Impact of different driving cycles and operating conditions on CO2 emissions and energy management strategies of a Euro-6 hybrid electric vehicle

Although Hybrid Electric Vehicles (HEVs) represent one of the key technologies to reduce CO2 emissions, their effective potential in real world driving conditions strongly depends on the performance of their Energy Management System (EMS) and on its capability to maximize the efficiency of the powertrain in real life as well as during Type Approval (TA) tests. Attempting to close the gap between TA and real world CO2 emissions, the European Commission has decided to introduce from September 2017 theWorldwide Harmonized Light duty Test Procedure (WLTP), replacing the previous procedure based on the New European Driving Cycle (NEDC). The aim of this work is the analysis of the impact of different driving cycles and operating conditions on CO2 emissions and on energy management strategies of a Euro-6 HEV through the limited number of information available from the chassis dyno tests. The vehicle was tested considering different initial battery State of Charge (SOC), ranging from 40% to 65%, and engine coolant temperatures, from 7 C to 70 C. The change of test conditions from NEDC to WLTP was shown to lead to a significant reduction of the electric drive and to about a 30% increase of CO2 emissions. However, since the specific energy demand of WLTP is about 50% higher than that of NEDC, these results demonstrate that the EMS strategies of the tested vehicle can achieve, in test conditions closer to real life, even higher efficiency levels than those that are currently evaluated on the NEDC, and prove the effectiveness of HEV technology to reduce CO2 emissions

Electric and hybrid vehicle testing: BMWi3 performance assessment in realistic use scenarios

A plug-in electric vehicle with range extender was tested at ambient temperatures varying between -30°C and 50°C. The objective was to assess energy efficiency variability depending on use conditions. The test campaign was performed in the framework of the transatlantic collaboration between the United States' Department of Energy (Argonne National Laboratory) and the European Commission's Joint Research Centre.JRC.C.4-Sustainable Transpor

On-road emissions and energy efficiency assessment of a plug-in hybrid electric vehicle

In order to assess potential benefits brought by the electrification of transport it becomes more and more important to evaluate the performance of hybrid electric vehicles (HEVs) in real-driving conditions, measuring on-road air pollutant emissions and energy efficiency. The present report describes a portable system used at JRC for e-measurements in hybrid and electric vehicles, as an upgrade of the classic PEMS (Portable Emission Measurement System). Preliminary results of a test campaign conducted on a Euro-6 Plug-in Hybrid Passenger Car (PHEV) equipped with a Flywheel Alternator Starter (FAS) are reported. The influence of different driving modes as well as of different initial battery state of charge on CO2 and NOx emissions and energy consumption has been evaluated.JRC.C.4-Sustainable Transpor

Joint Research Centre 2017 light-duty vehicles emissions testing

This report summarises the results of the pilot study on the market surveillance of light-duty vehicles. The emission performance and the CO2 emissions of 15 vehicles are presented. The methodology for vehicle compliance checks defined in the Guidance note published by the European Commission was applied and discussed.JRC.C.4-Sustainable Transpor

Joint Research Centre 2018 light-duty vehicles emissions testing

This report presents the activities of the JRC on tailpipe emissions compliance assessment of light-duty vehicles conducted throughout 2018. Criteria pollutant and CO2 emissions of 19 vehicles were measured in the laboratory and on the road in a wide range of driving conditions. Distance-specific emissions for individual vehicles and per vehicle technologies and standards are presented. The methodology for emissions compliance defined in the Guidance on the evaluation of Auxiliary Emission Strategies and the presence of Defeat Devices with regard to the application of Regulation (EC) No 715/2007 on type-approval of motor vehicles with respect to emissions from light passenger and commercial vehicles (Euro 5 and Euro 6) was applied and discussed.JRC.C.4-Sustainable Transpor

Power quality performance of fast-charging under extreme temperature conditions

Exposing electric vehicles (EV) to extreme temperatures limits its performance and charging. For the foreseen adoption of EVs, it is not only important to study the technology behind it, but also the environment it will be inserted into. In Europe, temperatures ranging from −30 °C to +40 °C are frequently observed and the impacts on batteries are well-known. However, the impact on the grid due to the performance of fast-chargers, under such conditions, also requires analysis, as it impacts both on the infrastructure’s dimensioning and design. In this study, six different fast-chargers were analysed while charging a full battery EV, under four temperature levels (−25 °C, −15 °C, +20 °C, and +40 °C). The current total harmonic distortion, power factor, standby power, and unbalance were registered. Results show that the current total harmonic distortion (THDI) tended to increase at lower temperatures. The standby consumption showed no trend, with results ranging from 210 VA to 1650 VA. Three out of six chargers lost interoperability at −25 °C. Such non-linear loads, present high harmonic distortion, and, hence, low power factor. The temperature at which the vehicle’s battery charges is crucial to the current it withdraws, thereby, influencing the charger’s performance.JRC.C.3-Energy Security, Distribution and Market

Effect of Low Ambient Temperature on Emissions and Electric Range of Plug-In Hybrid Electric Vehicles

