Browse Topic: All wheel drive
It's a crisp day in the Austrian Alps. A closed road has been plowed just for us. Well, piles of snow have been pushed aside, but the road remains covered in white. This is the type of drive usually reserved for an SUV or all-wheel-drive outfitted vehicle sporting cladding and a robust following amongst dog owners. Instead, I'm behind the wheel of the 2027 Mercedes-Benz CLA hybrid, and everything is going great. Well, mostly everything. The 2027 CLA hybrid uses one of two powertrains coming to the German sedan, alongside an electric version. Both will be available in the second half of 2026, according to Mercedes, and both are built on the new MMA (Mercedes Modular Architecture) platform. A platform that supports both EV and ICE powertrains, Mercedes says, allows the company to meet customer demand.
The Cadillac Celestiq is full of new technologies, from the 130+ parts made using additive manufacturing to the 655hp (488 kW) dual-motor AWD powertrain. ZF announced in early July that the $340,000, built-to-order EV is also the first vehicle with ZF's smart chassis sensors in series production ZF's smart chassis sensors are mounted on a control arm and use a magnetic measurement system that is integrated into the ball or cross axis joint of the control arm. A digital sensor detects the change in magnetic field with more than 2,000 increments over the full range of motion of the ball joint's articulation. “This means that even very small changes in the angle of the ball joint can be detected and translated into a change in height for the vehicle,” Matt Charboneau, communications manager for ZF North America, Inc, told SAE Media.
Continuing its rollout of EVs, Cadillac revealed the 2025 Optiq SUV, the company's most affordable EV yet and a smaller sibling to the popular Lyriq that was introduced last year. With a company-estimated range of 300 miles (482 km), the Optiq comes standard with dual-motor AWD, three years of Super Cruise hands-free driving, and what Cadillac officials say is segment-best cargo capacity and second-row space.
The test vehicle is All Wheel Drive (AWD) vehicle which is powered by four-cylinder engine. The power is transferred from the powertrain to the wheel through power transfer unit (PTU), propeller shaft, flexible rubber coupling and Integrated Rear Differential Assembly (IRDA) . Higher boom noise and vibration levels are observed when driving the vehicle in 4th gear WOT conditions. NVH levels are dominant between 1150 rpm to 2100 rpm and at 2200 rpm in 2nd order and 4th order respectively. Operational deflection shape (ODS) analysis is carried out on entire vehicle to identify the location where maximum deflection is observed at the problematic frequency. It is identified that higher torsional excitation from the powertrain is exciting the IRDA pitching mode and the propeller shaft bending mode which is the reason for higher 2nd order and 4th order NVH levels. The driveline forces are entering the body through the IRDA and rear cradle bushes. The dynamic stiffness of IRDA bushes is reduced which resulted in reduction of 2nd order vibration levels by ~ 7 dB at 2100 rpm. Further reduction of vibration is achieved by using mass dampers on IRDA and by reducing the stiffness of rear cradle bushes. Modal analysis is done on the propeller shaft to identify the mode shape at the problematic frequency. Various solutions like increasing the propeller shaft dynamic stiffness and tuned mass dampers on propeller shaft are investigated and the optimum solution which provides the best performance is selected. Stiffness of the rubber coupling used in driveline is modified to reduce the torsional excitation on the IRDA and various methods of reducing torsional excitation in driveline are discussed. With all the countermeasures, the boom noise is eliminated and vibration levels are reduced by ~ 10 dB.
Honda knows what U.S. buyers like: crossovers. So it makes perfect sense that the company chose a crossover SUV configuration for its first “mainstream” U.S.-market EV, the 2024 Prologue. The company's not postulating about how many Prologues it might sell annually once its new EV, co-developed with GM, goes on sale in early 2024. But Honda sold more than 350,000 CR-V crossovers in 2022, which left little doubt Honda wasn't going to take any chances regarding the bodystyle for its first North American mass-market EV. The Prologue's smooth and rounded sheetmetal is pleasant but cautious (Honda calls it “neo-rugged”) - and like many current EVs from volume automakers such as Hyundai (Ioniq 5) and Volkswagen (ID.4), it's lowish-roof profile stretches the definition of “SUV,” or even crossover. At an overall height of 64.7 in. (1643 mm), the 2024 Prologue seems noticeably lower, for example, than an all-wheel-drive CR-V's height of 66.5 in. (1689 mm).
