Browse Topic: Engine mounts
In the ongoing Road Load Data Acquisition (RLDA) for engine mounts, a load cell arrangement is being utilized, where the load cell must be placed between the mount arm and an engine mount bracket or an additional tower bracket. This configuration required the design of a custom mount arm with a crank in the Z direction, secured with a single bolt to accommodate the load cell. However, this method has revealed significant load coupling in the X and Z directions, resulting in incorrect load prediction for engine mount testing. This happens due to the architectural packaging of the engine mount on the long member to meet NVH requirements. To mitigate these issues, an alternative strain gauge-based RLDA approach was investigated. The optimal locations for strain gauge placement were determined using the inverse matrix method with the assistance of Computer-Aided Engineering (CAE) analysis. Strain gauges were then installed at these identified locations on the mount arm. The engine mount
Optimizing engine mounting systems is a complex task that requires balancing the isolation of vehicle vibrations with controlling powertrain movement within a limited dynamic envelope. Six Degrees of Freedom (6DOF) optimization is widely used for mounting stiffness and location optimization. This study investigates the application of various optimization algorithms for 6DOF analysis in engine mount design, where the system’s stochastic behaviour and probabilistic characteristics present additional challenges. Selecting an appropriate optimization framework is essential for achieving accurate and efficient NVH results. Recent advancements in research have introduced several 6DOF optimization algorithms to determine the optimal stiffness and location of engine mounts. The study evaluates a range of optimization methods, including Simultaneous Hybrid Exploration that is Robust, Progressive and Adaptive (SHERPA), Quadratic Programming (QP), Genetic Algorithm (GA), Particle Swarm
The primary functions of mounts include providing structural support, sound insulation, and vibration damping. Dynamic stiffness and loss angle are critical metrics for evaluating their NVH (Noise, Vibration, and Harshness) performance. This paper examines a floating decoupler hydraulic mount featuring a long decoupler membrane track. A nonlinear lumped parameter model is developed to calculate the dynamic stiffness and loss angle. The model incorporates fluid flow in the lower chamber and variations in the support reaction force of the decoupler membrane under switching conditions. Parameters of the nonlinear lumped parameter model, including rubber stiffness, equivalent piston area, and volumetric compliance of the fluid chamber, were analyzed and calculated using the finite element method. The influence of different decoupler membrane track structures on the frequency corresponding to the minimum high-frequency dynamic stiffness was investigated based on the established model. The
A methodology for optimizing natural properties of a powertrain for an electric vehicle has been presented. A model with six-degree-of-freedom was proposed utilizing ADAMS, and the natural frequencies and energy distribution of the powertrain are estimated using the proposed model. The calculated natural frequencies and energy distribution shown that the initial design of mount stiffness does not meet requirements of natural frequency and decoupling ratio, and vibration isolation standards. To overcome the limitations of conventional optimization techniques, a non-dominated sorting genetic algorithm (NSGA) was adopted for the enhancement optimization the mounts parameters. The optimization objectives included the refinement of the decoupling rates and frequency distribution at all mounting directions. Stiffness parameters of the mounts were optimized via the NSGA. The optimized results confirmed significant improvements for powertrain natural characteristics. This study presented an
Due to stringent emission norms, all OEMs are shifting focus from Internal combustion engine (ICE) to Electric vehicle (EV). NVH refinement of EVs is challenging due to less background noise in EVs in comparison with ICE vehicles. Motor whine noise is perceived inside cabin till the speed of 20 kmph. Vehicle is powered by electric powertrain (EPT). Electric powertrain is connected to the subframe with the help of three powertrain mounts. Subframe is connected to the body with the help of four mounts. With the help of Transfer Path Analysis (TPA), it is identified that the noise is structure borne and the dominant path is identified. By optimizing the stiffness of the EPT mounts, the structure borne noise levels are reduced. But reducing the stiffness of EPT mount deteriorated the road noise levels. The reason behind deterioration of road noise is investigated. The performance of double isolation of EPT is compared with single isolation of EPT with respect to both road and motor noise
