With the addition of the Altroz iCNG, which boasts of the company's patented "integrated mounting system for a vehicle", and the launch of an additional electric model this fiscal year, Tata Motors expects the share of gas-powered models and battery electric vehicles within its passenger vehicle portfolio to increase to 15% each from the current 8% and 9% respectively in three-four years, said Shailesh Chandra, managing director of Tata Motors Passenger Vehicles and Tata Passenger Electric Mobility.