Browse Topic: Vehicle drive systems
Direct current (DC) systems are increasingly used in small power system applications ranging from combined heat and power plants aided with photovoltaic (PV) installations to powertrains of small electric vehicles. A critical safety issue in these systems is the occurrence of series arc faults, which can lead to fires due to high temperatures. This paper presents a model-based method for detecting such faults in medium- and high-voltage DC circuits. Unlike traditional approaches that rely on high-frequency signal analysis, the proposed method uses a physical circuit model and a high-gain observer to estimate deviations from nominal operation. The detection criterion is based on the variance of a disturbance estimate, allowing fast and reliable fault identification. Experimental validation is conducted using a PV system with an arc generator to simulate faults. The results demonstrate the effectiveness of the method in distinguishing fault events from normal operating variations. The
An important characteristic of battery electric vehicles (BEVs) is their noise signature. Besides tire and wind noise, noise from auxiliaries as pumps, the electric drive unit (EDU) is one of the major contributors. The dynamic and acoustic behavior of EDUs can be significantly affected by production tolerances. The effects that lead to these scatter bands must be understood to be able to control them better and thus guarantee a consistently high quality of the products and a silent and pleasant drive. The paper discusses a simulation driven approach to investigate production tolerances and their effect on the NVH behavior of the EDU, using high precision transient multi-body dynamic analysis. This approach considers the main effects, influences, and the interaction from elastic structures of electric motor and transmission with accurate gear contact models in a fully coupled way. It serves as virtual end of line test, applicable in all steps of a new EDU development, by increasing
This SAE Recommended Practice covers the most common applications of electronically controlled on-demand clutch systems used in passenger (car and light truck) vehicle applications. This practice is applicable for torque modulation devices used in transfer cases, electronic limited slip differential (eLSD) cross-axle devices, rear drive module (RDM) integrated torque transfer devices with or without disconnect capability, and other related torque transfer devices.
A design is presented for an electro-mechanical switchgear, intended for reconfiguring the windings of an electric machine whilst in operation. Specifically, the design is developed for integration onto an in-wheel automotive motor. The motor features 6 phase fractions, which can be reconfigured by the switchgear between series-star or parallel-star arrangements, thereby doubling the torque or speed range of the electric machine. The switchgear has a mass of only 1.8kg – around one tenth of the equivalent 2-speed transmission which might otherwise be employed to achieve a similar effect. As well as the extended operating envelope, the reconfigurable winding motor offers benefits in efficiency and power density. The mechanical solution presented is expected to achieve efficiency and cost advantages over equivalent semiconductor-based solutions, which are practical barriers to adoption in automotive applications. The design uses only mechanical contacts and a single actuator, thereby
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.
Electric drive systems are central to the efficient and clean use of energy for electric and hybrid vehicles. They need to efficiently convert electrical energy into mechanical motion, but coupling mechanical and electrical components into a highly compact system requires a range of complex design and engineering tradeoffs. One challenge is that automotive companies typically use a wide range of design and simulation technologies from different suppliers. This has resulted in multiple iterations of model and data transfers between the design and simulation software, which is inefficient, error-prone, and results in a lack of decision traceability.
This SAE Recommended Practice covers power transfer units (PTUs) used in passenger car and sport utility vehicles to support all wheel drive (AWD) operation. PTUs are typically full-time use geared devices (see 3.1). Some PTUs have additional features such as part-time on-demand capability via electronically actuated disconnect features, and other configurations are possible.
The recent addition of fully electric powertrains to propulsion system options has increased the relevance of sound and vibration from electric motors and gearboxes. Electrified beam axles require different metrics from conventional beam axles for noise and vibration because they have multiple sources of vibration energy, including an electric motor and a reduction gearbox. Improved metrics are also driven by the stiff suspension connections and lack of significant isolation compared to electric drive units. Blocked force is a good candidate because it can completely characterize the vibration energy transmitted into a receiver and is especially useful because it is theoretically independent of the vehicle-side structure. While the blocked force methodology is not new, its application to beam axles is relatively unexplored in the literature. This paper demonstrates a case study of blocked force measurement of an electrified beam axle with a leaf spring suspension. The axle was tested
Gear whine has emerged as a significant challenge for electric vehicles (EVs) in the absence of engine masking noise. The demand from customers for premium EVs with high speed and high torque density introduces additional NVH risks. Conventional gear design strategies to reduce the pitch-line velocity and increase contact ratio may impact EV torque capacitor or its efficiency. Furthermore, microgeometry optimization has limited design space to reduce gear noise over a wide range of torque loads. This paper presents a comprehensive investigation into the optimization of transfer gear blanks in a single-speed two-stage FDW electric drive unit (EDU) with the objective of reducing both mass and noise. A detailed multi-body dynamics (MBD) model is constructed for the entire EDU system using a finite-element-based time-domain solver. This investigation focuses on the analysis and optimization of asymmetric gear blank design features with three-slot patterns. A design-of-experiment (DOE
Items per page:
50
1 – 50 of 1419