KPIT Cummins Develops Innovative Bolt-On, Plug-in Hybrid System
While some U.S.-based aftermarket startups are offering high-five-figure hybrid powertrain retrofits, an Indian original-equipment (OE) automotive supply firm is preparing to launch a simple $1,300-$3,500 bolt-on plug-in parallel hybrid system for the masses.
Having proven its effectiveness in testing so far, the prototype system called “Revolo” is being developed by KPIT Cummins as a gas- or diesel-engine add-on, first for the Indian market, but North American, European and Asian automakers have also already expressed interest in the system.
The anticipated installed cost of its belt-driven electric motor, battery and battery management system (BMS) works out to about one-third the selling price of a new vehicle in India, and the system functions essentially like GM’s eAssist.
While the batteries remain charged for average daily driving needs, fuel efficiency is said to be improved by 35 percent, emissions by 30 percent, and the system’s payback is to be less than two years from time of purchase.
If you’ve not heard of KPIT Cummins, briefly, it is a $309 million publicly traded company with over 7,700 employees, based in India, 11-percent owned by Cummins of North America. It has operations in North America, South America, Europe, Japan, Korea, China, and is a supplier to 14 of the top 20 original equipment manufacturers.
In a phone interview this week with one of the engineers involved in the project, we learned this will be the company’s first foray in automotive hardware plus software products, but it is building on its strengths as a behind-the-scenes automotive technology provider to most major automakers.
High Tech Low Tech
Because a low-cost but effective system had to be devised that could sell itself without any green car conversion incentives in India, KPIT had to think hard to come up with solutions to meet these criteria.
This was all the more challenging when trying to be viable in the light-duty commercial market for such vehicles as cabs and delivery trucks. Many Indian small businesses do not have pockets as deep as, say, American corporate fleet buyers who might spring for something like a $30,000 retrofit by the likes of ALTe or a $70-80,000 turnkey converted pickup from VIA Motors.
So to be sure, the several-hour installation of the Revolo parallel hybrid system upgrade – intended for engines up to 3.0 liters – is not as involved as these series hybrid powertrain retrofits, but it is said to get the job done with a quick return on investment.
Presently two motors are being developed for the system. One is for smaller passenger cars, rated at 2.2 kilowatt (3 horsepower, 22 pound-feet torque), the other is for light commercial vehicles rated at 7.5 kilowatts (10.2 horsepower, 55 pound-feet torque). KPIT Cummins says these continuous-output ratings can be peaked by triple these numbers for up to one minute bursts when needed.
The result is a system that adds 20-40 percent more power to the internal combustion engine’s output when needed without using any fuel.
The idea is when the engine needs it most – such as at low rpm – the instant torque of the electric motor assists, then tapers off above 1,800-2,000 rpm seamlessly thanks to the sophisticated engine control unit (ECU).
The BMS and ECU that come with the installation are the company’s own design, can be adapted to a variety of battery chemistries, and rely on algorithms fed signals by some retrofitted sensors, as well as the vehicle’s stock sensors used by its ECU sensors.
Another innovation is the use of a high-efficiency AC induction motor, instead of a more costly permanent magnet motor, and unique lead-acid batteries made more durable with carbon technology.
Comparatively inexpensive lead acid batteries are usually considered the bottom of the automotive battery hierarchy, but the added carbon and other technological innovations extend life to around 750 recharge cycles.
In contrast, lithium-ion – which by the way, the system is compatible with also – would normally cost 3-5 times more.
KPIT Cummins has also tested with lithium-ion, but the carbon-enhanced lead-acid chemistry is getting the nod for the Indian market at this juncture. The Revolo system would also work with nickel-metal hydride, but KPIT-Cummins has not gravitated to that chemistry in its development work.
Planned battery range with lead acid is expected to be up to 62 miles for commercial vehicles, and about two-thirds that for commuter applications.
The idea is to provide enough range to work for most applications, either light commercial vehicles traveling up to 62 miles per day, or commuters traveling the average 18-25 miles per day in India.
After the batteries deplete, the BMS shuts the system down, the petrol engine continues to operate as normal, and the electric motor simply freewheels with no parasitic drag.
Regenerative braking does also offer 10-12 percent recharging to the batteries on average, extending range somewhat. After the system finally depletes, the regen feature stays operative, and if the batteries reach a sufficient state of charge, the system will automatically turn back on.
Another low-cost, but effective aspect is this plug-in hybrid system uses a basic three-phase plug much like a computer cord. No fancy 5-pin SAE J1772 or CHAdeMO plugs here to pay for – or risk being stolen.
Economics and Pragmatism First
For now, the Revolo system is intended as an efficiency boost, and not as a speed or acceleration performance enhancer, so 0-60 runs will only barely be improved. The main goal is saving money without costing a lot of money, and the benefits have not been lost on some of KPIT’s existing OE customers who’ve shown interest.
For example, in testing the system mated to a sophisticated modern “European luxury SUV” with over 60 on-board ECUs – which KPIT Cummins was not at liberty to name – the Revolo system provoked no diagnostic error codes. This and other such testing have been taken as a good sign that the computer programming side of KPIT Cummins’ automotive engineered solution is as effective as the low-cost side of it is.
First things first however is to prove it works in the real world. The initial Indian market launch of the lead-acid system is anticipated to be a “lucrative” market with no downside for consumers.
Pending plans are for retrofitting the system through third-party franchises to existing vehicles. At the same time, KPIT Cummins is in discussions with automakers to build the system into new vehicles.
As mentioned, the company says it is talking with automakers about installing it in vehicles intended for the Indian market.
If all goes as intended, the company hopes for OE joint ventures, and in time to see its Revolo plug-in hybrid system installed in vehicles made for other markets also – possibly even the U.S. assuming it works as advertised.