Browse Topic: Valvetrains

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An eleventh one for CUR-1174PC11-CUR-1174 (Current)4/2/2024
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Flight Simulator Engineering and Maintenance Committee
7.0.101 - A New Image De-hazing Method for Safety Critical ADAS ApplicationsSAE-PP-002772/4/2021
Driver safety and Advanced Driver Assistance Systems (ADAS) is gaining lot of importance these days. In some countries, there are strict regulations in place which mandate the use of certain ADAS features in automobiles. However, as the need for these safety critical systems increases, the challenges associated also increase. These challenges can arise due to technology, human factors or due to nature. In countries like India, where one can expect different weather conditions with changing geography, the associated challenges are mainly due to the natural factors like haze, fog, rain and smoke. This poses a challenging problem in terms of visibility for the drivers as well as in vision based ADAS; thereby, leading to many fatal road accidents. In this paper, a novel pre-processing technique, which addresses the interesting problem of enhancing the perceptual visibility of an image that is degraded by atmospheric haze, is proposed. The solution to this problem is presented by combining model (Beer Lambert model) based and non-model based technique of haze removal. The combined hybrid model picks the best haze free image from the series of non-hazy outputs, that are derived based on multiple scattering coefficients of the input hazy image. The idea here is to restore the true color of an image that is affected by the atmospheric haze. In comparison with the state of the art methods that are available in literature, the proposed method is shown to be capable of recovering better haze-free images both in terms of visual perception and quantitative evaluation. The proposed method promises better perceptual understandings and visibility restoration for vision based ADAS under hazy driving conditions.
Lname, Fname
6.0.116 - Development of 6 Years Old Child Virtual Model by Automatic ScalingSAE-PP-002712/4/2021
Traffic accidents cause one of the highest numbers of severe injuries in the whole population. The numbers of deaths or seriously injured citizens prove that traffic accidents and their consequences are still a serious problem to be solved. A lot of effort is devoted to both passive and active safety systems development. The transportation standards usually define safety requirements by regulations (e.g. ECE-R94, 96/79/EC and ECE-R95, 96/27/EC in Europe) with specific dummies for children to be used. The dummies include hardware sensors for monitoring accelerations, loads and other signals and each dummy is developed for a specific scenario, but there are limitations of these dummies, such as only a specific age or calibration just for a specific test. Taking into account that the consequence of a traffic accident is highly influenced by the stature of the body, virtual human body models, including those for children, start to play a significant role because they can be scaled or even personalized towards a particular population or even a particular person. The paper contributes to the field of vehicle safety technology concerning child restraint systems development, assessment and optimization with a virtual numerical approach. The goal of the paper is to exploit the previously developed scaling algorithm to create a virtual model of a six-year-old (6YO) child and to compare its response to the virtual dummy used for child safety in order to propose an automatic scaling process for a population-based vehicle safety assessment. The automatic scaling algorithm developing virtual human body models for a given age and gender is used to create the virtual 6YO child model. The algorithm scales body dimensions and particular segments' mass and the flexibility of the body is driven by flexindex and stiffness scaling. The performance of the automatically developed virtual 6YO child model was tested in frontal and lateral directions. The frontal response was tested with a standard sled test simulation using the standardized AAMA pulse in the frontal direction. The lateral response was tested with a side barrier impact test. The results of both tests were compared to the validated virtual Q6 Child Dummy FE model. The paper shows good performance of the automatic scaling process for developing 6YO virtual model for safety assessment. The automatically developed 6YO child model corresponds well from both the anthropological point of view and performance point of view to the existing validated dummy model.
Mutagaana, Festo
6.0.101 - Piston Sealing System Structure Design for Automobile's Lightweight Auto-TransmissionSAE-PP-002572/4/2021
Current automobile's auto-transmission has problems of defects and cost reduction because of welding process and very complicated assembly process due to individualized transmission piston and sealing components. Also, size and heavy weight of transmission piston components are the source of low mileage because they are made of aluminum, steel material. In this study, therefore, we perform structure design for piston sealing system which integrates piston and sealing material for automobile's lightweight auto-transmission. Also performed stress analysis through finite element analysis to secure required suitable strength when internal pressure is applied after assemble.
Mutagaana, Festo
2.0.101 - Experimental Study of cooling of Continuously Variable Transmission (CVT) in ScooterSAE-PP-002102/1/2021
The continuously variable transmission (CVT), which was conceptualized more than 500 years ago, is just now beginning to replace traditional transmissions in some automobiles. It is mostly used in scooter transmission. Engine power is transmitted to wheel through belt drive between two pulleys. The diameter of belt contact with pulley can change continuously and hence provide infinite gear ratios between driver and driven shafts. This technology leads to a smoother ride of vehicle. Heat is generated inside CVT due to friction between drive belt and clutch pulley. Amount of heat generated is even more due to clutch slippage during acceleration and deceleration. This will affect the service life of CVT components such as front movable drive (FMD), clutch pulley, clutch outer, and belt. In scooters generally, air cooling is preferred over liquid cooling. Cooling is achieved by incorporating centrifugal fan inside CVT housing. For better durability/service life, the degree of heat generated at CVT components should be minimal. The objective of this work is to identify the parameters causing change in temperature of CVT components and to evaluate its surface temperature in accordance with changed parameters. With reference to this, experiments were conducted with requisite design modification inside CVT housing, which enhances cooling effect. Amongst, variables determining air flow rate, are studied and their effect on temperature inside CVT housing is observed experimentally. Keeping the previous variables unaltered, further design modifications related to air flow pattern are done and cumulative effect of all variables is observed. Experiments were performed on an 110cc scooter engine by following customer driving pattern on chassis dynamometer. Results showed that design modifications intended for better cooling effect, has brought down temperature at CVT components. So, desired cooling effect is observed inside CVT housing imparting better service life of CVT components.
Mutagaana, Festo
The Isochoric Engine2020-01-07964/14/2020
For the gasoline engine, the isochoric process is the ideal limit of the ideal processes. During the project, a combustion engine with real isochoric boundary conditions is built. A “resting time” of the piston for several degrees crank angle in the top dead center (TDC) can be realized with a special crank drive. This crank drive consists of two crankshafts with different strokes, which are combined. The two crankshafts rotate with a ratio of two to one in opposite directions. The total stroke corresponds to the amount of the first crankshaft, so it is possible to investigate different strokes of the second crankshaft in the same crankcase. Different “resting times” can be achieved by different strokes of the second crankshaft. A specific combination of both crankshafts make a stroke possible which corresponds to that of a conventional combustion engine. In addition to the standard cylinder pressure sensor, a quick surface temperature probe is also used as supplementary measurement technology. The influence of isochoric combustion is studied with constant air mass and constant lambda at three different strokes of the small crankshaft.
Burger, Benjamin, Bargende, Michael
A Study of Ignition Method for Gas Heat Pump Engine Using Low Temperature Plasma2019-32-06221/24/2020
Low temperature plasma ignition has been proposed as a new ignition technique as it has features of good wear resistance, low energy release and combustion enhancement. In the authors’ previous study, lean burn limit could be extended by low temperature plasma ignition while a voltage drop during discharge, leading to the transition to arc discharge, was found. In this study, the structure of plug and power supply’s performance with steep voltage rising with time, dV/dt, are examined to investigate the effects on combustion performance. As a result, comparing three power sources of conventional, IES and steep dV/dt, steep dV/dt showed small cycle-to-cycle variation and shorter combustion period, leading to higher peak value of the rate of heat release and better indicated thermal efficiency by relatively 6% and 4% compared to CIC and IES, respectively.
