|Chevrolet Malibu ECO PowerFlow screen. Click to enlarge.|
Chevrolet has introduced the 2013 Malibu ECO, its most fuel-efficient midsize sedan yet. The Malibu ECO features GM’s eAssist light electrification technology (earlier post), which is engineered to deliver an estimated 26 mpg in city driving and 38 mpg on the highway.
Malibu ECO’s eAssist system is mated to a 2.4L Ecotec direct-injection four-cylinder engine and six-speed automatic transmission. The 2.4L engine features dual-overhead cams, direct injection, continuously variable intake and exhaust timing and electronic throttle control, as well as a lightweight aluminum cylinder block and cylinder head. It is rated at an estimated 180 hp (134 kW) and 170 lb-ft (230 N·m) @ 4900 rpm and is a variant of the same engine that was recognized as one of Ward’s Ten Best Engines in 2010.
Along with the Ecotec 2.4L and six-speed transmission, the eAssist system uses power stored in the air-cooled, lithium-ion battery to provide needed electrical boost in various driving scenarios, optimizing engine and transmission operation. The 0.5 kWh, 115V lithium-ion battery and latest-generation 15-kW motor-generator unit help increase fuel economy through:
- Regenerative braking, which provides up to 15 kW of electricity to charge the battery.
- Providing up to 15 hp (11 kW) of electric power assistance during heavier acceleration.
- Using electricity instead of gasoline when stopped, with automatic and smooth engine start-stop functionality.
- Aggressive fuel cut-off during deceleration down to zero mph for added fuel savings.
- Intelligent charge/discharge of the high-voltage battery.
The eAssist system captures up to 15kW of energy that would be normally lost during braking and uses it to recharge the lithium-ion battery. The system also shuts down fuel delivery in certain deceleration conditions, further improving fuel economy. While in fuel shut-off mode, the motor-generator unit continues spinning along with the engine to provide immediate and smooth take-off power when the driver presses on the accelerator. As the vehicle comes to a stop, the engine’s start-stop function is active when the motor-generator unit brings the engine to a smooth stop to position it properly for a smooth restart when the brake is released.
A hill-assist system captures brake pressure to help keep the vehicle stationary when eAssist’s start-stop function is activated on a moderate or steep grade, allowing the driver to accelerate more smoothly from a stop.
Malibu ECO’s eAssist power pack brings together the lithium-ion battery, the integrated power inverter and 12V power supply. It is located in the trunk, behind the rear seat. The electric motor-generator is mounted to the engine in place of the alternator to provide both motor assist and electric-generating functions through an engine belt-drive system. The motor-generator is a high-performance, compact induction motor that is liquid-cooled for increased performance and efficiency. An electric fan cools the power pack, drawing air from a vent located behind the rear seat.
With eAssist technology, which also enables a numerically lower final drive ratio, the Malibu ECO can travel as much as 550 miles between fill-ups.
An ECO gauge in the cluster continuously responds to driving behavior, encouraging fuel-efficient driving, while an Auto Stop Indicator on the tachometer informs the driver when the engine is in start-stop mode.
ECO is based on the 2013 Malibu sedan (earlier post). In addition to the ECO’s Ecotec 2.4L engine, the new Malibu’s North American lineup also features an all-new Ecotec 2.5L dual overhead cam, four-cylinder engine with direct injection. Sales of the new Malibu begin with the ECO model in the United States in early 2012. The Malibu LS, LT and LTZ trim level offerings join the ECO in summer 2012. Pricing will be announced later.
Aero efficiency. Malibu ECO—and the entire 2013 Malibu lineup—was designed to be aerodynamically efficient, with a coefficient of drag near the standout performance of the Chevrolet Volt extended-range electric vehicle.
Malibu ECO is among the first in the midsize segment with a fuel-saving, active shutter system in the lower grille. The Malibu ECO’s active shutter system automatically closes airflow through the lower intake opening when air intake is least needed. When closed, the shutter system enhances aero performance by redirecting airflow around the front of the vehicle and down the sides, rather than through it. The shutter is open or closed based on engine coolant temperature and speed. For example, the shutters open when the car is traveling up a hill, pulling a trailer, or in hot city driving; the shutters close at highway speeds when engine cooling is less required.
Other aerodynamic features on the Malibu ECO include:
- Outside rearview mirrors designed to maximize aerodynamic efficiency
- Tail lamps are shaped for aero performance without design penalty
- Four underbody panels cover approximately 50% of the lower portion of the vehicle and provide an aerodynamically clean flow path under the vehicle
- Standard 17-inch wheels and low-rolling-resistance tires engineered to improve fuel economy