Browse Topic: Front wheel drive
Globally all OEMs are moving towards electric vehicle to reduce emission and fuel cost. Customers expect highest level of refinement and sophistication in electric vehicle. At present, the customers are sensitive to high pitched tonal noise produced by electric powertrain which gives a lot of challenges to NVH engineers to arrive at a cost-effective solution in less span of time. Higher structure borne tonal noise is perceived in electric vehicle at the vehicle speeds of ~ 28 kmph, 45 kmph and 85 kmph. The test vehicle is front wheel drive compact SUV powered by motor in the front. The electric drive unit is connected to cradle and subframe with help of three mounts. Transfer path analysis (TPA) using blocked forces method is carried out to identify the exact forces of the electric drive unit entering the mounts. Powertrain mount is characterized by applying the predicted forces and dynamic stiffness at problematic frequency is measured. By reducing the dynamic stiffness of powertrain
This paper focuses on reducing abnormal noise originating from suspension when driving on rough road at the speed of 20 kmph. The test vehicle is a front wheel driven monocoque SUV powered by four cylinder engine. Cabin noise levels are higher between 100 to 800 Hz when driven on rough road at 20 kmph. Vibration levels are measured on front and rear suspension components, front and rear subframe, subframe connections on body to identify the noise source locations. Since the noise levels are dominant only in certain rough patches at very narrow band of time, wavelet analysis is used for identification of frequency at which the problem exist. Based on wavelet analysis, it is identified that the vibration levels are dominant on front lower control arm (LCA). The dynamic stiffness of LCA bushes is reduced by ~ 40% to improve the isolator performance which reduced the noise levels by ~ 9 dB (A) at the problematic frequency band. Modal analysis is conducted on front suspension components to
Electric vehicles (EV) are much quieter than IC engine powered vehicles due to less mechanical components and absence of combustion. The lower cabin noise in electric vehicles make customers sensitive to even small noise disturbances in vehicle. Road boom noise is one of such major concerns to which the customers are sensitive in electric vehicles. The test vehicle is a front wheel driven compact SUV powered by electric motor. On normal plain road, noise levels are acceptable but when the vehicle has been driven on coarse road, the boom noise is perceived, and the levels are objectionable. Multi reference Transfer Path Analysis (MTPA) is conducted to identify the path through which maximum forces are entering the body. Based on MTPA, modifications are proposed on the suspension bushes and the noise levels were assessed. Operational Deflection Shape (ODS) analysis is conducted on entire vehicle components like suspension links, sub frame, floor, roof, and doors to identify the
Test procedure for anti-lock brake system (ABS/anti-lock) performance for trucks, truck-tractors, and buses over 4536 kg (10000 pounds).
As part of the U.S. Environmental Protection Agency’s (EPA’s) continuing assessment of advanced light-duty automotive technologies in support of regulatory and compliance programs, a 2018 Toyota Camry front wheel drive eight-speed automatic transmission was benchmarked. The benchmarking data were used as inputs to EPA’s Advanced Light-duty Powertrain and Hybrid Analysis (ALPHA) vehicle simulation model to estimate GHG emissions from light-duty vehicles. ALPHA requires both detailed engine fuel consumption maps and transmission torque loss maps. EPA’s National Vehicle and Fuels Emissions Laboratory has developed a streamlined, cost-effective in-house method of transmission testing, capable of gathering a dataset sufficient to characterize transmissions within ALPHA. This testing methodology targets the range of transmission operation observed during vehicle testing over EPA’s city and highway drive cycles. With this method, the transmission is tested as a complete system, as opposed to
This document establishes minimum performance criteria at GCWR and calculation methodology to determine tow-vehicle TWR for passenger cars, multipurpose passenger vehicles, and trucks. This includes all vehicles up to 14000 pounds GVWR.
In this SAE Recommended Practice, attention will be given to passenger cars and light trucks (through Class III).
Maximising the recovered regenerative braking energy during the deceleration can significantly reduce the Electric Vehicle (EV) energy consumption and increase the range. Compared with the Front Wheel Drive (FWD) or Rear Wheel Drive (RWD) EV, an All Wheel Drive (AWD) EV with 2 electric machines (e-machines) has more control degree freedom when developing the regenerative braking control strategy. By implementing the regenerative braking at the front axle, rear axle, or at the front and rear axles simultaneously, the amount of recovered kinetic energy will be affected. Furthermore, the e-machines at the front and rear axle in the AWD EV can have different sizes or be the same. Therefore, the ratio between front and rear e-machine power rating should also be investigated to understand its effect on the amount of recovered energy during deceleration. This paper starts with the analysis of the vehicle braking behaviour compared over different driving cycles, and the comparison of two
Any ROPS meeting the performance requirement of ISO 5700 (Static ROPS Test Standard) or ISO 3463 (Dynamic ROPS Test Standard) meets the performance requirements of this SAE Standard if the ROPS temperature/material and seat belt requirements of this document are also met.
