eMobility

Romax consulting and software supports GKN Driveline to design low-noise high-efficiency eDrive gearboxes

The evolution of electric vehicles (EVs) and hybrid electric vehicles (HEVs) is having a significant impact on Automotive engineering, particularly transmission and driveline design. The world’s leading manufacturer of Automotive driveline components, GKN Driveline has applied Romax software and consulting to focus the optimization of gearbox efficiency in electric motor-driven transmission without accepting trade-offs in noise and durability.

Client Solution The world’s leading manufacturer of Automotive Approx. 15 year (Japan since 2004 and Europe since driveline components: 24,000 employees at 2010) relationship with Romax, using Romax software 45 manufacturing facilities and three product and consulting expertise for advanced modeling, development centers in 22 countries. simulation and analysis of geared systems.

Challenge Benefits Develop more powerful and efficient transmissions One of the best-in-class ‘whole system’ approaches for greener electric-driven vehicles, capitalize on new for faster and more effective Right First Time design market opportunities without trade-offs in durability of low-noise gearboxes for hybrids and EVs; tests and noise and vibration (N&V). showed a 2% gain in overall gearbox efficiency without compromising on durability or N&V.

14 | Engineering Reality Magazine After identifying the main contributors Why Romax? design. GKN Driveline manufactured to power loss, investigating how changes a redesigned set of gears, with to macro- and micro-geometry would Conventional methods to increase extensive tests confirming overall affect efficiency, and optimizing the transmission efficiency can have efficiency improvements and, in the geared system in Romax software, GKN adverse effects on durability and all-important coast condition that Driveline manufactured the resulting quiet running; lack of engine noise in determines energy recuperation gears and evaluated experimentally the EVs renders current design practices performance, a 1-2% gain across the driveline efficiency. Results showed unacceptable. In addition, the pressure speed and torque range required. “The improvements across the speed and to improve efficiency of the eDrive efficiency of the gearbox was assessed torque range of interest of up to 2% gearbox in GKN Driveline’s all-wheel by calculation of the component without compromising on durability and drive hybrids required a new approach. losses from gears, bearings, seals N&V. This provided valuable insights “We’ve worked with Romax for several and oil churning,” Dr. Grunwald says. into how GKN Driveline continuously years, in a step-by-step process that “Efficiency results from the simulation initiates performance improvements in started in Japan then moved into are compared against frictional its customer applications. Germany and Sweden,” says Dr. Artur torque measurements taken during Grunwald, Supervisor, Advanced testing under a range of torque and Hybrids and EVs: Geared Systems Calculations. “We speeds. The methodology used allows a market opportunity saw the value of analyzing the whole advanced parametric studies to be system, to identify where the greatest carried out in an all-in-one approach GKN Driveline develops the latest benefits could be gained, then working with Romax software to consider driveshaft and geared component to balance efficiency, durability and the effect of a wide range of design technologies. “During first hype of N&V across the entire system. Romax changes on efficiency at the same time electrification, everyone talked about software provided the accuracy in as durability and NVH performance.” quick introduction of Battery-Electric modeling and analysis, and we worked Vehicles,” says Theo Gassmann, Vice with Romax people on a project and He adds, “We also have several years’ President Advanced Engineering. consulting basis to learn how to experience of working with Romax “The reality was that the technology best use the software and apply our people, who have been extremely wasn’t ready - for instance, battery engineering expertise. reliable and professional. We technology is too expensive – and clearly benefit from that valuable customers aren’t ready, particularly “We use Romax software for problem experience. As a business, we want to regarding range limitations. So the solving and for system optimization develop a common understanding of EV market experienced a slow start.” from concept to production design. simulation issues, and use consistent He says this led companies to change Perfect components don’t always methodologies from concept to strategy, embracing a hybrid approach equal a perfect system when production. Our requirement to to develop the marketplace. combined. That’s why we use Romax take a whole-system approach will software: it shows where you can increase with future projects and “GKN Driveline, as market leader in have the most impact and where applications, and across different driveline technology, is growing fast in the benefits lie. It’s one of the few regions and product ranges. The way conventional and electrified driveline software systems capable of this Romax software integrates with other systems. Coming from AWD systems we type of system analysis. Our goal is, software packages also saves us successfully launched transmissions systematically, to separate the useful time. Its ability to provide interfaces for Hybrid and Electric vehicles in the parameters from the possible in and to share results for interpretation last years. Transmission has not been order to enable the biggest benefit at by our engineers is another reason we our core business but we utilized our acceptable cost level.” use it internationally.” driveline expertise and technologies to expand our portfolio successfully.” Taking a ‘whole system approach’ Theo Gassmann adds, “We’re moving Gassmann says transmission issues to optimize design into a new era of hybrids and electric for EV and HEV are broadly similar to cars. Genuinely high-performance non-electric applications: “Powertrain Romax’s abilities to improve efficiency products demand the effective efficiency, durability and N&V. were tested in a project that saw application of system know-how Differences come regarding the duty an eDrive gearbox connecting an from concept to production, so you cycle and loads, between coast and electric drive to the rear axle of a PSA can find the best possible balance. drive. The driveline is different. And Peugeot Citroen passenger car, with To meet increasing customer when you have to invest in battery a conventional IC drive connected expectation and faster development capacity, you don’t want to waste to the front wheels. The original cycles, GKN Driveline has to get Right energy in the transmission. The biggest gearbox was analyzed using Romax First Time to the required product challenge is arguably N&V. Missing software, which explored potential performance, and Romax helps us masking noise from combustion engine improvements through changes to achieve that - so we can continually and lightweight-design leads to an early gear geometries, comparing predicted improve our methodologies and focus on NVH improvements.” N&V and durability with the original products for our customers.”

Volume XII - Winter 2020 | mscsoftware.com | 15