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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.

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.

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.

An investigation of the possibility to extend the 3-dimensional modeling capabilities from conventional diesel to the HCCI combustion mode simulation was carried out. Experimental data was taken from a single cylinder engine operating with early injections for the HCCI and a split-injection (early pilot+main) for the high speed Diesel engine operation. To properly phase the HCCI mode in the experiments, high amounts of cooled EGR and a decreased compression ratio were used. In numerical simulation performed using KIVA3-V code, modified to incorporate the Detailed Chemistry Approach the same conditions were reproduced. Special attention is paid on the analysis of the events leading up to the auto-ignition, which was reasonably well predicted.

Recently the analysis of air-fuel mixing and combustion has become important under the stringent emissions regulations of diesel engines. In the case of gasoline engines, the KIVA computer program has been developed and used for the analysis of combustion. In this paper, the calculations of combustion phenomena in DI diesel engines are performed by modifying the KIVA program so as to be applicable to multi-hole nozzles and arbitrary patterns of injection rate. The thermophysical and ther-mochemical properties of gasoline are altered to those diesel fuel. In order to investigate the ability of this modified program, the calculations are compared with the experiments on single cylinder engines concerning the pressure, flame temperature and mass change of chemical species in cylinders. Furthermore, the calculation for the heavy duty DI diesel engine is performed with this diesel combustion program.

Renewable fuels, such as bio- and e-fuels, are of great interest for the defossilization of the transport sector. Among these fuels, methanol represents a promising candidate for emission reduction and efficiency increase due to its very high knock resistance and its production pathway as e-fuel. In general, reliable simulation tools are mandatory for evaluating a specific fuel potential and optimizing combustion systems. In this work, a previously presented methodology (Esposito et al., Energies, 2020) has been refined and applied to a different engine and different fuels. Experimental data measured with a single cylinder engine (SCE) are used to validate RANS 3D-CFD simulations of gaseous engine-out emissions. The RANS 3D-CFD model has been used for operation with a toluene reference fuel (TRF) gasoline surrogate and methanol. Varying operating conditions with exhaust gas recirculation (EGR) and air dilution are considered for the two fuels.

In the last years motorsport is facing a technical revolution concerning the engine technology in every category, from touring car championships up to the F1. The strategy of the car manufacturers to bring motorsport engine technology closer to mass production one (e.g. turbo-charging, downsizing and direct injection) allows both to reduce development costs and to create a better image and technology transfer by linking motorsport activities to the daily business. Under these requirements the so-called Global Race Engine (GRE) concept has been introduced, giving the possibility to use one unique engine platform concept as basis for different engine specifications and racing categories. In order to optimize the performance of this kind of engines, especially due to the highly complex mixture formation mechanisms related to the direct injection, it is nowadays mandatory to resort to reliable 3D-CFD simulations.

This paper presents results of an analytical comparison between two alternative versions of a crankshaft for a 2.2L gasoline engine. The first version had 8 counterweights and a bay balance factor of 80.3%. The second had 4 (larger) counterweights giving a bay balance factor of 56.6% and a crankshaft mass reduction of 1.42 kg. The results presented in this paper relate to the main bearings in terms of specific loads, oil film thickness and shaft tilt angle under full load and no load conditions across the speed range. Torsional vibration analysis and crankshaft stress analysis were also performed but the results are not presented here. The differences in bearing force and oil film thickness were very small and the only major difference in terms of shaft tilt angle occurred at Mains 2 and 4 (increase of ∼ 20% compared with 8 counterweight version).

Today's agri-businessman is challenged to improve his efficiency to meet higher operating costs and to counter the effects of inflation. New concepts in John Deere's line of 4-wheel-drive tractors are targeted toward this goal and provide increased productivity through power increases, improved fuel economy, comfortable convenient operator environment and controls, increased hydraulic power, improved serviceability and repairability and monitoring of more critical vehicle functions.

The growing electrical power demands on bus electrical systems, such as the electric door operator, power steering, braking, air conditioning, windshield wipers, seat heating, and the need to improve emissions and fuel economy, are making current 12/24-volt electrical systems inadequate. For buses to continue to meet growing customer needs, electrical power must be increased. The industry is currently pursuing a 42-volt system as standard. In the U.S., that number (42 volts) was selected by an industry-wide research consortium led by the Massachusetts Institute of Technology. The switch to a 42-volt system would revolutionize the automotive industry. This would enable more electronic components and new technologies to be added to the vehicle. At the present time, the discussion and implementation of the 42-volt system is largely on luxury vehicles. The potential benefit of the system on heavy duty vehicles has not been fully explored.

The automotive industry is transitioning from the present 14V electrical system to a 42V system. This voltage evolution is due to the number of new systems (safety, fuel economy and customer convenience) being developed which require increased electrical power that a 14V system cannot deliver. During this transition, it will be necessary to control 14V subsystems in a 42V architecture. This paper presents 42V PWM (Pulse Width Modulation) voltage conversion and control technologies as a solution to control these 14V subsystems.

Fuel economy and emission reduction assume significant importance for automotive research activities and conversion of many mechanical / hydraulic loads to electrical loads helps in realizing this objective. As a result, many electrical power hungry loads are anticipated to be introduced soon in global market with average power requirement exceeding the practical limit of the present automotive electrical system implying the necessity of a suitable higher voltage system. Many OE and component manufacturers have come to a consensus to choose 42V as the system voltage for future passenger cars considering various aspects. This paper highlights the advantages of the high voltage system together with some of the issues associated with the new system.

