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Technical Paper

Using a Traffic Simulator to Evaluate and Minimize Carbon Dioxide Emissions in Conventional and Hybrid Electric Vehicles over Real World Emissions Tests

2018-05-30
2018-37-0001
This investigation analyzes the feasibility of using a traffic simulator, and in particular the open source software SUMO, to obtain speed profiles under Real Driving Emission (RDE) tests to be used for the modeling and the optimization of conventional and hybrid electric powertrains. The first step of the investigation is the setup and amendment of the SUMO software to reproduce real driving emissions tests performed in Lecce with a start&stop Class 3b diesel vehicle equipped with a Portable Emission Measurement System (PEMS) in spring-summer 2017. Due to the high cost of using a PEMS instrumentation and being the measurement of pollutant emissions optional in the present investigation, the experimental campaign is extended here with the help of a OBD-II scanner whose usefulness to obtain the real world levels of fuel consumption and CO2 with reduced costs and times is proved in literature.
Technical Paper

Effects on the Aerodynamic Characteristics of Vehicles in Longitudinal Proximity Due to Changes in Style

2018-05-30
2018-37-0018
The potential energy-saving benefit and reduction in emissions for road vehicles when travelling in a platoon formation arises from the possibility to achieve a reduction in the total aerodynamic drag for vehicles travelling in close proximity compared to the sum of the aerodynamic drag for the same number of vehicles when travelling alone. In the late 1980s, platooning was considered as an opportunity for fuel-saving in response to the fuel crises of the 1970s and 1980s but with particular regard to exploiting the trend of increasing traffic density on motorways (or freeways). Recent developments in advanced vehicle communication systems and the apparent enthusiasm for connected and autonomous vehicles have provided a renewed interest in proximity effects to assist in reducing energy consumption. However, the aerodynamic development processes employed by manufacturers today are designed to help meet stringent emission regulations based on the simulated driving of single vehicles.
Technical Paper

Numerical analysis of aerodynamic impact on passenger vehicles during cornering

2018-05-30
2018-37-0014
Governmental regulations and increased consumer awareness of the negative effects of green-house gases has led the automotive industry to massive invest in the energy efficiency of its fleet. One step towards accomplishing this, is to reduce fuel consumption by improving the aerodynamics and minimizing the drag of vehicles. Fuel consumption is measured by standardized driving cycles which do not consider aerodynamic losses during cornering. It is uncertain whether cornering has a significant impact on the drag, and the present study intends to investigate this numerically. Physical tests have been conducted in the past by placing, for instance, a car sideways in a wind tunnel or by using a curved test section. However, these attempts were far from being able to reproduce the same flow condition as in actual cornering situations. In this study, the effects of cornering on the drag force are investigated numerically using a generic vehicle model called the DrivAer.
Technical Paper

Influence of combustion efficiency on the operation of spark ignition engines fueled with methane and hydrogen investigated in a quasi-dimensional simulation framework

2018-05-30
2018-37-0012
Within the context of widening application of numerical simulations for shortening engine development times, the present work covers the issue of quasi-dimensional simulation of spark ignition engines. Multi-fuel operation was the main goal of the study, with the analysis of methane and its blends with hydrogen; gasoline was also considered as a reference case. Data recorded on two engines with practically the same geometry, was used for calibrating the model. The first power unit was of commercial derivation for small applications, while the second one featured optical accessibility through the piston crown. The relative difference between the two engines allowed the top-land region crevice to be identified as the major contributor to overall combustion efficiency. Using an in-cylinder pressure based method, compression ratio and blow-by losses were determined, and differences between fuel types were recognized in the sense of combustion efficiency.
Technical Paper

Application of adjoint methods on drag reduction of current production cars

2018-05-30
2018-37-0016
Road transport has been detected responsible of about 20% of CO2 emissions in Europe, with a significant incidence by passenger cars. Automotive manufacturers are facing stronger and stronger pressure to optimize all aspects related to fuel consumption of the car, and aerodynamic drag makes no exception, due to increasing governments enforcing rules for the reduction of the emissions and the increasing influence of aerodynamic performance on fuel consumption with WLTP and RDE driving cycles. Nowadays, CFD simulation is a common tool across automotive industries for the assessment and the optimization of vehicle resistance in the design phase. The full power of these numerical methods of studying many design variants in advance of experimental testing, however, can be fully exploited when coupled with optimization techniques, always keeping into account constraints and aesthetical demands.
Technical Paper

