NVH Performance Improvement Study Using a Dual Mass Flywheel (DMF), Inertia Ring Type Tuned Torsional Vibration Damper (TVD) and Single Mass Flywheel (SMF) in a Front Engine and Rear Wheel Driveline Architecture
Abstract At present, a Dual Mass Flywheel (DMF) system is widely known to provide benefits on driveline induced noise, vibration and drivability over a Single Mass Flywheel (SMF). A well-tuned DMF provides nice isolation of torsional vibrations generated in periodic combustion process of automobile IC engines. Similarly, a torsional vibration damper mounted on driveline component reduces the torsional excitation and results a lower torsional vibration at driveline components. Noise and vibration issues like boom noise and high vibrations at low engine RPM range drive are often resulted due to high engine firing order torsional excitation input to the driveline. More often, this becomes one of the most objectionable noise and vibration issues in vehicle and should be eliminated or reduced for better NVH performance. A 4 cylinder, 4 stroke small diesel engine equipped with SMF is found to have high engine firing order torsional excitation.
Abstract A Flywheel is a rotating mechanical device that evens out the energy fluctuations of an engine and establishes an even crank rotational speed by storing kinetic energy. This paper aims to study the effect of the potential failures on flywheel due to balancing hole position for a proposed grey cast iron material. Any change in its design requires a thorough comprehension of the expected failure modes during operation. For a flywheel, typical failure like crack is very critical for vehicle and occupant safety. Here, CAE test method is adopted for simulating the actual bench tests for design validation of the flywheel. This simulation helps to understand the stresses caused by the structural and thermal loads and recommend design solution which can be readily adopted. The simulation is followed by a rig test where the validation tests are performed for different balancing hole depths. The study revealed that 1. Balancing hole have immense role in crack initiation 2.
Abstract 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.
A New Two Cylinder Diesel Engine Family for Off-road in Naturally Aspirated and Turbocharged Intercooled Versions
Abstract The design and development of a new four-stroke two-cylinder diesel engine family of 1.29 litre capacity for off road are discussed. The engine is in naturally aspirated and turbocharged and intercooled versions and rated from 11.9 kW/1500 rpm to 25.7 kW/2500 rpm. The engines were tuned for air and fuel flows, air utilisation, fuel air mixing, performance and emissions at steady state at a development lab and later certified in national labs. The high altitude capability of the TCIC was checked using a model. The engines rated at less than 19 kW satisfy India Generator set and off road norms of India and Europe equivalent to USTier4 standard, and at higher ratings, standard equivalent to US Tier4-interim. In the second part of the paper, the design of coolant and oil pumps, oil cooler for TCIC engine and the piston with steel oil control ring are discussed. The higher loaded TCIC engines use fillet hardened crankshafts of chromium molybdenum steel.
Abstract There are different types of energy storage devices which are used in today’s hybrid and electric vehicles. Batteries, ultra capacitors and high speed flywheels are the most commonly used ones. While batteries and supercapacitors store energy in the form of electric energy, the flywheel (FW) is the only device that keeps the energy stored in the original form of mechanical energy the same as the moving vehicle. The flywheel needs to be coupled to the driveshaft of the vehicle in a manner which allows it to vary its speed independently of the moving vehicle in order to vary its energy content. In other words a continuously variable transmission (CVT) is needed. The common mechanical variators used in automotive applications, namely the rolling traction drives and the belt drives, have the disadvantage that their speed ratio range defined as the maximum to minimum speed ratio is generally not sufficient for flywheel energy storage system (FESS).
Abstract The term driveability describes the driver's complex subjective perception of the interactions with the vehicle. One of them is associated to longitudinal acceleration aspects. A relevant contribution to the driveability optimization process is, nowadays, realized by means of track tests during which a considerable amount of driveline parameters are tuned in order to obtain a good compromise of longitudinal acceleration response. Unfortunately, this process is carried out at a development stage when a design iteration becomes too expensive. In addition, the actual trend of downsizing and supercharging the engines leads to higher vibrations that are transmitted to the vehicle. A large effort is therefore dedicated to develop, test and implement ignition strategies addressed to minimize the torque irregularities. Such strategies could penalize the engine maximum performance, efficiency and emissions. The introduction of the dual mass flywheel is beneficial to this end.
