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Viewing 1 to 22 of 22
2017-09-04
Journal Article
2017-24-0079
Vittorio Ravaglioli, Fabrizio Ponti, Matteo De Cesare, Federico Stola, Filippo Carra, Enrico Corti
Abstract The continuous development of modern Internal Combustion Engine (ICE) management systems is mainly aimed at combustion control improvement. Nowadays, performing an efficient combustion control is crucial for drivability improvement, efficiency increase and pollutant emissions reduction. These aspects are even more crucial when innovative combustions (such as LTC or RCCI) are performed, due to the high instability and the high sensitivity with respect to the injection parameters that are associated to this kind of combustion. Aging of all the components involved in the mixture preparation and combustion processes is another aspect particularly challenging, since not all the calibrations developed in the setup phase of a combustion control system may still be valid during engine life.
2017-03-28
Journal Article
2017-01-0596
Vittorio Ravaglioli, Federico Stola, Matteo De Cesare, Fabrizio Ponti, Stefano Sgatti
Abstract Upcoming more stringent emission regulations throughout the world pose a real challenge, especially in regard to Diesel systems for passenger cars, where the need of additional after-treatment has a big impact in terms of additional system costs and available packaging space. Therefore, the need for strategies that allow managing combustion towards lower emissions, that require a precise control of the combustion outputs, is definitely increasing. Acoustic emission of internal combustion engines contains a large amount of information related to engine behavior and working conditions. Mechanical noise and combustion noise are usually the main contributions to the noise produced by an engine. In particular, recent research from the same authors of this paper demonstrated that combustion noise can be used as an indicator of the combustion that is taking place inside the combustion chamber and therefore as a reference for the control strategy.
2016-04-05
Technical Paper
2016-01-0613
Fabrizio Ponti, Vittorio Ravaglioli, Federico Stola, Matteo De Cesare
The need for strategies that allow managing combustion in an adaptive way has recently widely increased. Especially Diesel engines aimed for clean combustion require a precise control of the combustion outputs. Acoustic emission of internal combustion engines contains a lot of information related to engine behavior and working conditions. Mechanical noise and combustion noise are usually the main contributions to the noise produced by an engine. Combustion noise in particular can be used as an indicator of the combustion that is taking place inside the combustion chamber and therefore as a reference for the control strategy. This work discusses the correlations existing between in cylinder combustion and the acoustic emission radiated by the engine and presents a possible approach to use this signal in the engine management system for control purposes.
2015-09-06
Technical Paper
2015-24-2420
Fabrizio Ponti, Vittorio Ravaglioli, Matteo De Cesare, Federico Stola, Davide Moro
The increasing request for pollutant emissions reduction spawned a great deal of research in the field of innovative combustion methodologies, that allow obtaining a significant reduction both in particulate matter and NOx emissions. Unfortunately, due to their nature, these innovative combustion strategies are very sensitive to in-cylinder thermal conditions. Therefore, in order to obtain a stable combustion, a closed-loop combustion control methodology is needed. Prior research has demonstrated that a closed-loop combustion control strategy can be based on the real-time analysis of in-cylinder pressure trace, that provides important information about the combustion process, such as Start (SOC) and Center of combustion (CA50), pressure peak location and torque delivered by each cylinder. Nevertheless, cylinder pressure sensors on-board installation is still uncommon, due to problems related to unsatisfactory measurement long term reliability and cost.
2014-04-01
Journal Article
2014-01-1645
Fabrizio Ponti, Vittorio Ravaglioli, Enrico Corti, Davide Moro, Matteo De Cesare
The optimization of turbocharging systems for automotive applications has become crucial in order to increase engine performance and meet the requirements for pollutant emissions and fuel consumption reduction. Unfortunately, performing an optimal turbocharging system control is very difficult, mainly due to the fact that the flow through compressor and turbine is highly unsteady, while only steady flow maps are usually provided by the manufacturer. For these reasons, one of the most important quantities to be used onboard for optimal turbocharger system control is the rotational speed fluctuation, since it provides information both on turbocharger operating point and on the energy of the unsteady flow in the intake and exhaust circuits. This work presents a methodology that allows determining the instantaneous turbocharger rotational speed through a proper frequency processing of the signal coming from one accelerometer mounted on the turbocharger compressor.
