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Mild hybridisation, using a 48 V system architecture, offers fuel consumption benefits approaching those achieved using high-voltage systems at a much lower cost. To maximise the benefits from a 48 V mild-hybrid system, it is desirable to recuperate during deceleration events at as high a power level as possible, whilst at the same time having a relatively compact and low cost system. This paper examines the particular requirements of the battery pack for such a mild-hybrid application and discusses the trade-offs between battery power capabilities and possible fuel consumption benefits. The technical challenges and solutions to design a 48 V mild-hybrid battery pack are presented with special attention to cell selection and the thermal management of the whole pack. The resulting battery has been designed to achieve a continuous-power capability of more than 10 kW and a peak-power rating of up to 20 kW.

Current focus on techniques to reduce the tailpipe carbon dioxide (CO₂) emissions of road vehicles is increasing the interest in hybrid and electric vehicle technologies. Pure electric vehicles require bulky, heavy, and expensive battery packs to enable an acceptable drivable range to be achieved. Extended-range electric vehicles (E-REVs) partly overcome the limitations of current battery technology by having an onboard fuel converter that converts a liquid fuel, such as gasoline, into electrical energy whilst the vehicle is driving. Thus enabling the traction battery storage capacity to be reduced, whilst still maintaining an acceptable vehicle range. This paper presents results from a drive style analysis toolset that enable US and EU fleet vehicle drive data to be categorized and compared. Key metrics, such as idle frequency, idle duration, vehicle speed, and vehicle acceleration are analyzed.

MAHLE Powertrain has built a range-extended electric vehicle demonstrator, with a series hybrid configuration. The vehicle is intended to operate predominantly purely electrically. Once the battery state of charge is depleted a gasoline engine (range extender) is activated to provide the energy required to propel the vehicle. As part of the continuing development of this vehicle, MAHLE Powertrain has recorded data during real world driving, with the aim of further investigating the actual usage a range-extended electric vehicle under non-laboratory test conditions. The vehicle is instrumented with a data acquisition system which records physical parameters, for example coolant temperatures, as well as CAN-based data from the engine and vehicle management systems.

Current focus on techniques to reduce the tailpipe CO₂ emissions of road vehicles is increasing the interest in hybrid and electric vehicle technologies. Pure electric vehicles require bulky, heavy, and expensive battery packs to enable an acceptable drive-able range to be achieved. Extended-range electric vehicles (E-REV) partly overcome the limitations of current battery technology by having a "range extender" unit, which consists of an onboard fuel converter that converts a liquid fuel, such as gasoline, into electrical energy whilst the vehicle is driving. This enables the traction battery storage capacity to be reduced, whilst still maintaining an acceptable vehicle driving range. In a previous paper the power requirement of a range extender for a typical C segment passenger car was investigated using drive-cycle modeling over real-world cycles. This paper presents the detailed design of the range extender engine.

Today the light-duty commercial market is dominated by internal combustion engine powered vehicles, primarily diesel-powered delivery vans, which contribute to urban air quality issues. Global concerns regarding climate change have prompted zero emission vehicles to be mandatory in many markets as soon as 2035. For the light-duty commercial vehicle sector there is significant interest in pure electric vehicles. However, for some markets, or usage cases, electric vehicles may not be the best solution due to practical limitations of battery energy storage capacity or recharging times. For such applications there is growing interest in hydrogen fuel cells as a zero emissions alternative. Bramble Energy’s patented printed circuit board (PCB) fuel cell technology (PCBFC™) enables the use of cost-effective production methods and materials from the PCB industry to reduce the cost and complexity of manufacturing hydrogen fuel cell stacks.

Gasoline engine downsizing is already established as a technology for reducing vehicle CO2 emissions. Further benefits are possible through more aggressive downsizing, however, the tradeoff between the CO2 reduction achieved and vehicle drivability limits the level of engine downsizing currently adopted by vehicle manufacturers. This paper will present the latest results achieved from a very heavily downsized engine, and resulting demonstrator vehicle, featuring eSupercharging in combination with a conventional turbocharger. The original 1.2 litre, 3-cylinder, MAHLE downsizing engine has been re-configured to enable a specific power output in excess of 160 kW/litre. Of key importance is a cost effective, efficient and flexible boosting system.

In 2012 MAHLE Powertrain developed a range-extended electric vehicle (REEV) demonstrator, based on a series hybrid configuration, and uses a battery to store electrical energy from the grid. Once the battery state of charge (SOC) is depleted a gasoline engine (range extender) is activated to provide the energy required to propel the vehicle. As part of the continuing development of this vehicle, MAHLE Powertrain has developed control software which can intelligently manage the use of the battery energy through the combined use of GPS and road topographical data. Advanced knowledge of the route prior to the start of a journey enables the software to calculate the SOC throughout the journey and pre-determine the optimum operating strategy for the range extender to enable best charging efficiency and minimize NVH. The software can also operate without a pre-determined route being selected.

Gasoline engine downsizing is already established as a proven technology to reduce automotive fleet CO2 emissions by as much as 25 %. Further benefits are possible through more aggressive downsizing, however, the trade-off between the CO2 reduction achieved and vehicle drive-ability limits the level of engine downsizing currently adopted. This paper presents results showing the benefits of adding an eSupercharger to a very heavily downsized engine. Measurements are presented from a 1.2 litre, 3-cylinder, engine fitted with an eSupercharger in addition to a conventional turbocharger. The original MAHLE downsizing engine has been re-configured to enable a specific power output that exceeds 160 kW/litre. Of key importance is a cost effective, efficient and flexible boosting system.

Vehicle manufacturers are experiencing a shift in legislation and customer attitudes towards powertrain technologies. To support the pathway towards net-zero emissions by 2050, technologies that significantly reduce CO2 emissions will be needed. This will require increasing levels of electrification, and in the areas of compact cars and urban transportation, the adoption of pure battery electric powertrains is expected to become the dominant technology. For large passenger cars and light commercial vehicles (LCVs) meeting all customer requirements, including range, payload, towing capability, and purchase cost with a pure electric vehicle is challenging and requires the use of heavy and expensive battery packs, which have a high embedded CO2 content. The study builds on the work previously presented on the MAHLE modular hybrid powertrain (MMHP) concept and examines the suitability of this powertrain configuration to meet the future needs of large passenger cars and LCVs.

This paper, which is the fourth of a series, presents the REEV demonstrator vehicle developed by MAHLE Powertrain, which features a specifically designed range extender unit. The previous papers describe the specification setting, detailed design and the development of the range extender engine. A current production gasoline fuelled compact-class car was used as a donor vehicle and converted into a range-extended electric vehicle (REEV). The all-electric driveline specification has been developed to meet the performance criteria set for the demonstrator, matching the acceleration and maximum speed capabilities of the conventional donor vehicle. Also, a target electric only range has enabled the battery pack capacity to be specified. The resulting vehicle is intended to reflect likely, near to market, steps to further the wider adoption of electric vehicles in the compact-class passenger car segment.