Timing is everything. The 2013 Chevrolet Malibu Eco, equipped with a mild hybrid powertrain with an EPA rating of 25/37 city/highway and 29 mpg combined, began arriving at dealers a few weeks ago, just as gasoline began edging past $4 a gallon in several regions of the U.S. The arrival of the new family sedan at the same time that gas hit the $4 benchmark was likely more luck than astute planning, however. The Detroit Free Press reports that General Motors pushed the production of the Malibu Eco ahead by nearly seven months in January 2010 – when the average pump price was $2.74 a gallon.
Malibu Eco in between the latest Toyota Camry that debuted last fall and the upcoming fall introductions of the Fusion, Accord and Altima. That looks like an enviable position to be in, the new Eco won’t have to contend with the big dollar ad spending from three competitors around the same time. The question is, can Malibu Eco’s starting price of $25,235 and fuel economy rating attract enough buyers until the conventional gas powered models arrive in late summer?
A belt-alternator-starter (BAS) mild hybrid system is the major contributor to the 2013 Malibu Eco’s fuel economy numbers. General Motors calls it “eAssist” and it is already offered in Buick’s 2013 LaCrosse and 2013 Regal.
The eAssist name is quite appropriate. The system enhances fuel mileage by “assisting” the gasoline engine, either by shutting down the engine when the car comes to a stop or cutting off the fuel supply when cruising or decelerating. It can provide some electric assist to the engine at speed, but not all-electric operation.
eAssist has a 15-kilowatt liquid cooled motor-generator that generates 79 pounds-feet of torque. It is mounted on the engine in place of the alternator, providing both motor assist and battery charging via a belt-drive system connected to the engine’s crankshaft. A 115-volt air-cooled lithium-ion battery pack bolsters the engine with approximately 11 kilowatts (15 horsepower) of electric power assist during rapid acceleration or on demanding inclines and 15 kilowatts of regenerative braking power.
Under the Malibu Eco hood, the eAssist teams up with a 182 horsepower 2.4-liter direct injection four-cylinder engine that generates 172 pound-feet of torque. The engine has an aggressive fuel shut-off during deceleration that provides added fuel savings.
A new Hydra-Matic six-speed automatic transmission has high final-drive gearing that maintains lower engine revs at highway speeds, boosting mpg. An auxiliary electric-driven oil pump is added to the transmission, which keeps it primed and the fluid flowing when the engine shuts down at a stop. That sustains the transmission’s readiness to perform when the driver accelerates. The engine and transmission are engineered to enable regenerative braking and battery charging during coasting and braking.
About the eAssist system, Motor Trend says, “On the road, the electric motor imperceptibly blends in up to 15 horsepower and 79 pound-feet of torque, which, in addition to increasing accelerative power, also smoothes out power delivery and improves throttle response.”
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