Moriyoshi, Yasuo, Matsumoto, Osamu, Kuboyama, Tatsuya, Tsukamoto, Takahiro, Kinuzawa, Yoshiyuki, Maeshima, Hideaki
Study on Oil Consumption in Compact Motorcycle Engines2019-32-05701/24/2020
Because the scooter is convenient, the market continues increasing. As a result of market survey, it was revealed that the scooter repeated sudden acceleration and deceleration. Therefore, the oil consumption may occur in special pattern. The oil consumption is an important development target. On the other hand, the oil consumption is complicated phenomenon. In this study, the sulfur trace method was used for measurement of the oil consumption. When a throttle was closed and the intake pipe became the negative pressure, the SO2 emission (oil consumption) increases. Then, using a glass cylinder and a high-speed camera, motion of the engine oil was observed. It was revealed that the engine oil rises to the combustion chamber after stopping at the 4th Land. By a combination of the sulfur trace test and the visualization test, oil consumption phenomenon of the scooter was able to be understood.
Kohno, Taichi, Suda, Naoyuki, Ninomiya, Yoshinari
Engine Valve Train Dynamic Analysis using 1-D Simulation Approach2019-28-242211/21/2019
In order to reduce engine development timing and cost, a numerical calculation used to evaluate valve train systems. This paper discusses the work done on kinematic and dynamic analysis of Valve Train (VT) system of a diesel engine by using 1-D Ricardo Valdyn software. The goal is to meet optimum intake, exhaust valve timing requirement, maximize, valve open area and 30% over-speed requirement. Valve train model is prepared and inputs like mass and stiffness are estimated from 3-D model and finite element analysis, respectively. Simulation model is used for predicting valve bounce speed, valve displacement, cam-follower contact stress and strain in the rocker arm. Initially, Kinematic analysis is carried out to study the change in valve motion characteristics such as cam contour radius, tappet contact eccentricity etc. Further to this, dynamic analysis is carried out to assess forces and stresses on valve train components. Effect of cam tappet contact stresses, buckling load on push rod, spring surge, ratio of spring force to inertia force, valve seating velocity at increased speed condition etc. are discussed in detail. The optimized cam profile and ramp have improved overall valve dynamics in terms of valve seating velocity and valve seating force. The dynamic vibration described in this paper has been fully validated by measurement.
Nain, Ajay, Nene, Devendra
Possibilities of Wall Heat Transfer Measurements at a Supercharged Euro VI Heavy-Duty Diesel Engine with High EGR-Rates, an In-Cylinder Peak Pressure of 250 Bar and an Injection Pressure up to 2500 Bar2019-24-01719/9/2019
A raise of efficiency is the strongest selling point concerning the total cost of ownership (TCO), especially for commercial vehicles (CV). Accompanied by legislations, with contradictive development demands, satisfying solutions have to be found. The analysis of energy losses in modern engines shows three influencing parameters. Wall heat transfer (WHT) losses are awarded with the highest optimization potential. Critical for the occurrence of these losses is the WHT, which can be described by representing coefficients. To reduce WHT accompanying losses a decrease of energy transfer between combustion gas and combustion chamber wall is necessary. A measurement of heat fluxes is necessary to determine the WHT relations of the combustion chamber in an engine. As this has not been done for a Heavy-Duty (HD) engine, with peak pressures up to 250 bar, an increased in-cylinder turbulence and high exhaust gas recirculation (EGR)-rates before, it is presented in the following. Different methods to determine wall heat flux, as well as data transfer variants for data measured at the piston, are presented and compared. The non-integer system identification method (NISI) and the data transfer with a specially manufactured printed circuit board (PCB) therefore represent explicit novelties for the usage in an internal combustion engine. Finally the application chosen for the measurements to determine heat fluxes is described in greater detail. The assembly method, the positioning of the thermocouples at the engine parts and the considerations behind it are shown as well. The applied evaluation process, including a Fourier transformation and the method for a holistic determination of the WHT relations of a HD engine are presented. [1, 2]
Hennes, Christian, Lehmann, Jürgen, Koch, Thomas
Conceptual Investigations on Full Optical Accessibility to Large-Bore Medium-Speed Engines03-12-03-00205/15/2019
Optically accessible engines are an essential tool to investigate the combustion process in internal combustion engines via optical and laser optical methods. These methods can be applied to analyze the mixing formation, injection, combustion, and emission formation in situ for a better understanding of the combustion process. The derived findings result in new potentials for increased efficiency and reduced emissions. While the application for passenger car- and truck-size engines is quite common, the application of such an optically accessible engine is rather rare for large-bore engines driving ships or power plants due to their huge scale. The following sections show a conceptual design study to make a large-bore dual-fuel (DF) engine with a bore of 350 mm and stroke of 440 mm fully optically accessible according to the Bowditch principle. As the layout was based on an already existing and working engine of the same principle but half the bore, numerical investigations of the critical parts of the presented large-scale fully optical engine were carried out to consolidate the feasibility of the design study. On the other hand, the study emphasizes the extremely high efforts necessary to build a fully optical engine of this size. Two alternatives to the engine design study of the Bowditch fully optically accessible engine are presented with the advantage of reduced design effort. The first alternative uses a special modified con rod limiting the construction effort of the engine, but the possible observable field of view is quite limited. A second alternative mounts a wide-angle optic in the center of the cylinder head to realize the Bowditch typical horizontal view from the top instead of from the bottom. Comparing these conceptual designs, the wide-angle optic mounted in the cylinder head of alternative 2 presents the most promising approach to build a large-scale fully optically accessible engine with relatively low effort, offering maximum field of view and characteristics comparable to a fully optical engine concerning bearable engine load.
Karmann, Stephan Bernhard, Prager, Maximilian, Wachtmeister, Georg
Noise Problem Resolution and Sound Quality Improvement of Valve Timing Belt in 4 Cylinders PFI Gasoline Engine2019-01-07834/2/2019
IC Engine Timing belt is a major noise prone area and it takes time during development to achieve acceptable NVH characteristics. In an existing engine under series production noise problem observed due to excitation of timing belt span by crank timing sprocket tooth. From vehicle perspective noise was heard in vehicle cabin at around idling RPM and a second peak observed around twice the initial RPM. This paper includes a methodology for use of computer based analytical simulation methods to predict timing belt dynamic behavior and NVH characteristics. Along with development of computer based multi body dynamic model for timing belt, validation of simulation model with actual testing was done and after correlation of testing and simulated results countermeasure were finalized based on iterations in multi body simulation model. Multi body dynamics model of timing drive indicated resonance in one belt span when belt transverse vibration amplitude was converted from time domain to frequency domain using FFT. In an existing engine layout change to modify belt span length was not feasible to avoid resonance, other alternatives like reduction of belt natural frequency (by increasing belt mass density, tension reduction etc.) were explored using parametric simulation model. Final solution to avoid belt resonance in engine working RPM range was proposed as reduction of belt natural frequency by modifying the belt tension. Above proposal was checked on engine bench and anechoic vehicle test showed noise reduction of 5 and 11 dB at first and second harmonic respectively due to avoidance of resonance in engine working RPM range. Multi body dynamic simulation model helped to drastically reducing the number of testing trials/combination used to resolve the NVH issue of timing belt.
