It goes without saying that the current-generation Chevrolet Malibu has been something of a disappointment. Almost as soon as the Malibu hit the streets in late 2011, Chevrolet engineers began work on an all-new next-generation model that goes on sale this fall. While full details of the Chevy’s new midsize sedan will have to wait until next week’s New York Auto Show, I can now tell you about the all-new hybrid powertrain that will be available.
The current Malibu came to market two years later than originally planned, a victim of the product delays that resulted from the General Motors bankruptcy. When it did finally arrive, the design was underwhelming, rear seat room was tighter than the competition and the mild-hybrid eAssist drivetrain failed to impress leading to lower than expected sales in what is still the biggest car segment in America.
From 2008-2010, Chevrolet did sell what was labeled as a Malibu hybrid, equipped with its first-generation mild-hybrid system. The belted alternator starter motor system only provided about 5-kilowatts of electrical boost along with auto start-stop capability. The 2013-2014 version re-labled as eAssist, bumped that up to 15-kW but it barely managed to match the EPA mileage estimates of the Camry, Accord and Altima, all of which eschewed this fancy stuff.
This time around, the powertrain team has developed a proper strong-hybrid system that will look very familiar to any of you that have checked out the second-generation Volt extended-range electric vehicle (E-REV). GM’s new hybrid drive unit was developed in conjunction with the Volt’s electric drive unit and shares it’s basic architecture and many of its features. Both drive units are effectively an evolution of GM’s original two-mode hybrid system that was used on full-size pickups and SUVs from 2007-2012. A transverse front-wheel-drive version was also developed and was planned to go into production in the Saturn Vue in late 2008 before being canceled as a result of the financial meltdown.
Like the old two-mode, the new drive unit features two motor/generators and two planetary gear-sets. The main differences from the Volt are different sized motor/generators and one less clutch. Because the Volt uses electrical power to drive throughout its operating range, it uses both motors to provide tractive force at higher speeds necessitating an extra clutch to manage the power-flow. The hybrid unit only uses one motor for drive while the second motor is primarily a generator to recapture kinetic energy during braking and also charge the battery when driven by the engine during light load conditions.
As in the Volt, the main traction motor has no rare-earth metals while the secondary motor has 40 percent less rare earth metals than the older design. The motors are smaller than in the Volt but use a similar design and will be built at the same facility in Wixom, Mich. The drive unit uses the same integrated power electronics unit as the Volt which reduces the need for the large orange high-voltage cables running around the engine compartment. The hybrid and E-REV drive units will all be assembled at GM’s Warren, Mich. transmission plant and shipped to the Detroit-Hamtramck assembly plant for installation into the cars.
In the Malibu, the hybrid drive is paired with GM’s new 1.8-liter normally aspirated four-cylinder engine. This is part of GM’s new global midsize gasoline four-cylinder family. Similar to most new engines, this one is direct-injected and has an aluminum.block and head with integrated exhaust manifold. It does have a couple of interesting features such as GM’s first use of exhaust gas heat recovery (EGHR).
EGHR routes some of the hot exhaust gases through a heat exchanger with the engine coolant. The goal is to bring the engine temperature up faster after a cold start. The bulk of emissions from modern engines comes during the first few minutes of operation after a cold start, so reducing this time can dramatically improve emissions performance. It also cuts the time before the engine can be shut-off during idle further reducing fuel consumption on short trips and heats the cabin quicker on cold days. GM has also incorporated and electric oil pump for reduced parasitic losses and cooled exhaust gas recirculation for further emissions reduction.
The hybrid uses a surprisingly compact air-cooled battery pack filled with prismatic lithium ion cells supplied by Hitachi. The 80-cell pack has a capacity of 1.5-kilowatt-hours and has a peak discharge rate of 52-kW to provide plenty of electric power boost when needed for acceleration. The total combined output of the engine and electric drive is 182-horsepower which should combine with the 300 pound weight reduction in the new car for more than acceptable performance. The Malibu hybrid can drive on electricity alone at speeds up to 55 mph for short distances.
Final powertrain calibration and certification won’t be complete until later in 2015 but GM is projecting that the 2016 Malibu hybrid will score a combined rating of more than 45 mpg. The Malibu hybrid is expected to go on sale in early 2016 and I can’t wait to try it out.
Chevrolet Malibu Hybrid Derives Technology from Volt
GM estimates combined fuel economy ratings to exceed 45 mpg
DETROIT – Chevrolet’s recent production announcement of its all-electric vehicle based on the Bolt EV concept, as well as the introduction of the 2016 Chevrolet Volt, will be joined by a strong hybrid version of the next-generation Malibu.
Using technology from the 2016 Chevrolet Volt propulsion system, Malibu Hybrid will offer an estimated combined fuel economy rating exceeding 45 mpg, higher than the combined mileage ratings of the Ford Fusion, Toyota Camry and Hyundai Sonata hybrid variants.
“The 2016 Malibu Hybrid will offer impressive fuel economy, exceptional driving characteristics and gorgeous styling,” said Jesse Ortega, Chevrolet Malibu chief engineer.
“Besides leveraging innovation from the Chevrolet Volt, the Malibu Hybrid also has unique features that help improve aerodynamics, like upper and lower grille air shutters to improve airflow and a reduced ride height, all of which help reduce fuel consumption,” Ortega said.
An all-new direct-injection 1.8L 4-cylinder engine mated to a two-motor drive unit slightly modified from the 2016 Chevrolet Volt drive unit powers the Malibu Hybrid. The drive unit provides additional power to assist the engine during acceleration, for 182 horsepower (136 kW) of total system power.
The engine also features Chevrolet’s first application of Exhaust Gas Heat Recovery, or EGHR, technology, which uses exhaust heat to warm the engine and cabin. EGHR improves engine warm up and assures consistent fuel economy performance in cold weather. Additional fuel economy benefits come from Exhaust Gas Recirculation, or EGR.
An 80-cell, 1.5 kWh lithium-ion battery pack provides electric power to the Hybrid system. The advanced lithium-ion based chemistry can power the Malibu hybrid at up to 55 miles per hour on electricity alone. The gasoline-powered engine will automatically come on at higher speeds and high loads when necessary to provide additional power.
Besides the Volt drive unit, the Malibu Hybrid also shares power electronics and a blended regenerative braking system, which provides maximum kinetic energy recovery during braking to be stored into the battery system to help maintain charge.
The Malibu Hybrid will be manufactured in Kansas City, Kansas, at the Fairfax Assembly plant from globally sourced parts. It is due in Chevrolet dealer showrooms in spring 2016.
Founded in 1911 in Detroit, Chevrolet is now one of the world’s largest car brands, doing business in more than 115 countries and selling around 4.8 million cars and trucks a year. Chevrolet provides customers with fuel-efficient vehicles that feature engaging performance, design that makes the heart beat, passive & active safety features and easy-to-use technology, all at a value. More information on Chevrolet models can be found at www.chevrolet.com.