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Technical Paper

4 Versus 8 Counterweights for an I4 Gasoline Engine Crankshaft - Analytical Comparison

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).
Journal Article

4 Versus 8 Counterweights for an I4 Gasoline Engine Crankshaft - Measurements of Vibration and Bearing Wear

The authors have published SAE paper 2008-01-0088 on the analytical comparison between 4 and 8 counterweight crankshafts for an I4 gasoline engine. This paper showed that for a particular design of a 4 counterweight crankshaft, the differences in bearing force and oil film thickness were very small and the only major difference in terms of bearing shaft tilt angle occurred at mains 2 and 4 (increase of ∼20% compared with 8 counterweight version). The 4 counterweight crankshaft has a significant mass advantage as it was 1.42kg lighter than the 8 counterweight crankshaft. This new paper addresses the testing performed to validate the analysis results in bearing durability by subjecting the engine to a mixture of high speed and general durability cycles. A comparison was made on the bearing conditions after running a total of 100 hours through prescribed durability cycles on a gasoline engine with both 4 and 8 counterweight crankshafts.
Technical Paper

4-Stroke Multi-Cylinder Gasoline Engine with Controlled Auto-Ignition (CAI) Combustion: a comparison between Naturally Aspirated and Turbocharged Operation

Controlled Auto-Ignition (CAI) also known as Homogeneous Charge Compression Ignition (HCCI) is increasingly seen as a very effective way of lowering both fuel consumption and emissions. Hence, it is regarded as one of the best ways to meet stringent future emissions legislation. It has however, still many problems to overcome, such as limited operating range. This combustion concept was achieved in a production type, 4-cylinder gasoline engine, in two separated tests: naturally aspirated and turbocharged. Very few modifications to the original engine were needed. These consisted basically of a new set of camshafts for the naturally aspirated test and new camshafts plus turbocharger for the test with forced induction. After previous experiments with naturally aspirated CAI operation, it was decided to investigate the capability of turbocharging for extended CAI load and speed range.
Technical Paper

42V Integrated Starter/Alternator Systems

The increasing power demand in vehicles has resulted in a need for a higher onboard generation capacity. With the increasing generation requirement, the torque levels of the generator are found to closely converge with that of the starter motor. Hence, integrating the two machines and using a single machine for the two purposes would be technically viable and economically advantageous. This results in a more compact design solution as well. The Integrated Starter/Alternator (ISA) will be integrated directly to the crankshaft of the Internal Combustion Engine (ICE) and deliver 5 kW average and 12-15 kW peak power at 42V.
Technical Paper

42V Power Control System for Mild Hybrid Vehicle (MHV)

In the 42V Mild Hybrid System introduced into market by Toyota for the first time in the world, the crankshaft using belt(s) drives the motor/generator (MG). The set-up employs an inverter unit to control the MG electronically. This paper describes the system configuration, operations, characteristic features and development results of the new power control system. The focus is on the MG, the inverter-for-MG-control and energy regeneration, as well as DC/DC converter for the power supply to the 14V devices.
Technical Paper

430LNb - A New Ferritic Wire for Automotive Exhaust Applications

The increasing use of ferritic stainless steels (AISI 409, 439, 436 and 441) in automotive exhaust systems, especially for manifolds and catalytic converter canning, has led the authors to develop a new ferritic welding wire, designated 430LNb. This new material is recommended for the GMAW and GTAW processes and provides better metallurgical compatibility with the ferritic base metals, in terms of both thermal expansion and microstructure. The composition of the new welding wire has been adjusted in order to guarantee an entirely ferritic structure in the welds of ferritic sheet materials, together with good resistance of the welds to both wet corrosion and high temperature oxidation, corresponding to the conditions encountered respectively in the colder and hotter parts of the exhaust line. This is achieved by limitation of the C (<0.02%) and N (<0.02%) contents, stabilisation with Nb, such that Nb > 0.05 + 7 (C + N) and Nb < 0.5%, and a Cr content of 17.8-18.8%.
Technical Paper

49 Development of Pb-free Free-Cutting Steel Enabling Omission of Normalizing for Crankshafts

Crankshafts of motorcycles require high strength, high reliability and low manufacturing cost. Recently, a reduction of Pb content in the free-cutting steel, which is harmful substance, is required. In order to satisfy such requirements, we started the development of Pb-free free-cutting steel which simultaneously enabled the omission of the normalizing process. For the omission of normalizing process, we adjusted the content of Carbon, Manganese and Nitrogen of the steel. This developed steel can obtain adequate hardness and fine microstructure by air-cooling after forging. Pb-free free-cutting steel was developed based on Calcium-sulfur free-cutting steel. Pb free-cutting steel is excellent in cutting chips frangibility in lathe process. We thought that it was necessary that cutting chips frangibility of developed steel was equal to Pb free-cutting steel. It was found that cutting chips frangibility depend on a non-metallic inclusion's composition, shape and dispersion.
Technical Paper