The Ferrari Purosangue scurries up the snowbound pitches of Italy's Monte Bondone, the Alpine peak whose auto-hillclimb exploits date to 1925. Ferrari's first “SUV” - really, more a genre-blurring crossover - slices through Bondone's 38 devilish corners, gaining nearly 4,900 ft (1,494 m) of elevation over an 11.2-mile (18-km) workout. Its 715-hp (533-kW) V12 sings like the tragically-fated opera hero it is, to an 8,250-rpm height that's as lofty as the surrounding Dolomites. Emissions regulations may soon spell the end of that barrel-chested, 6.5-L engine, whose 12 naturally-aspirated cylinders describe every roadgoing Ferrari built between 1947 and 1973. But the rest is modern magic, the kind of prestidigitation that's required to transform a 4,774-lb (2165-kg), AWD machine - the first Ferrari with four doors and four adult-sized seats - into a stunning performer that feels lighter and lither than any driver would ever expect.
Applications in commercial and military fields created high demands on the steering performance of multi-axle vehicle. With the characteristic of more degrees of freedom (DOF), all-wheel cooperative steering is more conducive to improve the steering performance of multi-axle vehicle. This paper studies multi-axle vehicle assembled with steer-by-wire system, and proposes a control strategy to achieve all-wheel cooperative steering to improve the low-speed steering flexibility and high-speed steering stability of multi-axle vehicle. Based on the ideal steering performance at low-speed and high-speed, the steady-state gain of multi-axle vehicles at different speeds is reshaped. Also, the corresponding vehicle reference model is constructed to provide the ideal vehicle state as a reference. The precision of the vehicle reference model is verified by an all-wheel independent steering platform. Accordingly, the state feedback control module which contains a sliding mode controller and a disturbance observer is designed to make the actual state of the vehicle track the designed idea state, which is verified under a variety of path tracking conditions in the simulation environment. Simulation results show that the control strategy proposed for multi-axle vehicle can achieve all-wheel cooperative steering, improving the low-speed steering flexibility and high-speed steering stability of multi-axle vehicle.
An undeniable technical achievement since its U.S. launch for the 2001 model year, Toyota's Prius never has been able to shake its weenie-mobile reputation. It's an image formed largely by the combination off oddball, aerodynamics-first styling and the pursuit of ultimate fuel efficiency via low-power propulsion. With EVs looming as the propulsion endgame and attention to the 20th-century concept of “fuel-efficiency” waning, Toyota's said “enough!” The 2023 Prius bodywork now is smooth, low and sleek, so different that there's virtually no visual connection to its trippy forerunners. Under the hood is a larger, powered-up 4-cyl. engine and similarly boosted drive motor that, combined, take the Prius to 194 hp (196 hp for AWD models) - a 60% jump over the wheezy 121 combined hp of its predecessor. Almost paradoxically, though, the 2023 Prius still sips gasoline at pretty much the same pace - up to a 57 mpg (4.1L/100 km) combined rating for the most-efficient LE trim in front-wheel drive. The low is the 49 mpg (4.8L/100 km) combined rating for the top-trim XLE in AWD layout.
