Browse Topic: Crankshafts

Items (325)

In internal combustion engines, the majority of the friction loss associated with the piston takes place on the thrust side in early expansion stroke. Research has shown that the Friction Mean Effective Pressure (FMEP) of the engine can be reduced if proper modifications to the piston skirt, which is traditionally barrel-shaped, are made. In this research, an existing model was applied for the first time to study the effects of different oil supply strategies for the piston assembly. The model is capable of tracking lubricating oil with the consideration of oil film separation from full film to partial film. It is then used to analyze how the optimized piston skirt profile investigated in a previous study reduces friction. It was found that the profile is able to maintain a larger amount of lubricant between the lower part of the piston skirt and the cylinder liner during compression stroke, thereby generating more hydrodynamic pressure, instead of asperity contact pressure, to balance the lateral force from piston pin.

Meng, Zhen, Ahling, Sebastian, Tian, Tian

Nondestructive Measurement of Residual Strain in Connecting Rods Using Neutrons

05-12-03-001810/15/2019

Abstract Increasing the strength of materials is effective in reducing weight and boosting structural part performance, but there are cases where the residual strain generated during the process of manufacturing of high-strength materials results in a decline of durability. It is therefore important to understand how the residual strain in a manufactured component changes due to processing conditions. In the case of a connecting rod, because the strain load on the connecting rod rib sections is high, it is necessary to clearly understand the distribution of strain in the ribs. However, because residual strain is generally measured by using X-ray diffractometers or strain gauges, measurements are limited to the surface layer of the parts. Neutron beams, however, have a higher penetration depth than X-rays, allowing for strain measurement in the bulk material. The research discussed within this article consists of nondestructive residual strain measurements in the interior of connecting rods using the Second Generation Neutron Residual Stress Mapping Facility (NRSF2) at Oak Ridge National Laboratory (ORNL), measuring the Fe (211) diffraction peak position of the ferrite phase. The interior strain distribution of the connecting rod, which was prepared under different manufacturing processes, was revealed. By the visualization of interior strains, clear understandings of differences in various processing conditions were obtained. In addition, it is known that the peak width, which is also obtained during measurement, is suggestive of the size of crystallites in the structure; however, the peak width can additionally be caused by microstresses and material dislocations.

Ikeda, Tomohiro, Jeffery, Bunn R., Fancher, Christopher M., Motani, Ryuta, Matsuda, Hideki, Okayama, Tatsuya

Effect of Injector Cone Angle and NTP on Performance and Emissions of BS6 Engine

2019-28-010810/11/2019

The combustion phenomenon of diesel engines has got a very major impact on the performance and exhaust emission levels. Several important factors like engine components design, combustion chamber design, Exhaust gas recirculation, exhaust after treatments systems, engine operating parameters etc. decide the quality of combustion. The role of fuel injector is crucial on achieving the desired engine performance and emissions. Efficient combustion depends on the quantity of fuel injected, penetration, atomization and optimum timing of injection. The nozzle through flow, cone angle, no of sprays and nozzle tip penetration are the factors which lead to the selection of perfect injector for a given engine. This paper focusses on the selection of the best fit injector suiting the BS6 application on evaluating the performance and emission characteristics. Injectors used were with varying cone angles and NTP. The nozzle tip protrusion of the injectors were varied by changing the sealing washer thickness. With all the above injector configurations, the performance and emission were thoroughly analysed at every level. Final confirmation of the configuration was selected based on the Power & Torque, Fuel consumption, smoke, exhaust temperatures.

Muthusamy, Anbarasu, Shangar Ramani, Vagesh, Sinha, Pranav Kumar

Numbering System for Single Diameter Drills

J2122_201910 (Current)10/9/2019

This SAE Recommended Practice provides a systematic method for the identification of single diameter drills. It is intended to assist in the cataloging and supplying of these tools. NOTE 1— Caution must be taken when assigning codes for designators to prevent specifying drills that cannot be physically or economically manufactured. NOTE 2— In particular without limitation, SAE disclaims all responsibility for the accuracy or completeness of information contained within this report if the standards of this report are retrieved, combined, or used in connection with any software.

Motor Vehicle Council

Ford ‘cranks’ it up with another big V8 for Mustang

19AUTP09_119/1/2019

When Ford introduced the Mustang Shelby GT350 in 2015, it was the pinnacle of Mustang-ness thanks to its 5.2-L DOHC “Voodoo” V8 that featured a flat-plane crankshaft design to enable sky-high revs (the GT350's 8200-rpm redline is one reason Ferrari has long specified flat-plane V8s) and a rollicking 526 hp at 7,500. Then there's the exotic “rip” exhaust note unique to flat-plane V8s. But contemporary musclecar development times seemingly are as quick as their ever-dropping 0-to-60 mph runs-and before Ford released the Shelby GT350, its SAE-certified 526 hp already had been eclipsed by the 707-hp supercharged 6.2-L Hemi V8 in the Dodge Challenger SRT Hellcat and later the 797-hp Hellcat Redeye. Prior to all this, GM's Chevrolet started the hyper-power frenzy by generating 650 hp from the supercharged 6.2-L OHV V8 launched for the 2012 Camaro ZL1.

Visnic, Bill

Characteristics of Bending Stress with Whirling at the Rear End of a Crankshaft in an Inline 4-Cylinder High Speed Diesel Engine

2019-01-15926/5/2019

As engines become lighter and achieve higher output to meet carbon dioxide emissions targets, it becomes more challenging to design a crankshaft that is both lighter and capable of handling higher loads. Therefore, it is necessary to understand the characteristics of forces imposed on the crankshaft, and the mechanisms by which stresses are created in the crankshaft. This paper describes the characteristics of bending stresses measured on the rearmost crank pin fillet of a crankshaft. Two basic crankshaft resonant modes are described. Forward crankshaft whirl then has the effect of increasing the system natural frequencies by the stiffening effect, while reverse whirl reduces the system natural frequencies by the softening effect. The effect of whirl grows with increasing engine speed. This results in what appears to be four crankshaft natural frequencies rather than two. The four resonances appear at all non-zero engine speeds. The influence of flywheel mass on the stresses and natural frequencies is also described. It is shown that the bending stress in the crank fillet is proportional to the radial force acting on the crank pin. It is also shown that the direction of whirl affects the amplitude of stress imposed by the radial crank pin force, and that the effect of whirl becomes larger as the flywheel inertia is increased. Because increasing engine speed causes more whirl force and moment, engine speed has an influence on bending stress amplitude. Finally, the paper explains why the ratio of crank stress amplitude to radial force varies as a function of the rotational direction of whirl.

Kobayashi, Shinichiro

Evaluation and Selection of Turbocharger Meeting BS6 Emission Norms for 1.99l Engine

2019-26-00581/9/2019

Migration to BS6 emission norms from BS4 levels involves strenuous efforts involving advanced technology and higher cost. The challenging part is on achieving the stringent emission norms without compromising the engine fuel economy, performance and NVH factors. Selection of hardware and attaining an optimal behaviour is therefore vital. This article focuses on the evaluation of three different configuration of turbochargers for the same engine to meet the BS6 emission norms and performance. The turbocharger samples used measure the same compressor diameter with varying trim ratios. Simulation and testing of turbochargers ensured positive results for confirmation of the system. Parameters like low speed torque, smoke and compressor efficiency were evaluated and analysed for all configurations. The safe limits of surge and choke regions of all the compressors were also studied and verified. Influence of varying compressor trim on the performance and emissions were examined thoroughly in this work. Full throttle performance and 14 mode test for emissions concluded that the performance and emission parameters were satisfactory with all the turbochargers. However, 4778 Turbocharger gives best Full load performance than other Turbochargers and meeting the 14 mode emission target and it’s finally selected for the engine application.

