Special: IT & Reva

Revving up with Reva

Without IT this colourful electric car would never have existed, says Prashant L Rao. From design to testing to manufacturing to maintenance, software is crucial for the Reva

It all began in 1994 when Chetan Kumaar Maini, Managing Director of the Reva Electric Car Company (RECC) looked at the problem of city mobility. The company conducted surveys in six cities, based upon which it designed the Reva, an electric vehicle with a higher seating position, larger doors and dent proof body panels. Designing an electric vehicle gave Maini the advantage of offering features such as automatic gears that usually cost Rs 1 to 1.5 lakh over and above the cost of a base model. There were two problem areas—the price point of most electric vehicles was very high and battery performance tended to be inconsistent. The company took an IT-oriented approach to crack the battery management problem by devising adaptive control algorithms that predict battery performance based on historical data. RECC tested batteries for 18 months to develop these algorithms. Three to six engineers worked directly on the project and five to 10 contributed indirectly by providing data to fix the algorithms. “Our three year warranty is possible because of the battery management software,” says Maini.

To solve the cost equation, Maini and his team came up with a different approach to manufacturing, which integrated technology from the US and India using off-the-shelf components wherever it was possible to do so. Innovations include using common components for the converter (it converts the 48V generated by the car’s eight tubular lead acid batteries to provide 12V for its electric components) and the battery charger. They succeeded to the extent that Maini says, “Similar models elsewhere cost three times as much.”

Software is important for the Reva. As Maini says, the aim is to “move work from hardware to software to enable system-level changes.” For instance, this approach gives the company the flexibility of changing the top speed of the car by making a simple programming change.

Today, the Reva is poised to tap export markets in the European Union (EU) with its G-Wiz export model. In the UK, the G-Wiz is exempt from parking fees and congestion taxes. It is also exempt from sales and road tax, there are special subsidies and exemptions and 100 percent depreciation in the first year itself in many parts of Europe. RECC is also targeting the market of 30,000 units per year for vehicles such as quadracycles and micro cars—small cars meeting the requirements of the urban population for city mobility—in the EU.

Variety is the spice of Reva

The Reva comes in three versions—Standard, AC and Classe. The AC version comes with a stereo while the Classe has a remote controlled AC that can be used to pre-cool the vehicle while it is still charging. All these models are available in 2,000 colours. The Reva can be driven in two modes—economy, where the top speed is 50 kph and forward mode with greater acceleration and a top speed of 65 kph. The difference while driving in these two modes is quite noticeable, put the car in forward mode after driving for a while in economy and you feel the change as you put the pedal to the metal.

Maini and his machine

Chetan Maini built his first solar electric vehicle in 1990 while studying at the University of Michigan. He was part of the team that came in third at the World Solar Race in Australia, a million dollar project that involved building a car that ran on solar energy for a race spanning 3,000 kilometres. The Reva is the culmination of Maini’s lifelong passion for electric vehicles.

Climate control seats

The G-Wiz export model has climate-controlled seats. A solid state electronic pump is used to circulate hot or cold air through the seat using technology derived from the American aerospace industry. Continuous usage of this technology decreases the Reva’s range by less than 3 percent.

G-Wiz, it’s EU

The G-Wiz is the Reva’s European avatar. This latest addition to the Reva stable features climate control seats and remote controlled heating. It also has lower seats that leans back three inches to accommodate Europeans who tend to be taller than Indians are. The G-Wiz has a modified parking brake that’s easier to pull from the new seat position and an immobilising device that prevents the car from starting until it senses the presence of the car key via infrared. The G-Wiz is priced at a premium of 30-40 percent in comparison to the domestic market and is being exported to the UK and Malta. RECC is upbeat about the G-Wiz’s prospects in Japan, US, Norway and Ireland.

Inside the Reva (the EMS)

The Reva’s EMS (Energy Management System) is a black box located under the rear seat. It contains one of the car’s two microprocessors. The EMS takes care of battery management, data acquisition, data storage and diagnostics. “If the battery technology changes we can just flash or change the PROM,” says Maini. Today’s models come with PROMs (Programmable Read Only Memory) while future ones will have flash memory built-in.

Into the Palm

The PDA interface was developed two and a half years back. It took nine months to write the code. PETSOFT (Portable Electronic Tool Software) running on a Palm m100 is used to download data from the EMS. The data downloaded to a PDA is transferred to a PC where a bunch of Excel macros analyse and format it into meaningful info-graphics. The software lets a service engineer zero in on a problem without having to indulge in guesswork. RECC is working on a simplified version of PETSOFT for car owners that will give them useful information such as the estimated time it will take to charge the Reva or how many kilometres you can travel with the present charge.

The Reva comes together

As Reva was targeting lower volumes (sub-10,000 units) an assembly line didn’t make sense. To reduce the cost of operations, the company has a unique assembling set-up. The car’s space frame (a 3D metal structure that consists of the chassis and a metal frame) is fitted with wheels at the first station. From that point onwards, the space frame is wheeled from station to station (there are 14 stations and four substations), doing away with the need for an expensive conveyer belt.

Putting the Reva through its paces

Each Reva Car rolling out of the assembly is checked for over 100 parameters. In addition, each car is tested on a vehicle dynometer for performance, range, acceleration, speed and efficiency and has to pass a shower test.

prashant@expresscomputeronline.com