Abstract This paper investigates the torsional dynamic behaviour of a Dual Mass Flywheel (DMF) both numerically and experimentally. First, the experimental setup is described, followed by a mathematical description in the frequency domain of the mechanical system under test, using a lumped parameter model. An analytical expression for the frequency response function describing the rotational dynamics is derived and compared with experimental data. Sine sweep tests are used to characterise the system, imposing constant amplitude excitation, i.e. the torque applied to the engine side of the DMF. Moreover a method for enhancing the dynamic performance of the electric motor torque control is suggested in order to use it as a torsional shaker.
Abstract Farm trucks, otherwise known as a light truck, is a vehicle used to transport agricultural products from farmers in the farm fields. Originally, farm trucks are assembled by local truck workshops using used parts of cars scrapped from abroad. It causes a serious problem in terms of quality and safety, since conventional truck garages are lack of correct engineering principles in the assembly and there has a potential risk of accidents that may occur during use. This study is focused on enhancement of life quality and safety of farm truck users from different regions in Thailand. One problem encountered in the operation is that a clutch case to cover the flywheel-clutch-module, consisting of the engine flywheel and the clutch, is mostly fabricated without applying engineering understanding. This leads to time-consuming trial and errors manufacturing process and overweight parts.
Abstract In order to improve structure and performance of magneto-rheological dual mass flywheel (MRF-DMF), some parameters effects on dynamic characteristics are acquired by parameters analysis. The dynamic stiffness and loss angle in different current and different frequency are gained through dynamic characteristic test. The fluid-structure interaction finite element model of MRF-DMF is built and the accuracy is verified by comparison between test and simulation. Based on the model, the parameters analysis is done and the law of MRF viscosity, arc spring stiffness, working clearance, rotor radius and axial width effect on dynamic characteristics are gained, it will prove some guidance for the structure and performance improvement.
Control Research of Power Train Torsional Vibration Based on Magneto-Rheological Fluid Dual Mass Flywheel
Abstract To research the torsional vibration damping characteristic of magneto-rheological fluid dual mass flywheel (MRF-DMF) and the control system in power train, the multi-degree power train torsional vibration model which contains MRF-DMF and semi-active fuzzy control model are built, then the damping characteristic of MRF-DMF in several conditions are gained and compared with MRF-DMF when no control system. The result indicates: the damping characteristic of MRF-DMF effect on power train when using control is better than without control in idle, speed up, slow down, ignition and stalling, while the damping characteristic is less obvious in constant speed because the simulation condition and damping moment relatively stable.
Abstract Flywheels are excellent secondary energy storage devices and several applications in road vehicles are under development. They can be used in hybrid vehicles with an internal combustion engine (ICE) as the prime mover or can be used in hybrid energy storage (HES) to complement the battery. When used in HES, they are utilized to load level the battery so as to protect it from peak loads and enhance its capacity and life. This paper deals with defining the main characteristics of the flywheel for an application as a secondary energy storage device for an electric vehicle. Various strategies for defining flywheels are explained. A real world customer usage data is also presented. This data is analyzed and its results are used to support the selection of the flywheel characteristics. The results show that the chosen flywheel is sufficiently sized to perform its intended tasks for a c-segment passenger car electric vehicle.
Abstract The study of dynamical performance of new Flywheel for any type of engine is presented. Design and structure of proposed Flywheel is based on George Nerubenko US Patent 7,464,800 having the control system with instantaneous frequency tuner and variable damping device adjusted for all operational frequencies in running engine. The patented scheme would be applied for a design of Flywheels successfully replacing the conventional and dual mass flywheels. A description, structural details and mathematical model of considered Flywheel are presented. The model based on the system of differential equations describing the rotation and vibration of mechanical components combined to Coulomb dry friction equations reflecting the contacts in variable damping device has been used for the analysis of the dynamic behavior of engine crankshaft system having proposed Flywheel. The analysis is presented for semi-controlled version of Tuned Flywheel equipped with variable damping device.
