1,720,964 research outputs found
UEGO-based Exhaust Gas Mass Flow Rate Measurement
No full textNew and upcoming exhaust emissions regulations and fuel consumption reduction requirements are forcing the development of innovative and particularly complex intake-engine-exhaust layouts. Especially in the case of Compression Ignition (CI) engines, the HC-CO-NOx-PM after-treatment system is becoming extremely expensive and sophisticated, and the necessity to further reduce engine-out emission levels, without significantly penalizing fuel consumption figures, may lead to the adoption of intricate and challenging intake-exhaust systems configurations. The adoption of both long- and short-route Exhaust Gas Recirculation (EGR) systems is one example of such situation, and the need to precisely measure (or estimate) mass flow rates in the various elements of the gas exchange circuit is one of the consequences. Within this context, the paper presents an innovative solution for real-time estimation of the exhaust gas mass flow rate of a modern Turbo-Diesel Engine, equipped with Variable Geometry Turbine (VGT), Diesel Particulate Filter (DPF), and EGR
Development of an integrated control strategy for engine and SCR system based on effective EGR rate
No full textThe introduction of actual and upcoming emission standards, move the industrial attentions from laboratory towards real-world emission performance, In-Service Conformity testing (ISC) and life-time periods. Besides advanced air management, fuel injection pattern optimization and aftertreatment systems, the goal to realize optimal and robust powertrain setting under varying operating conditions, while ensuring the proper operation of ATs is challenging and require a massive calibration effort. To accomplish this task, the present research deals with supervisory controller for the integrated engine-SCR system, also referred in literature as EGR-SCR balancing. The goal is to comply with NOx emissions limit and, at the same time, to minimize global costs over transient operating conditions. The potential of this IEM strategy is demonstrated for a typical type-approval test case. The optimization identifies the effective EGR actuation, based on the actual powertrain state, engine settings and ATs performances. The resulting control strategy optimizes the overall performance
Instantaneous Engine Speed Measurement and Processing for MFB50 Evaluation
No full textEvaluation of MFB50 is very useful for combustion
control, since it gives an evaluation of the combustion
process effectiveness. Real-time monitoring its value
enables to detect for example the kind of combustion
that is taking place (useful for example for HCCI
applications), or could provide important information to
improve real-time combustion control. While it is
possible to determine the position where the 50% of
mass burned inside the cylinder is reached using an incylinder
pressure sensor, this work proposes to obtain
this information from the engine speed fluctuation
measurement. In-cylinder pressure sensors in fact are
still not so common for on-board applications, since their
cost will constitute an important portion of the whole
engine control system cost. Engine speed measurement
is instead already performed in modern engine control
systems and therefore being capable of obtaining
MFB50 related information from this signal means
obtaining it at approximately no additional costs.
The MFB50 estimation procedure presented in this
paper is based on the measurement of the engine speed
fluctuations and it mainly consists in two separated
steps. As a first step, a torsional behavior model of the
powertrain configuration is developed. The enginedriveline
torsional model enables to estimate the
indicated torque frequency components, from the
corresponding components of the instantaneous engine
speed fluctuation. This estimation can be performed
cycle by cycle and cylinder by cylinder. As a second
step, the analysis of the relationship between MFB50
and the phase of the frequency components over an
engine cycle allowed defining the final estimation
algorithm that reconstructs the MFB50 starting from the
instantaneous engine speed fluctuation analysis. The
developed approach has been applied with success to a
diesel engine mounted on-board a vehicle
Development of an Integrated Control Strategy for engine and SCR system based on effective EGR rate
No full textThe introduction of actual and upcoming emission standards, move the industrial attentions from laboratory towards real-world emission performance, In-Service Conformity testing (ISC) and life-time periods. Besides advanced air management, fuel injection pattern optimization and aftertreatment systems, the goal to realize optimal and robust powertrain setting under varying operating conditions, while ensuring the proper operation of ATs is challenging and require a massive calibration effort. To accomplish this task, the present research deals with supervisory controller for the integrated engine-SCR system, also referred in literature as EGR-SCR balancing. The goal is to comply with NO x emissions limit and, at the same time, to minimize global costs over transient operating conditions. The potential of this IEM strategy is demonstrated for a typical type-approval test case. The optimization identifies the effective EGR actuation, based on the actual powertrain state, engine settings and ATs performances. The resulting control strategy optimizes the overall performance. Copyright (C) 2020 The Authors
Review of combustion indexes remote sensing applied to different combustion types