The stiffness and positioning of engine mounts are crucial in determining the powertrain rigid body modes and kinetic energy distribution. Therefore, optimizing these mounts is essential in the automotive industry to separate the torque roll axis (TRA) and minimize vibration. This study aims to enhance mount locations by isolating the engine rigid body modes and predicting the inter-component force (ICF) and transfer function of the vehicle. The individual ICFs for engine mountings are calculated by applying a unit force at the bearing location. Critical frequencies are identified where the amplification exceeds the unit force at the mounting interface between the engine and the frame. The transfer function approach is utilized to assess the vibration at the handlebar. Both ICF and transfer functions analyze the source and path characteristics linked to critical response frequencies. This understanding aids in enhancing mounting positions to minimize vibration levels, thereby enhancing
The functionality of the Powertrain mount is to securely anchor the engine and gearbox within a vehicle, and effectively absorb vibrations, while simultaneously shielding the vehicle's body from powertrain movements and road irregularities. The mounts are supported by engine mount brackets, which serve as connectors between the engine mount and the vehicle's body-in-white (BIW), providing a structural link that secures the engine and gearbox assembly. Conventionally made with materials such as aluminum, sheet metal, or cast iron, a recent surge has been seen toward using a viable substitute in Fiber Reinforced Polymer (FRP). This transition is driven by the potential to reduce weight and cost, while also improving Noise, Vibration, and Harshness (NVH) characteristics. This study aimed to evaluate the relative strengths of existing brackets compared to those made of FRP, with a focus on their modal response and crash resistance. Due to the absence of a standardized method for modelling
This SAE Aerospace Recommended Practice (ARP) describes a method of conducting an endurance test using contaminated air when the applicable specification requires non-recirculation of the contaminants. The objective of the test is to determine the resistance of the engine mounted components to wear or damage caused by the contaminated air. The method described herein calls for non-recirculation of the contaminants and is intended to provide a uniform distribution of the contaminant at the inlet to the Unit Under Test (UUT). The UUT may require the use of a hydraulic fluid for actuation of components within the test unit. Contamination of the test hydraulic fluid is not part of this recommended practice. If contaminated hydraulic fluid is required by the applicable test specification, refer to MAP749.
A method of overall modeling and step-by-step solution was proposed to verify and analyze the strength of the mount shell. First, a reliable finite element simulation model was established based on testing of the mechanical properties of rubber materials, constitutive model construction, and stiffness tests of the mounts. Second, the displacement of the mount system under preloading and crash loads was calculated separately through the modeling of the powertrain mount simulation, which provided accurate load conditions of the mount for the following work. Finally, the strength calculation and evaluation of the mount shell was completed with the quasi-static solution method. This calculation method could consider the influence of complex factors comprehensively, such as assembly load distribution, large deformation of rubber, and contact nonlinearity on the stress distribution of the mount shell. In addition, the calculation method could solve the problem of balance between solution
To address the issue of engine jitter at idle conditions in a specific vehicle model, an initial test of the inertial parameters of the powertrain mounting system was conducted. Utilizing the Adams software, a system model was constructed and subjected to modal analysis. The stiffness of the mounting components was selected as the optimization variable. A deterministic multi-objective optimization was performed on the system’s decoupling rate, natural frequencies, and minimum dynamic reaction force, employing the multi-island genetic algorithm. sensitivity analysis regarding the stiffness of the mounts was conducted based on DOE method. The optimized stiffness values were then re-entered into the Adams software. The results of the deterministic optimization indicated a significant enhancement in the decoupling rate of the powertrain mounting system in the primary direction of concern, a reduction in the natural frequencies, and a decrease to 43.5% of the original scheme in the minimum