2013-09-08
Technical Paper
2013-24-0144
Gabriele Vandi, Davide Moro, Fabrizio Ponti, Riccardo Parenti, Gianpiero Einaudi
This paper presents a 14 degrees of freedom vehicle model. Despite numerous software are nowadays commercially available, the model presented in this paper has been built starting from a blank sheet because the goal of the authors was to realize a model suitable for real-time simulation, compatible with the computational power of typical electronic control units, for on-board applications. In order to achieve this objective a complete vehicle dynamics simulation model has been developed in Matlab/Simulink environment: having a complete knowledge of the model's structure, it is possible to adapt its complexity to the computational power of the hardware used to run the simulation, a crucial feature to achieve real-time execution in actual ECUs.
2013-04-08
Journal Article
2013-01-0305
Nicolo Cavina, Alberto Cerofolini, Enrico Corti, Fabrizio Ponti, Matteo De Cesare, Federico Stola
The purpose of this paper is to present some innovative techniques developed for an unconventional utilization of currently standard exhaust sensors, such as HEGO, UEGO, and NOx probes. In order to comply with always more stringent legislation about pollutant emissions, intake-exhaust systems are becoming even more complex and sophisticated, especially for CI engines, often including one or two UEGO sensors and a NOx sensor, and potentially equipped with both short-route and long-route EGR. Within this context, the effort to carry out novel methods for measuring the main exhaust gas dynamic properties exploiting sensors installed for different purposes, could be useful both for control applications, such as EGR rates estimation, or cost reduction, minimizing the on-board devices number. In this work, a gray-box model for measuring the gas mass flow rate, based on standard NOx sensor operating parameters of its heating circuit, is analyzed.
2013-04-08
Technical Paper
2013-01-0314
Fabrizio Ponti, Vittorio Ravaglioli, Enrico Corti, Davide Moro, Matteo De Cesare
Over the past years, policies affecting pollutant emissions control for Diesel engines have become more and more restrictive. In order to meet such requirements, innovative combustion control methods have currently become a key factor. Several studies demonstrate that the desired pollutant emission reduction can be achieved through a closed-loop combustion control based on in-cylinder pressure processing. Nevertheless, despite the fact that cylinder pressure sensors for on-board application have been recently developed, large scale deployment of such systems is currently hindered by unsatisfactory long term reliability and high costs. Whereas both the accuracy and the reliability of pressure measurement could be improved in future years, pressure sensors would still be a considerable part of the cost of the entire engine management system.
2012-04-16
Technical Paper
2012-01-1338
Fabrizio Ponti, Vittorio Ravaglioli, Davide Moro, Matteo De Cesare
Future regulations on pollutant emissions will impose a drastic cut on Diesel engines out-emissions. For this reason, the development of closed-loop combustion control algorithms has become a key factor in modern Diesel engine management systems. Diesel engines out-emissions can be reduced through a highly premixed combustion portion in low and medium load operating conditions. Since low-temperature premixed combustions are very sensitive to in-cylinder thermal conditions, the first aspect to be considered in newly developed Diesel engine control strategies is the control of the center of combustion. In order to achieve the target center of combustion, conventional combustion control algorithms correct the measured value varying main injection timing. A further reduction in engine-out emissions can be obtained applying an appropriate injection strategy.
2011-09-11
Technical Paper
2011-24-0145
Fabrizio Ponti, Matteo De Cesare, Vittorio Ravaglioli
Modern internal combustion engine control systems require on-board evaluation of a large number of quantities, in order to perform an efficient combustion control. The importance of optimal combustion control is mainly related to the requests for pollutant emissions reduction, but it is also crucial for noise, vibrations and harshness reduction. Engine system aging can cause significant differences between each cylinder combustion process and, consequently, an increase in vibrations and pollutant emissions. Another aspect worth mentioning is that newly developed low temperature combustion strategies (such as HCCI combustion) deliver the advantage of low engine-out NOx emissions, however, they show a high cylinder-to-cylinder variation. For these reasons, non uniformity in torque produced by the cylinders in an internal combustion engine is a very important parameter to be evaluated on board.
