Enhancement of Heavy-Duty Engines Performance and Reliability Using Cylinder Pressure Information

Sustainability issues are becoming increasingly prominent in applications requiring the use of heavy-duty engines. Therefore, it is important to cut emissions and costs of such engines to re-duce the carbon footprint and keep the operating expenses under control. Even if for some applications a battery electric equipment is introduced, the diesel-equipped machinery is still popular, thanks to the longer operating range. In this field, the open pit mines are a good example. In fact, the Total Cost of Ownership (TCO) of the mining equipment is highly impacted by fuel consumption (engine efficiency) and reliability (service interval and en-gine life). The present work is focused on efficiency enhancements achievable through the ap-plication of a combustion control strategy based on the in-cylinder pressure information. The benefits are mainly due to two factors. First, the negative effects of injectors ageing can be com-pensated. Second, cylindrical online calibration of the control parameters enables the combus-tion system optimization. The article is divided into two parts. The first part describes the tool-chain that is designed for the real time application of the combustion control system, while the second part concerns the algorithm that would be implemented on the Engine Control Unit (ECU) to leverage the in-cylinder pressure information. The assessment of the potential benefits and feasibility of the combustion control algorithm is carried out in a Software in the Loop (SiL) environment, simulating both the developed control strategy and the engine behavior (Liebherr D98). Our goal is to validate the control algorithm through SiL simulations. The results of the validation process demonstrate the effectiveness of the control strategy: firstly, cylinder dispari-ty on IMEP (+/-2.5% in reference conditions) is virtually canceled. Secondly, MFB50 is individual-ly optimized, equalizing Pmax among the cylinders (+/-4% for the standard calibration), without exceeding the reliability threshold. In addition to this, BSFC is reduced by 1%, thanks to the ac-curate cylinder-by-cylinder calibration. Finally, ageing effects or fuel variations can be implicitly compensated, keeping optimal performance thorough engine life

Battery state of charge management strategies for a real-time controller of a Plug-in Hybrid Electric Vehicle

Abstract This paper deals with the development of energy management strategies for a hybrid electric vehicle (HEV), aiming to reduce the global energy consumption. The vehicle is a Plug-in HEV, and its model had been validated on New European Driving Cycle (NEDC). A real-time model-based supervisory controller is implemented, called Equivalent Consumption Minimization Strategy (ECMS), and it is compared with the original heuristic control. Three ways to manage the energy stored in the battery along the driving mission are presented. Predictive information is then introduced to increase vehicle driveability. Conclusions summarize the benefits of such approach, showing satisfactory results also considering the driver comfort

Advances in Computational Techniques to Study GPCR-Ligand Recognition

G-protein-coupled receptors (GPCRs) are among the most intensely investigated drug targets. The recent revolutions in protein engineering and molecular modeling algorithms have overturned the research paradigm in the GPCR field. While the numerous ligand-bound X-ray structures determined have provided invaluable insights into GPCR structure and function, the development of algorithms exploiting graphics processing units (GPUs) has made the simulation of GPCRs in explicit lipid-water environments feasible within reasonable computation times. In this review we present a survey of the recent advances in structure-based drug design approaches with a particular emphasis on the elucidation of the ligand recognition process in class A GPCRs by means of membrane molecular dynamics (MD) simulations

The Multifaceted Role of GPCRs in Amyotrophic Lateral Sclerosis: A New Therapeutic Perspective?

Amyotrophic lateral sclerosis (ALS) is a degenerating disease involving the motor neurons, which causes a progressive loss of movement ability, usually leading to death within 2 to 5 years from the diagnosis. Much effort has been put into research for an effective therapy for its eradication, but still, no cure is available. The only two drugs approved for this pathology, Riluzole and Edaravone, are onlyable to slow down the inevitable disease progression. As assessed in the literature, drug targets such as protein kinases have already been extensively examined as potential drug targets for ALS, with some molecules already in clinical trials. Here, we focus on the involvement of another very important and studied class of biological entities, G protein-coupled receptors (GPCRs), in the onset and progression of ALS. This workaimsto give an overview of what has been already discovered on the topic, providing useful information and insights that can be used by scientists all around the world who are putting efforts into the fight against this very important neurodegenerating disease

