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Unmanned Aerial Vehicles (UAV) require simple and reliable engines of high power to weight ratio. Wankel and two stroke engines offer many advantages over four stroke engines. A two stroke engines featuring crank case scavenging, precise oiling, direct injection and jet ignition is analyzed here by using CAD, CFD and CAE tools. Results of simulations of engine performances are shown in details. The CFD analysis is used to study fuel injection, mixing and combustion. The CAE model then returns the engine performances over the full range of loads and speeds with the combustion parameters given as an input. The use of asymmetric rather than symmetric port timing and supercharging scavenging is finally suggested as the best avenue to further improve power density and fuel conversion efficiency.

The present paper is an introduction to a novel rotary valve engine design addressing the major downfalls of past rotary valves applications while permitting the typical advantages of the rotary valves. Advantages of the solution are the nearly optimal gas exchange, mixture formation, ignition and combustion evolution thanks to the large gas exchange areas from the two horizontal valves per engine cylinder, the good shape of the combustion chamber, the opportunity to place a direct fuel injector and a spark or jet ignition device at the centre of the chamber. The novel engine design also permits higher speed of rotation not having reciprocating poppet valves and the reduced friction losses of the rotating only distribution. This translates in better volumetric efficiencies, combustion rates and brake mean effective pressures for improved power density and fuel efficiency. Additional advantages are the reduced weight and the better packaging.

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.

In this paper, the concept of super-turbocharging is applied, in simulation, to a four-cylinder direct injection jet ignition gasoline engine. Turbocharging improves the power density of internal combustion engines, both the compression ignition and the spark ignition. However, a standalone turbocharger suffers from transient and steady state performance and efficiency degradation where the energy to turbine is either smaller or larger than what would be needed to optimize the engine operation in a specific point. Hence a concept is proposed to use a super-turbocharger, where the turbocharger shaft is connected to the crankshaft through a continuously variable transmission (CVT) and a gears pair. Energy is drawn from the crankshaft or delivered to the crankshaft to better work in every operating point. The concept was originally proposed for a diesel engine. Here it is applied to a gasoline engine.

Turbocharging dramatically improves the power density of internal combustion engines both in the compression ignition and the spark ignition cases. However, a standalone turbocharger suffers from transient and steady state downfalls where the energy to turbine is either smaller or larger than what would be needed to optimize the engine operation in a specific steady state or transient point. Hence a concept was proposed of a super-turbocharger where the turbocharger shaft is connected to the crankshaft through a continuously variable transmission and a gear. Energy is drawn from the crankshaft or delivered to the crankshaft to improve the work in every operating point of the steady map. In this paper, the concept of super-turbocharger is applied to a six-cylinder, dual fuel diesel injection ignition engine. The system is modelled using state-of-the-art automotive software and simulations of the steady-state operation are presented.

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.

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.

Racing continues to be the singular, preeminent source of powertrain development for automakers worldwide. Engineering teams rely on motorsports for the latest prototype testing and research. Endurance racing provides the harshest and most illuminating stage for system design validation of any motorsport competition. While advancements throughout the 20th Century brought about dramatic increases in engine power output, the latest developments from endurance racing may be more impactful for fuel efficiency improvements. Hybrid powertrains are a critical area of research for automakers and are being tested on the toughest of scales. Prototype Powertrain in Motorsport Endurance Racing brings together ten vital SAE technical papers and SAE Automotive Engineering magazine articles surrounding the advancements of hybrid powertrains in motorsports.

Direct injection and jet ignition is becoming popular in electrically assisted, turbocharged, F1 engines because of the pressure to reduce fuel consumption. Operation from homogeneous stoichiometric up to lean of stoichiometry stratified about λ = 1.5, occurs with fast combustion of reduced cyclic variability thanks to the enhanced ignition by multiple jets of hot, partially reacting products travelling through the combustion chamber. The fuel consumption has thus been drastically reduced in an engine that is, however, still mostly throttle controlled. The aim of the present paper is to show the advantages of direct injection and jet ignition based on model simulations of the operation of a high-performance throttle-controlled engine featuring rotary valves.

Cylinder deactivation has been proposed so far for improved part load operation of large gasoline engines. In all this application, the cylinder deactivation has been achieved keeping the intake and exhaust valves closed for a particular cylinder, with pistons still following their strokes. The paper presents a new mechanism between the piston and the crankshaft to enable selective deactivation of pistons, therefore decoupling the motion of the piston from the rotation of the crankshaft. The reduced friction mean effective pressure of the new technology enables the use of piston deactivation in large engines not necessarily throttle controlled but also controlled by quantity of fuel injected. Results of performance simulations are proposed for a HSDI V8 engine, producing significant savings during light operation.

