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Comparison Between MCC and MZCM Combustion Models

Pontifícia Universidade Católica de Minas Gerais-Paulo Ricardo da Penha, Rogério Jorge Amorim
  • Technical Paper
  • 2019-36-0133
Published 2020-01-13 by SAE International in United States
This paper evaluates the ability of two combustion models to predict a small HSDI diesel engine operation after changing its operational parameters. Both Multi-Zone Combustion Model (MZCM) and Mixing Controlled Combustion (MCC) are inherently coupled to the fuel injection process allowing great freedom of simulation for multistage injection engines but also requiring consistent calibration of the model parameters. In the present work, two operating conditions of a reference research engine are modelled and tuned in the AVL Boost® software using both MCC and MZCM to model the combustion process. The operational conditions evaluated are defined by changes in EGR rate, fuel injection start and distribution, boost pressure, and injection pressure. The predictive ability of each model is assessed by comparing the output results accuracy and the number of parameters changes needed to tune the model for a given change of operation. The novelty of this work resides in the comparison of the two models, as built in the software, in a practical simulation process. Both models have a similar amount of base parameters to be…
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Numerical Optimization of Compression Ratio for a PPC Engine running on Methanol

Lund University-Erik Svensson, Sebastian Verhelst
  • Technical Paper
  • 2019-01-2168
Published 2019-12-19 by SAE International in United States
Partially premixed combustion (PPC) has shown to produce high gross indicated efficiencies while yielding lower pollutant emissions, such as oxides of nitrogen and soot, than conventional diesel combustion. Gasoline fuels with a research octane number (RON) of 60-70 have been proposed as optimal for PPC as they balance the trade-off between ensuring good combustion stability at low engine loads and avoiding excessive peak pressure rise rates at high loads. However, measures have to be taken when optimizing the engine operating parameters to avoid soot emissions. In contrast, methanol has a much lower propensity for soot formation. However, due to a higher RON of methanol the required intake temperature is higher for the same engine compression ratio to ensure auto-ignition at an appropriate timing. Increasing the compression ratio allows a lower intake temperature and improves combustion stability as well as engine brake efficiency. Nevertheless, a higher compression ratio generally increases in-cylinder heat losses and peak pressure. These effects were investigated in a simulation study, which combined 0-D and 1-D models, of a multi-cylinder heavy-duty Scania D13…
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Experimental Proof-of-Concept of HiL Based Virtual Calibration for a Gasoline Engine with a Three-Way-Catalyst

FEV Europe GmbH-Pietro Gardini, Thomas Scheel, Vitali Walter, Jaykumar Kansagara Raul Tharmakulasingam, Marius Böhmer, Martin Nijs
Institute for Combustion Engines, RWTH Aachen University-Feihong Xia, Frank Dorscheidt, Stefan Lücke, Jakob Andert
  • Technical Paper
  • 2019-01-2301
Published 2019-12-19 by SAE International in United States
The increasing complexity of modern combustion engines together with the substantial variability of hybrid electric powertrains, lead to new challenges in function development, system integration and vehicle calibration processes. Hardware-in-the-Loop (HiL) simulations have been introduced to front-load part of the testing and calibration tasks from the vehicle to a virtual environment. With this approach, the simulation quality and the cost-benefit ratio are strongly dependent on the accuracy of the plant modelling and the computational effort.This paper introduces a novel HiL simulation platform for an engine control unit (ECU) with a crank-angle resolved real-time model (GT-Power) for a gasoline engine with direct fuel injection, single stage turbocharging and a three-way catalyst. By simplifying the fluid dynamics simulation model from the concept phase, a good compromise between model accuracy and computation speed can be achieved with relatively low effort. The coupling of the engine model and the hardware ECU has been implemented using a realtime workstation with a co-simulation platform (xMOD) coupled to a HiL-simulator with the necessary I/O boards (dSPACE). The closed-loop boost pressure and the…
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Enhancing Peak Firing Pressure Limit for Achieving Better Brake Thermal Efficiency of a Diesel Engine

New A.C.E. Institute Co., Ltd.-Kenji Enya, Noboru Uchida
  • Technical Paper
  • 2019-01-2180
Published 2019-12-19 by SAE International in United States
An increased cycle expansion ratio is beneficial from a thermodynamic viewpoint to increase the engine efficiency. In this study, the target compression ratio and corresponding thermodynamic cycle layout were investigated by means of a new ideal combustion cycle. To model the experimental pressure traces, the combustion was divided into three parts; constant volume combustion, early expansion combustion and late combustion. This study discussed optimal parameter values for compression ignition combustion under PFP constraints. These parameters included compression ratio, pressure ratios as well as cut-off ratios. Furthermore, this study experimentally investigated the limitation of thermal efficiency and the variation of energy losses under different geometric compression ratios, boosting pressure and degree of constant volume combustion. These experiments utilized a supercharged single-cylinder heavy duty diesel engine with PFP-capability of up to 30 MPa. In conclusion, it is confirmed that improvement in the indicated thermal efficiency and BTE was achieved by increasing the compression ratio. The trade-off between increased compression ratio and higher losses was also established and an optimum compression ratio found.
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Injection Pattern Investigation for Gasoline Partially Premixed Combustion Analysis