2011-05-17
Technical Paper
2011-01-1544
Vittorio Ravaglioli, Fabrizio Ponti, Federico Stola
This 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. The presented methodology allows identifying a dynamic model, expressed as a transfer function that depends only on the structure of the engine-driveline system. The identified model can be used to obtain information about torque delivered by the engine and combustion positioning within the engine cycle starting from engine speed measurement. The speed signal is picked up directly from the sensor facing the toothed wheel that is already mounted on the engine for control purposes.
2011-04-12
Technical Paper
2011-01-1420
Vittorio Ravaglioli, Davide Moro, Gabriele Serra, Fabrizio Ponti
In modern Diesel engine control strategies the guideline is to perform an efficient combustion control, mainly due to the increasing request to reduce pollutant emissions. Innovative control algorithms for optimal combustion positioning require the on-board evaluation of a large number of quantities. In order to perform closed-loop combustion control, one of the most important parameters to estimate on-board is MFB50, i.e. the angular position in which 50% of fuel mass burned within an engine cycle is reached. Furthermore, MFB50 allows determining the kind of combustion that takes place in the combustion chamber, therefore knowing such quantity is crucial for newly developed low temperature combustion applications (such as HCCI, HCLI, distinguished by very low NOx emissions). The aim of this work is to develop a virtual combustion sensor, that provides MFB50 estimated value as a function of quantities that can be monitored real-time by the Electronic Control Unit (ECU).
2010-10-25
Technical Paper
2010-01-2211
Fabrizio Ponti, Vittorio Ravaglioli, Davide Moro, Gabriele Serra
Proper design of the combustion phase has always been crucial for Diesel engine control systems. Modern engine control strategies' growing complexity, mainly due to the increasing request to reduce pollutant emissions, requires on-board estimation of a growing number of quantities. In order to feedback a control strategy for optimal combustion positioning, one of the most important parameters to estimate on-board is the angular position where 50% of fuel mass burned over an engine cycle is reached (MFB50), because it provides important information about combustion effectiveness (a key factor, for example, in HCCI combustion control). In modern Diesel engines, injection patterns are designed with many degrees of freedom, such as the position and the duration of each injection, rail pressure or EGR rate. In this work a model of the combustion process has been developed in order to evaluate the energy release within the cylinder as a function of the injection parameters.
2009-11-02
Journal Article
2009-01-2747
Fabrizio Ponti, Vittorio Ravaglioli, Gabriele Serra, Federico Stola
Evaluation 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 in-cylinder 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.
2008-04-14
Journal Article
2008-01-1017
Fabrizio Ponti, Gabriele Serra, Savino Lupo
Effective and precise torque estimation is a great opportunity to improve actual torque-based engine management strategies. Modern ECU often already implement algorithms to estimate on-board the torque that is being produced by the engine, even if very often these estimation algorithms are based on look-up tables and maps and cannot be employed for example for diagnostic purposes. The indicated torque estimation procedure presented in this paper is based on the measurement of the engine speed fluctuations, and is mainly based on two separated steps. As a first step a torsional behavior model of the powertrain configuration is developed. The engine-driveline torsional model enables to estimate the indicated torque frequency component amplitude from the corresponding component of the instantaneous engine speed fluctuation. This estimation can be performed cycle by cycle and cylinder by cylinder.
2007-04-16
Technical Paper
2007-01-0383
Fabrizio Ponti, Enrico Corti, Gabriele Serra, Matteo De Cesare
Multi-jet injection strategies open significant opportunities for the combustion management of the modern diesel engine. Splitting up the injection process into 5 steps facilitates the proper design of the combustion phase in order to obtain the desired torque level, whilst attempting a reduction in emissions, particularly in terms of NOx. Complex 3-D models are needed in the design stage, where components such as the injector or combustion chamber shape have to be determined. Alternatively, zero-dimensional approaches are more useful when fast interpretation of experimental data is needed and an optimization of the combustion process should be obtained based on actual data. For example, zero-dimensional models allow a quick choice of optimum control settings for each engine operating condition, avoiding the need to test all the possible combinations of engine control parameters.
2005-10-24
Technical Paper
2005-01-3762
Fabrizio Ponti
The paper presents the development of a model study whose results enable to evaluate the torque production non-uniformity between the cylinders of an Internal Combustion Engine (ICE). This non-uniformity can be due, for example, to different air breathing into the cylinders, to different injector characteristics, or to pathological operating conditions such as misfires or misfuels, as well as to other abnormal operating conditions. Between the nominal torque production and the one corresponding to the absence of combustion there exist, in fact, a series of possible intermediate conditions, each of them corresponding to a value of produced torque between the nominal value and the one corresponding to the lack of combustion (due for example to statistical dispersion in manufacturing, or aging in the injection system). The diagnosis of this type of non-uniformity is a very important issue in today's engine control strategies design.