Plug-in hybrid electrical vehicles (PHEVs) are generally considered to be a cleaner alternative to conventional passenger cars. However, there is still very limited information available regarding criteria pollutant emissions from these vehicles. This paper shows, for the first time, the emissions of criteria pollutants, unregulated pollutants, and CO2 and also electric range from two very different PHEVs, one Euro 6 parallel plug-in hybrid and one range-extended battery electric vehicle (BEVx), applying the new world harmonized light-duty test procedure at ambient temperatures equal to 23 and −7 °C. The impact of using a cabin air heating system on vehicle electric range and emissions at cold temperature has also been studied. Cold ambient temperatures and, to a larger extent, the use of heating systems have been shown to lead to a pronounced negative impact on emissions and shorter electric ranges. Results also show that modern PHEVs can emit similar, or even higher, levels of pollutants (e.g., particle number) as Euro 6 conventional gasoline and diesel vehicles

Effect of low ambient temperature on emissions and electric range of plug-in hybrid electric vehicles

Plug-in hybrid electrical vehicles (PHEVs) are generally considered to be a cleaner alternative to conventional passenger cars. However, there is still very limited information available regarding criteria pollutant emissions from these vehicles. This paper shows, for the first time, the emissions of criteria pollutants, unregulated pollutants, and CO2 and also electric range from two very different PHEVs, one Euro 6 parallel plug-in hybrid and one range-extended battery electric vehicle (BEVx), applying the new world harmonized light-duty test procedure at ambient temperatures equal to 23 and −7 °C. The impact of using a cabin air heating system on vehicle electric range and emissions at cold temperature has also been studied. Cold ambient temperatures and, to a larger extent, the use of heating systems have been shown to lead to a pronounced negative impact on emissions and shorter electric ranges. Results also show that modern PHEVs can emit similar, or even higher, levels of pollutants (e.g., particle number) as Euro 6 conventional gasoline and diesel vehicles.JRC.C.4-Sustainable Transpor

Energy Management Analysis under Different Operating Modes for a Euro-6 Plug-in Hybrid Passenger Car

This article analyses the Energy Management System (EMS) of a Euro 6 C-segment parallel Plug-In Hybrid (PHEV) available on the European market, equipped with a Flywheel Alternator Starter (FAS). The car has various selectable operating modes, such as the Zero Emission Vehicle (ZEV), Blended and Sport, characterized by a different usage of the electric driving with significant effects on the electric range and on CO2 emissions. The different hybrid control strategies were investigated applying the UNECE Regulation 83, used for the European type approval procedure, along the New European Driving Cycle (NEDC). To evaluate the influence of the forthcoming Worldwide Harmonized Light Vehicles Test Cycle (WLTC), which will replace the NEDC from September 2017, this testing procedure was also applied. Vehicle testing was carried out on a two-axle chassis dynamometer at the Vehicle Emission LAboratory (VELA) of the Joint Research Centre (JRC) of the European Commission. Through a limited amount of information, obtained as the results of the type approval procedure together with the characterization of the high voltage battery, it was possible to highlight, both in Charge Depleting and Charge Sustaining conditions, how the Internal Combustion Engine (ICE) works as a function of the battery State of Charge (SOC), vehicle speed, acceleration and coolant temperature. Moreover, the impact of different vehicle operating modes on CO2 emissions and Electric Range, computed as prescribed by the European regulation, was clearly highlighted for the considered driving cycles, pointing out differences of about 20% in terms of electrical range, and of more than 70% in terms of CO2 emissions.JRC.C.4-Sustainable Transpor

The Impact of WLTP on the Official Fuel Consumption and Electric Range of Plug-in Hybrid Electric Vehicles in Europe

Plug-in Hybrid Electric Vehicles (PHEVs) are one of the main technology options for reducing vehicle CO2 emissions and helping vehicle manufacturers (OEMs) to meet the CO2 targets set by different Governments from all around the world. In Europe OEMs have introduced a number of PHEV models to meet their CO2 target of 95 g/km for passenger cars set for the year 2021. Fuel consumption (FC) and CO2 emissions from PHEVs, however, strongly depend on the way they are used and on the frequency with which their battery is charged by the user. Studies have indeed revealed that in real life, with poor charging behavior from users, PHEV FC is equivalent to that of conventional vehicles, and in some cases higher, due to the increased mass and the need to keep the battery at a certain charging level. The discrepancy between official and real life figures of FC, electric range, and CO2 emissions has been often attributed, at least partly, to the inadequacy of the New European Driving Cycle (NEDC) to represent the real-world conditions of vehicle use. In an attempt to deal with this problem, which has strong implications on the effectiveness of the CO2-reduction policies, the European Commission has decided to introduce already in 2017 the Worldwide Harmonized Light Vehicles Test Procedure (WLTP). Aim of the present work is to compare WLTP and NEDC procedures for what concerns the determination of fuel consumption (FC), CO2 emissions and electric ranges of two plug-in hybrid vehicles tested in the Joint Research Centre (JRC) of the European Commission laboratories. Results show that the electric range determined following the WLTP procedure is significantly shorter than the NEDC electric range. On the contrary, results show that WLTP-based FC and CO2 will tend to be lower than the corresponding NEDC-based values with the increase in the battery size and corresponding electric range