J, Giftson, Muthusamy, Anbarasu, Shangar Ramani, Vagesh, Bhachchu, Gurtej, R, Sivasubramamanian, Anand, M, K, Arun

Development of Horizontal Water Cooled Diesel Engine to Achieve High Power Density

2018-32-006410/30/2018

The horizontal water cooled diesel engine has a structure including all component parts such as a fuel tank that are necessary to drive engine, and is often a single cylinder engine. It is mounted on many applications such as power tiller and water pump because of high general versatility of installing owing to belt drive. It has a simple structure because of single cylinder, and is active mainly in Southeast Asia. At the same time, the market requires this type of engine higher power while a compact structure is also required from the viewpoint of easy to supply and use. In other words, “High power density” that is improving the output per body size has been required. We have responded to the demand of “High power density” by increasing output without changing the engine size. In order to keep the engine size, we have been enlarging displacement by using our peculiar stroke-up expertise and original bore-up contrivance. In addition to those techniques, we introduced analytic technology for early approach to optimal solution. While we had used deep bowl combustion chamber for emphasizing medium and low speed torque, we adopted shallow dish combustion chamber because we shortened the compression height of piston for stroke-up. We utilized combustion analysis so as to approach optimal solution early because we have no base data of shallow dish combustion chamber. In addition, we used stress analysis to optimize the hardening of crankshaft. As written above, by incorporating analytic technology in addition to conventional development methods, we have been supplying correct size engines speedily in response to requirement of market. In this paper, we introduce the techniques that we adopted in order to realize the high power density.

Komai, Yoshinobu, Takashima, Yusuke, Fujiwara, Tsukasa, Okamoto, Hisao, Kawahara, Minoru

Limitations of Two-Stage Turbocharging at High Flight Altitudes

03-11-05-00349/17/2018

High-altitude long-endurance (HALE) unmanned aerial vehicles (UAVs) are used for high flight altitudes, which enable low drag and fast flight with minimal fuel consumption. Two-stage turbocharging is necessary to sustain sea-level power at high flight altitudes. In this study, the limitations of two-stage turbocharging at high flight altitudes typical for HALE UAVs are analyzed for the first time. The obtained results show that the minimum available engine power increases as the altitude rises. This will limit the ability of the aircraft to descend rapidly. Furthermore, at high altitudes, if a lower operating point is required for a fast descent, further recovery to full power for climbing or cruising could be unavailable. In the latter cases, a lower altitude must be reached before full power would be available again. A basic algorithm for the assessment and analysis of the limitations of UAV engines with two-stage turbochargers operating at high altitudes is suggested.

Fass, Yehuda, Tartakovsky, Leonid

DRIVE – TYPE XV ENGINE ACCESSORY - DESIGN STANDARD FOR

AS20005A (Current)7/16/2018

E-25 General Standards for Aerospace and Propulsion Systems

Comparative Studies of Different VGT Designs on Performance and Smoke of CRDe Engine

2018-28-00747/9/2018

Diesel engines have occupied a significant position in passenger car applications in the present automotive sector. Turbochargers find a very prominent role in diesel engines of all applications in order to achieve desired power and better fuel economy. Gaining higher torque at lower engine speeds with low smoke levels is a very tough task with fixed geometry turbochargers due to availability of lower air mass resulting in higher smoke emissions. Variable geometry turbochargers are capable of providing better torque at lower speeds and reduced smoke emissions on Common Rail Diesel engines. The Variable Geometry Turbocharger types used in this study are straight profile nozzle vanes (sample A) and curved profile nozzle vanes (sample B). The curved profile vanes as seen in sample B results in reduced variation of circumferential pressure distortions. Curved blade profile vane sample results in better low speed torque along with reduced fuel consumption and smoke emissions when compared to straight vane profile sample. Finally 5.5% of improved torque at lower speed was obtained with the equivalence ratio maintaining constant and optimizing the combustion variables ensuring safer smoke limits.

Shangar Ramani, Vagesh, Muthusamy, Anbarasu, Bahl, Sachin, Ramanathan, Hariharan, Halbe, Vasudeo Ganesh

PROPELLER SHAFT END, FLANGED TYPE - NO. 1, 2, 3, 4, 5, & 6

AS127E (Current)5/7/2018

E-25 General Standards for Aerospace and Propulsion Systems

Influence of Miller Cycles on Engine Air Flow

03-11-02-00114/18/2018

The influence of the intake valve lift of two Miller cycles on the in-cylinder flow field inside a DISI engine is studied experimentally since changes of the engine flow field directly affect the turbulent mixing and the combustion process. For the analysis of the impact of the valve timing on the general flow field topology and on the large-scale flow structures, high-speed stereo-scopic particle-image velocimetry measurements are conducted in the tumble plane and the cross-tumble plane. The direct comparison to a standard Otto intake valve lift curve reveals evidently different impacts on the flow field for both Miller cam shafts. A Miller cycle that features late intake valve closing shows a flow field comparable to the standard Otto valve timing and a tumble vortex of strong intensity can be identified. Hence, turbulent mixing is as sufficient as for the standard Otto valve timing, although the Miller cycle intake valve timing leads to a pressure reduction of approximately 20%. In contrast, a Miller cycle with early intake valve closing and reduced valve lift leads to an alteration of the in-cylinder flow field. The kinetic energy inside the cylinder as well as the vorticity decay to almost zero towards the end of combustion. In conjunction with an early dissolving tumble vortex of low intensity, turbulent mixing becomes insufficient for clean, efficient combustion.

Braun, Marco, Klaas, Michael, Schröder, Wolfgang

Review of Exhaust Gas Heat Recovery Mechanism for Internal Combustion Engine Using Thermoelectric Principle

2018-01-13634/3/2018

Automotive power packs have been the focus of research over a long period of time. Among various power packs when we consider internal combustion engines, there is an ample opportunity in developing systems that can make optimal utilization of all the energy streams related to the automotive engine. In this regard utilization of internal combustion engine exhaust waste heat and environmental pollution have been the focus of research in the recent past. About 35% of the automotive input fuel energy is converted to useful crankshaft work and about 30% energy is expelled with exhaust. This leaves about one-third (35%) of the total energy that must be transmitted from the enclosed cylinder through the cylinder walls and head to the surrounding. The exhausted energy from engine results in entropy elevation and solemn environmental pollution. So it is desired to utilize waste heat to the extent possible. The recuperation and utilization of waste heat not only conserves fuel but also additionally reduce the amount of waste heat and greenhouse gases dumped into environment. The objective of this study is to suggest waste heat recovery methods using thermoelectric generator which can be used to power various low energy consumption accessories of an automotive system. Thermo-electric generators are capable of enhancing the thermal efficiency of engines and can utilize the 35% of the exhaust gas stream energy efficiently.

