LOTUS ELISE
ELECTRIC VEHICLE CASE STUDY
ELECTRIFICATION DEVELOPMENT AHEAD OF ITS TIME
The California Air Resources Board Zero-Emission Vehicle Mandate
In the 1990s, the California Air Resources Board (CARB) issued Zero-Emission Vehicle (ZEV) mandate in North America:
Implemented in September, 1990, it originally required that, starting in 1998, 2% of the in-state new light duty vehicle sales of major automakers had no emissions of criteria pollutants.
EV Created to Showcase Zytek’s Capabilities
To present Zytek’s capabilities as a potential engineering partner to major OEMs, Zytek created an electric vehicle based on the Lotus Elise.
Zytek created two demonstrator platforms that were shown to North America and the major OEMs.
World Leading Technology
Two mules were created (largely similar) to showcase Zytek’s world-leading technology:
- Torque Vectoring (opposed to Tesla’s approach of a single motor driving a conventional gearbox).
- Electric motor and inverter technology.
- The benefit of two motor systems on handling.
Refining Handling Characteristics
A great deal of time was spent refining:
- The handling characteristics of the torque vectoring architecture
- How do the two inverters need to be controlled together in all situations, not just regular track, but also skid situations – how does that torque vectoring want to appear during a slide for example?
Many lessons were learned over the course of the project, not only on the drive train, but also on how to put together an electric vehicle, helping Zytek to become one of the pioneers of electric vehicle development.
Creating An Acceptable Vehicle Environment
We also looked at when the vehicle doesn’t have an internal combustion engine creating a level of background noise, what other sound or attenuation measures do you need to take to create an acceptable vehicle environment.
User Interface
The user interface was updated, so the conventional dashboard was replaced with information that was more relevant to drivers of electric vehicles; and the conventional gear lever was obviously removed (no gearbox so no gear linkage).
Drive neutral and reverse buttons were added to the dash with associated safety systems to ensure that drive modes were not accidentally engaged.
Testing and Validation
Vehicle was driven extensively on both public roads and test tracks for levels of validation, and the technology was successfully demonstrated to a large number of potential customers.
Outcome
Unfortunately, the CARB zero emissions mandate was then put on ice, which took the impetus out of the automotive industry at the time in their drive towards electrification technology.
It was certainly an ambitious and positive form of legislation that attempted to pull automotive electrification technology development forward, though in hindsight, was beyond the battery technology of the day.