5/8 Yard All Hydraulic Hoe

The Harnischfeger hydraulic hoe circuits are designed for fast digging cycles. The circuits have separate pump sections, control valves, cylinders, and motors. There is complete independence of action of all circuits in volume and pressure. The maximum horsepower that can be applied to any circuit is determined by the maximum volume of the pump section and relief setting. Forces that are applied to the structure are controlled by the area of the cylinders, the fixed volume of the motors, and the relief settings. The machine can fill the dipper at full digging depth, hoist to spoil pile height, swing 90deg, dump the load, and return to full depth in 17–22sec. The H312 5/8 yard machine can dig 2cu yd per minute.
Technical Paper

50cc Two-Stroke Engines for Mopeds, Chainsaws and Motorcycles with Catalysts

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.
Technical Paper

54 The Combustion Phenomena Under Corona Discharge Application

In this study, the effect of corona discharge on the combustion phenomenon has been made clear. A homogeneous propane-air mixture was used and six equivalence ratios were tested. For generating the positive and negative corona discharge, a non-uniform electric field was applied to the combustion chamber by the needle to plane gap. One or five needle-shaped electrodes were used to change the corona discharge state. When the positive corona discharge was applied, the luminescence from corona with five electrodes was weak as compared with that of one needle-shaped electrode. When the negative corona discharge was applied, the luminescence from corona and combustion were not affected by the number of electrode. When the positive corona discharge was applied by low voltage, the combustion was improved in the case of one needle-shaped electrode, but the index of combustion with one needle-shaped electrode was almost equal to that of five electrodes when the high voltage was applied.
Technical Paper

56 Development of two-cylinder liquid-cooled utility gasoline engine models with twin balancer shafts

The new small and lightweight 2-cylinder liquid-cooled OHC gasoline engines were developed. These new engines are featuring high output, low vibration and noise radiation and so able to improve the comfortableness and amenity of applied utility machines. In this paper, the features of the new engines and the process to realize development targets are introduced. The basic structure adopted on the new engines is a liquid-cooled, inline 2-cyilinder layout with 360-degree firing intervals, twin balancer shafts, and an overhead camshaft that is driven by a cogged belt. Also various parts made of aluminum alloy and plastics could make the engine lighter. By these measures, the new engines could satisfy their hardest development targets, and realize their easy installation, higher versatility, and have the excellent features such as compact size, lightweight, high output, low exhaust gas emission and low vibration and noise radiation.
Technical Paper

59 The Rotating Cylinder Valve 4-Stroke Engine A Practical Alternative

The Rotating Cylinder Valve (RCV) Engine is a novel 4 cycle engine that is a practical alternative to conventional 2 and 4 stroke designs, in particular for small capacity single cylinder applications. It is primarily intended to address applications where emissions legislation is forcing manufacturers to abandon the traditional carburetted 2 stroke. It has particular benefits for the moped/light motorcycle market. The engine operates on a simple principle. The cylinder liner is rotated around the piston at half engine speed via a pair of bevel gears. A port in the side of this cylinder indexes with inlet and exhaust ports in the surrounding casing. This rotary valve serves the cylinder as the engine cycles through the conventional 4 stroke cycle. The main technical issue that has been addressed is the design of a practical rotary valve seal.
Technical Paper

69 Development of Gear Train Behavioral Analysis Technologies Considering Non-linear Elements

A numerical calculation method, which enables the analysis of gear train behavior including non-linear elements in a motorcycle engine, was established. During the modeling process, it was confirmed that factors such as bearing distortion, radial bearing clearance and elastic deformation of a tooth flank could not be neglected because they effect the rotation behavior. To keep a high accuracy, those factors were included in the simulation model, after they were converted into the rigidity elements along the rotational direction of each gear model. In addition, the model was combined with a crankshaft behavior calculation model for a driving and excitation source. A time domain numerical integration method was used to perform the transient response simulation across a wide range of engine speeds. A jump phenomenon of response behavior of the driven gear was predicted that is a characteristic of non-linear response. The phenomenon was also observed in a physical test.
Technical Paper

7 Experimental Research Concerning the Effect of the Scavenging Passage Length on the Combustion State and Exhaust Gas Composition of a Small Two-stroke Engine

This paper presents the results of experiments conducted with a two-stroke engine that was the world's first such engine to comply with the emissions regulations applied to small off-road engines by the U.S. state of California in 2000. This engine is fitted with a scavenging passage that runs around the crankcase before the scavenging port. The aim of this research was to investigate how changes in the quantity of heat transferred to the fresh air as a result of varying the length of the scavenging passage would affect the state of combustion and exhaust gas composition. An ion probe was fitted to the end zone of the combustion chamber in order to detect the state of combustion. A voltage of 60 V was applied to the ion probe and measurements were made of the voltage drop that occurred due to the presence of high concentrations of ions (H3O+, C3H3+, CHO+, etc.) at the flame front.
Technical Paper

