressure with Massive EGR to Enable Simultaneous Reduction of Soot and NOx Emissions2018-01-022704/03/2018
In this study both double and triple injection strategies were used with fuel pressures up to 300 and 250 MPa, respectively. Tests were conducted at medium load conditions with cooled, high-pressure EGR at a ratio of 40% and higher. A four-cylinder production engine, featuring double turbochargers with one variable geometry turbocharger, was tested. The double injection strategy consisted of a 20% close-coupled pilot injection while the triple injection strategy introduced a post injection consisting of 10% the total cycle fuel. Results of this study do not indicate an advantage to extreme fuel pressure. The increased air entrainment reduces soot while increasing the premixed burn heat release, mean cylinder temperature, and NOx. Compared to the double injection scheme, triple injections achieved much lower soot for the same EGR rate with only a small NOx penalty. Under the conditions tested, triple injections could be used with high EGR as a mixing strategy, allowing for the use of
Ogren, Ryan M., Kong, Song-Charng
Engine Oil Components Effects on Turbocharger Protection and the Relevance of the TEOST 33C Test for Gasoline Turbocharger Deposit Protection2017-01-234110/08/2017
Countries from every region in the world have set aggressive fuel economy targets to reduce greenhouse gas emissions. To meet these requirements, automakers are using combinations of technologies throughout the vehicle drivetrain to improve efficiency. One of the most efficient types of gasoline engine technologies is the turbocharged gasoline direct injection (TGDI) engine. The market share of TGDI engines within North America and globally has been steadily increasing since 2008. TGDI engines can operate at higher temperature and under higher loads. As a result, original equipment manufacturers (OEMs) have introduced additional engine tests to regional and OEM engine oil specifications to ensure performance of TGDI engines is maintained. One such engine test, the General Motors turbocharger coking (GMTC) test (originally referred to as the GM Turbo Charger Deposit Test), evaluates the potential of engine oil to protect turbochargers from deposit build-up. In this paper, the authors
Yang, Kongsheng, Fletcher, Kristin A., Styer, Jeremy P., Lam, William Y., Guinther, Gregory H.
NVH Performance Improvement of a Turbo-Charged GDI Engine based on the Simulation and Experiment Studies2017-01-242610/08/2017
In recent years, Turbo-charged GDI technology is more and more widely used, which can meet the high demand of the engine performance and efficiency, but the resulting reliability and NVH issues also need to be paid attention to [1]. Traditional NVH performance improvement is mostly based on the experience design and repeatable test, which lead to longer development period, high cost, and also ineffective results. NVH performance simulations play more important role in engine vibration and noise prediction along with the development of the simulation technology[2][3]. The force response analysis is usually used to evaluate the NVH performance of the engine structure under the standard excitation. However, dynamic analysis of the crank train, valve train, and piston can be carried out based on the AVL software family, also the vibration and airborne noise of whole engine can be predicted directly at different speed and load [4]. The NVH performance of a turbo-charged GDI engine was
Zhang, Zhiming, Wang, Weimin, Wang, Jiangtao, Zhang, Jiming, Chen, Yuanda, Zhang, Wenlong, Yang, Guofang, Fan, Fugui, Zhang, Wenxiang, Huang, Fengqin, Li, Xiangwang
Unsteady Performance Simulation Analysis of a Waste-Gated Turbocharger Turbine under Different Valve Opening Conditions2017-01-241710/08/2017
An electronic waste-gated turbocharger for automotive application can accurately control the boost pressure and effectively reduce turbo-lag. It can improve the transient responsive performance of engine and the acceleration performance of vehicle, which makes vehicle have a better adaptation to the complex traffic environment. A detailed analysis of aerodynamic working principle of electronic wastegate is the foundation for designing the control strategy of electronic wastegate. Putting turbine with electronic wastegate under unsteady condition that simulates the pulse exhaust gas of engine and studying influences of different valve opening on the performance of turbine has the practical value. This paper sets fixed and periodical unsteady conditions and adopts numerical methods to explore the performance of turbine in twin-entry turbocharger and the flow loss of bypass. Steady simulation structure is given for reference. The influence and change rule of wastegate valve opening on
Fan, Houchuan, Ni, Jimin, Shi, Xiuyong, Jiang, Nan, Qu, Dayong, Zheng, Yi, Zheng, Yinghong
Study on Nonlinear Rotordynamics Characteristics for Electric Compound Turbocharger2017-01-241810/08/2017
The electric compound turbocharger(ECT) which integrates a high speed motor into a turbocharger rotor shaft can be used transiently to accelerate the turbocharger more quickly in response to an acceleration requirement. It can utilize the exhaust gas energy fully to improve the engine fuel efficiency and benefit for engine with lower emissions. The key technique of ECT is to solve the reliability problems when an electrical motor is integrated into a turbocharger shaft between the turbine and compressor wheels will increase the burden for the bearing support and affect the turbocharger shaft rotation characteristics. In order to know the dynamics behavior of higher load bearing system is explored for reliability, this paper focus on the nonlinear rotor dynamics characteristics of ECT rotor bearing system. Based on the principle and structure of ECT rotor bearing system, the basic theory method and dynamics model of rotor bearing system is established considered the nonlinear fluid film
Zhang, Hong, Wang, Zhuo, Hong, Zhouzhensen
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