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Potential of Electrification Applied to Non-Road Diesel Engines

Kohler Engines-Paolo Fregni, Simone Gaioli
UNIMORE-Enrico Mattarelli, Carlo Alberto Rinaldini, Francesco Scrignoli, Giovanni Franceschini, Davide Barater
  • Technical Paper
  • 2019-24-0202
To be published on 2019-09-09 by SAE International in United States
The new Stage 5 European regulation for Non Road Mobile Machinery has introduced a set of challenging limits on pollutant emissions, for all the categories of internal combustion engines (<19 kW; 19-56 kW; >56kW). The improvement of combustion may not be sufficient to comply with these limits, even for those engines already equipped with modern Common Rail injection systems: as a result, the after-treatment plant is bounded to become much more complex and expensive, both in terms of installation and lifetime management and service. Besides the technical aspects, the new components may have a negative impact also on the perception of customers, used to run their machinery without any particular care in very challenging environments. A viable alternative to the implementation of sophisticated after-treatment systems is to downsize the engine, when possible below the limit of 19 or 56 kW, and provide the extra power for peak demands with an electric motor, installed in place of the flywheel. Thanks to the electric assistance, the engine can skip the more critical conditions for pollutant emissions (high…
 

Investigation and Improvement of a Bouncing Torsional Vibration in Automotive Dual Mass Flywheel by Combining Testing and 1D CAE Modeling Approach

Doshisha University-Nobutaka Tsujiuchi, Akihito Ito
EXEDY Corp.-Yoshihiro Yamakaji, Daisuke Yoshimoto
Published 2019-06-05 by SAE International in United States
Dual mass flywheel (DMF) is a well-known isolation system for vehicle drivetrain. DMF has two typical elastic energy storage systems: long travel arc springs and in-series spring units (including two or more springs) and sliding shoes connected in series. DMF has such complex nonlinear characteristics as torque-dependent torsional stiffness and rotational speed-dependent hysteresis friction due to its dependency of centrifugal force that is applied to components and radial force of springs. Because of this complexity, sub-harmonic vibration (SHV) may occur under certain circumstances, such as under light-load and high-rotational conditions. In general, since SHV’s frequency is 1/2 or 1/3 of the engine’s combustion frequency and may cause human discomfort, DMF must be designed robust against such nonlinear vibration. In this paper to reduce the SHV occurrence and to show a more robust design indicator, the SHV causing the mechanism is researched by testing and 1D CAE modeling. In detail, DMF interior behavior in high-speed rotation is clarified with high-speed cinematography on a test bench, and high-resolution relative torsional angle of DMF is obtained by evaluating…
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Characteristics of Bending Stress with Whirling at the Rear End of a Crankshaft in an Inline 4-Cylinder High Speed Diesel Engine

Isuzu Motors, Ltd.-Shinichiro Kobayashi
Published 2019-06-05 by SAE International in United States
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…
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Design and Modelling of Single Cylinder 4 Stroke Gasoline Engine Crankshaft

CASRAE, Delhi Technological University-Shourya Paul, Devanshu Jain, Rohan Brella, Naveen Kumar
Published 2019-04-02 by SAE International in United States
The crankshaft translates the reciprocatory motion of the piston into rotary motion. A flywheel is generally connected to the crankshaft to reduce the vibrating characteristic of four stroke cycle. Counterweights are added for each reciprocating piston to provide engine balance while operating. Gasoline engines have curtailed compression ratio therefore shorter stoke length as a deduction have higher RPM in comparison to diesel counterpart. A crankshaft is subjected to enormous stresses, potentially equivalent of several tones of force. Failure of the crankshaft is predominantly due to violent vibrations, insufficient lubrication, excessively pressurized cylinder. This research aims to examine the stress subjected to acute points on a crankshaft. Three dimension model of 4 stroke single cylinder engine crankshaft is modeled using SolidWorks v18. End conditions were applied taking into consideration the engine mountings of the crankshaft. Stresses were applied to crankpin to replicate the forces of a running engine. Twisting moment causes Shear stresses; bending moment are determinant of the tensile and compressive stresses. This research was conducted for two different materials Stainless steel and Epoxy carbon…
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Simulation Research on Engine Speed Fluctuation Suppression Based on Engine Torque Observer by Using a Flywheel ISG

Dongfeng Commercial Vehicle-Weiqun Ren
Tsinghua University-Yaodong Hu, Fuyuan Yang, Lei Du, Minggao Ouyang
Published 2019-04-02 by SAE International in United States
This paper conducts simulation research on engine torque ripple suppression based on the engine torque observer by using a flywheel-ISG (integrated starter generator). Usually, engine torque can be suppressed by using a passive method such as by installing a flywheel or torsional damper. However, failure problems arise in hybrid system because of different mechanical characters of the engine and its co-axial ISG motor. On the prototype test bench, the flywheel of the engine has been removed and replaced by an ISG rotor, namely FISG (flywheel ISG). Besides, the crank and FISG rotor are directly connected, which means no dampers or clutches are installed. If the engine torque ripples can be suppressed by the same level as the flywheel and damper by FISG active torque compensation, the new system can be more compact and economical. Simulation efforts are made to verify its feasibility. Firstly, based on the experimental test bench, which is currently under construction. A mechanical model was built based on LMS AMESim. Secondly, the engine torque observer is built based on the simplified dual-lumped…
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Numeric Study on Torsional Characteristics of Dual Mass Flywheel with Circumferential ARC Spring