Poonia, Sanjay, Singh, Amandeep, Singh, Jaspreet, Sharma, Shailender, Kumar, Narinder
Investigation and Optimization of Cam Actuation of an Over-Expanded Atkinson Cycle Spark-Ignited Engine2019-01-02504/2/2019
An over-expanded spark ignited engine was investigated in this work via engine simulation with a design constrained, mechanically actuated Atkinson cycle mechanism. A conventional 4-stroke spark-ignited turbo-charged engine with a compression ratio of 9.2 and peak brake mean effective pressure of 22 bar was selected for the baseline engine. With geometry and design constraints including bore, stroke, compression ratio, clearance volume at top dead center (TDC) firing, and packaging, one over-expanded engine mechanism with over expansion ratio (OER) of 1.5 was designed. Starting with a validated 1D engine simulation model which included calibration of the in-cylinder heat transfer model and SI turbulent combustion model, investigations of the Atkinson engine including cam optimization was studied. The engine simulation study included the effects of offset of piston TDC locations as well as different durations of the 4-strokes due to the mechanism design. Incremental effects of adjusted combustion phasing, scaled valve durations, to a fully optimized cam duration and phasing are determined, and the impacts of each discussed. A constant speed load sweep was conducted to compare the net indicated fuel conversion efficiency difference between baseline and Atkinson cycle engine. Besides, two speed load conditions (1300rpm, 3.3bar IMEPnet and 1750rpm and 10.3bar IMEPnet) with valve timing optimization were also investigated. Results from the study indicate that with an increase in the load from 4bar to 12bar IMEPnet at 2500rpm, over expansion contributed to an increase of 2.3% in net indicated efficiency. Furthermore, with valve optimization, negative work was avoided in the Atkinson cycle engine at 3.3bar IMEPnet, 1300rpm with an increase of 2% in the net indicated fuel conversion efficiency. At 10.3bar IMEPnet and 1750rpm, net indicated fuel conversion efficiency increased by 4.6%.
Yang, Zhuyong, Miganakallu Narasimhamurthy, Niranjan, Miller, Tyler, Naber, Jeffrey
Variable Cam Timing (VCT) Knock Root Cause Analysis and Failure Mode Prevention2019-01-50031/18/2019
Knock in the Camshaft Torque Actuated (CTA) in the Variable Cam Timing (VCT) engine can be a NVH issue and a source of customer complaint. The knock noise usually occurs during hot idle when the VCT phaser is in the locked position and the locking pin is engaged. During a V8 engine development at Ford, the VCT knock noise was observed during hot idle run. In this paper investigation leading to the identification of the root cause through both test and the CAE simulation is presented. The key knock contributors involving torque and its rate of change in addition to the backlash level are discussed. A CAE metric to assess knock occurrence potential for this NVH failure mode is presented. Finally a new design feature in terms of locking pinhole positioning to mitigate or eliminate the knock is discussed.
Moetakef, Mohammad, Paul, Debabrata, Festag, Georg
Piston Detergency and Anti-Wear Performance of Non-Phosphorus and Non-Ash Engine Oil2019-01-00211/15/2019
The deposition of ash derived from engine oil on the surface of diesel particle filters (DPF) has recently been reported to degrade the performance of the DPF. It is generally known that phosphorus in engine oil is adsorbed on the surface of an automotive exhaust catalyst, reducing the performance of the catalyst. Thus, the amounts of ash and phosphorus in engine oil have been decreased. We have developed a non-phosphorus, non-ash engine oil (NPNA) that does not contain metal-based detergents or zinc dialkyldithiophosphate (ZnDTP). Various engine tests were performed, and we confirmed that under normal running conditions, the NPNA oil had a sufficiently high piston detergency and wear resistance-two important requirements for engine oil-to meet current American and Japanese standards. However, the piston detergency of NPNA required further improvement when engine running conditions were more severe. We performed a hot tube test to evaluate the piston detergency of NPNA at high temperatures and developed additives (ashless detergents) that did not contain ash (metallic elements). We then evaluated the piston detergency and valve train wear prevention of the improved NPNA. The tests were performed using two engines: one manufactured by Caterpillar Inc. and regulated by the guidelines of the American Society for Testing and Materials (ASTM) D6750, and one manufactured by Hino Motors, Ltd. and regulated by the Japanese Automotive Standards Organization (JASO) M354:2015. We confirmed that the improved NPNA possessed excellent piston detergency and provided outstanding valve train wear prevention.
Kasai, Moritsugu, Koshima, Hiroaki, Takashima, Yoriyuki
The Rotating Liner Engine (RLE) Diesel Prototype: Preliminary Testing2019-01-00841/15/2019
The Rotating Liner Engine (RLE) concept is a design concept for internal combustion engines, where the cylinder liner rotates at a surface speed of 2-4 m/s in order to assist piston ring lubrication. Specifically, we have evidence from prior art and from our own research that the above rotation has the potential of eliminating the metal-to-metal contact/boundary friction that exists close to the piston reversal areas. This frictional source becomes a significant energy loss, especially in the compression/expansion part of the cycle, when the gas pressure that loads the piston rings and skirts is high. This paper describes the Diesel RLE prototype constructed from a Cummins 4BT and the preliminary observations from initial low load testing. The critical technical challenge, namely the rotating liner face seal, appears to be operating with negligible gas leakage and within the hydrodynamic lubrication regime for the loads tested (peak cylinder pressures of the order of 80 bar).
Dardalis, Dimitrios, Hall, Matthew, Matthews, Ron, Basu, Amiyo, Ozel, Tayyar
A Study of Friction Behavior of a Single Cylinder Gasoline Engine2018-32-007810/30/2018
In order to improve the performance, fuel economy and future emission norms of a reciprocating engine, it is important to reduce the overall engine frictional losses. In this paper, author conducts an experimental study on the friction characteristics due to pumping loss, valve-train system, piston assembly, auxiliaries and transmission for a 110cc, single cylinder 4-stroke gasoline engine using frictional strip-down analysis. This paper deals with the friction performance results for the new concept piston skirt design called the unsymmetrical skirt for least piston skirt friction. Also, parameters like piston profile, oil film thickness optimized for least friction. The piston profile is arrived for optimum contact pattern with least piston slap noise. The modified engine reduced the engine friction by 10% in comparison to the base engine.
Joseph, Sumith, Johnson, Jayajothi, Umate, Mohan D, Vipin, TS
Preparing BMW Motorrad’s Boxer Engine for the Future: Improving Performance, Driveability and Efficiency While Fulfilling Future Emission Standards2018-32-008310/30/2018
Engine development mostly revolves around the same competing goals. With the implementation of the EU4 and EU5 emission standards for motorcycles, the difficulty of increasing performance and improving driveability and efficiency, while simultaneously fulfilling the Emission standards becomes even higher. Though the automotive industry offers a variety of solutions for the named topics, their implementation in a high performance motorcycle engine with specific needs regarding packaging, a wide operating range and full load behavior, represents a special challenge. This paper presents the approach of BMW Motorrad to meet these goals on the example of the boxer engine, focusing on the methodology throughout the development process. The gas exchange system of the engine was optimized using 1D gas dynamic simulations and 3D CFD analysis for a redesign of the valve train, ports and valves. The results of the calculations were further confirmed by experiments at the flow test bench measuring discharge coefficients and using particle image velocimetry (PIV). Combined simulation and engine testing led to a newly developed exhaust manifold enabling a faster light-off and a more stable operating temperature of the catalyst, while reducing raw exhaust emissions through a new injector layout. Engine experiments showed lower emissions, an improved efficiency and a more stable combustion in part load as well as an increased performance at full load. These results translated into lower exhaust emissions and fuel consumption when testing the motorcycle in the world motorcycle harmonized test cycle (WMTC).