This paper investigates the effect of tire inflation pressure on the directional stability of All Wheel Drive (AWD) vehicles during high-speed off-road maneuvers over different soft terrains such as loam, sand and clay. For this purpose, a fourteen-degrees-of-freedom (14-DOF) full parametrized vehicle model is employed and numerically simulated in MATLAB/Simulink environment to represent the full vehicle body dynamics such as roll, yaw and pitch motions. In order to calculate tire forces and moments over deformable terrains, the AS2TM Soft Soil Tire Model was successfully integrated with the vehicle model which enabled the possibility of changing tire pressure and consequently investigate its effect on vehicle dynamics. Numerous simulations are carried out to examine vehicle handling in case of different tires inflation pressure during steady state turning maneuvers such as ramp steer input. Simulation results at both moderate and high-speed turning maneuvers showed that changing tire inflation pressure is significantly affecting vehicle handling characteristics such that it can be changed from understeer to oversteer behavior for excessively reduced tire inflation pressure. The paper is also presenting a proposal for a Central Tire Inflation System (CTIS) which is verified using laboratory test-rig. The proposed CTIS is mainly intended to use a professional control system using Programmable Language Control (PLC). The control system is based on two analog pressure sensors which are used as feedback of the real tire inflation pressure. The driver can control tire pressure either manually by selecting the tire pressure value or automatically by specifying the soil type. The driver interface system is implemented using ten inches touch screen which is also used to show the tire pressure instantaneously. The proposed CTIS system is effective, reliable, inexpensive and request no modifications in vehicle axles.
Simplified vehicle dynamics models used to study the driveline durability are typically limited to the longitudinal dynamics and do not account for vertical and pitch dynamics. The influence of suspension on the vehicle ride and handling characteristics is studied extensively in the literature but its impact on the driveline torques is often not considered. In this paper, an effort is made to investigate the influence of suspension compliance on the driveline torque using a planar (longitudinal, pitch and vertical) vehicle dynamics model. An AWD vehicle is studied to understand its impact on the torque levels of both axles (primary and secondary). Subsequently the planar dynamics is explored in the context of anti-squat/anti-dive suspension. The primary focus of the paper is to predict the driveline torque. While more sophisticated suspension models are built and used to study the ride and handling characteristics of the vehicle, to the authors’ knowledge this is the first time, a model with this level of fidelity is used to evaluate driveline component durability.
Passive hydrocarbon traps (“HCT”) are limited in performance when installed in an oxygen deprived location, such as an underfloor that is downstream of a CC TWC. An OEM 1.0L close-coupled converter in a 1.4L turbo hybrid PZEV calibrated vehicle was replaced with a 1.24L HC trap. The HC trap consisted of a zeolytic storage layer beneath a Pd/Rh containing three-way catalyst layer. The UF converter was upgraded with a newer TWC technology. The HC trap and UF TWC were engine aged to simulate 150,000 miles, or full useful life conditions. Criteria for accelerated engine aging of the HC trap were selected based on the vehicle application’s peak operating bed temperatures in the field. Vehicle FTP and US-06 tests were conducted on an all-wheel drive dyno which facilitated normal hybrid powertrain operation. A SULEV20 engineering target for FTP nMHC+NOx emissions was met with the full useful life aged CC HC Trap (“HCT”) system, using a PGM amount that was lower than the OEM design. The aged experimental system resulted in nMHC and NOx emissions of 5 and 10 mg’s/mile, respectively. CO emissions were well below the 1.0 g/mi LEV-3 SULEV20 limit. US-06 nMHC + NOx emissions were below 10 mg/mile. A high level of HC performance for the CC HC trap was achieved due to oxygen availability during the desorption phase vs the case where the trap is installed downstream of a TWC in a secondary position.
All-wheel drive (AWD) and four-wheel drive (4WD) vehicles are becoming more prevalent in the market today. However, it is not well understood what the correct practice is when only one tire on the vehicle needs to be replaced. There are various recommendations and practices provided by tire dealers and car manufacturers to the consumer. The most common recommendation is to replace more than a single tire and match tread depths across all tires. The basis for this recommendation is the idea that tires with different tread depths will have a different number of revolutions per distance traveled due to differences in rolling radius. Mixing tires with different tread depths may cause extra wear or damage to the drivetrain components because, on a vehicle, the tires must rotate at different speeds to travel the same distance. In this study, the rolling radius of tires is measured on vehicle to understand the impact of tread depth, tire brand and model, and inflation pressure on the rolling radius. It was found that the rolling radius is not as sensitive to tread depth as it is to tire brand and model or even inflation pressure. Therefore, matching tread depths is not the most relevant criteria when replacing a single tire or tires in pairs. It is more important to match tire brand and model and maintain proper inflation pressure to ensure equal rolling radii across all tires.