In this work, we investigate the rotor bearing loads of a flywheel-based KERS that are caused by dynamic forces and gyroscopic torques during representative driving maneuvers. Based on the governing equations of motion of a gyroscope, the equations for the rotor-platform interactions are developed. These equations, which relate the vehicle's roll, pitch and yaw rate with the internal transverse torques on the flywheel, are integrated into a commercial vehicle dynamics program. An average passenger car model equipped with a typical high-speed flywheel energy storage system is used for the numerical investigations. The flywheel bearing loads produced by some selected, representative driving maneuvers are simulated for different orientations of the flywheel spin axis relative to the body frame. In addition, the dynamic response of the vehicle to the reaction torques is investigated in open and closed-loop vehicle dynamics simulations.
Effect of Flywheel Mass and Its Center of Gravity on Crankshaft Endurance Limit Safety Factor and Dynamics
The crankshaft is the component which transmits dynamic loads from cylinder pressure and inertial loads in engine operating conditions. Because of its crucial importance in functioning of engine and requisite to sustain high dynamic and torsional loading, crankshaft fatigue life is desired to be higher than the predicted engine operating life. Performance of the crank train in diesel engine applications largely depends on the components of its mass elastic system. Flywheel is one such component whose design affects the life of crankshaft. In the present study, the crank train comprising of torsional vibration damper, crankshaft and flywheel along with clutch cover is considered for analysis. Crankshaft dynamic simulation is performed with multi body dynamics technique, fatigue safety factors of crankshaft are calculated with dynamic loads under engine operating conditions.
This paper evaluates the effect of our new alternator concept for a conventional vehicle, which is able to generate electricity by storing kinetic energy of the vehicle in the high speed flywheel as rotation energy under deceleration. The alternator constructs a planetary gear device and multiple clutch-brakes perform CVT, alternator and high speed flywheel without an expensive electric device, mechanical CVT and vacuum pump. So it has high cost performance.
Dual Mass Flywheel (DMF) has better damping capacity than the conventional Clutch Torsional Damper (CTD), and is more suitable for diesel engine, Dual Clutch Transmission (DCT) and hybrid vehicles. Dual Mass Flywheel-Radial Spring (DMF-RS) is a DMF that has a specific structure. In the light of working principal and static analysis, the hard nonlinear torsional stiffness of DMF-RS is derived in this paper, which is very important to a driveline damper. On this basis, a simulation model is developed to analyze the dynamic response of DMF and CTD excited by idle engine; the comparison of the two dampers reveals that the DMF has better damping capacity, high-frequency filter ability and can reduce crankshaft load.
Interdependency of automotive transmission aggregates on electrical/ electronics systems is increasing day by day, offering more comfort and features. For a system integrator, it becomes very much important while selecting/designing any such component to take into consideration the relationship between such interdependent components from performance as well as endurance point of view. DMF failures due to inadequate starting system, is a major stumbling block in development of DMF for a particular vehicle application. The interface of DMF and starting system of a vehicle makes it essential to consider the effect of one on another. The study shows that the majority of DMF failures happen because of resonance phenomenon in the DMF during engine starting. The improper selection of starter motor makes the DMF more vulnerable for such failures.
Fuel Economy Benefits of a Flywheel & CVT Based Mechanical Hybrid for City Bus and Commercial Vehicle Applications
Hybrid drivetrain systems are becoming increasingly prevalent in Automotive and Commercial Vehicle applications and have also been introduced for the 2009 Formula1 motorsport season. The F1 development has the clear intent of directing technical development in motorsport to impact the key issue of fuel efficiency in mainstream vehicles. In order to promote all technical developments, the type of system (electrical, mechanical, hydraulic, etc) for the F1 application has not been specified. A significant outcome of this action is renewed interest and development of mechanical hybrid systems comprising a high speed composite flywheel and a full-toroidal traction drive Continuously Variable Transmission (CVT). A flywheel based mechanical hybrid has few system components, low system costs, low weight and dispenses with the energy state changes of electrical systems producing a highly efficient and power dense hybrid system.