Rathore, Souvik Singh, Singh, Anand, Kumar, Prashant, Alam, Nazish, Sahu, Mithilesh Kumar, R, Sanjay

Divided Exhaust Period Implementation in a Light-Duty Turbocharged Dual-Fuel RCCI Engine for Improved Fuel Economy and Aftertreatment Thermal Management: A Simulation Study

2018-01-02564/3/2018

Although turbocharging can extend the high load limit of low temperature combustion (LTC) strategies such as reactivity controlled compression ignition (RCCI), the low exhaust enthalpy prevalent in these strategies necessitates the use of high exhaust pressures for improving turbocharger efficiency, causing high pumping losses and poor fuel economy. To mitigate these pumping losses, the divided exhaust period (DEP) concept is proposed. In this concept, the exhaust gas is directed to two separate manifolds: the blowdown manifold which is connected to the turbocharger and the scavenging manifold that bypasses the turbocharger. By separately actuating the exhaust valves using variable valve actuation, the exhaust flow is split between two manifolds, thereby reducing the overall engine backpressure and lowering pumping losses. In this paper, results from zero-dimensional and one-dimensional simulations of a multicylinder RCCI light-duty engine equipped with DEP are presented. It is shown that while DEP helped reduce pumping penalty at medium and high loads, the pumping benefit was negated by crankshaft power consumption from a mechanical supercharger which made up for the boost deficit as the low exhaust enthalpy could not be efficiently utilized by a fixed geometry turbocharger (FGT). However, by replacing the FGT with a variable geometry turbocharger (VGT), a 1% improvement in brake-specific fuel consumption (BSFC) over the stock engine configuration was observed at high load, as the VGT allowed more efficient exhaust energy utilization through aspect ratio adjustment. In addition, by closing the blowdown valve at low load, higher exhaust gas temperatures were obtained by bypassing the turbocharger and thereby eliminating exhaust heat losses, which would be useful for aftertreatment thermal management.

Bharath, Anand Nageswaran, Reitz, Rolf, Rutland, Christopher

Integrated Exhaust Rocker Arm Lost Motion Compression Release Engine Brake with Novel Reset Mechanism for Heavy Duty Diesel Engines

2018-01-03814/3/2018

A new compression release engine brake system has been developed which utilizes the well-known lost motion idea along with an entirely new valve resetting mechanism. The engine brake is fully integrated into the exhaust rocker arm, making it highly compact. The novel reset mechanism provides a pressure sensing reset timing which optimizes engine brake performance and valve train stress at all engine speeds. Hydraulic system simulation studies were performed to first verify the concept on paper. Once acceptable performance was predicted, physical prototypes were produced. The Cummins ISL 8.9 L engine was chosen as a proof of concept platform due to its availability and its factory engine brake option. The factory engine brake gives a data set for comparison while validating this new technology. All targets for engine brake function were achieved, and a substantial increase in performance was demonstrated.

Batcheller, Devin, Taylor, Kody

A Prediction Method of Fatigue Strength for Crankshaft Fillet Rolling Process

2017-01-240610/8/2017

This work addresses the problem of fatigue strength prediction of crankshaft fillet rolling processes to improve its accuracy. It is empirical to usually consider the effect of fillet rolling process on crankshaft fatigue performance. The fatigue performance of rolling process is mainly determined by induced compressive residual stresses, increased hardness and reduced roughness. Because the first two factors are difficult to measure the arc surface of fillet rolled cranks, it is difficult to predict the enhanced rate of crankshaft rolled performance to baseline unrolled’s. In this work a prediction method of fatigue strength for ductile cast iron crankshafts rolling process is presented. This method indirectly predicts the effect of the increased hardness on fatigue performance by the resonant bending fatigue test and modelling of crankshaft fillet rolling dynamic for the induced compressive residual stress. The finite element (FE) model for the resonant bending fatigue test rig is validated by the dynamic stresses measured by the strain gauges. The dynamic model of rolling process is solved with an implicit finite element method (FEM) and validated by measurements of rolling displacements. Finally, this method is applied to a 1.5l I4 gasoline engine, in which crankshaft dynamic loads are calculated with Elastohydrodynamic (EHD) simulations.

Yang, Wu, Yin, Xiuting, Zhan, Zhang Song, Shen, Huixian, Qing, Huibin, Zeng, Qingqiang, Kang, Liyun

Study on the Lubrication Performances of Crankshaft Main Bearings in a 16V Marine Diesel Engine

2017-01-242310/8/2017

Ye, Xiaoming, Fu, Yan, Li, Wei, Jiang, Yuze, Zhu, Shixin

Resonance Charging Applied to a Turbo Charged Gasoline Engine for Transient Behavior Enhancement at Low Engine Speed

2017-24-01469/4/2017

Upcoming regulations and new technologies are challenging the internal combustion engine and increasing the pressure on car manufacturers to further reduce powertrain emissions. Indeed, RDE pushes engineering to keep low emissions not only at the bottom left of the engine map, but in the complete range of load and engine speeds. This means for gasoline engines that the strategy used to increase the low end torque and power by moving out of lambda one conditions is no longer sustainable. For instance scavenging, which helps to increase the enthalpy of the turbine at low engine speed cannot be applied and thus leads to a reduction in low-end torque. Similarly, enrichment to keep the exhaust temperature sustainable in the exhaust tract components cannot be applied any more. The proposed study aims to provide a solution to keep the low end torque while maintaining lambda at 1. The tuning of the air intake system helps to improve the volumetric efficiency using resonance charging effects. Actually it is possible to set up the intake line geometry to get high wave amplitude even at low frequency and thus low engine speed. Impact on combustion and mainly on knocking risk has to be taken into account. The system benefits are evaluated directly for steady conditions using simulation and measurement data. As the dynamic behavior is also a main target some transient load measurements are conducted. These tests simulate a strong torque demand while keeping the same engine speed. The last criteria consists of the simulation of vehicle behavior, considering its weight and drag coefficient, and applying the torque demand to the engine on the test bench. The results are the acceleration time for a defined speed range, such as the well-known 80-120km/h.

Raimbault, Vincent, Migaud, Jerome, Chalet, David, Bargende, Michael, Revol, Emmanuel, Montaigne, Quentin

Whirl of Crankshaft Rear End, Part 2: an L4-Cylinder Diesel Engine

2017-01-18116/5/2017

Since the sizes of the flywheel and clutch have been enlarged due to downsizing of diesel engines, the mass and moment of inertia at the crankshaft rear end have increased. Consequently, the serious bending stresses have appeared in the crankshaft rear. This paper describes the characteristics of those serious bending stresses, based on the mechanism for whirl resonance. The whirl resonance is largely impacted by the mass of the flywheel and clutch and by the distance from the crank-journal center of the rear end to the center of gravity of the flywheel and clutch.

Kimura, Jouji, Tanaka, Tatsuya, Hakomoto, Kenjiro, Kawase, Kousuke, Kobayashi, Shinichiro

Whirl of Crankshaft Rear End, Part1: an L6-Cylinder Diesel Engine

2017-01-18106/5/2017

As the issue of global warming has become more serious, needs for downsizing or weight saving of an engine has been getting stronger, and forces exerted on engine parts, especially force on a crankshaft, have been getting larger and larger. In addition, since a crankshaft is a heavy engine part, needs for saving weight have been getting stronger and stronger. Therefore, determining the mechanism of high stress generation in a crankshaft system is urgently needed. This paper describes the characteristics and mechanism of a severe bending stress caused by the whirl of crankshaft rear end of an inline 6-cylinder medium-duty diesel engine. The authors measured bending stress on the fillets of the crankshaft, and found severe levels of sharp peaks in the stress curves for the crankshaft rear. To figure out why the severe levels of sharp peaks appear, they analyzed and studied the measured data. As a result, they have revealed that the crankshaft rear end whirls, and have determined the mechanism of the crankshaft rear end bending resonance characteristic of the shaft whirling motion.