Conventional and Electrically Heated Diesel Oxidation Catalyst Physical Based Modeling

2018-05-30
2018-37-0010
Conventional Oxidation Catalysts are widely used in Diesel engines for their capability to achieve a huge reduction of CO and HC and, at the same time, to improve SCR catalysts performance promoting NO conversion into NO2 and generating exotherm. However, when the catalyst temperature is below the light-off, as it happens during a cold-start phase, the conversion performances are inadequate. This issue is further complicated by the upcoming regulations on CO2 that, due to the required improvements on combustion efficiency and heat loss reduction, will cause gas temperature at engine-out to decrease. Furthermore, the heating of the Exhaust Aftertreatment System by fuel-based strategies should necessarily be limited to contain the fuel penalty. In this context, the Electrically Heated Catalyst (EHC) is a solution to quickly warm up the exhaust line and reduce CO2 penalties.
Technical Paper

48V hybrid system technologies to develop the most efficient and cleanest Diesel

2018-05-30
2018-37-0011
The new exhaust emission requirements introduced by governments about light duty vehicles are becoming very tightening. As well as reaching legal emission limits, the car manufacturers must improve the fuel efficiency lowering average fleet CO2 value and also continue to improve the fun to drive. The Hybrid and Diesel propulsion systems are two important players on that competition. 48V hybrid is a cost-effective solution despite HV system and it could outline a new way to approach the well-known trade-off between CO2 and NOx on Diesel engine. The aim of this study is to investigate and measure how 48V Hybrid System could improve the engine efficiency, reduce the exhaust emission on new WLTP cycle and strengthen the performance of 7- seat multi purpose vehicle equipped with 1.6L Diesel engine.
Technical Paper

Robust Optimization for Real World CO2 Reduction

2018-05-30
2018-37-0015
Ground transportation industry contributes to about 14% of the global CO2 emissions. Therefore, any effort in reducing global CO2 needs to include the design of cleaner and more efficient vehicles. Their design needs to be optimized for the real-world conditions. Using wind tunnels that can only reproduce idealized conditions does not always translate in real-world CO2 reduction and increased energy efficiency. Several recent studies found that very rarely can the real-world environment be represented by turbulence-free conditions in wind tunnels. The real-world conditions consist of both a transversal flow velocity component (which creates an oncoming yaw flow) as well as large-scale turbulent fluctuations, with length scales of up to many times the size of the vehicle. The study presented in this paper shows how the realistic wind affects the aerodynamics of the vehicle.
Technical Paper

TAKE-HOME MESSAGES FROM THE APPLICATIONS OF LIFE CYCLE ASSESSMENT ON LIGHTWEIGHT AUTOMOTIVE COMPONENTS

2018-05-30
2018-37-0029
During the last few decades, the European regulations concerning CO2 emissions and vehicle recyclability/recoverability rates are leading OEMs to develop and apply several technological strategies to increase environmental performances of vehicles. In this context, lightweighting is a key concern because effectively contribute to reduce vehicle mass, fuel consumption and CO2 emissions during the operation stage of vehicle. The research advancements are enhancing the applicability of a diverse set of innovative materials (e.g. plastics, bio- composites) to different vehicle assemblies and so the weight reduction with the same mechanical performances. This paper is devoted to describe the implementation of LCA methodological approach in Magneti Marelli® allowing a wider environmental conscious related to the usage of innovative materials and related manufacturing processes.
Technical Paper

A dynamic test bench for the cooling water pump characterization under real operating conditions

2018-05-30
2018-37-0024
The dynamic performances of the cooling circuit have a great impact on ICE efficiency and CO2 emissions. Engine thermal management is among the most promising technologies able to offer a sensible reduction in terms of engine fuel consumption and CO2 emission. These aspects are widely treated in literature and many technologies are already on the market or ready to be used. A reduced attention in literature, has been done on the pump performances during the real operating conditions. Homologation cycles try to reproduce these conditions. In light duty vehicles these cycles consist in accelerating and decelerating the engine following a specified velocity-time sequence. According to this procedure, the propulsion power requested by the vehicle is low, and the power absorbed by the auxiliaries became significant. The pump of the cooling fluid is the most important component among the auxiliaries.
Technical Paper