Magneti Marelli SpA - Powertrain-Federico Stola, Matteo De Cesare
University of Bologna-Vittorio Ravaglioli, Giacomo Silvagni, Fabrizio Ponti
Published 2019-09-09 by SAE International in United States
Nowadays, compression-ignited engines are considered the most efficient and reliable technology for automotive applications. However, mainly due to the current emission regulations, that require increasingly stringent reductions of NOx and particulate matter, the use of diesel-like fuels is becoming a critical issue. For this reason, a large amount of research and experimentation is being carried out to investigate innovative combustion techniques suitable to simultaneously mitigate the production of NOx and soot, while improving engine efficiency.In this scenario, the combined use of compression-ignited engines and gasoline-like fuels proved to be very promising, especially in case the fuel is directly-injected in the combustion chamber at high pressure. The presented study analyzes the combustion process produced by the direct injection of small amounts of gasoline in a compression-ignited light-duty engine. The engine under investigation has been modified to guarantee a stable engine operation over its whole operating range, that is achieved controlling boost pressure and temperature, together with the design of the injection pattern.Experimental tests have been performed to highlight the impact of several control variables on the…
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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
Published 2019-09-09 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. To this regard, a major role is played by turbocharging, which allows an increase in engine power density, 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 a 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 to be a 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…
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A Comprehensive Study on Euro 6 Turbocharger Selections and Its Deterioration with Closed Crank-Case Ventilation in Heavy Commercial Vehicles

VE Commercial Vehicles Ltd-Aravind Mohan, Juzer Jaliwala, Kunaal Bhagat, Kumar Patchappalam
  • Technical Paper
  • 2019-24-0061
Published 2019-09-09 by SAE International in United States
Euro 6 emission norms are getting implemented in India from April 2020 and it is being viewed as one of the greatest challenges ever faced by the Indian automotive industry. In order to achieve such stringent emission norms a good strategy will be to optimize the engine out emission through in cylinder emission control techniques and a right sized after treatment system has to be used for this optimized engine. There exist several factors and trade-off between these should be established for in cylinder optimization of emissions. Since the turbocharger plays an apex role in controlling both the performance and engine out emissions of a CI engine, turbocharger selection is a crucial step in the development of new generation of Euro 6 engines in India. Such engines are equipped with additional actuators such as Intake Throttle Valve and Exhaust Throttle Valve and combination of these flap operations with turbocharger output plays a prominent role in controlling performance and emission. This study focusses on the use of different AVU (Air Valve Unit) controlled waste gate turbochargers…
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Charge Air Cooler Internal Cleanliness, Leakage, and Nomenclature

Cooling Systems Standards Committee
  • Ground Vehicle Standard
  • J1726_201909
  • Current
Published 2019-09-05 by SAE International in United States
This SAE Recommended Practice provides test methods and criteria for evaluating the internal cleanliness and air leakage for engine charge air coolers. This SAE Recommended Practice also provides nomenclature and terminology in common use for engine charge air coolers, related charge air cooling system components, and charge air cooling system operational performance parameters.
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Glossary of Engine Cooling System Terms

Cooling Systems Standards Committee
  • Ground Vehicle Standard
  • J1004_201904
  • Current
Published 2019-04-22 by SAE International in United States
The objective of this glossary is to establish uniform definitions of parts and terminology for engine cooling systems. Components included are all those through which engine coolant is circulated: water pump, engine oil cooler, transmission and other coolant-oil coolers, charge air coolers, core engine, thermostat, radiator, external coolant tanks, and lines connecting them.
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Optimization of a Diesel Engine with Variable Exhaust Valve Phasing for Fast SCR System Warm-Up

University of Michigan-Pavan Kumar Srinivas, Rasoul Salehi
Published 2019-04-02 by SAE International in United States
Early exhaust valve opening (eEVO) increases the exhaust gas temperature by faster termination of the power stroke and is considered as a potential warm up strategy for diesel engines aftertreatment thermal management. In this study, first, it is shown that when eEVO is applied, the engine main variables such as the boost pressure, exhaust gas recirculation (EGR) and injection (timing and quantity) must be re-calibrated to develop the required torque, avoid exceeding the exhaust temperature limits and keep the air fuel ratio sufficiently high. Then, a two-step procedure is presented to optimize the engine operation after the eEVO system is introduced, using a validated diesel engine model. In the first step, the engine variables are optimized at a constant eEVO shift. In the second step, optimal eEVO trajectories are calculated using Dynamic Programming (DP) for a transient test cycle. The optimized results indicate that with early EVO, the boost pressure should be increased to provide enough cylinder air charge and to maintain the engine torque. External EGR can be reduced due to increased internal EGR…
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