Kobayashi, Shinichiro, Hakomoto, Kenjiro, Kawase, Kousuke, Kidokoro, Makoto, Kimura, Jouji

Study for the Radiated Noise from Engine Depending on Assembly Condition

2017-01-18436/5/2017

This paper presents the influence of radiated noise from engine surface according to assembly condition between the engine block and oil pan. At the first, the force exciting the main bearing of cylinder block is calculated by using a multi-body dynamics model of the engine crankshaft. Secondly, the modal analysis is processed to obtain the mode contribution and modal participation factors for the FEM of a virtual cylinder block. Thirdly, the radiated noise from a structure is calculated by acoustic-FEM analysis. This structure is assembled by the virtual oil pan with a rigid connection method and a soft connection method. The sandwich panel connection model is used for the soft connection method. The sound radiated from this assemble structure is calculated according to two different connection properties respectively. The sound matrices for two results are compared using an objective method. Finally, the influence of the connection condition on the sound quality is investigated for the further research in a sound quality of the sound emitted by a real engine structure in a diesel engine.

Shin, Taejin, Jin, Jaemin, Lee, Sang Kwon, Jung, Insoo

Analysis of Engine Flywheel Wobbling Vibration

2017-01-10233/28/2017

Large axial displacement at the edge of a flywheel causes a clutch to fail to disengage in high-speed rotation. To find out the root cause, a numerical procedure is proposed to investigate the vibration source and to understand dynamic behavior of the crank-train system. A simulation of the whole engine system including block, crankshaft, piston, and connecting rod was performed with AVL/Excite. The resulting CAE baseline model had good correlation with measurements. A comprehensive study was conducted for a set of flywheel and crankshaft models with different materials and unbalanced masses. The contribution to flywheel wobbling of each vibration order was carefully investigated, and an optimal design was presented.

Jiang, Yaqun, Hsieh, C., Festag, Georg, Ahmed, Masood, Jiang, William

Dynamic Misfire Threshold Determination Based On Zone-Level and Buffer-Level Adaptations for Internal Combustion Engines

2017-01-05993/28/2017

Misfire is generally defined as be no or partial combustion during the power stroke of internal combustion engine. Because a misfired engine will dramatically increase the exhaust emission and potentially cause permanent damage to the catalytic converters, California Air Resources Board (CARB), as well as most of other countries’ on-board diagnostic regulations mandates the detection of misfire. Currently almost all the OEMs utilize crankshaft position sensors as the main input to their misfire detection algorithm. The detailed detection approaches vary among different manufacturers. For example, some chooses the crankshaft angular velocity calculated from the raw output of the crankshaft positon sensor as the measurement to distinguish misfires from normal firing events, while others use crankshaft angular acceleration or the associated torque index derived from the crankshaft position sensor readings as the measurement of misfire detection. Regardless which measurement is chosen, an optimized threshold setting that clearly separates misfiring and normal firing cylinder events is desired. Traditionally, the threshold setting is determined during pre-launch calibration process with test data obtained from development vehicles. The threshold for each speed-load zone is typically a fixed value by looking up of a 3D calibration table. Such threshold setting approach, however, faces more and more challenges from the application of new engine technologies, because the crankshaft position sensor outputs could gradually change over the vehicle’s life cycle, and could even change swiftly under stable engine speed and load conditions due to the application of certain new technologies. A fixed misfire threshold setting will yield false detections and result in regulation compliance concerns as well as unsatisfactory of the customers. To address this issue, this article propose a unique approach to dynamically determine the misfire threshold with zone-level adaptation to adjust thresholds for vehicle life-cycle changes and buffer-level adaption to address the needs to quickly adjust misfire thresholds in the same speed-load zone.

Guo, Yichao

Heat Release Calculation of Internal Combustion Engines by Analyzing the Flame Radiation with Crankshaft Angle Resolution

2017-01-07873/28/2017

Improving efficiency and reducing emissions are the principal challenges in developing new generations of internal combustion engines. Different strategies such as downsizing or sophisticated after-treatment of exhaust gases are pursued. Another approach aims at optimizing the parameterization of the engine. Correct adjustments of ignition timings, waste gate position and other factors have significant influence on the combustion process. A multitude of application data is generated during the development process to predefine appropriate settings for most situations. Improvements in regards to the application effort and the quality of the settings can be achieved by measuring the combustion process and optimizing the parametrization in a closed loop. However, cylinder pressure sensors that are used during the development process are too expensive for series applications. This paper focuses on an affordable combustion sensor based on the measurement of the electromagnetic radiation of the combustion flame. The intensity of electromagnetic radiation by chemiluminescence is a good indicator for the status of the combustion as it is primarily dependent on the number of excited molecules. A characteristic spectral band is emitted by the OH radical, which is created in the flame front and corresponds to the number of reactants that are burned. A research engine was equipped with an access for an optical measurement system for chemiluminescence and light emission in general. To achieve sufficient amplification and temporal bandwidth, a special detector circuitry was designed. The measurement data was used to analyze the quality of different light emission signals and to investigate their qualification for heat release calculations.

Von Imhoff, Benedikt, Mühlthaler, Markus, Wachtmeister, Georg

Local Deformation of Hollow Crankshafts under Transient Conditions and their Effect on Durability and Slider Bearing Behavior

2017-01-13313/28/2017

This paper describes a numerical study of the effect of hollow crankshafts on crankshaft local strength and durability as well as slider bearing contact behavior. Crankshaft dynamic simulation for durability is still a challenging task, although numerical methods are already worldwide established and integrated part of nearly every standard engine development process. Such standard methods are based on flexible multi-body dynamic simulation, combined with Finite Element analysis and multi-axial fatigue evaluation. They use different levels of simplification and consider the most influencing phenomena relevant for durability. Lightweight design and downsizing require more and more detailed methods due to higher deformation of the crankshaft. This is especially true for hollow shafts, as present in motorsport design or aerospace applications, but also for standard engine having high potential for significant weight savings. Here the local deformation of shaft cross section under dynamic loads during the transient working cycle cannot be neglected, as currently done by typical standard simulation methods. Those use simplifications on coupling the crankshafts to the engine block structure by the bearing models, especially in how the bearing model is connected to the shaft structure. By that, the cross section is artificially stiffened and load introduction is locally not correct. In presented work, accuracy of elasto-hydrodynamic model in slider bearings is improved by considering fully elastic surface-to-surface contact between hollow pins and connecting rods, as well as journals and engine. The present investigation presents a comparison for a Diesel engine inline 4-cylinder crankshaft to the standard approach and discusses the necessity of using surface-to-surface elasto-hydrodynamic slider bearing model. The main goal of this investigation is the evaluation of durability of the bore regions for hollow crankshafts where the crank pins and/or main journals have mass reduction bores. Focus is set on crankshaft strength in fillets and the mass reduction bores. In addition, the influence of the design/modeling on the slider bearings behavior is evaluated.

Basic, Marko, Resch, Thomas

Effect of Improvements on Crankshaft Pin Grinding and Superfinishing Processes

2017-01-03213/28/2017

This case study describes improvements to the pin grinding and superfinishing processes for a 900-mm long, 60-kg forged crankshaft used in a six-cylinder diesel engine. Machining vibrations caused by the eccentricity of the mass of the pins in relation to the journals increase the difficulty of achieving a stable and capable process. Through analysis of the crankshaft and connecting rod assembly, an opportunity is identified to improve the pin profile along its 30-mm length. Based on measurements, it is found that, owing to variations of the order of 5 μm, the pin profile (nominally flat) may vary between a concave and a convex shape. Process improvements are focused on the grinding profile. The amplitude of the grinding profile is established between 0 and 5 μm, tending toward a convex shape. The practical implementation of the proposed improvements involves the imposition of a greater restriction on the extent of the grinding profile to 3.5 μm. The improvements are based on changes to the following crankshaft manufacturing processes: the steadiness of the journals in semifinish grinding, the dressing frequency and feed rate of the finishing grinding wheel, and the paper grit for superfinishing. The results of this study and the implementation of the suggested improvements should bring benefits to crankshaft manufacturers and customers, reducing the number of product inspections needed and increasing product robustness.

