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Direct Injection (DI) is believed to be one of the key strategies for maximizing the thermal efficiency of Spark Ignition (SI) engines and meet the ever-tightening emissions regulations. This paper explores the use of Liquefied Petroleum Gas (LPG) liquid phase fuel in a 1.5 liter SI four cylinder gasoline engine with double over head camshafts, four valves per cylinder, and centrally located DI injector. The DI injector is a high pressure, fast actuating injector enabling precise multiple injections of the finely atomized fuel sprays. With DI technology, the injection timing can be set to avoid fuel bypassing the engine during valve overlap into the exhaust system prior to combustion. The fuel vaporization associated with DI reduces combustion chamber and charge temperatures, thereby reducing the tendency for knocking. Fuel atomization quality supports an efficient combustion process.

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.

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 aims to provide an assessment of the Homogeneous Charge Compression Ignition (HCCI) combustion, compared to a well-established alternative such as Direct Injection Compression Ignition (DICI) combustion, under the criteria of CO2 emission reduction potential. The assessment is performed by reviewing the relevant literature and analyzing the commercial products available on the market that are featuring these two technologies. DICI engines have demonstrated in the real world the ability to deliver top fuel conversion efficiencies of about 50%, and fuel conversion efficiencies largely above 40% over most of the load and speed range. Research-only HCCI engines have delivered fuel efficiencies well below 40% in the very few carefully selected map points where they working during carefully performed laboratory experiments.

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.

Improvements of vehicle fuel economy may be achieved by the introduction of advanced internal combustion engines (ICE) improving the fuel conversion efficiency of the engine and of advanced power trains (PWT) reducing the amount of fuel energy needed to power the vehicle. The paper presents a novel design of a variable compression ratio advanced spark ignition engine that also permits an expansion ratio that may differ from the compression ratio hence generating an Atkinson cycle effect. The stroke ratio and the ratio of maximum to minimum in-cylinder volumes may change with load and speed to provide the best fuel conversion efficiency. The variable ratio of maximum to minimum in-cylinder volumes also improves the full load torque output of the engine.

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.

Favorable and unfavorable properties of hydrogen as a combustion engine fuel have been accommodated in a design of a fuel efficient and clean engine providing similar to gasoline maximum torque and power. The advanced H2ICE being developed is a turbocharged engine fitted with cryogenic port hydrogen fuel injection and the hydrogen assisted jet ignition (HAJI). The combustion chamber is designed to produce a high compression ratio and therefore high thermal efficiency. A waste gated turbocharger provides pressure boosting for an increased power density running ultra lean for SULEV operation without after treatment. Thanks to the combustion properties of hydrogen further enhanced by the HAJI system, the engine load is mainly controlled throttle-less decreasing the fuel-to-air equivalence ratio from ultra lean ϕ=0.43 to ultra-ultra lean ϕ=0.18. The computational model developed for addressing the major design issues and the predicted engine performance and efficiency maps are included.

The Bishop Rotary Valve (BRV) has the opportunity for greater breathing capacity than conventional poppet valve engines. However the combustion chamber shape is different from conventional engine with no opportunity for a central spark plug. This paper reports the development of a combustion analysis and design model using KIVA-3V code to locate the ignition centers and to perform sensitivity analysis to several design variables. Central to the use of the model was the tuning of the laminar Arrhenius model constants to match the experimental pressure data over the speed range 13000-20000 rpm. Piston ring crevices lands and valve crevices is shown to be an important development area and connecting rod piston stretch has also been accommodated in the modeling. For the proposed comparison, a conventional 4 valve per cylinder poppet valve engine of nearly equal IMEP has been simulated with GT-POWER.

The specific power densities and therefore the level of sophistication and costs of FIM-MOTOGP engines 800 cm3 in capacity have reached levels similar to those of the traditionally much more expensive FIA-Formula One engines and some racing developments have no application at all in the development of production bikes. The aim of the paper is therefore to review FIM-MOTOGP engine rules and make recommendations that could reduce costs and make racing more directly relevant to the development of production bikes while enhancing the significant interest in technical innovation by the sports' fans.

Gasoline Direct Injection (DI) is a technique that was successful in motor sports several decades ago and is now relatively popular in passenger car applications only. DI gasoline fuel injectors have been recently improved considerably, with much higher fuel flow rates and much finer atomization enabled by the advances in fuel pressure and needle actuation. These improved injector performance and the general interest in reducing fuel consumption also in motor sports have made this option interesting again. This paper compares Port Fuel Injection (PFI) and DI of gasoline fuel in a high performance, four cylinder spark ignition engine for super bike racing. Computations are performed with a code for gas exchange, heat transfer and combustion, simulating turbulent combustion and knock.

