The 2017 Honda Accord Hybrid mid-size sedan returned last year, ending a one-year hiatus for the model.

The new version uses an updated version of the two-motor hybrid powertrain fitted to earlier hybrid Accords, which were sold as 2014 and 2015 models.

That powertrain is notable because it uses a gasoline engine to power the wheels in some situations—but without a transmission.

DON'T MISS: 2017 Honda Accord Hybrid first drive (Jul 2016)

This short video from Engineering Explained shows just exactly how the Accord Hybrid manages to do that.

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

As before, the Accord Hybrid offers three driving modes,with EV Drive using only electric power to drive the front wheels, providing there is sufficient charge in the lithium-ion battery pack.

2017 Honda Accord Hybrid

2017 Honda Accord Hybrid

Hybrid Drive allows for electric-only running using the propulsion motor, while the gasoline engine recharges the battery pack, using the second motor as a generator.

Engine Drive is the only mode that allows the gasoline engine to directly power the front wheels.

In this mode, a clutch that is disengaged in the other modes locks the engine and propulsion motor together.

ALSO SEE: Green Car Reports' Best Car To Buy: 2014 Honda Accord Hybrid (Nov 2013)

The engine spins the propulsion motor, both providing power to the wheels and using that motor as a generator to recharge the battery pack.

Lack of a transmission means the gear ratio is fixed, so the powertrain can only operate in this way at certain—generally higher—speeds.

The gear ratio in engine drive mode is similar to that of a 6-speed manual Honda Accord in its highest gear, notes Engineering Explained.

2017 Honda Accord Hybrid

2017 Honda Accord Hybrid

The 2017 Accord Hybrid is rated at 48 mpg combined by the EPA, giving it among the best fuel economy of hybrid mid-size sedans.

The car itself is a mildly-updated version of the 2014 and 2015 Accord Hybrid, but will be sold in much larger numbers.

MORE: 2018 Honda Clarity electric versions: first details, including 40-plus-mile range for plug-in hybrid (Aug 2016)

Honda has said it will target annual sales of more than double the 14,000 Accord Hybrids that were sold during 2014.

The previous Accord Hybrid received generally positive reviews, but limited availability turned away many potential buyers, who reported waits of up to several months for the car.

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