Oppelt, Maximilian, Schwarz, Frank, Eibl, Rüdiger, Gaitan, Pedro
Investigation of a Cylinder Activation Concept for a Turbocharged Direct-Injection Gasoline Engine2018-01-17139/10/2018
Today, downsizing through active displacement control is in series production using cylinder deactivation (CDA) concepts. However, current systems deactivating two cylinders of a four-cylinder engine are limited regarding the effective CO2 saving potential due to the confined usable operating range of the two-cylinder mode. Therefore, the objective of the current investigation is a three-cylinder engine with the possibility to activate an additional (fourth) cylinder. For this purpose, a four-cylinder series engine was modified to the firing order of a three-cylinder engine for the first three cylinders. The exterior cylinders 1 and 4 are operated in parallel, with the fourth cylinder deactivated in efficiency mode. Launching and idle mode are also operated with three active cylinders. Additional modifications to the valve train were carried out in order to further exploit the increased residual gas tolerance due to the load point shift. The increased ignition intervals, in conjunction with a very late intake closing timing (Atkinson cycle), improve the boundary conditions with respect to knocking tendency and lead to fuel saving potential even in the higher load range. This extends the map range of the efficiency mode up to full load in three-cylinder operation and therefore doubles the usable range compared to a conventional deactivation concept. The fourth cylinder is activated only when the maximum nominal power is required. In this operating mode, the load of the fourth cylinder can be continuously increased by the use of a fully variable valve train as an activation element. This activation strategy was simulated with a detailed 1d-simulation model. Based on the measurement data, simulation models of the original and the modified engine with a calibrated predictive combustion model have been set up. Using this simulation environment, both concepts were compared in a “virtual test drive” under the same boundary conditions.
Schurr, Anton, Guenthner, Michael, Flierl, Rudolf, Woike, David, Mueller, Florian
Development of a New 1.8L Down-Speeding Turbocharged Gasoline Engine with Miller Cycle2018-01-17129/10/2018
Upcoming China 4th stage of fuel consumption regulation and China 6a emission legislation require improvement of many existing engines. This paper summarizes an upgrade of combustion system and mechanical layout for a four-cylinder engine family. Based on an existing production process for a naturally aspirated 2.0-liter gasoline engine, a 1.8-liter down-speeded and turbocharged gasoline engine is derived. Starting development by analysis of engine base geometry, a layout for a Miller-Cycle gas exchange with early closing of intake valves is chosen. Requirements on turbocharger configuration are investigated with one-dimensional gas exchange simulation and combustion process will be analyzed by means of 3D-CFD simulation. Challenging boundary conditions of a very moderate long-stroke layout with a stroke/bore-ratio of only 1.037 in combination with a cost efficient port fuel injection system and fixed valve lift profiles are considered. To compensate reduced in-cylinder charge motion of small valve lift three measures are taken. Firstly, the intake port is modified for significantly increased tumble motion at higher valve lift. This is combined with a masking of the intake valve area in the combustion chamber and enables a high turbulence even at very small valve lift. Finally, the valve lift profile is optimized by changing cylinder head layout from tappet valve train to roller-finger follower. This has also positive impact on friction behavior. Further reduction of parasitic losses by reduced main bearing diameter, adapted piston ring layout and introduction of an oil pump with two pressure stages accompanies the increase of combustion efficiency. The development targets with almost ninety-two percent of the maximum torque achieved at an engine speed 1250 rpm and a minimum specific fuel consumption of 230 g/kWh are reached, which means maximum thermal efficiency of 36.8% normalizing to caloric value of 42.5 MJ/kg.
Ye, Yisu, Xu, Libing, Wang, Jinshi, Yao, Kefu, Zhao, Mingxiang, Dieterich, Carsten, Souren, Mike, Morcinkowski, Bastian
Power Cylinder Oil Consumption: Transport MechanismsJ2794_201807 (Current)7/27/2018
This document covers oil transport mechanisms from the power cylinder system which might affect oil consumption. It will not discuss in detail the oil consumption mechanisms from other systems or engine components.
Piston and Ring Standards Committee
Experimental Study of Friction Reduction by Reducing Piston Ring Pre-Load2018-28-01017/9/2018
The prime objective of this study is to check the friction reduction by reducing the tangential load of the piston ring. To examine this experimental study has been carried out under motored engine condition from 500 to 4000 engine speed at the step of 500 rpm at different oil temperatures ranging from 40 °C to 120 °C. 15 W40 oil was used for this study. Standard Strip down approach was followed in accessing the Friction. The whole friction measurement was split in crank train and piston group friction and was measured with base and modified piston ring pack. The modified piston ring pack was having 24% less ring tension as compared to base ring pack. The study was carried out using block, crankshaft & Piston of 100 hp, 1.5 litre, 3 cylinder engine with 92 mm stroke and 83 mm bore. In each test ring pack was tested as a part of complete piston assembly. The result shows a maximum benefit of 6.21% & 4.7% in FMEP in piston group and crank train friction respectively at 90 °C oil temperature and 2000 rpm with modified ring pack over the base ring pack. The Friction benefit observed to be higher at lower rpm which slightly decreased at higher rpm. The functionality and durability of the modified piston ring was also checked on the engine in terms of blow by, oil consumption and visual observation after the test. The blow by was observed to be comparable with the exiting ring pack and was well below the specified limit of 70 lpm. The Engine oil consumption with modified ring pack was also observed to be comparable with the existing ring pack and was below the design limit of 22 g/hr. No abnormality observed during durability test and during post test analysis of piston and ring pack.
Alam, Md Tauseef, Kumar PS, Venkatesh, Thakur, Anil, Ghadei, Sataya
Optimization of Oil Separation Unit for Two Stage Turbocharged Engine2018-28-00667/9/2018
In addition to performance target, recent stringent emission legislation and reduction in oil consumption are the major driving force for engine design and development. In this reference importance of crankcase ventilation has increased immensely and the manufacturers are bound to develop most efficient system with high oil trap efficiency. In crankcase ventilation system, the blow-by gases from the crankcase are routed to the intake manifold through Oil separator system. The oil separator task is to retain the oil part from the blow by gas and send it back to sump. Developing an oil separator for the engine studied here was very challenging considering double stage turbocharger which produces very fine mist of oil and is difficult to separate. The study shows that oil mist coming in blow by is of size 0.3 micron and lesser than it. The major contribution of these fine mists was from turbocharger. Keeping this in view, an oil separation unit which is an integral part of cam cover had been optimized for 1.5 litre, 3 cylinder engine with two stage turbo charging. The separation unit consists of two stage separation, pre & fine separation unit. Pre separation unit trap oil of higher size (Oil droplets) while fine unit separates oil mist from blow by. The optimization had done in stages and finally the oil carry over targets of 2 g/hr & 3 g/hr at 100% & 200% blow by had been achieved with optimized separation unit. 200% blow by was taken for worst condition which replicate the life of engine. The final oil carry values were 1.4 g/hr as against 2 g/hr at 100% blow by while it was 2.3 g/hr as against 3 g/hr at 200% blow by. During trial, it was also ensured that other parameter such as crankcase pressure & air intake depression remains within the target value.
Alam, Md Tauseef, Thakur, Anil, Kumar PS, Venkatesh, Ghadei, Sataya
Novel Three-Cylinder Engine Solutions Offering Low Noise Vibration and Harshness for Range-Extender and Hybrid Electric Vehicles2018-01-15536/13/2018
In recent years, automotive manufacturers have introduced an increasing array of in-line three cylinder engine solutions with the objective of providing efficient low CO2 emission power train solutions for small vehicles and in some cases to address down-sizing targets. At the same time, three cylinder engines have seen recent introduction in range-extender and hybrid electric vehicles such as the BMW i8. Unfortunately in-line three cylinder units present serious challenge to engineers in terms of noise, vibration and harshness and this often yields criticism from customer perceptions. The in-line three-cylinder arrangement however does offer an attractive packaging solution for vehicles and an effective method of reducing overall vehicle cost. This paper presents analysis and modelling of a high durability three-cylinder two-stroke cycle engine, which could offer advantages in this competitive and challenging sector for small automotive power plants particularly from a noise, vibration and harshness perspective. The engine uses segregated scavenging to overcome the durability problems of conventional two-stroke cycle engines. Configurations are presented with and without balance shaft and compared with a four stroke engine solution. The novel ability to combine the balance shaft with an integrated rotary valve system controlling gas exchange whilst simultaneously countering the problem of the pitching couple that three cylinder engines traditionally suffer from. Modelling of the benefits of the technology to address NVH issues are presented and discussed.