Maximizing Coasting of 48V Vehicles with Cold-Storage Evaporator

2018-05-30
2018-37-0023
One of the main features in 48V vehicles is the ability to coast at high vehicle speeds with the Internal Combustion Engine (ICE) off due to the high torque and power the 48V motor-generator provides which allows a quick and smooth re-cranking of the ICE. The coasting feature reduces the fuel consumption depending on frequency and duration of the coasting events. This depends in turn on driving pattern, driving style and the State-of-Charge (SoC) of the 48V and 12V batteries as well as the air-conditioning system. In summer, if the air-conditioning runs with a mechanically driven compressor, the cabin inlet air temperature from the evaporator inevitably increases during each coasting event as the ICE turns off and cannot operate the compressor. If the evaporator temperature reaches a certain threshold at which the cabin comfort is noticeably affected, the ICE is re-cranked for resuming air-conditioning.
Technical Paper

Thermal management architectures virtual evaluation for HEV/PHEV

2018-05-30
2018-37-0025
The CO2 emission regulations ask a dramatic fuel consumption reduction worldwide. In this scenario, the market penetration of BEVs and PHEVs is strictly related to their electrical driving range, which is strongly affected by the ambient conditions and the passenger comfort asking for an effective thermal management that becomes an opportunity for overcoming these barriers. In this context, a virtual analysis comparing different cooling and heating architectures has been conducted; efficiency and costs aspects have been considered as driving factors as well as the lay-out aspects and vehicle integration constrains which drive component selection and influence the performance. In order to perform a robust architecture comparison and obtain more reliable results, a vehicle thermal model has been developed. The model takes into account the main thermal load contributes and the simulations which have been performed considering different selected use cases.
Technical Paper

Powertrain Thermal Management for CO2 Reduction

2018-05-30
2018-37-0020
Significant transformations are ongoing in automotive powertrains, owing to the restrictive regulations, established by governments around the world, which limit the CO2 emissions into the atmosphere. Car manufacturers are developing, therefore, alternative powertrain systems. Hybrid/Electric vehicles and Fuel Cells powered vehicles are spreading and advanced internal combustion engines technologies are being developed. A common need of these powertrain systems is an effective cooling system. For ICEs, an optimized thermal management allows a significant reduction of frictional losses during warm-up, which is expected to contribute by about 3% to the total CO2 decrease in a homologation cycle. For hybrid/electric vehicles, the power electronic components have specific cooling requirements.
Technical Paper

A Comprehensive Approach for Estimation of Automotive Component Life Due To Thermal Effects

2018-05-30
2018-37-0019
Due to stringent environmental requirements, the vehicle underhood and underbody temperatures have been steadily increasing. The increased temperatures affect components life and therefore, more thermal protection measures may be necessary. In this paper, we present an algorithm for estimation of automotive component life due to thermal effects through the vehicle life. Traditional approaches consider only the maximum temperature that a component will experience during severe driving maneuvers. However, that approach does not consider the time duration or frequency of exposure to temperature. FCA engineers have envisioned a more realistic and science based approach to estimate component life based on vehicle duty cycles, component temperature profile, frequency and characteristics of material thermal degradation.
Technical Paper

Reduced Model of a Vehicle Cabin for transient thermal Simulation

2018-05-30
2018-37-0022
When describing the transient thermal behavior of a vehicle cabin, all three heat transfer mechanisms play an important role. Three-dimensional calculation models which resolve the geometry sufficiently precise and which account for all three mechanisms are still today, even with parallelized computation, typically orders of magnitude slower than real time. The integration of a transient thermal cabin model into a thermal simulation of a complete vehicle therefore demands a reduced model, which meets the requirements regarding both computation speed and accuracy of the calculated local temperatures. In the following, an approach for such a reduced model will be presented and verified with 3D CFD simulation results. One focus hereby is on modeling heat conduction in the considered solid bodies with respect to the spatial and temporal resolution in the three-dimensional and the reduced model.
Technical Paper