This paper has the objective to present the study made on a front wheel drive passenger car with “3 Points Pendular Mounts System” to minimize the “Power Hop effect” (powertrain forced oscillation) and reduce the loads on Powertrain Mounts System. In this study, we used the Taguchi Method (Design of Experiments) to optimize the number of tests performed to evaluate the influence of powertrain mounts system design characteristics, as well as axle shafts stiffness, and tire/wheels assemblies size. The data acquisition work was all done in a physical hardware (vehicle) on test track used instrumented parts and load cells. Accelerometers were used in previous tests to get qualitative understanding of the behavior of all interface components (mounts and wheels hubs) during the power hop event. The study results showed the best components combination in order to reduce peak loads over Powertrain System and, as a consequence, reducing the potential of components breakage under extreme
Driveshafts are composed of a transmission side joint, wheel side joint, and shaft which connect the two joints. The Rzeppa type constant velocity joint (CVJ) is usually selected as the wheel side joint of a drive shaft for front wheel drive automobiles. Due to recent needs of fuel efficiency and lighter weight for vehicles, it is necessary to reduce the joint size and improve the efficiency of a CVJ. In order to reduce the weight, solving tribology details for long life under high contact pressure is an important issue for developing a CVJ. It is difficult to understand the characteristics of a contact surface, such as relative slip velocity or spin behavior, because the outer race, inner race, cage, and balls, act complicatedly and exchange loads at many points. Meanwhile, after joint endurance tests, ball spalling marks at pole of the ball are sometimes observed. Simulating ball rotational behavior and solving the formation mechanism of such phenomena could contribute to joint
Introducing all-new front wheel drive hybrid system installed in the 2016 Toyota Prius. This system was completely re-designed to maximize the potential of THS-II (Toyota Hybrid System-II). This system was designed to be able to minimize the mechanical and electrical losses from the previous generation system, improve environmental performance, and also tried to reduce size and weight. We’d like to take this opportunity to introduce the new technology of each component, and hybrid system performance.
This document establishes minimum performance criteria at GCWR and calculation methodology to determine tow-vehicle TWR for passenger cars, multipurpose passenger vehicles and trucks. This includes all vehicles up to 14000 lb GVWR.
In order to illustrate the constant development of the automatic transmission controls area, this paper describes how the garage shift calibration works in vehicles with transverse front wheel drive powertrains. A garage shift (GS) is the turbine speed transient commanded by the shift lever movement from Park to Drive or Reverse, from Neutral to Drive or Reverse, from Drive to Reverse, from Reverse to Drive, or from Drive or Reverse to Neutral [1]. A usual metric to verify the garage shift comfort is the data acquisition of the fore-aft acceleration on the seat track, but also the shift time should be considered, as well as the clutch energy and the repeatability of the shift feeling for different temperatures and engine idle speed levels. This paper demonstrates the transmission calibration strategies to determine a sensitive and a non-sensitive garage shift and its interactions with the engine calibration. Many factors may affect the garage shift calibration, like hardware controls
The extent of test conditions on the dynamometer must be sufficient to determine the efficiency characteristics corresponding to the following range of vehicle operations in all gear ratios with locked torque converters (open converter can also be done where appropriate and noted). a Efficiency versus output speed versus input torque b Torque ratio versus output speed c Input speed versus output speed d Output torque versus output speed e Parasitic loss versus input speed (spin losses) f Cooler flow g Output torque bias (front wheel drive transaxles)
Tactile vibration during vehicle key on/off is one of the critical factors contributing to the customer perceived quality of the vehicle. Minimization of the powertrain transient vibration in operating conditions such as key on/off, tip in/out and engagement/disengagement of engine in hybrid vehicles must be addressed carefully in the vehicle refinement stage. Source of start/stop vibration depends on many factors like engine cranking, engine rpm at which the combustion process starts and rate of engine rpm rise etc. The transfer path consists of elastomeric mounts of powertrain and the part of vehicle structure from mounts to tactile response location. In this paper, the contribution of rigid body motion of powertrain of a front wheel drive vehicle during key on/off is analyzed in both frequency and time domain. The signal is analyzed in frequency domain by using fast fourier transform, short time fourier transform and wavelet analysis. The merits and demerits of each method are
A regenerative braking system coordinated controller was developed for a front wheel drive BEV that also includes an ultra-capacitor storage system. This controller integrates the dual-motor regenerative braking with the hydraulic braking and stability control systems. The vehicle braking mode and the distribution of braking torque were determined according to the vehicle braking requirements, vehicle status and energy storage system (battery plus ultra-capacitor) state, and the stability control torque was provided according to the real-time vehicle stability condition. Simulation results show that, compared with a motor unilateral independence control strategy, the integrated coordinated controller improves the vehicle's stability when the vehicle corners while braking.