2005-10-24
Technical Paper
2005-01-3761
Fabrizio Ponti
Effective and precise torque estimation is a great opportunity to improve actual torque-based engine management strategies. Modern ECU often already implement algorithms to estimate on-board the torque that is being produced by the engine, even if very often these estimation algorithms are based on look-up tables and maps and cannot be employed for example for diagnostic purposes; In other cases the obtained precision is not very high. This work presents the development of a torque estimation procedure based on the instantaneous engine speed measurement. The steps that allowed defining this procedure are briefly explained in the following. The definition of a model that describes the torsional behavior of the engine-load system made first possible to analyze the relationship between the corresponding frequency components of the instantaneous engine speed fluctuations and the indicated torque developed by the cylinders.
2003-03-03
Technical Paper
2003-01-1058
Davide Moro, Fabrizio Ponti, Giovanni Cipolla, Marco Mammetti, Luca Poggio
The optimization of a high performance engine in order to achieve maximum power at full load and high speed can cause an unstable behavior when the engine is running at different conditions, thus making a robust combustion diagnosis for on board diagnostic EOBD/OBD II purposes (misfiring detection) particularly challenging. In fact, when a misfire occurs, its detection can be critical because of the high background noise due to high indicated mean effective pressure (IMEP) cyclic variability. A partial reduction of the high IMEP variability had been achieved by optimizing control parameters of a new prototype high performance V8/4.2 l engine. Spark advance and VVT phasing maps had in fact been re-designed based on in-cylinder pressure variability (cycle by cycle and cylinder by cylinder) analysis.
2002-12-02
Technical Paper
2002-01-3330
Fabrizio Ponti
This paper presents some results of a methodology capable of extracting instantaneous engine speed information from acoustic emission measurements, obtained from Formula 1 (F1) vehicles during qualifying or race sessions, from the early races in 50s-60s until present days. The results presented in the paper show that, from this signal, it is possible to gain information regarding the instantaneous engine speed (that in racing engines is strongly related to the power developed by the engine itself), but also regarding the way the combustions are distributed within an engine cycle, the time needed for a gear shift, the gear ratios employed, the driving strategy and so on. The analysis conducted in this work is applied to acoustic emission data recorded by microphones placed on-board the investigated cars. In recent years each F1 vehicle has been equipped with its own microphone while, in early races, in-car microphones had not been systematically used.
2002-03-04
Technical Paper
2002-01-0456
Davide Moro, Fabrizio Ponti
The paper presents the development of a methodology for the evaluation of the Wide-Open-Throttle (WOT) torque production when the engine is running free. Under such conditions the engine speed shows a sudden increase due to the high engine torque production associated with the WOT conditions, and to the absence of a load connected to the engine. The acoustic emission of the engine contains information related to this speed increase and thus to the engine torque production. The methodology unveils the information contained in the engine acoustic emission to estimate the torque produced under WOT operating conditions. This estimation can be performed without the need of coupling the engine to a brake, and does not require installing any additional sensor. For this reason the approach here presented could be very useful for engine testing at the end of the assembly line.
1999-03-01
Technical Paper
1999-01-0541
Nicolò Cavina, Fabrizio Ponti, Giorgio Rizzoni
Electronic Throttle Control systems substitute the driver in commanding throttle position, with the driver acting on a potentiometer connected to the accelerator pedal. Such strategies allow precise control of air-fuel ratio and of other parameters, e.g. engine efficiency or vehicle driveability, but require detailed information about the engine operating conditions, in order to be implemented inside the Electronic Control Unit (ECU). In order to determine throttle position, an interpretation of the driver desire (revealed by the accelerator pedal position) is performed by the ECU. In our approach, such interpretation is carried out in terms of a torque request that can be appropriately addressed knowing the actual engine-vehicle operating conditions, which depend on the acting torques. Estimates of the torque due to in-cylinder pressure (indicated torque), as well as the torque required by the vehicle (load torque), must then be available to the control module.
Viewing 1 to 22 of 22

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