Virtual simulation for clutch thermal behavior prediction

2018-05-30
2018-37-0021
The clutch is that mechanical part located in an internal combustion engine vehicle which allows the torque transmission from the shaft to the wheels, permitting at the same time gear shifting and supporting engine revolutions while the car is idling. This component exploits friction as working principle, therefore heat generation is in its own nature. The comprehension of all the critical issues related to thermal emission, and also of the principal physical parameters driving the phenomena are a must in design phases. The subject of this paper is the elaboration of an accurate, but also easy to use and easily replicable, methodology to simulate thermal behavior of a clutch operating inside its usual environment. The present methodology allows to prevent corrective actions in the last phase of the projects, such as changes in gear ratios, that likely worsen CO2 emissions, permitting to achieve the wished thermal performance of the clutch avoiding late changes.
Technical Paper

A Model Based Definition of a Reference CO2 Emissions Value for Passenger Cars under Real World Conditions

2018-05-30
2018-37-0031
With the adoption of the Worldwide harmonized Light Vehicles Test Procedure (WLTP) and the Real Driving Emissions (RDE) regulations for testing and monitoring the vehicle pollutant emissions, as well as CO2 and fuel consumption, the gap between real world and type approval performances is expected to decrease to a large extent. With respect to CO2, however, WLTP is not expected to fully eliminate the reported 40% discrepancy between real world and type approval values. This is mainly attributed to the fact that laboratory tests take place under average controlled conditions that do not fully replicate the environmental and traffic conditions experienced over daily driving across Europe. In addition, any uncertainties of a pre-defined test protocol and the vehicle operation can be optimized to lower the CO2 emissions of the type approval test. Such issues can be minimized in principle with the adoption of a real-world test for fuel consumption.
Technical Paper

Affordable Lightweight Automobiles ALLIANCE project: first results of environmental and economic assessment from a Life-Cycle perspective

2018-05-30
2018-37-0027
In the last years the research activities in the field of lightweighting have been advancing rapidly. The introduction of innovative materials and manufacturing technologies has allowed significant weight reduction. Despite this, novel technologies and materials have not reached a wide distribution. The reasons for this are mainly high production costs and environmental impacts of manufacturing that do not compensate benefits during operation. The AffordabLe LIghtweight Automobiles AlliaNCE (ALLIANCE) project has the goal of developing novel advanced materials and production technologies, aiming at an average 25% weight reduction over 100k units/year, at costs of <3 €/kg. The project will develop a mass-optimizer software tool and a multi-parameter design optimization methodology, aimed at accelerating the pre-assessment of innovative lightweight solutions and technologies over the current design procedures.
Technical Paper

Total Thermal Management of Battery Electric Vehicles (BEVs)

2018-05-30
2018-37-0026
Battery Electric Vehicles (BEVs) are encountering weather-dependent drive range, higher cost and limited battery life as the key hurdles to achieving wide consumer acceptance. This translates into a strong need to reduce a significant energy drain and resultant drive range loss due to auxiliary electrical loads of which the cabin thermal management load is predominant. Studies have shown that thermal sub-system loads can reduce the drive range by as much as 45% under ambient temperatures below -10oC. Often, cabin heating relies purely on resistive energy extraction (PTC heater) contributing to the significant range loss. Regaining a significant part of this range loss may significantly improve the attractiveness of electric vehicles among consumers. The authors present a unified thermal management system (UTEMPRA) that satisfies diverse thermal and design needs of the auxiliary loads in electric vehicles.
Technical Paper

Extended Target Weighing Approach – Estimation of technological uncertainties of concept ideas in product development processes

2018-05-30
2018-37-0028
The "Extended Target Weighing Approach" presented here describes a holistic, cross-component, function-based lightweight design method - in terms of conceptual lightweight design - for the identification and evaluation of lightweight design potentials in the concept phase of product development. It systematically extends the existing, purely mass-based "Target Weighing" approach by the key factors of CO2 emissions and costs. The selection of concept alternatives to be pursued in the early phase of product development often depends on the experience of the product developer. Therefore, the potential of some concepts is not recognized correctly or the risk according to the intended solution caused by missing knowledge or uncertainties is misjudged. This paper presents a method for the evaluation of uncertainties of concept ideas based on the PGE - Product Generation Engineering.
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