Hooper, Peter R.
Power Cylinder Friction: MechanismsJ2904_201805 (Historical)5/16/2018
This document covers the mechanisms from the power cylinder which contribute to the mechanical friction of an internal combustion engine. It will not discuss in detail the influence of other engine components or engine driven accessories on friction.
Piston and Ring Standards Committee
1D Engine Simulation Approach for Optimizing Engine and Exhaust Aftertreatment Thermal Management for Passenger Car Diesel Engines by Means of Variable Valve Train (VVT) Applications2018-01-01634/3/2018
Using a holistic 1D engine simulation approach for the modelling of full-transient engine operation, allows analyzing future engine concepts, including its exhaust gas aftertreatment technology, early in the development process. Thus, this approach enables the investigation of both important fields - the thermodynamic engine process and the aftertreatment system, together with their interaction in a single simulation environment. Regarding the aftertreatment system, the kinetic reaction behavior of state-of-the-art and advanced components, such as Diesel Oxidation Catalysts (DOC) or Selective Catalytic Reduction Soot Filters (SCRF), is being modelled. Furthermore, the authors present the use of the 1D engine and exhaust gas aftertreatment model on use cases of variable valve train (VVT) applications on passenger car (PC) diesel engines. The VVT applications consider a wide range of variables such as exhaust cam phasing, late intake valve opening, Miller, 2nd exhaust event and cylinder deactivation. The model has been validated with the results of experimental investigations to do this in a first step. Secondly, the VVT applications are implemented to the model to analyze their heating potential according to an efficient engine and exhaust gas thermal management. Various heating strategies have been investigated for a full-size vehicle within extended engine speed and load ranges which are relevant for the Worldwide Harmonized Light Vehicles Test Cycle (WLTC) and even more for the determination of Real Driving Emissions (RDE). The results are compared to a conventional heating measure to demonstrate the potential in terms of a faster aftertreatment light-off with increased conversion efficiencies and benefits in CO2 emissions. As conclusion out of the investigations it can be seen, that a cylinder deactivation or a second exhaust event could provide up to 5-10% CO2 reduction under RDE conditions that comply with the EU6d legislation limit.
Deppenkemper, Kai, Özyalcin, Can, Ehrly, Markus, Schoenen, Markus, Bergmann, Dirk, Pischinger, Stefan
Technology to Achieve Engine Efficacy: Friction Reduction2018-01-09834/3/2018
The engine efficacies require the blend of friction reduction approach for optimising the attained output. The research elucidates the scope of friction reduction mechanism to increase engine power and life. The engine components piston and piston rings are coated with the unique composite of graphite, molybdenum disulfide, tantalum layer to reduce friction and wear. The coating on piston minimizes direct contact between piston and cylinder liner, which reduces friction, BSFC and lead to better thermal stability, and engine life. The research also focuses on friction reduction of camshaft bearing by replacing sliding contact bearing with low friction roller bearing. The friction between engine components reduces output power, and the engine oil temperature plays a significant role in it. The research empowers zirconium dioxide coating on oil sump in order to reduce the temperature decay rate so that the optimized engine oil temperature of 100 °C can be retained for longer time. The cars because of traffic gets on and off sporadically, where engine oil temperature role become more prominent, as optimised temperature reduces the problems caused by cooler engine oil temperature which is more viscous and absorbs chamber warmup temperature. The absorption of chamber temperature leads to extra combustion affecting BSFC. The variable flow of oil according to engine RPM reduces oil pump friction by and BSFC by significant amount. The use of lightweight ceramic and sheet metal material in valve train reduces FMEP by 38%. The effect of different engine oils grading on friction have been elucidated on the basis of kinematic viscosity and viscosity index.
Singh, Aditya Pratap, Wadhwani, Diwanshu, Sharma, Prashant, Rai, Vivek, Sharma, Vijay
Design and Development of Cooling System for a Formula SAE Race Car2018-01-00794/3/2018
In Formula Student, the vehicle working parameters are quite disparate from that of a commercially designed vehicle. The inability of teams to incorporate the atypical running conditions in their design causes multiple unforeseen issues. One such condition where the teams fail to improvise upon is the cooling system. Due to the high performance requirement of the competition, multiple teams participating face recurring heating problems. Maximum efficiency from a combustion vehicle can only be achieved when the cooling system is designed to handle the increasing power demand. This paper brings forth a detailed study on the intricate design of the cooling system. The problem has been approached using both theoretical and simulation models. Firstly, NTU-ℇ method was used to calculate the overall heat transfer coefficient and the temperature drop through the radiator core. Various parameters like core size, mass flow rate of water and air, fan configurations etc., were taken into consideration. Star CCM+ software was used to perform full body analysis to study the positioning of the radiator on the race car. Following this, the theoretical calculations were validated by performing thermal analysis on the same software. The results obtained from these models were validated experimentally on the vehicle using data acquisition. Temperature sensors placed at inlet and outlet of the radiator were used to record the data. The study not only resulted in designing an efficient cooling system but also laying out a systematic approach for further development.
Bahuguna, Rishabh, Prasad, Tanmay, Khanna, Rishabh, Kumar, Akshyt Bimal, gopal, K Nantha, Srivastava, Sushant, Mishra, Aagosh, B, Ashok
An Innovative Hybrid Powertrain for Small and Medium Boats2018-01-03734/3/2018
Hybridization is a mainstream technology for automobiles, and its application is rapidly expanding in other fields. Marine propulsion is one such field that could benefit from electrification of the powertrain. In particular, for boats to sail in enclosed waterways, such as harbors, channels, lagoons, a pure electric mode would be highly desirable. The main challenge to accomplish hybridization is the additional weight of the electric components, in particular the batteries. The goal of this project is to replace a conventional 4-stroke turbocharged Diesel engine with a hybrid powertrain, without any penalty in terms of weight, overall dimensions, fuel efficiency, and pollutant emissions. This can be achieved by developing a new generation of 2-Stroke Diesel engines, and coupling them to a state-of-the art electric system. For the thermal units, two alternative designs without active valve train are considered: opposed piston and loop scavenged engines. The design of the alternative engines is carried out through CFD simulations. The CFD has been calibrated and validated using experimental data from single-cylinder loop scavenged engine. The study demonstrates that the new Loop scavenged engine with a 23 kWh battery pack and an Opposed Piston design with a 15 kWh battery pack can meet the goals of the project while providing 5% and 10% fuel efficiency improvement at cruise conditions respectively, in comparison to the reference 4-stroke engine.
