A WhatsApp forward going around, shows a person in a petrol filling station desperately trying to locate the fuel tank in a Tesla electric car and a couple of people laughing in the background.

This probably explains the status of the powertrain of automobiles. From the time of the Ford Model T (the first mass produced car), nothing much has changed in the generation of power and its transmission to the wheels, which we call “powertrain”.

The prime mover, the same internal combustion (IC) engine, had a system of mixing fuel with air and feeding it into cylinders for firing (hence the name IC engine), and getting that power out through a crankshaft. Being a reciprocating engine the power had to be smoothed and regulated with a flywheel and transmission and then fed to the rear wheels through a differential and axle.

This configuration has not changed much for the last 100 years, though a number of refinements have gone into the entire system. Fuel injection, supercharging, turbocharging, variable valve timing, automatic transmissions, automated manual transmissions, dual clutch transmissions, front wheel drive, all-wheel drive, etc. to name a few, are developments in the powertrain system. More of electronics, electrically actuated mechanics, and complex engine management systems have contributed to refined performance, improved features and safer vehicles.

In spite of all the improvements, the engine’s efficiency in terms of the energy put in (fuel) vs usable energy taken out, is only about 50 per cent.

The pollution caused by exhaust and limited fossil fuel resources underscores the need for finding alternative propulsion. The powertrain technology could undergo a disruptive transformation.

IC engines if replaced completely by electric motors, controlled by computers, will have the greatest impact on the powertrain because it could eliminate the need for transmissions, clutch, axle shafts etc. Alternatively we could have a hybrid system where both are available and a computer selects the most efficient drive depending on driving conditions. Plugged-in Hybrid Electric Vehicles (PHEVs) have electrical motors as prime drivers but the vehicle also has a compact IC engine to extend the range when batteries run out. CNG, Hydrogen, Ethanol, fuel cells, etc. are other options being researched.

Despite the advances in motors/electronic controls, the main stumbling block for full scale conversion to electric is the battery and the infrastructure required for charging it. Batteries are heavy, occupy a lot of space, are flammable (hence a hazard), expensive (though prices are falling rapidly), and use electrodes made of metals that have limited availability. There is also the negative impact on environment caused by end of life disposed batteries.

Notwithstanding the progress in electric mobility, research in IC engines has not stopped. Engineers are racing against time to improve its efficiency and reduce emissions. Some even claim that the exhaust out of a car would become cleaner than the air we breathe. All these add to cost, of course.

In the final analysis, the total well-to-wheel cost, not excluding overall impact on environment, will decide the way forward. Currently, the cost balance is tilted in favour of the IC engine but the stricter legislations on emission norms are forcing auto makers to invest in electrical powertrain technology.

The writer is an independent consultant

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