Mild hybrid topology with 48V battery packs offers a cost-effective solution with considerable improvement in fuel economy and performance over the conventional vehicles. Thermal management of the battery pack is of utmost importance to ensure a safe, reliable, and optimal operation over the target lifetime and under varying operating conditions. The battery management system needs to take into consideration the temperature of all the cells in the pack for estimating the maximum allowed current for charge/discharge. For example, at lower temperature the coldest cell in the pack would be more probable to lithium plating and hence will be the limiting case while at higher temperature the allowed current should be such that the hottest cell in the pack is taken care. Pack design with temperature sensor for each cell in the pack will increase the cost, hardware, and software complexity.

48V mild hybrid powertrains are promising technologies for cost-effective compliance with future CO2 emissions standards. Current 48V powertrains with integrated belt starter generators (P0) with downsized engines achieve CO2 emissions of 95 g/km in the NEDC. However, to reach 75 g/km, it may be necessary to combine new 48V powertrain architectures with alternative fuels. Therefore, this paper compares CO2 emissions from different 48V powertrain architectures (P0, P1, P2, P3) with different electric power levels under various driving cycles (NEDC, WLTC, and RTS95). A numerical model of a compact class passenger car with a 48V powertrain was created and experimental fuel consumption maps for engines running on different fuels (gasoline, Diesel, E85, CNG) were used to simulate its CO2 emissions. The simulation results were analysed to determine why specific powertrain combinations were more efficient under certain driving conditions.

The tighter exhaust emissions standards introduced by governments for light duty vehicles are challenging car manufactures to meet at the same time legal emission limits and fuel efficiency improvements, still providing excellent fun to drive characteristics. The Hybrid and Diesel propulsion systems are two important players on that competition. In this scenario, the 48 V hybridization has the potential to become a cost-effective solution compared to High Voltage systems, outlining a new way to approach the well-known trade-off between CO2 and NOx in Diesels. Aim of this study has been to investigate the benefits offered by a P0 48 V Hybrid system when coupled with a 1.6 L Diesel engine in a 7-seat multi-purpose vehicle.

Diesel injection equipment is required to be more accurate and higher in pressure to meet the increasingly strict emission, fuel consumption regulations and higher engine performance. It also needs to achieve a number of requirements such as robustness against diversified market fuels, easy installation to engine, etc.

The performance of three way and NOx catalysts was evaluated on vehicles utilizing non-feedback fuel control and electronic feedback fuel control. The vehicles accumulated 80,450 km (50,000 miles) using fuels representing the extremes in hydrogen-carbon ratio available for commercial use. Feedback carburetion compared to non-feedback carburetion improved highway fuel economy by about 0.4 km/l (1 mpg) and reduced deterioration of NOx with mileage accumulation. NOx emissions were higher with the low H/C fuel in the three way catalyst system; feedback reduced the fuel effect on NOx in these cars by improving conversion efficiency with the low H/C fuel. Feedback had no measureable effect on HC and CO catalyst efficiency. Hydrocarbon emissions were lower with the low H/C fuel in all cars. Unleaded gasoline octane improver, MMT, at 0.015g Mn/l (0.06 g/gal) increased tailpipe hydrocarbon emissions by 0.05 g/km (0.08 g/mile).

4 different engine concepts with Catalyst have been developed in regard to pollutant emission, fuel efficiency and performance. Despite the wide power range from 1,2 HP to 12 HP and the different applications of these engines to Mopeds, Chainsaws and Motorcycles, the problems to solve have been similar. Internal measures such as optimized carburetion, cooling, piston shape and clearance, scavenging and tuning of the exhaust must enable the engine to run on the lean side. This is imperative to supply sufficient oxygen for the exothermal reaction and to keep the energy to be converted in the Oxidation Catalyst at a minimum. Secondary measures have been taken to shorten the Catalyst's light-off and to keep the temperature range in limits.

There is a movement to apply emission control in a marine engine as well due to high public awareness of environmental concern in the United States. We started at the development of 3-seater Personal Watercraft (PWC) equipped with 4-stroke engines in taking environment conformity and potential into account. The PWC employed series 4-cylinder 1100cc displacement engine that has been used for mass production motorcycles. The engine was modified to satisfy requirements for PWC, as a marine engine, such as performance function and corrosion. In order to achieve greater or equal power/weight ratio as against two-stroke PWCs, a four-stroke engine for PWC with an exhaust turbo charger was developed. As a result, we succeeded in developing an engine that attained top-level running performance and durability superior to competitors' 2-stroke engines.

Weight reduction and high transmission efficiency demands are getting heavier to manual transmission (MT) for vehicle driving and fuel economy performance. Also comfortable shift feeling and low gear noise level are continuously required by customer because those sensitivity performances are directly recognized by driver which can determine the transmission's merchantability. Newly developed high torque capacity MT is based on serial transmission BG6 which is adopted into a lot of customer' vehicle. This new MT is weight reduced, shift feeling and gear noise performance are highly improved that keeps strong competitiveness in the future. Concerning shift feeling, its smoothness, force balance and cross shift performance are improved and optimized. Also for low gear noise performance, it was reduced to the level which can have advantage to competitor and highly comfortable for passenger vehicle. Those improvement technologies are reported as follows.