Mattarelli, Enrico, Rinaldini, Carlo Alberto, Savioli, Tommaso, Warey, Alok, Gopalakrishnan, Venkatesh, Potter, Michael
A Quasi-Dimensional Charge Motion and Turbulence Model for Diesel Engines with a Fully Variable Valve Train2018-01-01654/3/2018
With the increasingly strict emission regulations and economic demands, variable valve trains are gaining in importance in Diesel engines. A valve control strategy has a great impact on the in-cylinder charge motions, turbulence level, thus also on the combustion and emission formation. In order to predict in-cylinder charge motions and turbulence properties for a working process calculation, a zero−/quasi-dimensional flow model is developed for the Diesel engines with a fully variable valve train. For the purpose of better understanding the in-cylinder flow phenomena, detailed 3D CFD simulations of intake and compression strokes are performed at different operating conditions with various piston configurations. In the course of model development, global in-cylinder charge motions are assigned to idealized flow fields. Among them, swirl flow is characterized by an engine swirl number that is determined by both developments of the swirl angular momentum and the moment of inertia. The generation of swirl angular momentum during intake is estimated from the intake mass flow and instantaneous stationary swirl number. The latter is obtained from virtual flow bench simulations in consideration of valve phasing. When modeling swirl losses during compression and expansion, the effects of wall friction, turbulent conversion as well as piston motion are taken into account. Furthermore, a sub-model describing the flows induced by piston motion including axial and squish flows is set up. In conjunction with the charge motion model, a quasi-dimensional turbulence model is developed based on the k-ε turbulence model. Turbulence production rate and dissipation are determined through sub-models. Inflow turbulence is modeled as local shear in the cylinder entrance area. TKE out of axial flows is transferred latish from the axial kinetic energy. Besides, turbulence productions from squish and swirl flows are approximated using idealized flow fields. Dissipation is estimated in a zero-dimensional sub-model by means of a newly developed turbulence length scale, which takes account of all the influences of in-cylinder flow, inflow and back squish flow. The results from the performed validations demonstrate that the proposed flow model accurately predicts the temporal change of in-cylinder flow quantities and also responds correctly to the variations of piston configuration as well as operating conditions such as engine speed, charging pressure and valve actuation. Further application of the model in other Diesel engines is feasible by tuning certain model parameters.
Yang, Qirui, Grill, Michael, Bargende, Michael
Integrated Exhaust Rocker Arm Lost Motion Compression Release Engine Brake with Novel Reset Mechanism for Heavy Duty Diesel Engines2018-01-03814/3/2018
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
Making the Switch from Manual Squeeze Bottles to Benchtop Fluid DispensingTBMG-286824/1/2018
Depositing small, repeatable volumes of fluid in assembly applications spans a diverse range of industries. The ability to deposit precise amounts of material is an ever-increasing necessity for manufacturers, particularly when assembling electronics and medical devices. These fluids must be dispensed reliably, accurately, and with consistent repeatability in dosage and placement. The precise positioning and quantity of the fluids deposited is integral to the assembly, function, quality, appearance, and viability of the final products being manufactured.
An Overview of VCR Technology and Its Effects on a Turbocharged DI Engine Fueled with Ethanol and Gasoline2017-36-035711/7/2017
The possibility to vary compression ratio offers a new degree of freedom that may enable so far not exploited benefits for the combustion process especially for highly boosted spark ignited engines. Numerous approaches to enable a variable compression ratio (VCR) have been tried and tested in the past. Nevertheless, none of these systems reached series production because of several reasons, ranging from too much complexity and moveable parts to deep modification required on existing engine architectures and manufacturing lines. Instead, the approach of a variable length conrod (VCR conrod) could be the solution for integration in almost any type of engine with minor modifications. It is then considered by several OEMs as a promising candidate for midterm series production. This paper shows, firstly, a discussion of the benefits of a variable compression ratio system. Secondly, an overview of the various solutions known to realize VCR is provided, as well as the reason why the approach of a VCR conrod is promising with respect to ease of integration into different engine architectures. Next, various layouts of VCR conrods are presented. Out of these, one concept is comprehensively presented in detail: an eccentrically piston pin suspension in the small eye and the principle of exploiting gas and mass forces for actuation. Examples of application are presented and possible design variants are discussed and outlook is given regarding the possibility to operate the VCR conrod in a fully variable mode by means of fast actuation, smart real-time sensing of the current compression ratio and intelligent control. A modern 3-cylinder turbocharged DI spark-ignited engine was tested with one of the concepts. Preliminary test results pointed to up to 6% higher brake efficiency with RON 95 gasoline, but only at low loads due to knock-limited combustion at high loads. The same engine was tested with ethanol (E100) showing an overall efficiency improvement of 6% over most of load range and a maximum of near 8% at low load.
Wittek, Karsten, Geiger, Frank, Andert, Jakob, Martins, Mario, Oliveira, Maurício
Analyses of Cycle-to-Cycle Variation of Combustion and In-Cylinder Flow in a Port Injection Gasoline Engine Using PIV and PLIF Techniques2017-01-221310/8/2017
Reduction in the cycle-to-cycle variation (CCV) of combustion in internal combustion engines is required to reduce fuel consumption, exhaust emissions, and improve drivability. CCV increases at low load operations and lean/dilute burn conditions. Specifically, the factors that cause CCV of combustion are the cyclic variations of in-cylinder flow, in-cylinder distributions of fuel concentration, temperature and residual gas, and ignition energy. However, it is difficult to measure and analyze these factors in a production engine. This study used an optically accessible single-cylinder engine in which combustion and optical measurements were performed for 45 consecutive cycles. CCVs of the combustion and in-cylinder phenomena were investigated for the same cycle. Using this optically accessible engine, the volume inside the combustion chamber, including the pent-roof region can be observed through a quartz cylinder. CCV of in-cylinder flow for 45 continuous firing cycles were measured by Time-Resolved Particle Image Velocimetry (TR-PIV) technique. The in-cylinder flow was measured at intervals of 2 crank angle degrees from the intake to compression strokes using a dual-cavity, high-frequency Nd:YLF laser. In order to analyze the CCV, the measured instantaneous flow was converted to a time-averaged flow by low-pass filtering to remove the high-frequency component. Moreover, CCVs of fuel distribution at intake valve closing (IVC) and just before ignition timing were obtained by Planar Laser Induced Fluorescence (PLIF) technique. The fourth harmonic generation of a dual-cavity Nd:YAG laser was used as the excitation light source. 3-Pentanone, which was mixed with iso-octane and injected to the intake port, was used as a PLIF tracer. These two visualization techniques were applied simultaneously during the continuous firing cycles. As a result, it was confirmed that the CCVs of in-cylinder flow and fuel distribution significantly affect the CCV of combustion at low-load conditions. In particular, flow in a direction opposite to the tumble flow was observed in the lowest load cycle.
Hokimoto, Satoshi, Kuboyama, Tatsuya, Moriyoshi, Yasuo, Iida, Minoru, Watanabe, Takahiro
Research on Opposed Piston Two-Stroke Engine for Unmanned Aerial Vehicle by Thermodynamic Simulation2017-01-240810/8/2017
The Opposed Piston Two-Stroke (OPTS) engine has many advantages on power density, fuel tolerance, fuel flexibility and package space. A type of self-balanced opposed-piston folded-crank train two-stroke engine for Unmanned Aerial Vehicle (UAV) was studied in this paper. AVL BOOST was used for the thermodynamic simulation. It was a quasi-steady, filling-and-emptying flow analysis -- no intake or exhaust dynamics were simulated. The results were validated against experimental data. The effects of high altitude environment on engine performance have been investigated. Moreover, the matching between the engine and turbocharger was designed and optimized for different altitude levels. The results indicated that, while the altitude is above 6000m, a multi-stage turbocharged engine system need to be considered and optimized for the UAV.