Study on Natural Torsional Vibration Characteristics of Dual Mass - Flywheel Radial Spring Type Torsional Vibration Damper
The working principle of dual mass flywheel - radial spring (DMF-RS) type torsional vibration damper was analyzed, and the design method of natural torsional vibration characteristics control of DMF-RS type torsional damper for automotive powertrains was studied herein. Based on the multi-freedom lumped mass - torsional vibration spring analysis model of powertrain, the natural torsional vibration characteristics of the system with DMF-RS type torsional damper were analyzed, and compared with the clutch type torsional vibration damper, the effectiveness of DMF-RS type torsional damper on the torsional vibration control was verified.
Mechanical Hybrid System Comprising a Flywheel and CVT for Motorsport and Mainstream Automotive Applications
Hybrid drivetrain systems focusing on Kinetic Energy Recovery Systems (KERS) will be introduced in Formula 1 for the 2009 season with the clear intent of directing technical developments in motorsport that will have an impact to the key issue of fuel efficiency in road cars. The 2009 season specification defines a system that can recover, store and reapply 400kJ of energy per lap at a maximum rate of 60kW. In order to promote technical development, neither the type of system (be it electrical, mechanical, hydraulic, etc), the weight of the system nor the strategy for reapplication of the recovered energy have been defined.
There are 30 million people in remote, rural communities in China without access to electricity. The government of China has initiated an ongoing effort to provide constant, reliable power to these citizens. Renewable energy is being utilized to solve this problem, which necessitates the use of a storage medium for energy, because renewable energies (i.e. wind and/or solar power) are inherently intermittent, variable, and largely unpredictable. By storing excess energy when it is plentiful (for a maximum feasible time of two days) and distributing it to the community in times of scarcity, the intermittent power is effectively leveled and auxiliary power is provided. A high-inertia flywheel was designed for this application because of its simplicity, ease of maintenance, low cost, and reliability. This design addresses many problems including bearing losses, aerodynamic losses, and distribution losses. The proposed design consists of a six spoke layout with a large outer ring.
Dynamic Simulation and Endurance Limit Safety Factor Calculation for Crankshaft - Comparison of Single Mass and Dual Mass Flywheel
The crankshaft is the component which transmits dynamical loading from cylinder pressure and inertial loads in engine operating conditions. Because of the crucial importance of its function, crankshaft fatigue life is desired to be higher than the predicted engine operating life. In this study, Puma I5 crankshaft dynamic simulation is performed with multi body dynamics technique. Fatigue safety factors are calculated with the dynamical loadings of engine operating conditions. The effects of single mass and dual mass flywheel on endurance limit are analyzed in this study.
Anti-Jerk & Idle Speed Control with Integrated Sub-Harmonic Vibration Compensation for Vehicles with Dual Mass Flywheels
Over more than 20 years 50 million LuK dual mass flywheels (DMF) have been produced for use in passenger cars and light trucks. A typical DMF consists of two flywheels connected by long travel arc-springs. It is located between the combustion engine and the clutch or automatic transmission. The DMF reduces driveline oscillations by mechanically decoupling the transmission from the periodic combustion events that excite the engine crankshaft. Existing engine control systems are generally designed for conventional single mass flywheel (SMF) systems. In the future, to facilitate the best possible control of engines equipped with DMF systems, these conventional control systems may require modification or even replacement. With the integration of the highly non-linear DMF, the complexity, and thus the order of the powertrain system increase.
Hybrid vehicles provide the most viable medium term solution to meet the demands of the automotive marketplace. Currently electric hybrids dominate the marketplace but mechanical hybrid systems, including flywheel, pneumatic and hydraulic systems all have the potential to compete with electrical systems. This paper provides an overview of a mechanical hybrid project created by the University of Warwick. The aim of the project is to assess alternative hybrid powertrains, in particular pneumatic, hydraulic and flywheel systems. This paper provides a description of a simulation tool to investigate and evaluate the mechanical alternatives to electric hybrid vehicles and the results from two fuel economy case studies using the simulation tool: 2.6 ton SUV and 17 ton bus applications. The paper also outlines a feasibility study of the mechanical hybrid options, including a cost benefit analysis of the different systems.
