Modeling and control of advanced powertrain systems and Waste Heat Recovery technologies for the reduction of CO2 emissions in light-duty vehicles

2014 - 2015Transportation is the major sector in the EU where greenhouse gas emissions are still rising. Therefore, in the recent years, the OEMs research and development has focused on the reduction of carbon dioxide (CO2) and pollutants emissions. On the other hand, the European Commission proposed targets for the further reduction of CO2 emissions from new cars by 2020. In this scenario, concepts such as the engines downsizing and other advanced technologies as well as more costly hybrid solutions and, more recently, waste heat recovery (WHR) systems have been proposed... [edited by author]XIV n.s

Modeling Analysis of Waste Heat Recovery via Thermo-Electric Generator and Electric Turbo-Compound for CO2 Reduction in Automotive SI Engines☆

Abstract In order to face with the increasing EU restrictions on CO2 emissions from light-duty vehicles, concepts such as the engines downsizing, stop/start systems as well as more costly full hybrid solutions and Waste Heat Recovery (WHR) technologies have been proposed in the last years by OEMs. WHR technologies include Thermo-Electric Generator (TEG), Organic Rankine Cycle (ORC) and Electric Turbo-Compound (ETC) that have been practically implemented on few heavy-duty applications but have not been proved yet as effective and affordable solutions for passenger cars. The paper deals with the analysis of opportunities and challenges of TEG and ETC technologies for a compact car, powered by a turbocharged SI engine. Specifically, the benefits achievable by TEG and ETC have been investigated by simulation analyses carried out by a dynamic engine-vehicle model, validated against steady-state and transient experimental data. The in-cylinder processes and friction losses of the engine are modeled by a black-box scalable parametric approach while grey-box dynamic models are applied for intake/exhaust manifolds and turbocharger. The TEG model is based on existing and commercial thermoelectric materials, specifically Bi2Te3. The simulations have been carried out considering standard driving cycles (i.e. NEDC, WLTC) and the results evidence that significant improvement of fuel economy and CO2 reduction can be achieved by suitable management and configuration of the WHR systems, depending on engine speed and load and auxiliaries demand

Anastomosis configuration and technique following ileocaecal resection for Crohn's disease: a multicentre study

A limited ileocaecal resection is the most frequently performed procedure for ileocaecal CD and different anastomotic configurations and techniques have been described. This manuscript audited the different anastomotic techniques used in a national study and evaluated their influence on postoperative outcomes following ileocaecal resection for primary CD. This is a retrospective, multicentre, observational study promoted by the Italian Society of Colorectal Surgery (SICCR), including all adults undergoing elective ileocaecal resection for primary CD from June 2018 May 2019. Postoperative morbidity within 30 days of surgery was the primary endpoint. Postoperative length of hospital stay (LOS) and anastomotic leak rate were the secondary outcomes. 427 patients were included. The side to side anastomosis was the chosen configuration in 380 patients (89%). The stapled anastomotic (n = 286; 67%), techniques were preferred to hand-sewn (n = 141; 33%). Postoperative morbidity was 20.3% and anastomotic leak 3.7%. Anastomotic leak was independent of the type of anastomosis performed, while was associated with an ASA grade ≥ 3, presence of perianal disease and ileocolonic localization of disease. Four predictors of LOS were identified after multivariate analysis. The laparoscopic approach was the only associated with a reduced LOS (p = 0.017), while age, ASA grade ≥ 3 or administration of preoperative TPN were associated with increased LOS. The side to side was the most commonly used anastomotic configuration for ileocolic reconstruction following primary CD resection. There was no difference in postoperative morbidity according to anastomotic technique and configuration. Anastomotic leak was associated with ASA grade ≥ 3, a penetrating phenotype of disease and ileo-colonic distribution of CD

National variations in perioperative assessment and surgical management of Crohn's disease: a multicentre study

