Stop-Start As Standard
Fuel-saving technology sees inclusion for 2015
Andy Bolig - June 25, 2014 03:40 PM
Chrysler Group is offering fuel-saving Engine Stop-Start (ESS) technology as standard equipment on certain 2015 models.
Chrysler 200 customers who opt for the 2.4-liter Tigershark I-4, and Jeep Cherokee customers who choose the available 3.2-liter Pentastar V-6, will experience estimated fuel-economy improvements of up to three percent, compared with the conventional vehicle-engine pairings.
“We’re taking highly efficient engines and upping the ante to further benefit our customers,” said Mike Duhaime, Global Director-Electrified Powertrain Propulsion Systems. “ESS leverages intricate control strategies to deliver a superior driving experience, as well as the expected fuel-savings and emissions-reduction.”
ESS applications in the Chrysler 200 and Jeep Cherokee will account for an estimated C02 emissions-reduction of up to three percent. Availability in the popular Jeep Cherokee is scheduled for third quarter. ESS arrives the following quarter in the all-new Chrysler 200. The technology made its NAFTA-region debut in the Ram 1500 full-size pickup, where ESS accounts for a one-mpg city-cycle fuel-economy gain in the Ram, the most fuel-efficient truck in its segment.
At the heart of ESS is a high-speed/high-durability starter that reduces crank time, culminating in quicker restarts. Its function is regulated by algorithms that act on a vehicle’s powertrain and chassis components. As a result, acceleration is always aligned with driver inputs. Passive accelerator application is met with measured throttle response; hard inputs trigger aggressive starts. And there’s no waiting for either.
ESS works this way:
•Engine controls constantly monitor vehicle speed
•When the vehicle brakes to a stop, fuel flow is cut and engine turns off
•Beefier batteries maintain other vehicle systems so in-cabin comfort is unaffected
•When the brake pedal is released, the engine automatically restarts and the automatic transmission is engaged – all within 0.3 seconds
If a driver chooses to forgo the benefits of ESS, the feature can be deactivated with the push of a button, and then reactivated. Efficiency and refinement are hallmarks of the Tigershark and Pentastar engine families. ESS just complements these attributes.
The 16-valve, 184-hp 2.4-liter Tigershark comes standard in the all-new 2015 Chrysler 200. The slickly engineered I-4 also features the unique MultiAir2 electro-hydraulic fully variable valve-lift system. MultiAir technology uses a column of oil in place of the traditional mechanical link between the camshaft and intake valves and sophisticated electronic control of the MultiAir components maximizes intake manifold pressure, significantly reducing pumping losses.
MultiAir2 takes the innovation further by simultaneously controlling both valve opening and closing events to more effectively manage combustion quality. This ensures the appropriate, effective compression ratio and efficient internal exhaust-gas recirculation (EGR) for improved fuel economy.
The Cherokee’s available 271-hp 3.2-liter Pentastar V-6 helps the Cherokee deliver fuel-economy improvements of up to 30 percent, compared with the model it replaces. Individual exhaust-manifold runners are integrated into the aluminum cylinder-head casting, a key Pentastar-family differentiator. This design feature reduces weight and affords packaging benefits.
The 24-valve engine’s 10.7:1 compression ratio aids in lowering fuel consumption and improves performance while its variable-displacement oil pump further reduces parasitic losses to maximize fuel economy. The pump is programmed to operate as needed, staying in low-pressure mode below 3,500 rpm, and then bumping up pressure as demand follows engine-speed.