Engine off control is conducted on parallel hybrid vehicles in order to reduce fuel consumption. It is efficient in terms of fuel economy, however, noise and vibration is generated on engine cranking and transferred through engine mount on every mode transition from EV to HEV. Engine crank position control has been studied in this paper in order to reduce vibration generated when next cranking starts. System modeling of an architecture composed of an engine, P1 and P2 motors has been conducted. According to the prior studies, there exists correlation between crank vibration level and the crank angle. Thus a method to locate pistons on a specific crank angle which results in a local minimum of vibration magnitude could be considered. The P1 motor facilitates this crank position control when engine turns off, for its location directly mounted on a crankshaft allows the system model to obtain more precise crank position estimation and improved linearity in torque control as well. For the
To enhance the transient vibration performance of the vehicle at key on and key off, a method for optimizing mount parameters of a powertrain mounting system (PMS) is proposed. Uncertainties of mount parameters widely exist in a PMS, so a method for optimizing mount parameters of a PMS, which treats the mount parameters of a PMS as uncertain, is also proposed in this paper. Firstly, a 13 degrees of freedom (DOFs) model including car body with 3 DOFs, a PMS with 6 DOFs and unsprung mass with 4 DOFs is established, and the acceleration of the active side of mounts is calculated. An experiment is carried out to measure the accelerations located at active and passive sides of each mount and the accelerations of seat track. A comparison is made between the measured and estimated accelerations, and the proposed model is validated. Two optimization methods for the PMS are proposed based on the developed 13 DOFs model. One method treats mount parameters as deterministic variables, while
With the aim of decarbonizing the vehicles fleet, the use of hydrogen is promising solution. Hydrogen is an energy carrier, carbon-free, with high calorific value and with no CO2 and HC emissions burning in ICE. Hydrogen use in spark ignition engines has already been extensively investigated and optimized. On the other hand, its use in compression ignition engines has been little developed and, therefore, there is a lack of information regarding the combustion in ultra-lean conditions, typical of diesel engines. Several applications employ dual fuel combustion for the easy management of the PFI injection system to be applied in addition to the DI Common Rail system. However, this mode suffers from several problems regarding the management of the maximum flow rate of hydrogen into the intake. In particular, to avoid throwing hydrogen into the exhaust, injection must be started after the valve crossing. Furthermore, it is not possible to introduce gaseous fuel into the engine when the
NVH refinement of commercial vehicles is the key attribute for customer acceptance. Engine and road irregularities are the two major factors responsible for the same. During powertrain isolators’ design alone, the mass and inertia of the powertrain are usually considered, but in practical scenarios, a directly coupled subsystem also disturbs the boundary conditions for design. Due to the upgradation in emission norms, the exhaust aftertreatment system of modern automotive vehicles becomes heavier and more complex. This system is further coupled to the powertrain through a flexible joint or fixed joint, which results in the disturbance of the performance of the isolators. Therefore, to address this, the isolators design study is done by considering a multi-body dynamics model of vehicles with 16 DOF and 22 DOF problems, which is capable to simulate static and dynamic real-life events of vehicles. Design indicators are thoroughly analyzed and validated through the rigid body modes and
In automotive Front End Accessory Drives (FEAD), the crankshaft supplies power to accessories like alternators, pumps, etc. FEAD undergoes forced vibration due to crankshaft excitation, dynamic tension fluctuations can cause the belt to slip on the accessory pulleys. By considering the criticality of the system, when engine mounting is longitudinally to the vehicle which makes it directly exposed to the air flow containing foreign particles which may cause the damage to the FEAD system and deteriorate the intended functionality. FEAD cover is introduced in the system to enhance belt-pully system functionality by restricting the entry of foreign particles during engine operation. This paper contains a study of FEAD cover failure and provides the stepwise approach to capture such issue during novel model development for 4 cylinder naturally aspirated engine during engine bench testing. The failure mechanism was studied using various methodology such as CAE and G-Load measurement to
With the advancement of regulatory norms in automobile industry, there is a challenge to meet performance efficiency targets, especially with a lightweight platform, while providing superior driving experience to customers. The shift towards weight optimization, makes the vehicle structure more susceptible to transfer a diverse range of noise and vibrations through body. Although most undesirable noises perceived inside the cabin can be reduced by superior technology engine mounts and NVH packaging, all such solutions lead to cost addition. Intelligent considerations in part design can be used to supplement predictable transfer paths to quell the unwanted vibrations. One such case is of the gear whine noise in certain rpm bands caused by inherent gear meshing frequency coinciding with natural frequency of an engine mounting bracket. This paper demonstrates two methodologies to counter such a phenomenon, either through engine mount bracket natural frequency optimization or addition of a