Cylinder Balancing Based on Reconstructed Engine Torque for Vehicles Fitted with a Dual Mass Flywheel (DMF)
The integration of a Dual Mass Flywheel (DMF) in the conventional vehicle driveline leads to various benefits, and hence today it has established its position in many passenger cars and light trucks. Transmission and driveline oscillations are reduced by mechanically decoupling the transmission from the periodic combustion events that excite the engine crankshaft, improving driving comfort and reducing transmission stresses. For systems with conventional single mass flywheel (SMF) reliable engine control systems have already been developed. However, the complexity of the driveline increases with the integration of a DMF. Hence, in the future conventional engine control systems may require adaptation, modification or even replacement, in order to guarantee the optimal control of engines equipped with advanced DMF systems.
Unfortunately car magazines give too much importance for acceleration times and top speed, but for the customer, speed recovery is the best and most perceived performance metric. Based on production parts, the compression ratio, camshaft and engine inertia were changed aiming the best compromise for acceleration, top speed and speed recovery. The vehicle is a current production 1.0L vehicle, assembled with 1.8L engine, resulting in a sport behavior. The vehicle performance was measured with full package and some combinations, allowing the definition of the best compromise and where the money should be spent.
This study generates a conceptual vehicle hybrid power driving system that consists of an internal combustion engine, a motor, two continuously variable transmissions, a generator, a pulse width modulation electric controller, a planetary gear, and an energy storage flywheel. The flywheel drives a generator that generates electric power for the motor to drive the vehicle. The controller with the fuzzy theory is used to determine the torque distribution of the engine and the motor. Using the Japanese 10-15 mode, the driving shaft torque, the engine torque, the motor torque, the torque distribution percentages of the engine and the motor and the flywheel angular velocity versus time were studied with the flywheel moment of inertia to be e 0.6 kg·m2 and 1.2 kg·m2 and the reduction speed ratio to be 0.231. The flywheel moment of inertia to be 1.2 kg·m2 is selected for the system to have more stable operation.
Today, in many passenger cars and light trucks, the conventional driveline is extended by a dual mass flywheel (DMF). The DMF reduces driveline oscillations by mechanically decoupling the crankshaft and the transmission. Existing engine control systems are general designed for use with conventional single mass flywheel (SMF) systems. In the future, to facilitate the optimal control of engines equipped with advanced DMF systems, these conventional control systems may require adaptation, modification or even replacement. In the past, misfire detection has been done by expensive dedicated sensors; seismic, ion current measurement at the spark plugs or even by measuring in-cylinder pressures directly. Typically misfire detection is performed using signals derived from the crankshaft position sensor, which works well for engines with a limited number of cylinders and which are connected to relatively simply drivelines.
NVH Analysis of Balancer Chain Drives with the Compliant Sprocket of the Crankshaft with a Dual-Mass Flywheel for an Inline-4 Engine
The work presented in this paper outlines the design and development of a compliant sprocket for balancer drives in an effort to reduce the noise levels related to chain-sprocket meshing. An experimental observation of a severe chain noise around a resonant engine speed with the Dual-Mass Flywheel (DMF) and standard build solid (fixed) balancer drive sprocket. Torsional oscillation at the crankshaft nose at full load is induced by uneven running of crankshaft with a dual-mass flywheel system. This results in an increase of the undesirable impact noise caused by the meshing between the chain-links and the engagement/disengagement regions of sprockets, and the clatter noise from the interaction between the vibrating chain and the guides. This paper evaluates and discusses the benefits that the compliant sprocket design provided. A multi-body dynamics system (MBS) model of the balancer chain drive has been developed, validated, and used to investigate the chain noise.
The principles of regenerative soaring with a dual-role propeller and windmill, or “windprop,” are described. Emphasizing the aerodynamic design and performance of the vehicle and windprop, principles of regenerative flight are derived. Approximate models of atmospheric updraft velocity are suggested. Regenerative aircraft total energy is defined, and the rate of change thereof is studied. We find that regenerative soaring appears both feasible and attractive in relation to classical soaring. In addition, the study reveals good efficiency for both propeller and windmill modes.