Challenges in NVH Refinement of Electric Vehicle Built on ICE Platform 2024-26-0216
Electric car markets experience exponential growth. As per IEA battery electric vehicles sales exceeded 10 million in 2022 [1] . There is projection from IEA that EV sales will touch 40 million mark by 2030, major contribution from China (12 m) and Europe (13.3 m) regions [2]. This growth projection attributed to many global factors, government policies, automakers commitment, climate change, etc. There is a massive push from global institutions and automobile community for transition to electric mobility. There is a 66% likelihood that the annual average near-surface global temperature between 2023 and 2027 will be more than 1.5°C above pre-industrial levels for at least one year. There is a 98% likelihood that at least one of the next five years, and the five-year period, will be the warmest on record [3]. Hence transition is imperative to reduce greenhouse gases and adhere to climate change commitments.
Today EVs are not popular as ICE. As per WEF [4] there are three major reasons for that (a) high upfront costs of EVs (b) Limited access to charging infrastructure (c) concern about EV range. Last two are related to ecosystem, battery research and exploration. But first one is engineering challenge. To overcome this, especially emerging markets or cost sensitive markets, adopted strategy is to develop EVs from the traditional ICE vehicle design. Developing an EV from existing ICE vehicle design is found to be cost-feasible solution. At the same time, this strategy leads to new challenges. Some engineering issues, customer concerns not so prominent in ICE vehicle becomes very significant in EV. One of those discussed in this paper is NVH.
BEV developed from traditional ICE design generally has common top hat. Most of the parts are common. By this approach product is optimized for validation time and cost. However, the underbody needs to be redesigned for accommodating battery module and the electric powertrain. NVH challenges that could arise in such vehicle can be categorized into broadly two types. Firstly, electric vehicle specific challenges due to new underbody and electric powertrain. Secondly, issues that were not prominent in ICE version of the car, like road noise, wind noise, component noises, etc. Aim of this paper is to discuss about such challenges in meeting NVH performance of a battery electric vehicle built on a traditional ICE vehicle design. This includes performance targets, engineering issues, and approach to resolve those issues in the time and cost constraint of the market.