Engine mount is an integral part of any Internal Combustion engine. It is the medium which isolates the vibrations coming from engine being transferred to the chassis or body. Engine or power plant is the main source of unbalanced vibrations. The major role of an engine mount is to reduce those vibration levels, improve ride comfort and increase the life of an engine and its parts [1]. This work determines the Test methodology development for passenger car engine mounts in the Laboratory by using Multi-axial environment [2]. This explains the details of truly Multi-axial test rig development, Drive file creation and the Durability Testing with the maintained vehicle conditions by simulating field conditions in the laboratory. The Multi-axial test rig developed with incorporation of vehicle’s both Front Drive shafts torques and One Propeller shaft which simulates the Front wheel drives and the rear prop shaft torque. Drive file generation done by using MTS controller using rpc software
Key on/off (KOKO) Vibration plays a vital role in the quality of NVH (Noise Vibration and Harshness) on a vehicle. A good KOKO experience on the vehicle is desirable for every customer. The vibration transfer to the vehicle can be refined either by reducing the source vibrations or improving isolation efficiency. For the engine mounting system of passenger cars, the mounts are an isolating element between the powertrain and receiver. Various noise, Vibration, and harshness criteria must be fulfilled by mounting system performance like driver seat rail vibration (DSR), tip-in/tip-out, judder performance, DSR at idle and Key on/off Vibration. Out of these requirements, in the paper, the investigation is done on KOKO improvement without affecting other NVH parameters related to mount performance. Higher damping is required to isolate Vibration generated during the Key-on event, and lower damping is required during the idle condition of the vehicle. These contradictory damping requirements
IC (Internal Combustion) engines are evolved and refined over time to greater levels of technology in terms of emission, performance, NVH (Noise, Vibration & Harshness), and design philosophy. Crank-train generates a greater impact on NVH optimization due to its geometry and dynamics. Hence, more attention to mass balancing is required to minimize the negative impact on NVH. The present work demonstrates the evaluation of balancing rate of crank-train system from the first principle of couple balancing. Calculations are conducted at the concept stage to estimate an internal rotating couple balancing of crank-train system due to counterweights and rotating masses. As crankshaft weighs approximately 10-12% weight of an engine and its counter weight plays a vital role in balancing, its optimization will result in a significant impact on NVH. Therefore, based on balancing rate, engines’ crankshaft was optimized and to validate the methodologies, forces on engine mount and main bearings
A robust process of specifying engine mounting systems for internal combustion engines (ICE) has been established through decades of work and countless applications. Vehicle vibration is a critical consideration in the early stage of vehicle development. Apart from comfort, it also affects the overall vehicle's performance, reliability, Buzz-squeak and rattle (BSR), parts durability and robustness. The most dynamic system in a vehicle is the powertrain, a source of vibration inputs to the vehicle over the frequency range. The mounting system supports a powertrain in a vehicle and isolates the vibration generated from the powertrain to the vehicle. In addition, it also controls the overall dynamic movement of the powertrain system when the vehicle is subjected to road load excitations and avoids contact between the powertrain and other adjacent components of the vehicle. This paper investigates the effect of the mounting position, stiffness, and progressivity on overall vehicle-level
NVH is of prime importance in buses as passengers prefer comfort. Traditionally vehicle NVH is analysed post completion of proto built however this leads to modifications, increases cost & development time. In modern approach physical validation is replaced by CAE. There are many sources of NVH in vehicle however this article is focused about the methodology to improve NVH performance of bus by analysing and improving the stiffness and mobility of various chassis frame attachment points on which source of vibrations are mounted or attached. In this study chassis frame attachment stiffness of Engine mounts and propeller shafts is focused.
