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A combustion fuel tank, an internal combustion engine (ICE), and a generator provide the best opportunity to store extra energy onboard battery electric vehicles (BEV). This energy may be used for on-demand electricity production when needed, for example, rural or interstate driving. Specific to this work, the design of a high-efficiency ICE that works at a single speed and a single load, continuously, during the operation of this series hybrid vehicle is considered. The ICE and generator provide a fuel conversion efficiency chemical to electric η~50%. The series hybrid vehicle may deliver miles-per-gallon-of-gasoline (MPG) 13% better than current production plug-in hybrid electric vehicles (PHEV), and miles-per-gallon-of-gasoline-equivalent (MPGe) 12% better than the BEV of the same platform with a larger battery pack to permit capital cities commuting.

Data of battery electric vehicles (BEV) with and without a range extender internal combustion engines (ICE) are reviewed and integrated with weight and performance models. A BEV with an on-board, high efficiency, electricity generator based on positive ignition (PI) ICEs is proposed to improve the uptake of the BEV targeting city commuters while improving their economic and environmental impacts. The small ICE, that is working stationary, fixed load and speed, and the generator similarly optimized for a single point operation, permit an efficiency fuel chemical-to-electric of about 49%. This is much better than producing electricity centralized from combustion fuels (average efficiency with included distribution and recharging losses), and it does not require any electric recharging infrastructure. The range of cars can be extended to about the same values of today's car with traditional combustion engines.

Policy makers, especially in the European Union, are pushing towards an early transition to electric mobility, with the internal combustion engine supposed to be phased out by 2030. With a world population projected to exceed 10 billion peoples by 2050, the electric car mobility still lacks the significant development needed to become a real alternative to the internal combustion engine based mobility. Resources availability, and environmental, energetic and economic downfalls, are currently largely underrated or simply unassessed. It is unclear how many will be able to afford to purchase and recharge an electric vehicle in this new world.

The paper captures the recent events in relation with the Volkswagen (VW) Emissions Scandal and addresses the impact of this event on the future of power train development. The paper analyses the impact on the perspectives of the internal combustion engine, the battery based electric car and the hydrogen based technology. The operation of the United States Environmental Protection Agency (EPA), VW and the United States prosecutor, sparked by the action of the International Council on Clean Transportation (ICCT) is forcing the Original Equipment Manufacturers (OEM) towards everything but rationale immediate transition to the battery based electric mobility. This transition voids the value of any improvement of the internal combustion engine (ICE), especially in the lean burn, compression ignition (CI) technology, and of a better hybridization of powertrains, both options that have much better short term perspectives than the battery based electric car.

Regenerative braking coupled to small high power density engines are becoming more and more popular in motorsport applications delivering improved performances while increasing similarities and synergies in between road and track applications. Computer aided engineering (CAE) tools integrated with the telemetry data of the car are an important component of the product development. This paper presents the CAE model developed to describe the race track operation of a LMP1-H racing car covering one lap of the Le Mans circuit. The friction and regenerative braking is discussed.

Real driving cycles are characterized by a sequence of accelerations, cruises, decelerations and engine idling. Recovering the braking energy is the most effective way to reduce the propulsive energy supply by the thermal engine. The fuel energy saving may be much larger than the propulsive energy saving because the ICE energy supply may be cut where the engine operates less efficiently and because the ICE can be made smaller. The present paper discusses the state of the art of hydro-pneumatic drivelines now becoming popular also for passenger cars and light duty vehicle applications permitting series and parallel hybrid operation. The papers presents the thermal engine operation when a passenger car fitted with the hydro-pneumatic hybrid driveline covers the hot new European driving cycle. From a reference fuel consumption of 4.71 liters/100 km with a traditional driveline, the fuel consumption reduces to 2.91 liters/100 km.

The paper considers a novel waste heat recovery (WHR) system integrated with the engine architecture in a hybrid electric vehicle (HEV) platform. The novel WHR system uses water as the working media and recovers both the internal combustion engine coolant and exhaust energy in a single loop. Results of preliminary simulations show a 6% better fuel economy over the cold start UDDS cycle only considering the better fuel usage with the WHR after the quicker warm-up but neglecting the reduced friction losses for the warmer temperatures over the full cycle.

Kinetic energy recovery systems (KERS) placed on one axle coupled to a traditional thermal engine on the other axle is possibly the best solution presently available to dramatically improve the fuel economy while providing better performances within strict budget constraints. Different KERS may be built purely electric, purely mechanic, or hybrid mechanic/electric differing for round trip efficiency, packaging, weights, costs and requirement of further research and development. The paper presents an experimental analysis of the energy flow to and from the battery of a latest Nissan Leaf covering the Urban Dynamometer Driving Schedule (UDDS). This analysis provides a state-of-the-art benchmark of the propulsion and regenerative braking efficiencies of electric vehicles with off-the-shelve technologies.

Small, high power density turbocharged engines coupled to kinetic energy recovery systems are one of the key areas of development for both passenger and racing cars. In passenger cars, the KERS may reduce the amount of thermal energy needed to reaccelerate the car following a deceleration recovering part of the braking energy. This translates in a first, significant fuel energy saving. Also considering the KERS torque boost increasing the total torque available to accelerate the car, large engines working at very low brake mean effective pressures and efficiencies over driving cycles may also be replaced by small higher power density engines working at much higher brake mean effective pressures and therefore much higher part load efficiencies. In racing cars, the coupling of small engines to KERS may improve the perception of racing being more environmentally friendly. The KERS is more a performance boost than a fuel saving device, permitting about same lap times with smaller engines.