Recent developments in front wheel drive based all-wheel drive (AWD) systems have focused on the disconnection of the secondary driveline to provide a high efficient 2-Wheel Drive (2WD) mode in order to minimize parasitic losses and increase fuel economy when all-wheel drive is not required. This present study compares a base on-demand all-wheel drive system without disconnect features to one with disconnect features in the rear drive module (RDM) and power transfer unit (PTU) to fully disconnect the secondary drive line. In order to further reduce parasitic losses the RDM also utilized an on-demand lubrication system. In conjunction with the active lubrication system, the oil sump level was reduced to assure all clutch housings and their associated plates were above the oil level at all times in order to minimize shear losses. Positive plate separation was also employed to assure ample clearance for free-running clutch plates. Essentially, the tested disconnect system represents the
One of the key challenges in developing a vehicle for excellent vehicle dynamics is being able to achieve a high level of driving comfort without degrading the steering and handling performance. The part of driving comfort discussed in this paper are tactile vibrations up to f = 100 Hz. This paper describes how Multi-Body Dynamics (MBD) Computer Aided Engineering (CAE) tools are applied to optimize such vibrations in the early phase of the development process. The approach hereby presented combines system level testing with MBD for the study of ride comfort, similar to the way that system level kinematics and compliance testing is combined with MBD to support steering and handling investigations. Laboratory investigations have been executed to fully characterize a reference suspension with respect to frequency and amplitude behavior. The respective MBD models have been subsequently refined and validated versus physical laboratory measurements. Several examples for a front wheel drive
This paper presents the implementation of a vehicle and powertrain model of the parallel hybrid electric vehicle which can be used for several purposes: as a model for estimating fuel consumption, as a model for estimating performance, and as a control model for the hybrid powertrain optimisation. The model is specified as a multi-domain physical model in MATLAB Simscape, which captures the key electrical, mechanical and thermal energy flows in the vehicles. By applying hand crafted boundary conditions, this model can be simulated either in the forwards or backwards direction, and it can easily be simplified as required to address specific control problems. Modelling in the forwards direction, the driver inputs are specified, and the vehicle response is the model output. In the backwards direction, the vehicle velocity as a function of time is the specified input, and the engine torque, and fuel consumption are the model outputs. The model represents a parallel hybrid vehicle, which is
One primary concern with applying an AWD system to a front wheel drive (FWD) vehicle architecture is the additional weight and drag associated with the AWD drivetrain components, resulting in an increase in fuel consumption compared to FWD-only models. Therefore, Honda recently developed a next-generation integrated AWD unit that reduces weight and drag loss, and increases the SH-AWD cornering performance while maintaining the performance requirements of the previous rear drive unit. These targets were achieved primarily through the application of hydraulically-actuated clutches and an increase in the “speed-increasing ratio”. This paper describes the development, system validation and future technology implications of this recent advancement.
This paper details the lightweighting efforts of the Ford Research & Advanced Transmission team as part of the Multi Material Lightweight Vehicle Project. The Multi Material Lightweight Vehicle (MMLV) developed by Magna International and Ford Motor Company is a result of a US Department of Energy project DE-EE0005574. The project demonstrates the lightweighting potential of a five passenger sedan, while maintaining vehicle performance and occupant safety. Prototype vehicles were manufactured and limited full vehicle testing was conducted. The Mach-I vehicle design, comprised of commercially available materials and production processes, achieved a 364kg (23.5%) full vehicle mass reduction, enabling the application of a 1.0-liter three cylinder engine resulting in a significant environmental benefits and fuel consumption reduction. Several Ford 6-speed Front Wheel Drive (FWD) automatic transmission components were considered for lightweighting action with three ultimately being chosen as
General Motors has introduced a new front wheel drive seven speed dry dual clutch automatic transmission in 2014. The 250 Nm input torque rated gear box was designed and engineered for a global market in both front wheel drive and all-wheel drive configurations. The transmission has integrated start/stop capability enabled by the use of an electric motor driven pump and a pressurized accumulator. The architecture selected was chosen for optimization of packaging, fuel economy, mass, shift pleasability, and NVH. High mileage durability and world class drivability were the cornerstone deliverables during the engineering and design process Fuel efficiency is estimated to be 3% - 10% improvement over a conventional six speed automatic transmission. FWD variant wet mass of 78.1 kg was achieved through the rigorous engineering processes used to optimize the transmission system.