In today's volatile market environment, and with the change of user priorities, NVH refinement results in silent, vibration-free vehicle. The commercial vehicle industry is also starting to embrace this development in NVH vehicle refinement. There are health concerns associated with the discomfort experienced by occupants. This calls for cabins with no boom noise and less tactile vibrations. Noise within the vehicle is contributed by excitation from the Powertrain, Intake, Exhaust system, driveline, road excitations, suspension (structure borne noise) and its radiation into the air (air borne noise). This paper discusses the approach used to reduce “In-cab boom” noise in the operating speed sweep condition and seat track vibration during engine IDLE condition to improve driver comfort. In this paper NVH refinement was carried out on small commercial vehicles. Higher Seat track vibrations during IDLE and cabin boom noise during wide open throttle condition were observed during
Motorcycles are a preferred means of transportation in most of the countries due to its economic factor and ease in travelling. Rider comfort is an important aspect while designing a vehicle. Rider comfort is often compromised by unwanted vibrations experienced at human interface points also called as tactile points. These unwanted vibrations also affect rider’s motorcycle control and overall health. There are two major source of vibrations in a motorcycle that is engine & road inputs. In current study, a method is being explored to predict engine induced vibrations. Engine induced vibrations at various locations are simulated through multi body dynamics (MBD) and finite element (FE) simulation methods at vehicle level. Motorcycle model comprising of engine, frame and subassemblies are modeled in FE tool and then condensed to be used in MBD tool. Piston assembly, connecting rod, bearings and engine mounts are modeled in MBD tool. Vibration response resulting from unbalanced inertia
This Paper has as objective to describe the powertrain mount system and its relation with the Power Hop phenomenon. It will be present the Powertrain mounts stiffness characteristics and how the mounts manage the loads inputs. In this study, we will review a summary about powertrain mounts main characteristics to help the understanding how to establish the static and dynamic characteristics, with the engine torque applied over the system. It will be present how the Powertrain mounts shall manage the loads inputs. As a Case Study, it was applied one small passenger vehicle as hardware. This vehicle presents the powertrain mounts system as pendulum three points configuration. In addition, this vehicle presents the Power Hop phenomenon mainly in Reverse take off flat road. The required load data was collected through load cells installed on the powertrain mount system. The Power Hop phenomenon is mainly impacted by the rear mount, so the load data is related to rear mount direction X. The
Vehicle vibration is the key consideration in the early stage of vehicle development. The most dynamic system in a vehicle is the powertrain system, which is a source of various frequency vibration inputs to the vehicle. Mostly for powertrain mounting system design, only the uncoupled powertrain system is considered. However, in real situations, other subsystems are also attached to the powertrain unit. Thereby, assuming only the powertrain unit ignores the dynamic interactions among the powertrain and other systems. To address this shortcoming, a coupled powertrain and driveline mounting system problem is formulated and examined. This 16 DOF problem is constructed around a case of a front engine-based powertrain unit attached to the driveline system, which as an assembly resting on other systems such as chassis, suspensions, axles, and tires. First, the effect of a driveline on torque roll axis and other rigid body modes decoupling is examined analytically in terms of eigensolutions
This paper describes idle vibration reduction methods using a Stellantis vehicle as a case study. The causes of idle vibration are investigated using the NVH source, path, and receiver method. The torque transfer path into a vehicle has shown to be very important in determining vehicle idle vibration response. New electronic control enablers that affect idle vibration are tested and discussed, including Neutral Idle Control (NIC), Transfer-case Idle Control (TIC,®), and Switchable Engine Mounts (SEM). The Design For Six Sigma (DFSS) analysis method is used to arrive at an optimized result for vehicle idle vibration. This paper also discusses the results confirming TIC’s capability of reducing idle vibration on all-wheel drive vehicles. Transfer-case Idle Control is a new idle vibration control enabler developed by Stellantis and a patent was awarded by the United State Patent and Trademark Office.