Comparison of Knock Indexes Based on CFD Analysis

Abstract Recent trends in gasoline engines, such as downsizing, downspeeding and the increase of the compression ratio make knocking combustions a serious limiting factor for engine performance. A detailed analysis of knocking events can help improving the engine performance and diagnostic strategies. An effective way is to use advanced 3D Computational Fluid Dynamics (CFD) simulation for the analysis and prediction of the combustion process. The effects of Cycle to Cycle Variation (CCV) on knocking combustions are taken into account, maintaining a \RANS\ (Reynolds Averaged Navier-Stokes) \CFD\ approach, while representing a complex running condition, where knock intensity changes from cycle to cycle. The focus of the numerical methodology is the statistical evaluation of the local air-to-fuel and turbulence distribution at the spark plugs and their correlation with the variability of the initial stages of combustion. \CFD\ simulations have been used to reproduce knock effect on the cylinder pressure trace. For this purpose, the \CFD\ model has been validated, proving its ability to predict the combustion evolution with respect to \SA\ variations, from non-knocking up to heavy knocking conditions. The pressure traces simulated by the \CFD\ model are then used to evaluate cylinder pressure-based knock indexes. Since the model is able to output other knock intensity tracers, such as the mass of fuel burned in knocking mode, or the local heat transferred to the piston, knock indexes based on the cylinder pressure trace can be related to parameters only available in a simulation environment, that are likely to be more representative of the actual knock intensity, with respect to the local pressure trace for the sensor position. The possibility of simulating hundredths of engine cycle allows using the methodology to compare the indexes quality (correlation with actual knock intensity) on a statistical base

Can the impact of bed closure in intensive care units be reliably monitored?

Objective: To assess the properties of various indicators aimed at monitoring the impact on the activity and patient outcome of a bed closure in a surgical intensive care unit (ICU). Design: Comparison before and after the intervention. Setting: A surgical ICU at a university hospital. Patients: All patients admitted to the unit over two periods of 10months. Intervention: Closure of one bed out of 17. Measurements and results: Activity and outcome indicators in the ICU and the structures upstream from it (emergency department, operative theater, recovery room) and downstream from it (intermediate care units). After the bed closure, the monthly medians of admitted patients and ICU hospital days increased from 107 (interquartile range 94-112) to 113 (106-121, P=0.07) and from 360 (325-443) to 395 (345-436, P=0.48), respectively, along with the linear trend observed in our institution. All indicators of workload, patient severity, and outcome remained stable except for SAPS II score, emergency admissions, and ICU readmissions, which increased not only transiently but also on a mid-term basis (10months), indicating that the process of patient care delivery was no longer predictable. Conclusions: Health care systems, including ICUs, are extraordinary flexible, and can adapt to multiple external constraints without altering commonly used activity and outcome indicators. It is therefore necessary to set up multiple indicators to be able to reliably monitor the impact of external interventions and intervene rapidly when the system is no longer under contro

Accelerometer Based Methodology for Combustion Parameters Estimation

Due to increasingly stringent emission regulations and the need of more efficient powertrains, obtaining information about combustion process becomes a key factor. Low-cost in-cylinder pressure sensors are being developed, but they still present longterm reliability issues, and represent a considerable part of the engine management system cost. Research is being conducted in order to develop methodologies for extracting relevant combustion information using standard sensors already installed on-board. The present work introduces a methodology for combustion parameters estimation, through a control-oriented analysis of structureborne sound. The paper also shows experimental results obtained applying the estimation methodology to different passenger car engines. © 2015 The Authors. Published by Elsevier Ltd

Transient Spark Advance Calibration Approach

Combustion control is assuming a crucial role in reducing engine tailpipe emissions while maximizing performance. The effort in the calibration of control parameters affecting the combustion development can be very demanding. One of the most effective factors influencing performance and efficiency is the combustion phasing: in Spark Ignition (SI) engines it is affected by factors such as Spark Advance (SA), Air-Fuel Ratio (AFR), Exhaust Gas Recirculation (EGR), Variable Valve Timing (VVT). SA optimal values are usually determined by means of calibration procedures carried out in steady state conditions on the test bench by changing SA values while monitoring performance indicators, such as Brake and Indicated Mean Effective Pressure (BMEP, IMEP), Brake Specific Fuel Consumption (BSFC) and pollutant emissions. The effect of SA on combustion is stochastic, due to the cycle-to-cycle variation: the analysis of mean values requires many engine cycles to be significant of the performance obtained with the given control setting. Moreover, often the effect of SA on engine performance must be investigated for different settings of other control parameters (EGR, VVT, AFR). The calibration process is time consuming involving exhaustive tests followed by off-line data analysis. This paper presents the application of a dynamic calibration methodology, with the objective of reducing the calibration duration. The proposed approach is based on transient tests, coupled with a statistical investigation, allowing reliable performance analysis even with a low number of engine cycles. The methodology has been developed and tested off-line, then it has been implemented in Real-Time. The combustion analysis system has been integrated with the ECU management software and the test bench controller, in order to perform a fully automatic calibration. © 2013 The Authors