Bastos, Silvio César

Critique of Torsional Vibration Damper (TVD) Design for Powertrain NVH

2017-26-02171/10/2017

Crank train torsional vibration is an important aspect for design and development of Powertrain for NVH refinement and durability. Crank train torsional vibration parameters like angular acceleration of flywheel or twist, depends upon various design parameters like geometry of crankshaft, mass of flywheel, stiffness of clutch, mass of pulley etc. It also depends upon engine operating conditions like engine speed, engine load, combustion peak pressure and combustion pressure variation etc. Most of these parameters are decided by engine power, torque, engine architecture and packaging constraints. Addition of torsional vibration damper (TVD), which works on the principle of tuned dynamic absorber, is commonly deployed design solution to control the torsional vibrations as well as stresses (to improve durability of crank train) induced in crank train assembly at specified modal frequency. This paper is critique study, which emphasizes on importance of accurate tuning of TVD frequency to make it work for NVH & durability improvement rather than deterioration. It also emphasizes whether crank train really need TVD or not. As its principle of working calls for, it needs to be tuned at right frequency to reduce the torsional vibration peak/twist at particular frequency. Any deviation in tuning of TVD frequency will force it to act as additional mass rather than tuned absorber. This will lead to the lowering of torsional frequency of crank train assembly and can shift the crank train assembly mode to critical operating frequency range of engine.

Yadav, Arvind Kumar, Birari, Mayur, Bijwe, Vilas, Billade, Dayanand

Mechanisms for Achieving Non-Sinusoidal Waveforms on Stirling Engines

TBMG-261491/1/2017

The current state-of-the-art Stirling engines use sinusoidal piston and displacer motion to drive the thermodynamic cycle and produce power. Research performed at NASA Glenn has shown that non-sinusoidal waveforms have the potential to increase Stirling engine power density, and could possibly be used to tailor engine performance to the needs of a specific application. However, the state-of-the-art Stirling engine design uses gas springs or planar springs that are very nearly linear, resulting in a system that resonates at a single frequency. This means that imposing non-sinusoidal waveforms, consisting of multiple frequencies, requires large forces from the drive mechanism (either the alternator or the crank shaft). These large forces increase losses, and increase the size and requirements of the control system. This innovation aims to reduce the external forcing requirements by introducing internal mechanical components that provide the forces necessary to achieve the desired waveforms.

A Hybrid Development Process for NVH Optimization and Sound Engineering Considering the Future Pass-by Homologation Demands

2016-32-004311/8/2016

Beside hard facts as performance, emissions and fuel consumption especially the brand specific attributes such as styling and sound are very emotional, unique selling prepositions. To develop these emotional characters, within the given boundary conditions of the future pass-by regulation, it is necessary to define them at the very beginning of the project and to follow a consequent development process. The following paper shows examples of motorcycle NVH development work on noise cleaning and sound engineering using a hybrid development process combining front loading, simulation and testing. One of the discussed solutions is the investigation of a piston pin offset in combination with a crankshaft offset for the reduction of friction. The optimization of piston slap noise as a result of the piston secondary motion was performed by simulation. As another example a simulation based development was performed for the exhaust system layout. A prerequisite for the optimization of the exhaust orifice sound was the definition and artificial generation of the target sound. The challenge for the target sound development was to comply with the future pass-by noise legislations and to feature a distinctive, brand specific sound. A third example in terms of front loading shows the NVH concept design review and evaluation of different cover solutions with a combination of measurement and simulation to avoid disturbing mechanical noise phenomena originating from the engine and gearbox. The outlined examples demonstrate the flexibility and capability of the hybrid development process.

Graf, Bernhard J., Hubmann, Christian, Resch, Markus, Mehrgou, Mehdi

Alternative Engine Speed Sensing Using the Electric Signals of the Alternator

2016-32-008811/8/2016

In the low-cost segment for 2-Wheelers legislative, economic and ecologic considerations necessitate a reduction of the emissions and further improvement in fuel consumption. To reach these targets, the commonly used carburetors are being replaced by engine management systems (EMS). One option to provide these systems for acceptable and attractive system costs is to save a sensor device and to substitute its measure by an estimation value. In many motorcycles the rotor of the vehicle's alternator is rigidly attached to the crankshaft. Therefore, the voltage and current signals of the alternator contain information about the engine's speed, which can be retrieved by evaluating these electric signals. After further processing of this information inside the electronic control unit (ECU), the absolute crankshaft position can be obtained. A high-resolution speed signal without mechanical distortions like tooth errors is gained, whose signal quality equals the one of a common speed sensor. Hence, it can be used for the timing of injection and ignition and for calculations of more elaborate speed based control functions. Because the existing alternator signals are used to determine the speed and no extra installations inside the crankcase are necessary, this method may ease the transition from carburetors to EMS.

Reineke, Bastian, Müller, Jonathan, Grodde, Stefan, Fischer, Wolfgang, Heikes, Henning

Mass Balancing Measures of a Linkage-Based Extended Expansion Engine

2016-32-009611/8/2016

The enhancement of efficiency will play a more and more important role in the development of future (small) internal combustion engines. In recent years, the Atkinson (or Extended Expansion) cycle, realized over the crank drive, attracted increasing attention. Several OEMs have investigated this efficiency-increasing principle in the whole range from small engines up to automotive engines until now. In prior publications, the authors outlined the remarkable efficiency potentials of an Extended Expansion (EE) cycle. However, for an internal combustion engine, a smooth running performance as well as low vibrations and noise emissions are relevant aspects. This is especially true for an Extended Expansion engine realized over the crank drive. Therefore, design measures concerning friction and NVH need to be taken to enable possible series production status. Basically, these measures strongly depend on the reduction of the free mass forces and moments. Hence, the focus of this publication is laid on mass balancing measures of an Extended Expansion engine based on a linkage system. This paper first gives a brief overview of the specific 2-cylinder engine layout of the designed EE prototype engine. The second part deals with the determination of occurring free mass forces and moments. In the following, possible as well as performed mass balancing arrangements are presented and evaluated. Finally, a comparison between the EE prototype engine and other conventional 2-cylinder engines is performed. The determination of free mass forces and moments is based on numerical calculations. They include a kinematic simulation of the crank drive and, derived from that, accelerations of each relevant engine part. The geometry data are determined via CAD and the appropriate masses are calculated according to the corresponding density of the applied materials. In addition, results based on a Fourier transformation are presented, whereas free mass forces and moments are mathematically split into harmonic orders, which are helpful to evaluate balancing measures.

