The mid-size sedan was once the default for a majority of U.S. car buyers.

While the segment's position has been eroded by the rise of crossover utility vehicles of many sizes, these sedans still remain quite popular.

Given the number of options available among hybrid mid-size sedans, that should remain the case among buyers who want passenger vehicles with high fuel-economy ratings.

DON'T MISS: 2018 Toyota Camry Hybrid: two different battery packs, 'best-in-class' fuel economy claimed

Many of the top-selling mid-size sedans offer a hybrid option, with the segment average hovering in the 40-mpg range.

We've listed all of the 2017-model-year hybrid mid-size sedans here, in order of EPA combined fuel economy.

We've also added in the upcoming 2018 Toyota Camry Hybrid, the only updated mid-size sedan hybrid expected for 2018, and one that is gunning for "best-in-class" fuel economy.

2017 Honda Accord Hybrid

2017 Honda Accord Hybrid

2017 Honda Accord Hybrid (48 mpg)

The Accord Hybrid is the most fuel-efficient mid-size sedan, although the redesigned 2018 Toyota Camry Hybrid may surpass it.

Honda's hybrid mid-size sedan returned for the 2017 model year after skipping 2016.

It uses an updated version of the two-motor powertrain fitted to the 2014 and 2015 Accord Hybrid.

ALSO SEE: 2017 Honda Accord Hybrid first drive (Jul 2016)

The hybrid system is paired with a 2.0-liter 4-cylinder engine that uses the lean Atkinson Cycle combustion sequence for the highest output on the least fuel.

The gasoline acts primarily as a generator, only powering the wheels directly in limited circumstances.

Besides the powertrain, the Accord Hybrid is largely similar to other versions of the Accord sedan, which remains fairly popular among consumers.

2017 Chevrolet Malibu

2017 Chevrolet Malibu

2017 Chevrolet Malibu Hybrid (46 mpg)

The current-generation Chevy Malibu Hybrid was launched as a 2016 model, and remains largely unchanged for 2017.

Its powertrain borrows heavily from the Chevy Volt plug-in hybrid, helping the Malibu achieve relatively high fuel economy while giving General Motors economies of scale.

CHECK OUT: 2016 Chevrolet Malibu Hybrid: First Drive Of Sedan Using Volt Hybrid System (Jan 2016)

The Malibu's electric-drive system is a modified version of the Voltec system, and the sedan shares a blended brake-regeneration system with the Volt as well.

However, the Malibu uses its own 1.8-liter 4-cylinder gasoline engine and a much smaller battery pack—1.5 kilowatt-hours, compared to the Volt's 18.4 kwh.

2017 Ford Fusion Hybrid

2017 Ford Fusion Hybrid

2017 Ford Fusion Hybrid (42 mpg)

The Fusion Hybrid received some notable updates for 2017, resulting in a slight increase in fuel efficiency.

Combined fuel economy is up 1 mpg, despite changes to EPA testing standards for the 2017 model year that have caused ratings for many cars to fall slightly.

READ MORE: 2017 Ford Fusion Hybrid and Energi: how engineers increased fuel efficiency (Sep 2016)

The powertrain—encompassing a 2.0-liter Atkinson-cycle 4-cylinder engine and electric motor—remains unchanged.

But Ford engineers tweaked the software, and squeezed efficiency gains from other areas, such as aerodynamics and even a new, low-drag brake-caliper design.

As before, the Fusion Hybrid is paired with a Fusion Energi plug-in hybrid model, with an EPA-rated 22 miles of electric-driving range.

2017 Kia Optima Hybrid

2017 Kia Optima Hybrid

2017 Kia Optima Hybrid (42 mpg)

As a whole, the Kia Optima Hybrid is new for 2017, but its main components are not.

Its body was introduced on non-hybrid Optima models for the 2016 model year, while its powertrain debuted in the Hyundai Sonata Hybrid, also for 2016.

That powertrain includes a 2.0-liter 4-cylinder engine and 6-speed automatic transmission, working with an electric motor.

While the Optima and Sonata share both a powertrain and basic underpinnings, the Optima Hybrid edges its sibling by 2 mpg in EPA combined fuel economy.

The Optima is also available as a plug-in hybrid, with an EPA-rated 29 miles of electric range.

2017 Hyundai Sonata Hybrid

2017 Hyundai Sonata Hybrid

2017 Hyundai Sonata Hybrid (40 mpg)

Introduced for the 2016 model year, the current-generation Sonata Hybrid transitioned to the 2017 model year with few changes.

As stated above, it uses the same powertrain as its Kia Optima Hybrid sibling.

Hyundai owns Kia, so many of the two Korean automakers' models share powertrains and platforms, in what is a common practice in the auto industry.

The companion Sonata Plug-In Hybrid is rated at 22 miles of electric range by the EPA.

2017 Toyota Camry Hybrid

2017 Toyota Camry Hybrid

2017 Toyota Camry Hybrid (40 mpg LE; 38 mpg SE/XLE)

The Toyota Camry Hybrid currently sits at the bottom of fuel-efficiency rankings for hybrid mid-size sedans, but that may change when a redesigned version appears for the 2018 model year.

Note that fuel economy is slightly higher for the LE model than the SE and XLE trim levels.

All versions use a 2.5-liter Atkinson-cycle 4-cylinder engine, with the ubiquitous Toyota Hybrid Synergy Drive system.

Toyota remains the leader by far in hybrid sales, and the Camry Hybrid helped pioneer the mid-size sedan hybrid segment.

2018 Toyota Camry

2018 Toyota Camry

COMING SOON: 2018 Toyota Camry Hybrid

A redesigned Camry Hybrid was unveiled in January at the 2017 Detroit Auto Show, as part of a complete overhaul of the Camry lineup.

Toyota claims "best-in-class" fuel economy for this latest version of its hybrid mid-size sedan, meaning it must surpass the Honda Accord Hybrid's 48 mpg.

The hybrid Camry will continue to use a 2.5-liter 4-cylinder engine, optimized to work with what the company calls its Toyota Hybrid System II, effectively the successor to the current Hybrid Synergy Drive system.

The new Camry also uses elements of the Toyota New Global Architecture component set that underpins the current-generation Prius.

Like the Prius, the Camry Hybrid will also be offered with two battery-pack options.

Base models are expected to get a nickel-metal hydride pack, while higher-level models will use lithium-ion chemistry.


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