Aim: Crohn's disease (CD) requires a multidisciplinary approach and surgery should be undertaken by dedicated colorectal surgeons with audited outcomes. We present a national, multicentre study, with the aim to collect benchmark data on key performance indicators in CD surgery, to highlight areas where standards of CD surgery excel and to facilitate targeted quality improvement where indicated. Methods: All patients undergoing ileocaecal or redo ileocolic resection in the participating centres for primary and recurrent CD from June 2018 to May 2019 were included. The main objective was to collect national data on hospital volume and practice variations. Postoperative morbidity was the primary outcome. Laparoscopic surgery and stoma rate were the secondary outcomes. Results: In all, 715 patients were included: 457 primary CD and 258 recurrent CD with a postoperative morbidity of 21.6% and 34.7%, respectively. Laparoscopy was used in 83.8% of primary CD compared to 31% of recurrent CD. Twenty-five hospitals participated and the total number of patients per hospital ranged from 2 to 169. Hospitals performing more than 10 primary CD procedures per year showed a higher adoption of laparoscopy and bowel sparing surgery. Conclusions: There is significant heterogeneity in the number of CD surgeries performed per year nationally in Italy. Our data suggest that high-volume hospitals perform more complex procedures, with a higher adoption of bowel sparing surgery. The rate of laparoscopy in high-volume hospitals is higher for primary CD but not for recurrent CD compared with low-volume hospitals

Real-Time Estimation of Intake O2 Concentration in Turbocharged Common-Rail Diesel Engines

Automotive engines and control systems are more and more sophisticated due to increasingly restrictive environmental regulations. Particularly in both Diesel and SI lean-burn engines NOx emissions are the key pollutants to deal with and sophisticated Engine Management System (EMS) strategies and after-treatment devices have to be applied. In this context, the in-cylinder oxygen mass fraction plays a key-role due its direct influence on the NOx formation mechanism. Real-time estimation of the intake O2 charge enhances the NOx prediction during engine transients, suitable for both dynamic adjustments of EMS strategies and management of after-treatment devices. The paper focuses on the development and experimental validation of a real-time estimator of O2 concentration in the intake manifold of an automotive common-rail Diesel engine, equipped with turbocharger and EGR system. The paper analyzes the air intake process and the influence of the exhaust gas recirculation system based on a mean value modeling approach. All variables required are available at EMS level, thus allowing an on-board implementation without extra costs for additional sensors. The accuracy of the developed estimator is assessed by comparing simulated and experimental trajectories of O2 concentration, measured by a Universal Exhaust Gas Oxygen (UEGO) sensor located in the intake manifold. The experimental tests were carried out at the test bench, imposing severe engine transients. The results evidence that the O2 estimator presents a good accuracy vs. experiments and offers significant opportunities for improving engine control and after-treatment devices management during transient operation

Least Square Adaptation of a Fast Diesel Engine NOxEmissions Model

The paper focuses on the development of an adaptive NOxemissions model, whose intended deployment is to provide accurate estimation, throughout engine lifetime, in correspondence of the engine exhaust port of a Diesel propulsion system. Particularly, black-box modelling approach is proposed, which specifically in this paper takes advantage of an intake manifold oxygen estimator previously developed. The resulting multi-linear regression model was preliminary validated in steady-state conditions. Upon successful verification of model accuracy, the above NOxpredictor was integrated within a least-square adaptation algorithm, which relies on the experimental NOxmeasurement performed downstream the selective catalytic reduction catalyst. Therefore, it was possible to perform further validation analyses, both to assess prediction reliability in transient conditions, as well as to verify the adaptation capability of the proposed least-square-based algorithm

A methodology to enhance design and on-board application of neural network models for virtual sensing of Nox emissions in automotive diesel engines

The paper describes suited methodologies for developing Recurrent Neural Networks (RNN) aimed at estimating NOx emissions at the exhaust of automotive Diesel engines. The proposed methodologies particularly aim at meeting the conflicting needs of feasible on-board implementation of advanced virtual sensors, such as neural network, and satisfactory prediction accuracy. Suited identification procedures and experimental tests were developed to improve RNN precision and generalization in predicting engine NOx emissions during transient operation. NOx measurements were accomplished by a fast response analyzer on a production automotive Diesel engine at the test bench. Proper post-processing of available experiments was performed to provide the identification procedure with the most exhaustive information content. The comparison between experimental results and predicted NOx values on several engine transients, exhibits high level of accuracy. Copyright © 2013 SAE International