With the purpose of reducing emission level while maintaining the high torque character of diesel engine, various solutions have been proposed by researchers over the world. One of the most attractive methods is to use dual fuel technique with premixed gaseous fuel ignited by a relatively small amount of diesel. In this study, Methane (CH4), which is the main component of natural gas, was premixed with intake air and used as the main fuel, and diesel fuel was used as ignition source to initiate the combustion. By varying the proportion of diesel and CH4, the combustion and emissions characteristics of the dual fuel (diesel/CH4) combustion system were investigated. Different cases of CFD studies with various concentration of CH4 were carried out. A validated 3D quarter chamber model of a single cylinder engine (diesel fuel only) generated by using AVL Fire ESE was modified into dual fuel mode in this study.

The paper considers different options to design a multi fuel engine retaining the power densities and efficiencies of the latest Diesel heavy duty truck engines while operating with various other fuels. In a first option, an igniting Diesel fuel is coupled to a main fuel that may have any Cetane or octane number in a design where every engine cylinder accommodates a direct Diesel injector, a glow plug and the multi fuel direct injector in a bowl-in-piston combustion chamber configuration. Alternatively, an igniting gasoline fuel replaces the Diesel fuel in a design where every engine cylinder accommodates a gasoline direct injector, the multi fuel direct injector and a jet ignition pre chamber also with a bowl-in-piston combustion chamber configuration. Both these designs permit load control by changing the amount of fuel injected and Diesel-like, gasoline-like and mixed Diesel/gasoline-like modes of operation modulating the amount of the multi fuel that burn premixed or diffusion.

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.

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.

Direct injection (DI) and jet ignition (JI), plus assisted turbocharging, have been demonstrated to deliver high efficiency, high power density positive ignition (PI) internal combustion engines (ICEs) with gasoline. Peak efficiency above 50% and power density of 340 kW/liter at the 15,000 rpm revolution limiter working overall λ=1.45 have been report-ed. Here we explore the further improvement in power density that may be obtained by replacing gasoline with ethanol or methanol, thanks to the higher octane number and the larger latent heat of vaporization, which translates in an increased resistance to knock, and permits to have larger compression ratios. Results of simulations are proposed for a numerical engine that uses rotary valves rather than poppet valves, while also using mechanical, rather than electric, assisted turbocharging. While with gasoline, the power density is 410-420 kW/liter, the use of oxygenates permits to achieve up to 475 kW/liter working with methanol.

A kinetic energy recover system (KERS) captures the kinetic energy that results when brakes are applied to a moving vehicle. The recovered energy can be stored in a flywheel or battery and used later, to help boost acceleration. KERS helps transfer what was formerly wasted energy into useful energy. In 2009, the Federation Internationale de l’Automobile (FIA) began allowing KERS to be used in Formula One (F1) competition. Still considered experimental, this technology is undergoing development in the racing world but has yet to become mainstream for production vehicles. The Introduction of this book details the theory behind the KERS concept. It describes how kinetic energy can be recovered, and the mechanical and electric systems for storing it. Flybrid systems are highlighted since they are the most popular KERS developed thus far. The KERS of two racing vehicles are profiled: the Dyson Lola LMP1 and Audi R18 e-tron Quattro.

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.

The turbocharged direct injection stoichiometric spark ignition gasoline engine has less than Diesel full load brake engine thermal efficiencies and much larger than Diesel penalties in brake engine thermal efficiencies reducing the load by throttling. This engine has however a much better power density, and therefore may operate at much higher BMEP values over driving cycles reducing the fuel economy penalty of the vehicle. This engine also has the advantage of the very well developed three way catalytic converter after treatment to meet future emission regulations. In these engines the efficiency may be improved recovering the waste heat, but this recovery may have ultimately impacts on both the in cylinder fuel conversion efficiency and the efficiency of the after treatment.

The turbocharged direct injection lean burn Diesel engine is the most efficient now in production for transport applications with full load brake efficiencies up to 40 to 45% and reduced penalties in brake efficiencies reducing the load by the quantity of fuel injected. The secrets of this engine's performances are the high compression ratio and the lean bulk combustion mostly diffusion controlled in addition to the partial recovery of the exhaust energy to boost the charging efficiency. The major downfalls of this engine are the carbon dioxide emissions and the depletion of fossil fuels using fossil diesel, the energy security issues of using foreign fossil fuels in general, and finally the difficulty to meet future emission standards for soot, smoke, nitrogen oxides, carbon oxide and unburned hydrocarbons for the combustion of the fuel injected in liquid state and the lack of maturity the lean after treatment system.

The consumption of fossil fuels is one of the largest problems facing humankind. One of the heaviest users of non-renewable energy sources is the transport industry. Tightening worldwide legislation aims to place restrictions on the transport industry to reduce its use of fossil fuels and reduce the levels of pollution being released to the atmosphere. Although several different alternatives to the vehicles only powered by internal combustion engine (ICEs) have been investigated, none have as yet become equally widespread. Alternative research into development of hybrid vehicles was specifically concerned with electric hybrids especially for passenger vehicles. Currently there is a resurgence of interest in the Hybrid Hydraulic Vehicle (HHV) in application to commercial and to a lesser degree to passenger vehicles. This paper gives an overview of hydraulic hybrid technology.