In this paper, the influence of the decoupler-cage structure on the hitting noise of the hydraulic mount is studied, the abnormal noise of the hydraulic mount is mainly caused by the collision impact between the decoupler and the cage, the hitting noise was simulated and evaluated using calculation and experiment. a finite element model of the collision impact between the decoupler and the cage is developed, and an explicit finite element analysis is performed to obtain the time history of the vibration acceleration of the model, which is used as the boundary condition of the noise analysis. The acoustic boundary element method is used to analyze the impact noise of the decoupler-cage, and the frequency domain distribution characteristics of the impact sound pressure are obtained. The influence of different decoupler structure on the hitting noise is studied, and the recommended values for each parameter for a structure are given. The structure of a decoupler with hitting noise is
Many chassis and powertrain components in the transportation and automotive industry experience multi-axial cyclic service loading. A thorough load-history leading to durability damage should be considered in the early vehicle production steps. The key feature of rubber fatigue analysis discussed in this study is how to define local critical location strain time history based on nominal and complex load time histories. Material coupon characterization used here is the crack growth approach, based on fracture mechanics parameters. This methodology was utilized and presented for a truck engine mount. Temperature effects are not considered since proving ground (PG) loads are generated under isothermal high temperature and low frequency conditions without high amounts of self-heating. This novel methodology for fatigue life calculation involves finding independent load channels and mapping all load history through converting single or multichannel load-displacement history into stress
SAE/USCAR-46 defines test methods and outputs for engine oil pump bench testing. Performance and durability testing are the primary focus of this standard. This is written to specifically address testing of electronically controlled variable displacement pumps but can be adapted to mechanically controlled pumps and other pump technologies as needed. This standard outlines critical inputs and outputs in order to perform the testing and report results, but does not specifically set the acceptance standards or pass/fail criteria. Acceptance criteria must be set by the customer.
With the improvement of connectivity technologies, and the increase of data exchange capacity and cloud technologies, the usage of connected vehicle data by automakers is growing fast, and it represents an exciting, multi-faceted and high-growth area in the data analytics development – enabling a myriad of new possibilities, by including but not limited to: predicting failures in parts, accelerating issue detection and resolution, improve design validation, calibration updates over the air, advanced navigation assistance, passenger entertainment. The aim of this work is to present the process, methodologies and tools adopted in the implementation of an unsupervised machine learning solution based on data collected from connected vehicles whose main objective will be support the analysis of usage severity of the engine and transmission mounts parts of the vehicle. Since there is no specific signal or parameter collected directly from mounts parts made available in databases, the method
The purpose of this SAE Aerospace Information Report (AIR) is to illustrate the effect of installation power losses on the performance of a helicopter. Installation power losses result from a variety of sources, some associated directly with the basic engine installation, and some coming from the installation of specific items of aircraft mission specific equipment. Close attention must be paid to the accurate measurement of these losses so that the correct aircraft performance is calculated. Installation power losses inevitably result in a reduction in the overall performance of the aircraft. In some cases, careful attention to detail will allow specific elements of the overall loss to be reduced with immediate benefit for the mission performance of the aircraft. When considering items of equipment that affect the engine, it is important to understand the effect these will have on overall aircraft performance to ensure that mission capability is not unduly compromised. Alternatively
The powertrain mount is an important component, which reduces the vibrations generated from the powertrain. Vibration isolation is achieved with help of modal separation by predicting the kinetic energy fraction (KEF) and natural frequency (NF) at each mode. The soft mounts reduce vibrations transferred from the engine to the chassis, but if stiffness is very low, the displacement of the mount will be high, and hence, the lifetime of the mount will be less. Vibration isolation using a powertrain mount is a compromise between the displacement of the mount, displacement of the center of gravity of the powertrain, KEF, and NF. In this paper knowledge-based engineering (KBE) application methodology is explained to initially find out the optimum values of mount parameters using permutation and the combination of mount stiffness, mount angle, and mount locations. Using these permutations and combinations, KEFs, NF, and the displacement of the center of gravity of the powertrain are found. At
This document provides an overview on how and why EGR coolers are utilized, defines commonly used nomenclature, discusses design issues and trade-offs, and identifies common failure modes. The reintroduction of selectively cooled exhaust gas into the combustion chamber is just one component of the emission control strategy for internal combustion (IC) engines, both diesel and gasoline, and is useful in reducing exhaust port emission of nitrogen oxides (NOx). Other means of reducing NOx exhaust port emissions are briefly mentioned, but beyond the scope of this document.