Pertl, Patrick, Lang, Michael, Schmidt, Stephan, Kirchberger, Roland

Development of High-Performance 25 cm ³ Two-Stroke SI Engine for Light Weight Arborist-Chainsaw

2016-32-004911/8/2016

A new air-cooled SI two-stroke gasoline engine has been developed for an arborist-chainsaw. This engine has a displacement of 25 cm3 and generates about 1.1 kW and complies with the latest CARB and EPA exhaust regulations by optimizing scavenging flows and the use of a catalytic converter. Characteristics of lightweight, compact and high power-to-weight ratio are required for handheld chainsaws, especially for arborist chainsaws. As a matter of course, these characteristics are needed for engine itself in order to satisfy such market requirements for hand-held power equipment. To realize lightweight and compact design, the placement of catalytic converter is optimized for the engine and a two-piece crankshaft is adopted. Moreover, as preliminary studies, computer analyses such as CFD simulations of in-cylinder flow and cooling air flow, boundary pressure of piston surface during piston movement were performed to estimate output power, short circuit losses of fuel-air mixture, engine cooling performance and anti-seizure performance. Then, these performances were evaluated and modified by experimental studies. This paper presents overview of the arborist chainsaw, results of the simulation analyses and experimental evaluations.

Eto, Kuniyoshi, Nozawa, Masaru, Nara, Masato, Kobayashi, Buhei, Shibasaki, Daiki, Shirai, Ken

A Study Isolating the Effect of Bore-to-Stroke Ratio on Gasoline Engine Combustion Chamber Development

2016-01-217710/17/2016

A unique single cylinder engine was used to assess engine performance and combustion characteristics at three different strokes, with all other variables held constant. The engine utilized a production four-valve, pentroof cylinder head with an 86mm bore. The stock piston was used, and a variable deck height design allowed three crankshafts with strokes of 86, 98, and 115mm to be tested. The compression ratio was also held constant. The engine was run with a controlled boost-to-backpressure ratio to simulate turbocharged operation, and the valve events were optimized for each operating condition using intake and exhaust cam phasers. EGR rates were swept from zero to twenty percent under low and high speed conditions, at MBT and maximum retard ignition timings. The increased stroke engines demonstrated efficiency gains under all operating conditions, as well as measurably reduced 10-to-90 percent burn durations. The results were quite non-linear, with the majority of the gains achieved in going from the 1:1 to 0.87:1 bore-to-stroke ratio cases. The further change to 0.75:1 showed significantly diminished returns. Flame speed and chamber geometry estimates were used to project further advantages at reduced bore and constant displacement.

Hoag, Kevin L., Mangold, Barrett, Alger, Terrence, Abidin, Zainal, Wray, Christopher, Walls, Mark, Chadwell, Christopher

A New Two Cylinder Diesel Engine Family for Off-road in Naturally Aspirated and Turbocharged Intercooled Versions

2016-01-233510/17/2016

The design and development of a new four-stroke two-cylinder diesel engine family of 1.29 litre capacity for off road are discussed. The engine is in naturally aspirated and turbocharged and intercooled versions and rated from 11.9 kW/1500 rpm to 25.7 kW/2500 rpm. The engines were tuned for air and fuel flows, air utilisation, fuel air mixing, performance and emissions at steady state at a development lab and later certified in national labs. The high altitude capability of the TCIC was checked using a model. The engines rated at less than 19 kW satisfy India Generator set and off road norms of India and Europe equivalent to USTier4 standard, and at higher ratings, standard equivalent to US Tier4-interim. In the second part of the paper, the design of coolant and oil pumps, oil cooler for TCIC engine and the piston with steel oil control ring are discussed. The higher loaded TCIC engines use fillet hardened crankshafts of chromium molybdenum steel. The crankcase integrated with the flywheel housing and the timing case at the front, in conjunction with a cast iron sump makes the engine rigid against torsion and bending in an agricultural tractor. The firing order 0°-360° with the two pistons moving in phase allows lower cyclic irregularity and a light flywheel as well as turbocharging. The resultant primary reciprocating inertia force is neutralized by a counter-rotating balancer shaft and the fluctuations in crankcase pressure are taken care by a valve in the breather to avoid oil carry over.

Lakshminarayanan, P. A., Senthilkumar, P. K.

Study on the Use of Springs in a Dual Free Piston Engine Alternator

2016-01-223310/17/2016

The free piston engine combined with a linear electric alternator has the potential to be a highly efficient converter from fossil fuel energy to electrical power. With only a single major moving part (the translating rod), mechanical friction is reduced compared to conventional crankshaft technology. Instead of crankshaft linkages, the motion of the translator is driven by the force balance between the engine cylinder, alternator, damping losses, and springs. Focusing primarily on mechanical springs, this paper explores the use of springs to increase engine speed and reduce cyclic variability. A numeric model has been constructed in MATLAB®/Simulink to represent the various subsystems, including the engine, alternator, and springs. Within the simulation is a controller that forces the engine to operate at a constant compression ratio by affecting the alternator load. The complex interdependence of the free piston engine alternator is analyzed with respect to parametric changes to the spring stiffness. For a fixed compression ratio, it is shown that an increase in spring stiffness from 50 to 350 kN/m (which practically must be associated with an increase in total moving mass) raises system frequency (18%) and power (12%), but can also lead to a relatively small loss of system efficiency (2%). This is due to the decrease of charging efficiency (EGR increased by 12%) for fixed intake/exhaust conditions and higher frictional losses (4%). The gain in system frequency and power output is diminished according to the increased moving mass associated with stiffer springs. This study also investigates the ability of springs to dampen cyclic variation in response to combustion variation. Normally distributed noise is added to combustion efficiency and duration. Coefficients of variation of compression ratio and peak pressure are used to represent cycle to cycle variation response and compared for varied spring stiffnesses. It is shown that the stiff springs can be used to dampen the effects of combustion stochastics and the resulting variation brought on by cylinder pressure variation. This results in lower controller demand and higher operational sustainability.

Robinson, Matthew C., Clark, Nigel N.

Multi-Body Dynamic Simulation and Fatigue Analysis of the Unique Crank - train for a Creative Two-stoke Opposed Piston Diesel Engine

2016-01-233210/17/2016

For an innovative opposed-piston diesel engine (OPE) with two-stroke operation mode, it attracted even more attentions than ever in some developed countries all around the world, attributed to the unique advantages of higher power density that conducive to downsize IC engine, as well as the potential of further reducing fuel consumption for outstanding thermal efficiency. To achieve fast practical application and ensure the feasibility in concept design stage, the performance characteristic of OPE crankshaft system was investigated, and thus a theoretical analytic model of crankshaft system in an OP2S (Opposed-piston two stroke) engine was established. The effects of all structural design variables on averaged output torque of OPE crankshaft were analyzed, respectively. It was found that the initial crank angle difference between inner crank web and outer crank web was considered as a most critical contributor to boost the averaged torque output than other design variables. The related 3D model of crankshaft was updated automatically on the basis of the optimized results. Eventually a prototype of unique OPE crankshaft was processed and bend fatigue testing was carried out in laboratory. Based on S-N Curve the HCF (High Cycle Fatigue) calculated results showed that the minimum safety factor on crank journal fillet can meet relevant evaluation criterion.

Changming, He, Sichuan, Xu

Prediction of Fretting Fatigue in Engine Cylinder Block

2016-01-03824/5/2016

The reduction of engine weight is today a widely used and effective approach to increasing automotive fuel efficiency . However, the realization of weight savings in the engine can increase deformation of the crankshaft and cylinder block, resulting in fretting fatigue of the contact surfaces of the bearing caps and the cylinder block. Although researchers have identified the mechanism of fretting fatigue on the cylinder block, as yet there is no effective method of addressing the issue in the development stage. The research discussed in this paper applied quality engineering methods to investigate a variety of factors considered to influence fretting fatigue in unit test equipment. The results of the study indicated a good correlation between unit tests and actual engine tests. The paper will also discuss analytic methods for obtaining basic materials data, and methods of prediction of fretting fatigue at an early design stage.