This study is inspired by the calculations and validations required for front wheel drive (FWD)-halfshaft joint selection. To increase design efficiency with decreased response time; a tool is required to validate calculations of strength based on maximum impact torque and endurance life based on corresponding vehicle usage. The tool has been developed to cover both strength and endurance life calculations. It also includes a constant velocity joint (CVJ) size library in order to compare different cases and to be able to see opportunities between different sizes. Validation and correlation has been completed using road load data from actual vehicles and standard load cycle (SLC) rig test results. This study introduces a more efficient methodology that will help the user select a joint that is sized best for strength and cost. After the completion of the study, one can be assured that the joint selected is the proper size-for all kinds of FWD vehicles.
This paper describes the interdisciplinary architecture selection study conducted by Embry-Riddle Aeronautical University (ERAU) to determine the Plug-in Hybrid Electric Vehicle (PHEV) architecture for its entry into EcoCAR2: Plugging In To The Future. This study includes a fuel, component, and architecture comparison to determine the most viable strategy to convert the competition vehicle, a 2013 Chevrolet Malibu, into a strong PHEV. Performance, energy, emissions, and consumer acceptability goals were established and summarized in the Vehicle Technical Specifications (VTS). Drive cycle simulations were used to create vehicle and component requirements for achieving the VTS targets. Three candidate architectures were then evaluated and compared for energy consumption, well to wheel (WTW) emissions, WTW petroleum energy usage, performance, packaging, and consumer acceptability. The architectures compared were a front wheel drive Series PHEV, a series-parallel through the road PHEV, and
The customer demand for all wheel drive (AWD) vehicles is increasing over the period of time which also requires NVH performance on par with front wheel drive vehicles. AWD vehicles are equipped with power transfer unit, propeller shaft and independent rear differential assembly to achieve their functional requirement. The additional drive train components in AWD vehicles may amplify torsional fluctuations in the drive line. Hence achieving the NVH performance of AWD vehicles on par with FWD vehicles without any major change in the existing design is a major challenge. In this work, an AWD vehicle with severe body vibration and booming noise is studied. The operational measurements are taken throughout the drive train on all sub-systems from engine to the rear part of the body in the problematic operating condition. An operational deflection shape analysis is conducted to visualize the vibration behavior of the drive train. The result of analysis shows that the dynamic torsional
We have developed the new SPORT HYBRID SH-AWD system, a hybrid system that provides best in class fuel economy and drivability to exceed customer expectations. The powertrain has a V6 engine and comes with three drive types modes: front wheel drive powered by a 7-speed dual clutch transmission with one built-in motor, rear wheel drive powered by a twin motor unit with two built-in motors, and all-wheel drive powered by a combination of the two. The system can automatically select the most efficient drive method for the driver's needs and the road conditions. The two motors built into the twin motor unit are individually controlled and torque vectoring is used to create a torque difference between the left and right tires, improving the turning performance. The electric drive system was developed with consideration for layout feasibility and quietness. The two motors built into the twin motor unit and the inverter that drives the motors have been newly developed. By installing this
At the GF6 six-speed, front-wheel transmission line at General Motors Powertrain in Toledo, OH, a new front-wheel-drive transmission line for smaller, more fuel-efficient vehicles such as the Chevy Malibu and Chevy Cruze is currently ramping up to its initial goal of 2,200 units per day. A closer look reveals the method used to program this line, implement changeover, stage the workpiece flow, perform all machining and secondary operations, and assemble the finished transmissions.
In this SAE Recommended Practice, attention will be given to passenger cars and light trucks (through Class III).
Vicura is a developer of manual transmissions and dry dual clutch transmissions, as well as powertrain integration in a large number of front wheel drive and all wheel drive applications. The company’s engineers are responsible for a broad range of complex simulation and analysis testing including system, structure, and fluid mechanics. The team performs critical simulation and analysis to ascertain the strength, stiffness, thermal, and dynamic behaviors of all possible transmission assemblies and components (housings, shafts, gears, synchronizers, clutches, etc.).