The refresh of the 2021 model-year Chrysler Pacifica minivan premiers a top-of-the-line luxury trim, the debut of a next-generation infotainment system, and the return of all-wheel-drive. Chrysler minivans haven't offered AWD since 2004, but the driveline choice is revived for the 2021 model. “We'll make AWD available in the current generation minivan for about 90 days, starting in the second quarter of 2020, to get it into the market,” Matt Davis, director of Chrysler and Fiat Brands for Fiat Chrysler Automobiles, said prior to the 2021 Pacifica's unveiling at the 2020 Chicago Auto Show.
Electrification of the powertrain is one of the most promising trends in the automotive industry. Among the novel architectures, this paper aims to study the latent advantages provided by in-wheel motors, particularly an All-Wheel-Drive powertrain composed by four electric machines directly connected to each wheel-hub of a high performance vehicle. Beyond the well-known packaging advantage allowed by the in-wheel motor, the presence of four independent torque sources allows more flexible and complex control strategies of torque allocation. The study explores three different control modules working simultaneously: torque vectoring, regenerative braking and energy efficiency optimization protocol. The main objectives of the project are: improving handling, measured through the lap time of the virtual driver in a simulated track, and enhance energy efficiency, assessed by the battery state of charge variation during standard events. The torque vectoring strategy is based on a feedback PID controller working in parallel to a feedforward logic that predict the desired behavior based on the driver demands (such as steering angle) and vehicle states (chassis accelerations and velocities). The regenerative braking manages the demand of the driver by transferring decelerating torque from mechanical brakes to electric motors, based on their saturation condition, longitudinal slip of tires and the harmony with torque vectoring. Furthermore, a simulated ‘engine braking’ is developed and analyzed. The energy efficiency optimization protocol, allowed exclusively due to the presence of four independent electric motors, is an innovative approach to analyze the efficiency maps of the electric machines and find the best torque allocation in terms of power consumption without impact to longitudinal acceleration and yaw moment creation. The study successfully highlights the benefits of the all-wheel-drive in-wheel electric motors powertrain architecture and builds a solid platform to the development of the three control strategies and their relation, considering both the vehicle dynamics and the electric subsystem performance.
Amid a steadily contracting sedan universe, Hyundai has dug in its heels and thoroughly redesigned and engineered its Sonata for 2020. The eighth-generation model sports a shapely (to our eyes) exterior form slightly reminiscent of Audi's A7. It's underpinned by a new platform shared with its 2021 Kia Optima cousin that will serve multiple FWD/AWD passenger cars and crossovers, according to senior U.S. product-planning manager, Mike Evanoff. New technology applications include a “Digital Key” that allows Sonata drivers to unlock and start their cars via their smart phones, Hyundai's first continuously-variable valve duration system in the new 1.6-L turbo engine, and a solar array that extends driving range in a new hybrid propulsion option.
Valeo is an industry leader in technologies essential to vehicle electrification and connected/automated driving. The French Tier 1 pioneered 48V mild-hybrid systems and is a major producer of e-hardware and software including belt-starter generators, power electronics, electric superchargers and traction motors. Valeo recently entered a collaboration with Dana Inc. to develop and supply electrified AWD systems featuring 48-V hybrid power. The first of these is scheduled to launch in volume in early 2020 with a major European OEM. One of the architects of Valeo Group's steady evolution as a mobility-tech supplier is Guillaume Devauchelle, vice president of Innovation & Scientific Development. He joined Valeo in 2000 after the acquisition of Italy-based wiring harness maker Sylea where he served as VP of R&D. Monsieur Devauchelle recently spoke by phone with editor-in-chief Lindsay Brooke.
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