Shi, Chao, Sato, Kenji, Hamakawa, Takeru, Ishihara, Yoshimichi, Takahashi, Shinichi

Design and Optimization of Web Fillets for Commercial Vehicle Crankshaft for Improving SCF and Theoretically Correlated

2016-01-13424/5/2016

Crankshaft is one of the critical components of an engine (5C: cylinder head, connecting rod, crankshaft, camshaft and cylinder block). It is subjected to repetitive and dynamic loads due to cyclic operation of an engine and inertia forces. Due to uneven mass distribution, failure zones occur near fillets and holes in journal locations during operation of the engine. Hence, this topic was chosen because of increasing interest in higher payloads, lower weight, higher efficiency and shorter load cycles in crankshaft equipment. Calculation of Crankshaft strength consists initially in determining the nominal alternating bending and nominal alternating torsional stresses, which multiplied by the appropriate SCF (Stress Concentration Factor), result in an equivalent alternating stress. This equivalent alternating stress is then compared with the fatigue strength of the selected crankshaft material. This comparison will show whether or not the crankshaft concerned is dimensioned adequately. Hence, SCF is main focus point. The present study emphasizes on a CAE based approach for prediction of SCF for crankshaft web fillets. Using FE Solver (Optistruct), the dimensions and shape of the web fillet are optimized for Improving SCF. On the basis of the analysis various design parameters of web fillet are determined and finally the results obtained from FE analysis were theoretically validated.

Kandreegula, Suresh Kumar, Mukherjee, Sayak, Paroche, Sonu, Ayyar, Diwakar, Gupta, Umashanker

Development of a New 2.0L I4 Turbocharged Gasoline Direct Injection Engine

2016-01-10174/5/2016

It is important to take action regarding environmental issues on a global scale, and automakers are adding downsized turbocharged engines to their line-ups as a means of reducing CO2 emissions, particularly in Europe. Honda has recently announced a next-generation powertrain series that realizes a good balance between environmental performance and driving pleasure. As part of this series, the company has developed a downsized and turbocharged 2.0L gasoline direct injection engine. This is a high-powered sports car engine positioned in the European “hot hatch” category. The development balanced engine power with good environmental performance. The new powertrain featured a range of technologies to enable these demands to be satisfied, including a high-tumble port, a dual VTC(Valve Timing Control),variable exhaust valve lift mechanism, a two-piece water jacket for the exhaust manifold, which has been integrated with the cylinder head, a mono-scroll turbocharger, pistons equipped with cooling channels and lightweight crankshaft. The engine realizes a maximum torque of 400Nm and a maximum output of 228kW, while achieving CO2 emissions of 170g/km in the EU fuel economy test cycle (36.6% maximum thermal efficiency) and clearing the Euro 6b standards. This paper will report on the technologies employed in the new powertrain.

Jono, Mitsutaka, Taguchi, Masayuki, Shonohara, Toshimitsu, Narihiro, Shigeru

New Approaches for Reducing Crankshaft Vibrations in a Lightweight and Fuel-Efficient Engine

2016-01-10574/5/2016

To achieve lightweight, low friction and fuel efficient engine, the crankshaft is required to be designed lightweight, small-diameter shaft, long stroke. In this case, vibration of the crankshaft is increased by reduction of shaft stiffness. The conventional way of dealing with this increased vibration used to be to add an inertia mass ring or a double mass damper. Such an approach, however, increases weight, making the balance of weight reduction and vibration reduction less readily achieved. This paper therefore reports on how the main factors causing crankshaft vibration to increase in the shaft with reduced stiffness were clarified. Based on that clarification, efforts were made to reduce crankshaft vibration without increasing the weight of the crankshaft system. Measurement and analysis were used to analyze crankshaft vibration during operation. This showed that the main factors in the increase of vibration in a crankshaft with reduced stiffness are the coupled modes of crankshaft bending and crankshaft damper pulley bending. The relationship between the distribution of eigenvalues in these coupled modes and the stiffness of the crankshaft damper pulley hub was then investigated by carrying out FEM analysis of the crankshaft system. The results showed that when the stiffness of the crankshaft damper pulley hub is increased, the coupled modes are separated, and crankshaft vibration is reduced. Finally, a prototype crankshaft damper pulley hub with increased stiffness was used to conduct verification. The results showed that by changing the shape of the crankshaft damper pulley, the increase in vibration of the reduced-stiffness crankshaft could be recovered by 28% without increasing the weight of the crankshaft system.

Miyazawa, Masaya, Mochizuki, Kei, Takashi, Kondo

Design Optimization of Crankshaft Bearing Based on Crankshaft-Bearing System

2016-01-13884/5/2016

In current design optimization of engine crankshaft bearing, only the crankshaft bearing is considered as the studying object. However, the corresponding relations of major structure dimensions exist between the crankshaft and the crankshaft bearing in engine, and there are the interaction effects between the crankshaft and the crankshaft bearing during the operation of engine. In this paper, the crankshaft-bearing system of a four-cylinder engine is considered as the studying object, the multi-objective design optimization of crankshaft bearing is developed. The crankshaft mass and the total frictional power loss of crankshaft bearings are selected as the objective functions in the design optimization of crankshaft bearing. The Particle Swarm Optimization algorithm is used in the optimization calculation. The optimization results are compared to the ones of original engine design and the single-objective design optimization of crankshaft bearing. The results show that the total frictional power loss of crankshaft bearing and the crankshaft mass are decreased respectively by 26.2% and 5.3% by the multi-objective design optimization of crankshaft bearing, which are more reasonable than the ones of single-objective design optimization in which only the crankshaft bearing is considered as the studying object.

Huang, Baoke, Sun, Jun, Wang, Hu, Zhao, Xiaoyong, Teng, Qin

Directional Mahalanobis Distance and Parameter Sensitivities

2016-01-02894/5/2016

Mahalanobis Distance (MD) is gaining momentum in many fields where classification, statistical pattern recognition, and forecasting are primary focus. It is a multivariate method and considers correlation relationships among parameters for computing generalized distance measure to separate groups or populations. MD is a useful statistic in multivariate analysis to test that an observed random sample is from a multivariate normal distribution. This capability alone enables engineers to determine if an observed sample is an outlier (defect) that falls outside the constructed (good) multivariate normal distribution. In Mahalanobis-Taguchi System (MTS), MD is suitably scaled and used as a measure of severity in abnormality assessment. It is obvious that computed MD depends on values of parameters observed on a random sample. All parameters may not equally impact MD. MD could be highly sensitive with respect to some parameters and less sensitive to some other parameters. Knowledge of parameter sensitivities help develop variation control plan in manufacturing so all produced parts belong to the good normal distribution and the scrap (waste) is eliminated. In this paper, the author has developed a formulation to calculate parameter sensitivities in terms of Eigenvalues and Eigenvectors of the characteristic (A-1) matrix where A is the correlation matrix of parameters. The formulation is further extended to develop Directional Mahalanobis Distance (DMD) where MD is measured in a desired direction to assess goodness of a random sample. This feature of the DMD method enhances discrimination power and has a huge potential for continuous monitoring of patient health or online product quality. Usefulness of this formulation is illustrated with an example.