The Wayne State University (WSU) EcoCAR2 student team designed, modeled, Model-In-the-Loop (MIL) tested, Software-In-the-Loop (SIL) simulation tested, and Hardware-In-the-Loop (HIL) simulation tested the team's conversion design for taking a 2013 Chevrolet Malibu and converting it into a Parallel-Through-The-Road (PTTR) plug-in hybrid. The 2013 Malibu is a conventional Front Wheel Drive (FWD) vehicle and the team's conversion design keeps the conventional FWD and adds a Rear Wheel Drive (RWD) powertrain consisting of an electric motor, a single speed reduction gearbox and a differential to drive the rear wheels -where none of these previously existed on the rear wheels. The RWD addition creates the PTTR hybrid powertrain architecture of two driven axles where the mechanical torque path connection between the two powertrains is through the road, rather than a mechanical torque path through gears, chains, or shafts. Finally, a battery pack and an on-board charger are added to complete
As vehicle fuel economy continues to grow in importance, the ability to accurately measure the level of efficiency on all driveline components is required. A standardized test procedure enables manufacturers and suppliers to measure component losses consistently and provides data to make comparisons. In addition, the procedure offers a reliable process to assess enablers for efficiency improvements. Previous published studies have outlined the development of a comprehensive test procedure to measure transfer case speed-dependent parasitic losses at key speed, load, and environmental conditions. This paper will take the same basic approach for the Power Transfer Units (PTUs) used on Front Wheel Drive (FWD) based All Wheel Drive (AWD) vehicles. Factors included in the assessment include single and multi-stage PTUs, fluid levels, break-in process, and temperature effects. The resultant procedure is proposed as a new SAE J-standard (Surface Vehicle Recommended Practice) for release by the
This paper presents a forward-looking simulation (FLS) approach for the front wheel drive (FWD) General Motors Allison Hybrid System II (GM AHS-II). The supervisory control approach is based on a dynamic programming-informed Equivalent Cost Minimization Strategy (ECMS). The controller development uses backward-looking simulations (BLS), which execute quickly by neglecting component transients while assuming exact adherence to a specified drive cycle. Since ECMS sometimes prescribes control strategies with rapid component transients, its efficacy remains unknown until these transients are modeled. This is addressed by porting the ECMS controller to a forward-looking simulation where component transients are modeled in high fidelity. Techniques of implementing the ECMS controller and commanding the various power plants in the GM AHS-II for FLS are discussed. It is shown that FLS-derived component states agree well with states commanded using the BLS-derived robust control strategy, with
Hydrodynamic launch elements, from the Foettinger principle of the torque converter to the first series production HCC wet clutch, are becoming more relied on in the transmission world for their high power density, launch comfort, and vibrational isolation capability. In order to attain the ambitious fuel economy objectives of the future, engine vibrations have to be successfully isolated from the driveline at low engine speed ranges without the use of the hydrodynamic circuit. This is now all the more challenging as new combustion engines are producing higher torsional vibrations as a result of fewer cylinders, higher combustion pressures, cylinder deactivation, and lower critical speeds. This paper will describe the next generation of powertrain vibrational isolation, dampening via powersplit. Additionally, a next generation wet launch element, the Hydrodynamically Cooled Clutch will be discussed. A brief description of the current state of the art dampening technologies will be
Shengrui Transmission Limited Corporate (Shengrui) has developed a new 8 speed automatic transmission (SR 8AT) for front wheel drive (FWD) vehicle. The concept of SR 8AT is unique and different from the conventional automatic transmission. The design of the SR 8AT system and components are new and compact. By combining an innovative gear train which is similar with the conventional manual transmission and the simple planetary gear structure, SR 8AT achieved 8 speed with the shortest length of the FWD transmission, the competitive fuel economy and the smooth shift performance among comparable automatic transmissions.
This paper presents an alternative launch device for layshaft dual clutch transmissions (DCT's). The launch device incorporates a hydrodynamic torque converter, a lockup clutch with controlled slip capability and two wet multi-plate clutches to engage the input shafts of the transmission. The device is intended to overcome the deficiencies associated with using conventional dry or wet launch clutches in DCT's, such as limited torque capacity at vehicle launch, clutch thermal capacity and cooling, launch shudder, lubricant quality and requirement for interval oil changes. The alternative device enhances drive quality and performance at vehicle launch and adds the capability of controlled capacity slip to attenuate gear rattle without early downshifting. Parasitic torque loss will increase but is shown not to drastically influence fuel consumption compared to a dry clutch system, however synchronizer engagement can become a concern at cold operating temperatures. The performance of the
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