Chrysler Group is adding fuel-saving engine stop-start (ESS) technology as standard on some versions of the 2015 Jeep Cherokee and Chrysler 200 mid-size sedan models.

ESS has been added to the 2.4-litre 'Tigershark' I4 in the 200 and the Cherokee's optional 3.2-litre 'Pentastar' V6 with estimated fuel economy improvements of up to 3%.

A CO2 emissions reduction of up to 3% is estimated.

Cherokee models with ESS are scheduled for third quarter sales with ESS equipped 200s following in the fourth quarter.

The technology made its NAFTA-region debut in Chrysler's Ram 1500 full size pickup. ESS accounts for a 1mpg, city cycle fuel economy gain in the Ram, claimed to be the most fuel-efficient truck in its segment.

The ESS system is based on a high-speed/high-durability starter that reduces crank time, culminating in quicker restarts. Its function is regulated by algorithms that act on the vehicle's powertrain and chassis components.

ESS can be deactivated by a pushbutton.