71 Scavenging system layout of a 25 cc two-stroke engine intended for stratified scavenging

A sequentially stratified scavenged engine is characterised by the principle that the cylinder is first scavenged by pure air, followed by the air/fuel mixture. The air is introduced into the upper part of the scavenging ducts through a piston port or a reed valve. To take full advantage of the stratified scavenged principle, the scavenging ducts have to be designed in a way, so that they can accommodate all the air that is delivered into the scavenging ducts. When converting a conventional two-stroke engine into a stratified scavenging engine, it is also important that the tuning and basic scavenging characteristics of the standard engine are not deteriorated. In this paper it is shown how these two aspects can be combined. Together with a theoretical approach for dimensioning the volume and length of the scavenging ducts, it gives a guideline on how to design the basic engine layout, for a stratified scavenged two-stroke engine.
Technical Paper

79 Study on Bearing Lubricity of Two-cycle Engine Oil

Polybutene is generally formulated in two-cycle engine oil in order to prevent smoke and carbon accumulation on exhaust system in motorcycles. The higher content of polybutene in oil is said to be essential to maintain the initial performance of two-cycle engines. However, it is not so known that this polybutene deteriorates the lubricity of bearing. Therefore, we developed a method for evaluating the lubricity of bearing to verify the influence caused by two-cycle engine oils. The test was conducted to measure the temperature of the big end of connecting rod directly while running the engine. The bearing lubricity was evaluated by comparing the temperature of the big end of connecting rod of candidate oils with that of standard oil. A better two-cycle engine oil formulation was able to be led by adding this bearing lubricity test to the JASO(or ISO) standard tests.
Technical Paper

A 0D Phenomenological Model Using Detailed Tabulated Chemistry Methods to Predict Diesel Combustion Heat Release and Pollutant Emissions

In the last two decades, piston engine specifications have deeply evolved. Indeed, new challenges nowadays concern the reduction of pollutant emissions (EURO regulations) and CO2 emissions. To satisfy these new requirements, powertrains have become very complex systems including a large number of high technology components (high pressure injectors, turbocharger, Exhaust Gas Recirculation (EGR) loop, after-treatment devices...). In this context, the engine control plays a major role in the development and the optimization of powertrains. Few years ago, engine control strategies were mainly defined by experiments on engine test benches. This approach is not adapted to the complexity of future engines: on the one hand, tests are too expensive and on the other hand, they do not give much information to understand interactions between components. Today, a promising alternative to tests may be the use of 0D/1D simulation tools.
Technical Paper

A 1,5 KW Electric Power Microcogeneration Unit Suitable for Domestic Applications

The paper discusses the concept, specification and overall performance of a small microcogeneration unit of about 1,5 kW of electric power and about 4,5 kW of thermal power, suitable for domestic applications, designed at Istituto Motori CNR of Italy. This unit has been conceived specifically as a energy conversion system for houses, having in durability, electric and thermal efficiency the most important goals to be achieved. The paper starts by defining the state of art of small power microcogeneration units and then the ratio which leaded to the adoption of a single cylinder internal combustion engine derived from a motorcycle unit, in order to produce the above mentioned electric and thermal power. This is followed by an explanation of the main design characteristics of the system, with a discussion over the modified elements, made to enhance electric efficiency, emissions and durability and reduce, at the same time, cost coming from new design and manufacture.
Technical Paper

A 1-D Simulation Model for Analysis and Optimization of Gearbox Rattle Noise

In the design or match process of vehicle powertrain system, gearbox rattle is a common NVH problem which directly affects passengers’ judgment on the quality and performance of vehicle. During the development process of a passenger car, prototype vehicles have serious gear rattle problem. In order to efficiently and fundamentally control this problem, this work first studied the characteristics and mechanisms of the gearbox rattle. The study results revealed that the torsional vibration of powertrain system was the root cause of gearbox rattle. Then a simulation model of the full vehicle was built with the aid of Simulink® toolbox, which is a graphical extension to MATLAB® for modeling and simulation of variety of systems. With this model, the sensitivity analysis and parametrical optimization were performed, and the simulation results indicated that the dual-mass flywheel (DMF) was the best measure to control the rattle.
Technical Paper

A 1D Real-Time Engine Manifold Gas Dynamics Model Using Orthogonal Collocation Coupled with the Method of Characteristics

In this paper, a new solution method is presented to study the effect of wave propagation in engine manifolds, which includes solving one-dimensional models for compressible flow of air. Velocity, pressure, and density profiles are found by solving a system of non-linear Partial Differential Equations (PDEs) in space and time derived from Euler’s equations. The 1D model includes frictional losses, area change, and heat transfer. The solution is traditionally found by utilizing the Method of Characteristics and applying finite difference solutions to the resulting system of ordinary differential equations (ODEs) over a discretized grid. In this work, orthogonal collocation is used to solve the system of ODEs that is defined along the characteristic curves. Orthogonal polynomials are utilized to approximate velocity, pressure, sound speed, and the characteristic curves along which the system of PDEs reduce to a system of ODEs.