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The paper describes a numerical study, supported by experiments, on light aircraft 2-Stroke Direct Injected Diesel engines, typically rated up to 110 kW (corresponding to about 150 imperial HP). The engines must be as light as possible and they are to be directly coupled to the propeller, without reduction drive. The ensuing main design constraints are: i) in-cylinder peak pressure as low as possible (typically, no more than 120 bar); ii) maximum rotational speed limited to 2600 rpm. As far as exhaust emissions are concerned, piston aircraft engines remain unregulated but lack of visible smoke is a customer requirement, so that a value of 1 is assumed as maximum Smoke number. For the reasons clarified in the paper, only three cylinder in line engines are investigated. Reference is made to two types of scavenging and combustion systems, designed by the authors with the assistance of state-of-the-art CFD tools and described in detail in a parallel paper.

2-step variable valve actuation using early-intake valve closing is a strategy for high fuel economy on spark-ignited gasoline engines. Two discrete valve-lift profiles are used with continuously variable cam phasing. 2-step VVA systems are attractive because of their low cost/benefit, relative simplicity, and ease-of-packaging on new and existing engines. A 2-step VVA system was designed and integrated on a 4-valve-per-cylinder 4.2L line-6 engine. Simulation tools were used to develop valve lift profiles for high fuel economy and low NOx emissions. The intake lift profiles had equal lift for both valves and were designed for high airflow & residual capacity in order to minimize valvetrain switching during the EPA drive cycle. It was determined that an enhanced combustion system was needed to maximize fuel economy benefit with the selected valve lift profiles. A flow-efficient chamber mask was developed to increase in-cylinder tumble motion and combustion rates.

The University of Maryland team converted a model year 2000 Chevrolet Suburban to an ethanol-fueled hybrid-electric vehicle (HEV) and tied for first place overall in the 2000 FutureTruck competition. Competition goals include a two-thirds reduction of greenhouse gas (GHG) emissions, a reduction of exhaust emissions to meet California ultra-low emissions vehicle (ULEV) Tier II standards, and an increase in fuel economy. These goals must be met without compromising the performance, amenities, safety, or ease of manufacture of the stock Suburban. The University of Maryland FutureTruck, Proteus, addresses the competition goals with a powertrain consisting of a General Motors 3.8-L V6 engine, a 75-kW (100 hp) SatCon electric motor, and a 336-V battery pack. Additionally, Proteus incorporates several emissions-reducing and energy-saving modifications; an advanced control strategy that is implemented through use of an on-board computer and an innovative hybrid-electric drive train.

Every year global automakers introduce new or significantly re-engineered passenger vehicles with increasingly advanced technology intended to exceed consumer expectations and satisfy increasingly stringent government regulations. Some of these technologies are firsts-of-their-kind and start trends that other automakers soon follow—with the innovations becoming adopted across the board. The supply community is also increasingly playing a more significant role in helping the original equipment manufacturers research, develop, and introduce the latest engineering innovations that help bring competitive advantage for their automaker partners. Each year, the editors of SAE’s Automotive Engineering magazine publish many articles focused on the technology and engineering innovations of new passenger and concept vehicles, and these articles have been collected into this volume.

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NAIPC reflects modern developments in alternative, electrified propulsion systems, high tech gasoline, diesel ICEs, hydrogen fuel cells, battery electric systems, variable transmissions.

We have developed a small-displacement gasoline direct-injection engine (1.3L). Gasoline direct-injection engines rely on ultra-lean stratified combustion to deliver significantly better fuel economy, and are already used in many practical applications. When gasoline direct-injection is applied to a small-displacement engine, however, the amount of wall wetting of fuel on the piston surface will increase because the traveled length of the fuel spray is short. This may result in problems such as smoke production, high emissions of unburned HC, and poor combustion efficiency.

To provide optimal performance of a small DI diesel in relation to noise, emissions and fuel economy, an experimental investigation was carried out using Taguchi methods. A single cylinder 3.5 kW diesel was selected for performance test at different engine speeds, loads and static injection timings. These controlled parameters were varied at three levels and the resulting changes in response variables viz. engine noise, smoke, HC, NOx, CO, CO2 emissions and fuel economy (b.s.f.c) were observed. The levels for low noise, smoke, emissions and b.s.f.c could be predicted and relevant combination of controlled parameters specified. Confirmation engine runs were carried out and the results showed good agreement with the predicted optimized quantities of interest based on Taguchi analysis. The effect of engine parameters to the above responses was evaluated in terms of percent contributions by using analysis of variance.