With the increasing competition in the automotive industry, customer experience & satisfaction is at the top of every organization's goals. The customers have evolved & NVH refinement has become the parameter for their decision making in buying a car. The major source of rumble noise in a vehicle is the induced vibrations due to combustion forces in an IC engine. These vibrations are then transferred to the vehicle body through engine mounts. Hence engine mounts play a key role in defining the NVH & the ride performance of any vehicle. However, it is infeasible to validate every mount design through the physical test as it will be both costly & time-consuming. But multiple design iterations can be verified by the CAE approach quite effectively. This paper focuses on the novel CAE approach to evaluate the mount vibrations due to engine dynamics. The process involves preparing a FEA model of the complete Powertrain system. The whole system is analyzed sequentially for Mount Mobility FRF
The hybrid structure of Engine Mounts made of rubber casing with cast iron reinforcing. Use of two materials made it unique both in application and testing. The rubber provides damping for engine vibrations and the cast iron provides necessary strengthening to hold the heavy engine in place. In this research paper the FEA (Finite Element Method) methodology is being discussed to evaluate and optimize the design analysis to enhance overall engine mount capacity. The existing and modified designs are validated and considerable improvement is being observed in modified design in physical testing. Accurate modeling of engine mounts assembly is presented in this paper. FEA analysis results have good correlation with physical validation for both designs. Impact of design parameters of rubber mounts has been presented.
This SAE Aerospace Recommended Practice (ARP) provides a guide for the preparation of a helicopter engine/airframe interface document and checklist. This document and checklist should identify the information needed by the engine manufacturer and the aircraft manufacturer to integrate the engine design with the aircraft design and either provide this information or give reference to where this information is located. The intent is to assure that the engine manufacturer and the airframe manufacturer identify and make provision for this information so it can be easily accessible to either manufacturer as needed in the development stages of an engine-airframe integration project. A related document, SAE Aerospace Information Report AIR6181, provides guidance on creating an interface control document (ICD) which addresses a subset of the aircraft-engine interface information concerning the physical and functional interfaces of the electronic engine control system (EECS) with the aircraft
Electromagnetic semi-active hydraulic engine mount (HEM) with double inertia tracks can realize the opening and closing of the inertia tracks through the control of electromagnetic actuator, so as to meet the needs of vibration isolation in different working conditions, but the cost is high. In this paper, without using electromagnetic actuator, a mechanical semi-active HEM with double inertia tracks is designed and manufactured with simple structure and low cost. In this study, the feature of mechanical semi-active HEM with double inertia tracks is that a baffle-current limiting column structure is added in the inertia track. Under different excitation amplitudes, the baffle-current limiting column structure can open and close the inertia track passively. Several mechanical semi-active HEM with double-inertia tracks samples and conventional inertia tracks HEM samples are manufactured and the dynamic characteristics of these samples under low frequency excitation are tested. By
Today, noise perceived by the occupants is becoming an important factor driving the design standards for the design of most of the interior assemblies in an automotive vehicle. Buzz, Squeak and Rattle (BSR) is a major contributor towards the perceived noise of annoyance to the vehicle occupants. An automotive vehicle consists of many chassis assemblies which are the potential sources of BSR noise. The potential locations of critical BSR noise could be contained within such assemblies as well as across their boundaries. Engine mount design is major area where BSR noises can be heard inside cabin on various road conditions. Natural rubber is regular rubber used in engine mount applications but in this paper BSR problems are solved by changing the rubber compound i.e., NR+BR (slippery compound). Detailed case study is presented where slippery rubber compound is used which is solving BSR issue and also meeting durability targets.