Full text linkThis paper summarizes the main studies carried out by the authors for the development of indexes for remote combustion sensing applicable to different combustion types, i.e. conventional gasoline and diesel combustions, diesel PCCI and dual fuel gasoline-diesel RCCI. It is well-known that the continuous development of modern Internal Combustion Engine (ICE) management systems is mainly aimed at complying with upcoming increasingly stringent regulations throughout the world, both for pollutants and CO2 emissions. Performing an efficient combustion control is crucial for efficiency increase and pollutant emissions reduction. Over the past years, the authors of this paper have developed several techniques to estimate the most important combustion indexes for combustion control, without using additional cylinder pressure sensors but only using the engine speed sensor (always available on board) and accelerometers (usually available on-board for gasoline engines). In addition, a low-cost sensor based on acoustic sensing can be integrated to support combustion indexes evaluation and other engine relevant information. The real-time calculation of combustion indexes is even more crucial for innovative Low Temperature Combustions (such as diesel PCCI or dual fuel gasoline-diesel RCCI), mainly due to the high instability and the high sensitivity to slight variations of the injection parameters that characterize this kind of combustions. Therefore, the authors of this paper have applied the developed techniques not only to conventional engines (gasoline and diesel combustion), but also to engines modified for Low Temperature Combustions, with promising results in terms of validation and applicability for real-time combustion control. The developed methodologies have been tested and validated through a large amount of experimental tests. To run the estimation algorithms in real-time, they have been all implemented in a specifically designed rapid control prototyping system, the goal being to quantify the accuracy of the estimations and optimize the strategy implementations for the extensive use (in the near future) in modern Engine Control Modules (ECM)
Torsional Analysis of Different Powertrain Configurations for Torque and Combustion Phase Evaluation
No full textThis paper presents the results of several studies, performed on different powertrain configurations, aimed at analyzing the correlations existing between torque and speed frequency components in an internal combustion engine. Engine speed fluctuations depend in fact on torque delivered by each cylinder, therefore it is easy to understand how these two quantities are directly connected
Performance Assessment of Gasoline PPC in a Light-Duty CI Engine
Full text linkIn the past years, stringent emission regulations for Internal Combustion (IC) engines produced a large amount of research aimed at the development of innovative combustion methodologies suitable to simultaneously reduce fuel consumption and engine-out emissions. Previous research demonstrates that the goal can be obtained through the so-called Low Temperature Combustions (LTC), which combine the benefits of compression-ignited engines, such as high compression ratio and unthrottled lean operation, with a properly premixed air-fuel mixture, usually obtained injecting gasoline-like fuels with high volatility and longer ignition delay.
Gasoline Partially Premixed Combustion (PPC) is a promising LTC technique, mainly characterized by the high-pressure direct-injection of gasoline and the spontaneous ignition of the premixed air-fuel mixture through compression, which showed a good potential for the simultaneous reduction of fuel consumption and emissions in CI engines. Despite its potential, gasoline PPC might suffer from low combustion controllability and stability, because gasoline spontaneous ignition is significantly affected by slight variation of the local in-cylinder thermal conditions.
This paper summarizes the work carried out to optimize gasoline PPC in a light-duty CI engine, operated in a test cell. The investigated system has been slightly modified to guarantee a stable operation, using gasoline instead of diesel, over a wide load range. The first part of the analysis has been focused on the study of gasoline auto-ignition, the goal being to define an injection strategy suitable to guarantee combustion stability. Then, further activity has been focused on performance investigation through a properly defined span of the main control parameters of interest, such as injection pressure and exhaust gas recirculation
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Investigation of Gasoline Partially Premixed Combustion with External Exhaust Gas Recirculation
Full text linkThe stringent emission regulations for Internal Combustion Engines (ICEs) spawned a great amount of research in the field of innovative combustion approaches characterized by high efficiency and low emissions. Previous research demonstrate that such promising techniques, named Low-Temperature Combustion (LTC), combine the benefits of Compression Ignition (CI) engines, such as high compression ratio and unthrottled lean mixture, with low engine-out emissions using a properly premixed air-fuel mixture. Due to longer ignition delay and high volatility compared to diesel, gasoline-like fuels show good potential for the generation of a highly premixed charge, which is needed to reach LTC characteristics. In this scenario, gasoline Partially Premixed Combustion (PPC), characterized by the high-pressure direct injection of gasoline, showed good potential for the simultaneous reduction of pollutants and emissions in CI engines. However, previous research on gasoline CI highlight that a key factor for the optimization of both efficiency and pollutants is the proper management of Exhaust Gas Recirculation (EGR). This work presents the experimental investigation performed running a light-duty CI engine, operated with gasoline PPC, and varying the mass of recirculated gases trapped in the combustion chamber. To guarantee the stability of gasoline autoignition in all the tested conditions, a specific experimental layout has been developed to accurately quantify the amount of trapped residual gases due to the internal and external EGR. The obtained results clearly highlight the impact of EGR on the combustion process and emissions, demonstrating that optimization of charge dilution with EGR is fundamental to guarantee the optimal compromise between efficiency and emissions over the whole operating range
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