Zhou, Lei, Zhang, Hongxing, Zhao, Zhenfeng, Zhang, Fujun
Development of a Two-Step Variable Valve Actuation Mechanism Equipped with an Electronic Switching System to Realize Switching Performance within One Cycle2017-01-241210/8/2017
This paper introduces a two-step variable valve actuation (VVA) mechanism equipped with an electronic switching system, which can be applied to OHC valve trains with end pivot rocker arms. The electronic switching system is driven by a dedicated solenoid and is not affected by the temperature or pressure of the engine oil. Therefore, not only can the dynamic stability be secured at the time of mode switching but the operation delay time can also be kept short enough. Several models of two-step VVA mechanisms were fabricated and the operability of the mechanism and switching system was experimentally confirmed. The two-step VVA mechanism developed in this study can also be used as a cylinder deactivation (CDA) system by assigning the lift of the low-speed cam to be zero. By attaching a roller to the portion of the rocker arm that is in contact with the base cam, the problem of pad wear, which is often present in CDA mechanism, is also fundamentally solved.
Kim, Dojoong, Lee, Dong Hyeong, Park, Jong Wung, Hwang, Soo Hyun, Jeon, Wan Jae
NVH Performance Improvement of a Turbo-Charged GDI Engine based on the Simulation and Experiment Studies2017-01-242610/8/2017
In recent years, Turbo-charged GDI technology is more and more widely used, which can meet the high demand of the engine performance and efficiency, but the resulting reliability and NVH issues also need to be paid attention to [1]. Traditional NVH performance improvement is mostly based on the experience design and repeatable test, which lead to longer development period, high cost, and also ineffective results. NVH performance simulations play more important role in engine vibration and noise prediction along with the development of the simulation technology[2][3]. The force response analysis is usually used to evaluate the NVH performance of the engine structure under the standard excitation. However, dynamic analysis of the crank train, valve train, and piston can be carried out based on the AVL software family, also the vibration and airborne noise of whole engine can be predicted directly at different speed and load [4]. The NVH performance of a turbo-charged GDI engine was studied based on the simulation and experiment in this paper. Firstly the engine NVH targets including the airborne noise, mount vibration and so on are set up, and the targets are broken down into system and component if possible. Secondly, the mechanism dynamics, engine vibration and noise simulations were carried out, and the weaknesses of the original engine design had been found out. Some appropriate structural improvements to the main parts and new NVH performance prediction were done according to the targets of NVH performance. Then experiment results show that simulation method of radiation noise OA level prediction is basically correct, and a series of structural improvement measures are very effective. Some special problems such as the turbocharger noise were also investigated, and some remarkable effects have been achieved.
Zhang, Zhiming, Wang, Weimin, Wang, Jiangtao, Zhang, Jiming, Chen, Yuanda, Zhang, Wenlong, Yang, Guofang, Fan, Fugui, Zhang, Wenxiang, Huang, Fengqin, Li, Xiangwang
A Comparative Study on Influence of EIVC and LIVC on Fuel Economy of A TGDI Engine Part I: Friction Torques of Intake Cams with Different Profiles and Lifts2017-01-224510/8/2017
In order to better understand how the Atkinson cycle and the Miller cycle influence the fuel consumption at different engine speeds and loads, an investigation was conducted to compare influences of early intake valve closing (EIVC) and late intake valve closing (LIVC) on the fuel consumption of a 1.5L turbo-charged gasoline direct injection (TGDI) engine. The engine was tested with three different intake cams, covering three intake durations: 251 degCA (the base engine), 196 degCA (the Miller engine), and 274 degCA (the Atkinson engine). Compression ratios are 9.5:1 for the base engine and 11.4:1 for the Atkinson and Miller engines, achieved with piston modifications. Results of this investigation will be reported in three papers focusing respectively on characteristics of the engine friction, in-cylinder charge motions for different intake events, and combustion and fuel economy without and with EGR for the naturally aspirated mode and boost mode. The present paper is Part I of this investigation. This study reports the results of detailed analyses as well as experiments on characteristics of the cam dynamics and friction forces for the three different intake cams at engine speeds from 700 to 5700 rpm. It was found that, for the three engines investigated in this study, the maximum motoring friction torque for the Atkinson engine was about 3% greater and the Miller engine was about 3% less than that of the base engine. Differences in the engine friction torques decreased with increasing the engine speed, and became insignificant at 5700rpm.
Ouyang, Xianlin, Teng, Ho, zeng, Xiaochun, Luo, Xuwei, Hu, Tingjun, Huang, Xianlong, Luo, Jiankun, Zhou, Yongli
Piezo Technology in Pneumatic ValvesTBMG-270756/1/2017
Pneumatic valves made with piezo technology offer many advantages. They are small, lightweight, extremely precise, durable, fast, and save energy. Piezo valves do not need energy to maintain a switching status, and therefore generate almost no heat. What's more, piezo valves can potentially be operated without any noise. Another key advantage is that they always work proportionally.
12 Techniques For Better Fluid Dispensing ControlTBMG-268885/1/2017
In any manufacturing environment, including life science manufacturing, it is difficult to evaluate a process that cannot be quantified and measured. But today's precision dispensing technologies provide many ways for medical OEMs to achieve accurate, repeatable, and measureable results.
Ejector Energy-Saving Technology for Mobile Air Conditioning Systems2017-01-01203/28/2017
This study reports on a new generation ECS (Ejector Cycle System) which includes a highly efficient ejector and a novel system configuration. The ejector is working as a fluid jet pump that recovers expansion energy which is wasted in the conventional refrigeration cycle decompression process, and converts the recovered expansion energy into pressure energy and raises the compressor suction pressure. Consequently, the ejector system can reduce power consumption of the compressor by using the above mentioned pressure-rising effect and improve energy efficiency of the refrigeration cycle. The ejector consists of a nozzle, a suction section, a mixing section and a diffuser. The objective of this study is to improve actual fuel economy of all vehicles by ejector technology. The previous generation ECS was reported in 2012 SAE World Congress1. Now, a new generation ECS has been successfully developed and released in the market for Mobile Air Conditioning systems as of 2013. It achieves higher energy efficiency through the development of ARC (Active flow Ratio Control. It means to control the refrigerant flow ratio of the suction flow to the total flow by separating gas-liquid two phase flow), improved design of each ejector part, and improved internal flow distribution inside the evaporator. The ejector is integrated into the tank of evaporator like the previous generation, so there is no impact to vehicle packaging space. Test results demonstrated that the new generation ECS reduced annual power consumption of compressor by 10% compared to previous generation and by 20% compared to conventional expansion valve systems. The new generation ejector technology can significantly improve actual fuel consumption of Mobile Air Conditioning systems and contribute to global greenhouse gas reduction.
Shan, Zhiwei, Kawamoto, Yoichiro, Ogata, Gota
Analysis of Engine Flywheel Wobbling Vibration2017-01-10233/28/2017
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
Understanding Limits to the Mechanical Efficiency of Opposed Piston Engines2017-01-10263/28/2017
A study of the crank and gear-train dynamics of a two-stroke opposed piston diesel engine design uncovered a disconnect between the thermodynamic process and its conversion to mechanical work. The classic two-stroke opposed piston design phases the intake piston to lag the exhaust piston in order to achieve favorable gas exchange, overcoming the disadvantage of piston-controlled ports. One result of this is that significantly more of the engine torque is delivered by the leading crank than from the trailing one. This paper will examine why this torque difference occurs showing that it is not simply a proportioning of the available thermodynamic work but a result of a fundamental mechanical loss mechanism that limits the achievable brake efficiency of this engine architecture. This analysis will provide a basis for developing effective design solutions to overcome the mechanical loss by providing an understanding of this loss mechanism.
Morton, Richard, Riviere, Romain, Geyer, Stephen
Valvetrain Ticking Noise Analysis2017-01-10573/28/2017
Valvetrain ticking noise is one of the key failure modes in noise vibration harshness (NVH) evaluation at idle. It affects customer satisfaction inversely. In this paper, the root cause of the valvetrain ticking noise and key parameters that impact ticking noise will be presented. A physics based math model has been developed and integrated into a parameterized multi-body dynamic model. The analytical prediction has been correlated with testing data. Valvetrain ticking noise control is discussed.