The primary function of an engine mounting bracket is to support the powertrain system in all road conditions without any failure. The mount has to withstand different road conditions and driving maneuvers which exert loads on it. Also, it is challenging to change the mounting locations and types after the engine is built; hence it is paramount to verify the mounting brackets against all abuse loads in the design stage. The Car manufacturers ensure engine mount bracket design meets CAE's (Computer-aided engineering) static and fatigue load cases. The CAE is performed using digital RLD (Road load data) loads. The design checks cumulative strain or stress against specified service life requirements during break and fatigue FOS (Factor of safety) calculations. However, it is difficult to simulate the material's fracture toughness to estimate the effect of the impact load on the mounting bracket. The energy absorption ability of the engine mount brackets is mainly influenced by two
The torque required to tighten any threaded joint is different from the necessary torque to untighten threaded bolt or nut, and it is not observed or widely known since this is a regular and straightforward operation. Typically the torque needed to untighten a newly tightened clamp is around 10% to 30% less than the torque to stretch it further. During tightening a threaded bolt, a significant amount of torque required to overcome friction in the threads and under the nut face. The proportion of the torque used to overcome frictional resistance depends upon the friction value. When we tighten a joint with a coefficient of friction of 0.12, only about approximately 14% of the torque required to stretch the fastener producing the clamp load with 86% of the torque is lost overcoming friction. The torque needed to pull the bolt always acts in the untightening direction, resulted in untightening torque lags behind the tightening torque. Sufficient preload has to be there in the bolted joint
In this paper, a linear oscillatory actuator (LOA) with moving magnets used in active engine mount is modeled and theoretically analyzed considering its performance decline at high temperature. Firstly, a finite element model (FEM) of the LOA with moving magnets is established. The actuator force is decomposed to ampere force and cogging force through formation mechanism analysis. By using the FEM, ampere forces and cogging forces of the LOA with moving magnets under different current loads and different mover positions are calculated. The FEM and calculation method are validated by bench level test. The voice coil constant and cogging coefficient at normal temperature are identified, which indicates the actuator force is a linear model related to the current and the mover position. Then, considering temperature-dependent magnetic hysteresis curve (B-H curve) of permanent magnet (PM) material used in the LOA with moving magnets, thermal demagnetization analysis and actuator force decay
In a passenger car, suspension link bushings, engine and transmission mount bushings and bump-stops are made of elastomeric materials, to maximize the durability and comfort. Thus, deformation behavior of rubber and its durability is important for product design and development. In virtual engineering, simulating rubber fatigue is a complex exercise, since it needs right modeling strategy and coupon based testing material data. Principal stretches based Ogden model is used to characterize the hyper elastic deformation behavior of natural rubber. Fatigue crack growth approach used here for the fatigue analysis. Engine torque strut mount is used to control the engine and transmission fore aft motion and it is connected between body and Powertrain (PT) system. Powertrain events are predominant for damage contribution to mount failure. So, it is important to predict fatigue life of mount elastomer bushing under Powertrain loading. The objective of this work is CAE fatigue life prediction
Automotive industry is focusing on NVH reduction and customer comfort for passenger vehicle. Structural optimization is a one of the effective tool to obtain an optimum design to achieve NVH reduction. For an internal combustion engine, there exist two basic dynamic disturbances: a) the firing pulse due to the explosion of the fuel in the cylinder and b) the inertia force and torque caused by the rotating and reciprocating parts (piston, connecting rod and crank). The usage of engine mounts is the best solution for dampening the effect of vibrations and transmitting forces between the engine and the automotive body structure. In this paper, application of structural optimization in the design of a engine mount has been carried out. Effort has been taken to develop engine-mounting arm with two different designs solution. Further, engine with two different configurations has been tested at Engine test bed and vehicle level to understand the behaviour in real environment. Further results
In order to resolve global atmospheric environmental issues, latest diesel engines for industrial machinery are required to reduce the emission of harmful gases such as carbon monoxide (CO), hydrocarbon (HC) and nitrogen oxide (NOx), and particulate matter (PM). For this reason, it is essential to mount exhaust gas after treatment devices such as diesel particulate filter (DPF) and diesel oxidation catalyst (DOC) on diesel engine. Engines mounted DPF must carry out DPF regeneration that burns and removes PM. Generator engine has characteristic of being operated for a long time under light load condition with low exhaust temperature which is difficult for DPF regeneration. In addition, generating white smoke and inlet face clogging of DOC are caused by accumulated soot containing HC at the DOC when operating engine continuously under light load condition. In this study, DPF regeneration system suitable for generator engine and method for preventing white smoke and inlet face clogging of
This document summarizes types of heat sinks and considerations in relation to the general requirements of aircraft heat sources, and it provides information to achieve efficient utilization and management of these heat sinks. In this document, a heat sink is defined as a body or substance used for removal of the heat generated by thermodynamic processes. This document provides general data about airborne heat sources, heat sinks, and modes of heat transfer. The document also discusses approaches to control the use of heat sinks and techniques for analysis and verification of heat sink management. The heat sinks are for aircraft operating at subsonic and supersonic speeds.
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