Modelling powertrain for modern vehicles
The automotive industry is poised to go through a mega transformation. More than 50% of the consumers are considering buying an EV during their next purchase. Environmental awareness, stringent regulatory norms, and recent development in technologies are reshaping tomorrow’s vehicles. Automotive OEMs are forced to re-engineer the conventional powertrain. In the last few years, the industry has seen GDI, turbocharged gasoline, downsizing, auto-start stop, Fuel cells and various versions of hybrid to entirely full electric drivetrains. Globally, several countries have announced a targeted end date for ICE. However, through the transition period in the next decade, ICE will remain the dominant technology with 60 to 80% share of mild hybrid. Every change is making powertrain designs efficient, smart, sophisticated, and require a large amount of design and testing efforts. These changes are very disruptive and any delay or failure can cost significant market share and tarnish the reputation.
Let us take a deep look at the complex nature of the modern powertrain designs. Be it ICE, hybrid or electric, every powertrain has several systems and sub systems. An ICE has engine fuel system, air handling system, lubrication system, thermal management system, and transmission systems. In addition to this, you need to fit in the battery system and the electric control system for a HEV. For robust and optimal powertrain performance, OME must ensure a fine design and integration of these complex systems, sub systems and components. This is where engineering simulations are playing key roles today. Right from ICE analysis & designing it to solving high fidelity chemical kinetics, complex fuel models and fluid structural interactions, Ansys has a comprehensive software suite covering all the aspects of it. The Chemkin pro tool from Ansys can simulate underlying detailed chemistry, which is very critical for costeffective design of systems with reduced pollutant emissions or undesired byproducts. The feature called reaction path analyzer provides a clear view of dominant reaction paths, facilitating mechanism development and reduction. It can also efficiently predict soot emission and provide flamelet tables for CFD models. In summary, Ansys Chemkin-pro is one of the favorite tools to optimize the fuel effect, efficiency, knocking and emission.

For electric and hybrid vehicles, thermal analysis of the battery system is immensely critical. It is not only linked to safety but is also of paramount importance to the peak power and battery life. On the other hand, weight reduction or increasing energy storage capacity, fast charging are ongoing quests. Volkswagen engineers were able achieve the same using Ansys’ six step Multiphysics simulation approach and beat the Pikes Peak World Record.
Turbo charger plays significant role in boosting the power output and reducing the emission while keeping smaller engine size. It is desired to have high accuracy reliable CFD solver to predict the physics for hundreds of designs and at different operating conditions. Apart from fluid dynamics, structural integrity is essential for the life cycle and reliability prediction. Ansys software suite is proven and most dependable tool for turbomachinery.

Apart with pumps, the other important moving components of powertrain system are gearbox and motors. Any small misalignment in these components will not only dwindle the life expectancy, but also affects the comfort and performance. Many times, the Noise Vibration and Harshness (NHV) analysis is of the focus. Simulation tools like Ansys Maxwell, Ansys Mechanical, Ansys Fluent and Ansys Motion can be seamlessly coupled to get best in class physics solution with detailed insights. It is now possible to achieve high quality NHV postprocessing. For example, NVH assessment with Signal duration extension, Psychoacoustic analysis, Sound design and Characterization.

A safer vehicle is of prime importance. In electric and hybrid vehicles, the size of battery pack, casing and its position in the car is a very important factor to ascertain safety rating in a crash test and also to minimize the risk of battery fire. Ansys has both explicit and implicit structural solvers strengthened by detailed material models and a comprehensive battery modelling technology. Using it, experts from automotive OEMs are accurately carrying simulation for mechanical abuse, crash, crush, and nail penetration tests. Also, by using Fluid-Structure Interaction (FSI) coupling capabilities for modelling joints and crash simulation, a high degree of accuracy can be obtained.

The gear box modelling of lubrication and heat transfer with high-fidelity is an important aspect for predicting fatigues-life, NVH and losses. Therefore, to predict oil flow patterns and churning losses, a good accuracy flow and thermal solver is needed. Ansys Fluent has wide-ranging multiphase models which used with flow solver to perform such high-fidelity simulation at affordable computational cost.

Integration of these components in a powertrain system and their interaction after integration once again needs to be verified. Modelling this system level integration requires an accurate component level modelling to obtain their reduced order models (ROM) for 3D physics. Static and Dynamic ROMs are crucial technologies to achieve accuracy, speed and therefore to generate system models. Ansys has capabilities to generate ROMs for Batteries, BMS, Motor and most of the components associated with electric or hybrid vehicles. These multiple ROMs, when combined, helps us to analysis the system level performance. Ansys Twin Builder provides a virtual platform to host all these ROMs, validate and deploy compete system simulation. Also, some OEMs are now developing a digital twin model to manage the vehicle performance after it has been deployed. With Ansys Twin Builder engineers can use systems simulations at every step of the vehicle development cycle.

According to a survey done by Aberdeen Group, automotive executives believe that the use of engineering simulation improves the time to market by 17%, cost-effectiveness by 22%, and product quality by 17%. Engineering simulations was never so important as it is today, especially so in the era of technology disruption. Ansys, with a broad portfolio of physics solvers and vast experience of addressing complex engineering challenges, is the right simulation partner to ride this disruption wave and deliver your product promise.