Direct Injection (DI) is believed to be one of the key strategies for maximizing the thermal efficiency of Spark Ignition (SI) engines and meeting the ever-tightening emissions regulations. This paper explores the use of propane and methane gas fuels in a 1.5 liter SI four cylinder gasoline engine with double over head camshafts, four valves per cylinder, and a centrally located DI injector. With DI technology, the injection timing can be set to avoid fuel bypassing the engine during valve overlap into the exhaust system prior to combustion. DI of fuel reduces the embedded air displacement effects of gaseous fuels and lowers the charge temperature. Injection timings and compression ratio are optimized for best performances at Wide Open Throttle (WOT) conditions when configured to achieve homogeneous charge at stoichiometry or run lean jet controlled stratified.

This paper explores through engine simulations the use of LPG and CNG gas fuels in a 1.5 liter Spark Ignition (SI) four cylinder gasoline engine with double over head camshafts, four valves per cylinder equipped with a novel mixture preparation and ignition system comprising centrally located Direct Injection (DI) injector and Jet Ignition (JI) nozzles. With DI technology, the fuel may be introduced within the cylinder after completion of the valve events. DI of fuel reduces the embedded air displacement effects of gaseous fuels and lowers the charge temperature. DI also allows lean stratified bulk combustion with enhanced rate of combustion and reduced heat transfer to the cylinder walls creating a bulk lean stratified mixture.

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.

Downsizing and Turbo Charging (TC) and Direct Injection (DI) may be combined with Variable Valve Actuation (VVA) to better deal with the challenges of fuel economy enhancement. VVA may control the load without throttle; control the valve directly and quickly; optimize combustion, produce large volumetric efficiency. Benefits lower fuel consumption, lower emissions and better performance and fun to drive. The paper presents an engine model of a 1.6 litre TDI VVA engine specifically designed to run pure ethanol, with computed engine maps for brake specific fuel consumption and efficiency. The paper also presents driving cycle results obtained with a vehicle model for a passenger car powered by this engine and a traditional naturally aspirated gasoline engine. Preliminary results of the VVA system coupled with downsizing, turbo charging and Direct Injection permits significant driving cycle fuel economies.

Improvements of vehicle fuel economy are being considered using a mechanically driven flywheel to reduce the amount of mechanical energy produced by the thermal engine recovering the vehicle kinetic energy during braking. A mechanical system having an overall efficiency over a full regenerative cycle of about 70%, about twice the efficiency of battery-based hybrids, is coupled to a naturally aspirated gasoline engine powering a full size sedan. Results of chassis dynamometer experiments and engine and vehicle simulations are used to evaluate the fuel benefits introducing a kinetic energy recovery system and downsizing of the engine. Preliminary results running the new European driving cycle (NEDC) show KERS may reduce fuel consumption by 25% without downsizing, and 33% with downsizing of the 4 litre engine to 3.3 litres.

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.

Jet ignition and direct fuel injection are potential enablers of higher efficiency, cleaner Internal Combustion Engines (ICE). Very lean mixtures of gaseous fuels could be burned with pollutants formation below Euro 6 levels (in the ultra-lean mode), efficiencies approaching 50% full load and small efficiency penalties when operating part load. The lean burn Direct Injection Jet Ignition (DI-JI) ICE uses a fuel injection and mixture ignition system comprising one main chamber direct fuel injector and one small-size jet ignition pre-chamber per engine cylinder. The jet ignition pre-chamber is connected to the main chamber through calibrated orifices and accommodates a second direct fuel injector. In the spark plug version, the jet ignition pre-chamber includes a spark plug that ignites the slightly rich pre-chamber mixture that then bulk ignites the ultra lean, stratified main chamber mixture through multiple jets of hot reacting gases entering the in-cylinder.

The paper compares Road Racing World Championship Grand Prix (WGP) engine solutions developed in compliance with the 2002 Federation Internationale de Motocyclisme (FIM) Technical Regulations. Ad-hoc assumptions, similarity rules and nondimensional parameters from previous projects are used to define geometric and operating parameters for partly similar engine solutions basically differing in the number of cylinders, three, four, five or six, and the cylinder layout, in-line or V-angle. Results are shown as computed classical engine outputs versus engine speed, including brake, indicated and friction values. By increasing the number of cylinders, charging efficiency reduces, while thermal efficiency increases. Higher values of brake torque and power and lower values of brake specific fuel consumption are provided by the V-angle six cylinder engine.

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.