Tongji University-Lifu Zhang, Guangqiang Wu
Published 2019-04-02 by SAE International in United States
The rapid development of automotive technology has promoted the application of higher efficiency engines, while also putting higher requirements on the control of crankshaft torsional vibration. The traditional clutch driven disc torsional vibration damper can no longer meet the current new vibration and noise reduction requirements. Under these circumstances adopting dual mass flywheel (DMF) could be an efficient measure to reduce powertrain torsional fluctuations.For the sake of studying the torsional characteristics of DMF, a dual mass flywheel with circumstance arc spring (DMF-CS) is taken as the research subject. Firstly, According to lumped mass model, a multi-degree of freedom torsional vibration model of DMF-CS is established, which takes the mutual conversion of dry friction and viscous friction into consideration. Then, the overall and partial torsion characteristics of dual mass flywheel are obtained through numerical analysis. The results show that the DMF-CS exhibits hysteresis nonlinear torsion characteristics because of damping force, its torsional stiffness and damping characteristics are affected by flywheel speed, transmitted torque, amplitude and frequency of the fluctuating torque. Besides, the heat generated by the…
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Sensitivity Analysis and Control Methodology for Linear Engine Alternator

West Virginia University-Mehar Bade, Nigel Clark, Parviz Famouri, PriyaankaDevi Guggilapu, Mahdi Darzi, Derek Johnson
Published 2019-04-02 by SAE International in United States
Linear engine alternator (LEA) design optimization traditionally has been difficult because each independent variable alters the motion with respect to time, and therefore alters the engine and alternator response to other governing variables. An analogy is drawn to a conventional engine with a very light flywheel, where the rotational speed effectively is not constant. However, when springs are used in conjunction with an LEA, the motion becomes more consistent and more sinusoidal with increasing spring stiffness. This avoids some attractive features, such as variable compression ratio HCCI operation, but aids in reducing cycle-to-cycle variation for conventional combustion modes. To understand the cycle-to-cycle variations, we have developed a comprehensive model of an LEA with a 1kW target power in MATLAB®/Simulink, and an LEA corresponding to that model has been operated in the laboratory. This MATLAB®/Simulink numerical model has been used to examine the sensitivity of the LEA dynamics and performance parameters to changes in the design and operating inputs. The sensitivity analysis provides insight into the pathway for improving and optimizing the design, as well as…
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Achieving Carbon Footprint Reduction with Flywheel Technology

  • Magazine Article
  • TBMG-34146
Published 2019-04-01 by Tech Briefs Media Group in United States

Recent technical advances have enabled flywheel energy storage systems (FESS) to become more compact and able to support higher-power applications. Due to their proven reliability, low cost of ownership, and favorable green environmental aspects, engineers and managers of data centers, hospitals, industrial systems, electric rail, and microgrid applications are reaping the benefits of clean energy storage that flywheels offer.

 

Multi-Objective Optimization of Counterweights: A Substitute for the Balance Shaft or Mass Unbalancing in Three-Cylinder Engines

SAE International Journal of Engines

Amirkabir University of Technology, Islamic Republic of Iran-Somaye Mohammadi, Abdolreza Ohadi
IranKhodro Powertrain Company (IPCO), Islamic Republic of Iran-Reza Keshavarz
  • Journal Article
  • 03-11-05-0038
Published 2018-10-18 by SAE International in United States
Three-cylinder engines were launched, given the increasing demand for improved fuel economy and efficiency along with reduced friction and weight. Unlike four-cylinder engines, these engines are not naturally balanced. So, in order to compete with four-cylinder engines, some methods to solve this inherent weakness, such as balance shaft, mass unbalancing of flywheel and crankshaft pulley, or counterweights configuration (angular orientation and correction amount), have been used. Considering the undesirable characteristics of the balance shaft, such as cost, weight, friction, and noise, as well as dynamically inappropriate mass unbalancing method, this research proposes multi-objective optimization of counterweights to reduce vibrations. In this regard, after modeling a three-cylinder engine in constant speed and without the gas force effects, counterweights are optimized by non-dominated sorting genetic algorithm (NSGAII) method, to reduce shaking force, pitch and yaw moments, and bearing loads. Then possibility of removing the balance shaft and mass unbalancing, as the main purpose, with the help of counterweights is shown. Finally, a simple formula aimed at determining counterweights configuration to prevent the implementation of a long-term optimization…
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A Study on Attenuating Gear Teeth Oscillations at Low Engine Speeds Using Nonlinear Vibration Absorbers

Brett Friskney, Ahmed Haris, Mahdi Mohammadpour
Lougborough University-Eliot Motato PhD
Published 2018-06-13 by SAE International in United States
Gear oscillations are one of the most common sources of Noise, Vibration and Harshness (NVH) issues manifested in automotive powertrains. These oscillations are generated mainly due to impacts of the meshing gear teeth over a broad frequency range. To mitigate NVH phenomena, automotive manufacturers traditionally couple linear tuned vibration absorbers to the driveline. Common palliatives used are clutch dampers and dual mass flywheels, which generally suppress vibrations effectively only over narrow frequency bands. Nonlinear Energy Sinks (NESs) are a class of vibration absorbers with essentially nonlinear characteristics that are designed for dissipating vibration energy over broad frequency ranges (due to the employed nonlinearity). The NES does not have a preferential natural frequency; this is rather characterized by the nonlinear stiffness. An NES functions on the principle of transferring energy between the primary system (e.g. driveline) and the absorber in two ways: (i) the NES induces a unidirectional transfer of the vibration energy excess from the primary system to the absorber and (ii) the NES induces a redistribution of the vibration energy excess in the modes…
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