Chinta, Balakrishna

Balancing Optimization of a Motorcycle Engine Crankshaft for Vibration Reduction

2016-01-10604/5/2016

With ride comfort in a motorcycle gaining significance, it is important to minimize vibration levels at the customer touch points. The reciprocating piston imparts rotary motion to the crankshaft which in turn induces unbalance forces and produces vibration in the vehicle, thus influencing the ride quality. Generally, the primary inertial forces are balanced by a combination of balancer body and crank web. However, being a commuter bike, a balancer body could not be accommodated due to cost and space constraints. In such scenario, the first order unbalance force cannot be completely eliminated but can only be redistributed by adding counterweight to the crankshaft. Proper distribution of these forces is required for optimum vibration levels at motorcycle touch sensitive points (TSP) such as handle bar, footrest etc. In the current study, crankshaft of a single cylinder motorcycle engine is optimized for balancing to reduce vibration at the TSP through multi body dynamics (MBD) and finite element (FE) simulation tools. The complete crank train comprising of piston assembly, connecting rod, bearing, crankpin and crankshafts are modelled with accurate mass and inertia in a commercially available MBD software. Crankshaft balancing factor and the angle of unbalance force are varied by changing different design parameters of the crankshaft such as web radius and width, modification in shape etc. Inertia forces at engine mounting locations due to the first order unbalance of crankshaft are predicted using MBD simulation. These forces are then given as input to full vehicle FE model to predict the vibration response at TSP for the operating speed range of vehicle. Crankshaft design is finalized based on optimal vibration response at TSP.

Ganguly, Arnab, Bhatia, Niket, Agarwal, Vikas Kumar, Mohite, Ulhas

In-Situ Measurement and Numerical Solution of Main Journal Bearing Lubrication in Actual Engine Environment

2016-01-08944/5/2016

A simple method is frequently used to calculate a reciprocating engine’s bearing load from the measured cylinder pressure. However, it has become apparent that engine downsizing and weight reduction cannot be achieved easily if an engine is designed based on the simple method. Because of this, an actual load on a bearing was measured, and the measured load values were compared with a bearing load distribution calculated from cylinder pressure. As a result, it was found that some of actual loads were about half of the calculated ones at certain crank angles. The connecting rod’s elastic deformation was focused on as a factor behind such differences, and the rod’s deformation due to the engine’s explosion load was studied. As a result, it was found that the rod part of the engine’s connecting rod was bent by 0.2 mm and became doglegged. Additional investigation regarding these findings would allow further engine downsizing. In this paper, the authors mainly report that an actual load on a bearing during the engine’s combustion could not be determined by simplified calculation based on the engine’s cylinder pressure, and that it is necessary to take into account a connecting rod’s deformation as well as a piston ring’s friction and a crank shaft’s deformation which were not measured at this time. As a follow up of this report, the authors plan to report minimum oil film thickness and the distribution of oil film thickness with respect to an engine’s individual rotation speed when Elastohydrodynamic Lubrication (EHL) is used.

Matsumoto, Kenji, Harada, Hironori, Ono, Yuki, Mihara, Yuji

Lubrication on Demand: A Novel Polymeric Bearing Coating with Oil-Filled Microcapsules

2016-01-04934/5/2016

Modern High-Speed Diesel (HSD) engines place increasing demands on engine components. Specifically, for connecting rod bearings there is a requirement to endure increased peak cylinder pressures and the resulting loads transmitted through the connecting rods to the crankshaft. In addition to these high loads, the operating environment for bearings is becoming more aggressive. Reductions in oil film thickness combined with the move towards lower viscosity oils means that the seizure and wear resistance of the bearings play a crucial role in modern engine development. In order to attend to these demands, MAHLE has developed a novel high-performance polymer coating containing lubricant-filled microcapsules. The Microcapsules are designed to rupture during nascent scuff and high wear events and consequently release the contained lubricant ‘on demand’. This introduces additional lubrication when required to prevent seizure. A clear tendency for the novel polymer coating to provide improved recovery after scuffing events was measured, allowing for continuing safe operation of the bearings and thus reducing the seizure risk. Testing shows that microcapsules improved the recovery rate after seizure events to 66% whereas conventional polymer overlays show a recovery rate of 25%. As an additional benefit, the microcapsulefilled polymer coatings provide a wear improvement of more than 20% compared to current polymer bearing coatings. Simultaneously, they maintain the exceptional fatigue performance expected of polymer overlay coatings. The present paper reviews the development of the novel polymeric overlay with lubricant-filled microcapsules and details rig test as well as engine test results.

Gorges, Roger, Latham, David, Laing, Ian, Brock, Ronald

Engine Noise Reduction Using Self-Tuning Torsional Vibration Damper

2016-01-10634/5/2016

Nerubenko, George

A Review of Spark-Ignition Engine Air Charge Estimation Methods

2016-01-06204/5/2016

Accurate in-cylinder air charge estimation is important for engine torque determination, controlling air-to-fuel ratio, and ensuring high after-treatment efficiency. Spark ignition (SI) engine technologies like variable valve timing (VVT) and exhaust gas recirculation (EGR) are applied to improve fuel economy and reduce pollutant emissions, but they increase the complexity of air charge estimation. Increased air-path complexity drives the need for cost effective solutions that produce high air mass prediction accuracy while minimizing sensor cost, computational effort, and calibration time. A large number of air charge estimation techniques have been developed using a range of sensors sets combined with empirical and/or physics-based models. This paper provides a technical review of research in this area, focused on SI engines. The purpose is to provide an overview of current SI engine air charge estimation techniques and their performance in key areas such as transient and steady-state accuracy, calibration effort and computational load. Several common air estimation methods are replicated and compared over similar operating conditions. Particular focus is given to methods utilizing mass air flow (MAF) sensors, speed-density algorithms, and observers. Speed density approaches evaluated include those with neural networks and physics-based volumetric efficiency models. Observer methods employing open-loop air charge, high gain input and Extended Kalman Filters (EKF) are also evaluated and compared.

Wang, Zhe, Zhu, Qilun, Prucka, Robert

Development of a High Speed Laser Induced Fluorescence (HSLIF) System in a Single Cylinder Engine for Oil Transport Studies

2016-01-06424/5/2016

Understanding oil transport mechanisms is critical to developing better tools for oil consumption and piston skirt lubrication [1]. Our existing Two-Dimensional Laser Induced Fluorescence (2DLIF) system with an acquisition rate of 1 frame every one or two cycles was proven to be effective to display oil accumulation patterns and their evolution over many cycles in the piston ring pack system [2,3,4]. Yet, the existing system is unable to resolve instantaneous oil flow patterns in the piston-liner interface. In this work, a high-speed LIF system was developed. After a number of iterations the finalized high speed LIF system includes a 23 W, 100 kHz, 532 nm laser and a high speed camera capable of 100,000 FPS at 384 × 264 pixel resolution. After each component was selected, optimization of the quality of images taken from the system began. Each component in the optical system was tested for improvement of image quality; such components include: camera lens, beam expander, beam splitter, and optical filter. A few examples will be shown demonstrating the effectiveness of the system at visualizing oil flow mechanisms inside an IC engine. The first demonstrates the importance of understanding oil flow in the skirt region of the piston while the second focuses on the behavior of oil flow through the ring pack; specifically the Oil Control Ring (OCR) gap. Lubrication phenomena such as separation, cavitation, shearing, etc. can be seen using the high speed LIF system allowing for correlations between piston/ring pack design and oil behavior to be derived. Quantitative results are not currently possible with the current system, but will be researched in the near future. Videos produced by the high speed LIF system are also used to further the development of piston and ring pack lubrication models [5].

Zanghi, Eric, Tian, Tian

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