Zeng, Paul, Paul, Debabrata, Solferino, Vincent, Stickler, Mark
Crack Failure Mode Analysis for Cam-Housing Rocker Arm and Pin2017-01-03583/28/2017
During the extensive testing under NATO and Commercial Standards, crack is observed in camshaft housing to initiate from the eccentric shaft bore and go toward the hold down bolt hole. Hence lab test proposal is originated to induce similar failure in a controlled method and then to compare new design alternatives. CAE analysis follows the same set up as the lab test to duplicate failure mode in stress analysis and fatigue analysis with duty cycle loads, and then figures out two strategies on how to improve the design, including geometry change and material change. In geometry wise, four new design iterations are evaluated for comparison. In material wise, one new material for camshaft housing and five manufacturing effect parameters for pin and rocker arm are compared, including ground, machined, machined and decarburization, casting, as well as casting and nitride. With those comparisons, all manufacturing parameters are compared based on effectiveness to affect the fatigue life. Besides design change, manufacturing cost is also prone to be a relatively critical factor. By all means above, the new architecture is decided and successfully validated by the following testing and can meet production criteria as well. The CAE software applied in the analyses are Abaqus for stress analysis and nCode DesignLife for fatigue analysis.
Song, G
DigitalAir™ Camless FVVA System – Part 1, Valve Train Design, Capability and Performance2017-01-06353/28/2017
This paper provides an overview of the analysis and design of the DigitalAir™ camless valve train including the architecture and design of the valve and head; the details of the electric valve actuator, and the flow characteristics of the valves and resulting charge motion in a motoring engine. This valve train is a completely new approach to fully variable valve actuation (FVVA), which allows almost unlimited continuously variable control of intake and exhaust valve timing and duration without the use of a camshaft. This valve train replaces conventional poppet valves with horizontally actuated valves located above the combustion deck. As the valves move, they open and close a number of slots connecting the cylinder with the intake and exhaust ports. The valve stroke necessary to provide the full flow area is approximately 25% of the stroke of the equivalent poppet valve, thus allowing direct electrical actuation with very low power consumption. This design arrangement avoids the risk of poppet valve to piston collision, or the need for cut-outs in the piston crown, since the valves do not open into the cylinder. The results from the analytical models used to predict the performance of the valve train are presented and compared with experimental data (when available). JP SCOPE Inc. has been running engines with this valve train for several years and has successfully completed preliminary performance and durability tests. Part 2 of this paper [1] will present analytical and experimental data which confirms that the proposed FVVA system can meet the basic performance requirements of modern GTDI engines.
Babbitt, Guy, Rogers, Jeff, Weyer, Kristina, Cohen, Drew, Charlton, Stephen
Physically Motivated Model for Efficient Dynamic Simulation of Chain Tensioners with Labyrinth Seals2017-01-10733/28/2017
The object of this study is a new chain tensioner with two labyrinth seals. For the simulation of chain tensioners within the framework of multi-body dynamics, a physically orientated model to describe the fluid dynamics of the labyrinth seals is derived. The easiest way to describe labyrinth seals is to use maps obtained from measurements. As this is very time-consuming, methods of 1D and 2D fluid-mechanics are used in this work to model the labyrinth seals. The seals are characterized by physically motivated parameters e.g. coefficients of resistance or friction. As these parameters can be derived from geometric data, a very good forecast feasibility without experimental investigations is provided. For high accuracy simulations model parameters can be refined by experimental data. As many and highly complex parameters have to be identified, this refinement is very time-consuming and requires lots of experiments. Therefore, a third approach for modeling a labyrinth sealing is derived. Using dimensional analysis the labyrinth can be described by a non-dimensional equation. Only a few coefficients have to be determined by measurements. Hence, the effort for parameter identification as well as the number of necessary experiments is significantly reduced. All three approaches are validated with experimental data. Next, a dynamic model of a complete chain tensioner including labyrinth seals was built up. A comparison between simulation and measured data of the flow characteristics as well as of the dynamic behavior is presented to prove accuracy, benefits and practicability of the presented approach. Furthermore, the influence of fluid inertia in the hydraulic lines is analyzed.
Huber, Robert, Clauberg, Jan
Mass Balancing Measures of a Linkage-Based Extended Expansion Engine2016-32-009611/8/2016
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
Applying Combustion Chamber Surface Temperature to Combustion Control of Motorcycle Engines2016-32-008711/8/2016
Motorcycle usage continues to expand globally. Motorcycles use various fuels in different countries and regions, and it is required that they comply with emissions and fuel consumption regulations as specified in UN-GTR No.2 (WMTC). In general, a motorcycle engine has a large bore diameter and a high compression ratio due to demands of high performance. Poor fuel quality may cause damage to the engine, mainly by knocking. Knock control systems utilizing high-frequency vibration detection strategies like knock sensors, which are equipped on several sport-touring motorcycles, are not used widely for reasons of complex construction and high cost. This research aims to develop a new concept of combustion control for common motorcycle as an alternative. The new combustion control focuses on the effect of engine combustion-chamber surface temperature, because a proportional relationship exists between the combustion chamber surface temperature and the pressure peak within the cylinder, and the combustion chamber temperature shows a sharp increase when knocking occurs. The difference between the combustion chamber surface temperature and the engine reference temperature was used as an indicator of the combustion state, and it was compared with that of an ideal state calculated from the generated torque. The ignition timing is adjusted so that, if the actual temperature is lower than the ideal temperature, the cylinder internal pressure is increased in order to raise the temperature, and if the actual temperature is higher than the ideal temperature, the cylinder internal pressure is reduced in order to lower the temperature. When we applied this control algorithm to actual motorcycles, we obtained results showing its effectiveness in preventing engine damage from knocking and improving transient torque in the transition of acceleration from low-load to high-load.
Ichihashi, Satoshi
Comparison of Different Downsizing Strategies for 2- and 3-Cylinder Engines by the Use of 1D-CFD Simulation2016-32-003711/8/2016
The internal combustion engine is still the most important propulsion system for individual mobility. Especially for the application of motorcycles and recreation vehicles the extraordinary high power density is crucial. Today, these engines are mainly 4-stroke naturally aspirated MPFI engines. The main difference to the automotive sector is the abandonment of all cost intensive technologies, like variable valve timing, intake air charging or gasoline direct injection. The need for further investigations and implementation of new technologies is given due to the very high share of total road transport emissions of motorcycles and the introduction of the emission limits of EURO5 in 2020. One possibility to reach the future emission limits is the downsizing strategy. For this, the potential for emission and fuel consumption reduction is well known. The question remains if this technology is applicable for high revolution engines without any variability in the valve train, an extraordinary high demand on drivability and a low number of cylinders. The research work in this sector tends up to now to a power increase with relative low importance on fuel consumption and emissions. The here presented investigations deal with the possibility of downsizing two- and three-cylinder engines within the power sport application to combine both investigation targets, power respectively torque increase and fuel consumption improvements. Therefore, two different engines with different charging concepts are compared and analyzed regarding stationary and transient behavior. The analysis implies the interaction of the charging concepts with the engines, the impact on power and torque characteristics, influence regarding fuel consumption as well as the effects on the IMEP and torque build-up after a load step. The challenge hereby is the trade-off between the very wide engine speed range, the high demands regarding response and the very unsteady mass flow distribution.
Zinner, Christian, Jandl, Stephan, Schmidt, Stephan
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