The need for efficient space utilization has provided a framework for the design of a 248mm family of torque converters that supports a wide choice of engine and transmission combinations. The axial length of the part and its weight have been substantially reduced while the performance range has been broadened without degradation of efficiency. The new converter operates in an expanded slipping clutch mode. It significantly contributes to the performance and fuel economy improvements of related vehicles. To meet the cost target, the comprehensive lineup and the resulting complexity have required a high level of component interchangeability. During the design phase, the manufacturing core competencies were scrutinized and process redundancies eliminated, both resulting in optimization of material selection and applicable technology.

Weight reduction of automobiles is key technology in order to improve fuel economy and driving performance. Concerning of the motorcycle engine, weight reduction is also the fundamental and important technologies. Cylinder is one of the main parts of engine and the wear characteristics of the cylinder liner are largely related to the engine performance. Gray iron liners squeezed in aluminum cylinder block have been widely used. This is due to the excellent resistance to abrasion of gray iron. In order to realize light all aluminum cylinder, the good abrasion resistant method is necessary to develop to be applied with inner surface of liners. We have developed the new Rapid Composite Plating System for the motorcycle engine cylinders. This system made it possible to adopt all aluminum cylinders without cast iron liners to new type of engine.

This paper describes the set-up and testing of a single cylinder 25cc, air cooled, 4-stroke Spark Ignition (SI) engine converted to run in Homogeneous Charge Compression Ignition (HCCI) mode with the aid of various combustion control systems. The combustion control systems were investigated regarding their effects on combustion stability and heat release phasing. Engine operation was compared with unique findings from previous work done on a very small 2-stroke HCCI engine. HCCI engine operation was possible between 1000 - 4000 rpm when using Diethyl Ether (DEE) as the test fuel. Maximum operational fuel-air equivalence ratio (Φ) was 0.75 when operating without Exhaust Gas Recirculation (EGR). This relatively high equivalence ratio was attainable due to thermal gradients induced by the high surface area to volume ratio of the small engine combustion chamber, resulting in high chamber heat transfer.

A historical review of the patents and literature pertaining to 3-valve stratified charge engines is presented in this paper. This very old invention appears to be a practical approach for the “clean engine” being sought for vehicular use since it has the intrinsic capability of simultaneously giving good fuel economy and producing minimal objectionable exhaust emissions. The prime requisites of this engine are a rich prechamber charge and a very lean main chamber charge regardless of prechamber volume, nozzle diameter, valving and spark plug location. Fuel-air equivalence ratios of the charges in the two combustion chambers are significantly important in order to achieve the proper optimization. These ratios should be about 15% rich for the prechamber and 15 to 30% lean for the main chamber at the moment of ignition.

Due to the requirements of the market, engine manufacturers and their suppliers must develop new products in a short lead time, with high quality, high reliability and lowest possible costs. A method to obtain a short lead time for a complicated aluminum cylinder head is the design in 3 D CAD and the use of simultaneous engineering. A practical example shows the design of a 16-valve cylinder head in 3 D CAD (Catia). The cylinder head supplier received a CAD-tape with the main dimensions such as valve locations, shape of the combustion chamber and ports and location of the bolts. A design team completed the cylinder head design in 3 D CAD in consideration of the needs for foundry technology, casting tool design and machining of the part. Special casting tools for the prototyping were manufactured parallel to the cylinder head design.

Today turbo-diesel powertrains offering low fuel consumption and good low-end torque comprise a significant fraction of the light-duty vehicle market in Europe. Global CO₂ regulation and customer fuel prices are expected to continue providing pressure for powertrain fuel efficiency. However, regulated emissions for NO and particulate matter have the potential to further expand the incremental cost of diesel powertrain applications. Vehicle segments with the most cost sensitivity like compacts under 1400 kg weight look for alternatives to meet the CO₂ challenge but maintain an attractive customer offering. In this paper the concepts of downsizing and downspeeding gasoline engines are explored while meeting performance needs through increased BMEP to maintain good driveability and vehicle launch dynamics. A critical enabler for the solution is adoption of gasoline direct injection (GDi) fuel systems.