Prior papers have shown the potentials of gasoline-like internal combustion engines fitted with waste heat recovery systems (WHR) to deliver Diesel-like steady state fuel conversion efficiencies recovering the exhaust and the coolant waste heat with off-the-shelf components. In addition to the pros of the technology significantly increasing steady state efficiencies - up to 5 % in absolute values and much more in relative values - these papers also mentioned the cons of the technology, increased back pressures, increased weight, more complex packaging, more complex control, troublesome transient operation, and finally the cold start issues that prevent the uptake of the technology. This paper further explores the option to use Rankine cycle systems to improve the fuel economy of vehicles under normal driving conditions. A single Rankine cycle system is integrated here with the engine design.

Cold start driving cycles exhibit an increase in friction losses due to the low temperatures of metal and media compared to normal operating engine conditions. These friction losses are responsible for up to 10% penalty in fuel economy over the official drive cycles like the New European Drive Cycle (NEDC), where the temperature of the oil even at the end of the 1180 s of the drive cycle is below the fully warmed up values of between 100°C and 120°C. At engine oil temperatures below 100°C the water from the blowby condensates and dilutes the engine oil in the oil pan which negatively affects engine wear. Therefore engine oil temperatures above 100°C are desirable to minimize engine wear through blowby condensate. The paper presents a new technique to warm up the engine oil that significantly reduces the friction losses and therefore also reduces the fuel economy penalty during a 22°C cold start NEDC.

Recovery of kinetic energy during driving cycles is the most effective option to improve fuel economy and reduce green house gas (GHG) emissions. Flywheel kinetic energy recovery systems (KERS) may boost this efficiency up to values of about 70%. An engine and vehicle model is developed to simulate the fuel economy of a compact car equipped with a TDI diesel engine and a KERS. Introduction of KERS reduces the fuel used by the 1.6L TDI engine to 3.16 liters per 100 km, corresponding to 82.4 g of CO₂ per km. Downsizing the engine to 1.2 liters as permitted by the torque assistance by KERS, further reduces the fuel consumption to 3.04 liters per 100 km, corresponding to 79.2 g of CO₂ per km. These CO₂ values are 11% better than those of today's most fuel efficient hybrid electric vehicle.

Recovery of braking energy during driving cycles is the most effective option to improve fuel economy and reduce green house gas (GHG) emissions. Hybrid electric vehicles suffer the disadvantages of the four efficiency-reducing transformations in each regenerative braking cycle. Flywheel kinetic energy recovery systems (KERS) may boost this efficiency up to almost double values of about 70% avoiding all four of the efficiency-reducing transformations from one form of energy to another and keeping the vehicle's energy in the same form as when the vehicle starts braking when the vehicle is back up to speed. With reference to the baseline configuration with a 1.6 liters engine and no recovery of kinetic energy, introduction of KERS reduces the fuel usage to 3.16 liters per 100 km, corresponding to 82.4 g of CO₂ per km. The 1.6 liters Turbo Direct Injection (TDI) diesel engine without KERS uses 1.37 MJ per km of fuel energy, reducing with KERS to 1.13 MJ per km.

Improvements of fuel economy of passenger cars and light- and heavy-duty trucks are being considered using a flywheel energy storage system concept to reduce the amount of mechanical energy produced by the thermal engine recovering the vehicle kinetic energy during braking and then assisting torque requirements. The mechanical system has an overall efficiency over a full regenerative cycle of about 70%, about twice the efficiency of battery-based hybrids rated at about 36%. The technology may improve the vehicle fuel economy and hence reduced CO₂ emissions by more than 30% over driving cycles characterized by frequent engine start/stop, and vehicle acceleration, brief cruising, deceleration and stop.

Improvements of truck fuel economy are being considered using a flywheel energy storage system concept. This system reduces the amount of mechanical energy needed by the thermal engine by recovering the vehicle kinetic energy during braking and then assisting torque requirements. The mechanical system has an overall efficiency over a full regenerative cycle of about 70%, about twice the efficiency of battery-based hybrids rated at about 36%. The technology may improve the vehicle fuel economy and hence reduced CO₂ emissions by more than 30% over driving cycles characterized by: frequent engine start/stop, vehicle acceleration, brief cruising, deceleration and stop. The paper uses engine and vehicle simulations to compute: first the fuel benefits of the technology applied to passenger cars, then the extension of the technology to deal with heavy-duty vehicles.

Several race car competitions seek to limit engine power through a rule that requires all of the engine combustion air passes through a hole of prescribed diameter. As the approach and departure wall shapes to this hole, usually termed orifice or restrictor are not prescribed, there is opportunity for innovation in these shapes to obtain maximum flow and therefore power. This paper reports measurements made for a range of restrictor types including venturis with conical inlets and outlets of various angles and the application of slotted throats of the ‘Dall tube’ type. Although normal venturis have been optimized as subsonic flow measuring devices with minimum pressure losses, at the limit the flow in the throat is sonic and the down stream shocks associated with flow transition from sub-sonic to sonic are best handled with sudden angular changes and the boundary layer minimized by the corner slots between the convergent and divergent cones.