[Sheldon]

The new Honda Insight hybrid combines super gas mileage and very good acceleration. What kind of transmission does it use? Is it an e-CVT like the Gen2 Volt? Or a pure series hybrid like the Gen 1 volt?

 

[jcanoe]

The new Honda Insight hybrid combines super gas mileage and very good acceleration. What kind of transmission does it use? Is it an e-CVT like the Gen2 Volt? Or a pure series hybrid like the Gen 1 volt?

It is a good question, don't know about the Insight. Note that the Gen 2 Volt, like the Gen 1 Volt, does not use a CVT. The Voltec transmission consists of two sets of planetary gears and uses two clutches to connect the Volt's gas engine and the two electric motors to the front wheels. A major difference is that in the Gen 1 Volt the gas engine is not connected to the drive the front wheels except in rare situations. In the Gen 2 Volt, when the gas engine is running, the engine's drive shaft is both turning one of the electric motors to generate electricity to power the second electric motor to drive the wheels while any excess power is used to charge the traction battery; most of the time the output of the gas engine is also helping driving the front wheels. When using gas the Gen 1 Volt operates most like a series hybrid while for the Gen 2 Volt, when the gas engine is running, the car operates most like a parallel hybrid.

 

[FI Spyder]

You can check out the drive train on Gen1 and Gen 2 on YouTube. Gen1 is 1 speed gear driven, Gen 2 is 1 speed chain driven.

 

[Sheldon]

It is a good question, don't know about the Insight. Note that the Gen 2 Volt, like the Gen 1 Volt, does not use a CVT... In the Gen 2 Volt, when the gas engine is running, the engine's drive shaft is both turning one of the electric motors to generate electricity ... When using gas the Gen 1 Volt operates most like a series hybrid while for the Gen 2 Volt, when the gas engine is running, the car operates most like a parallel hybrid.

You're correct that gen1 operates as a series hybrid, but the gen2 Volt definitely uses an e-CVT to improve city mpg to allow the ICE to operate at always operate at its most efficient rpm while both driving the wheels and the generator.

https://gm-volt.com/2015/02/20/gen-2-volt-transmission-operating-modes-explained/
Extended range, when the gas engine starts up, now has 3 modes instead of 2 in the original Voltec design. The new operating modes increase efficiency, especially in city driving. In 2 of the modes the motors can be dynamically “mixed” with the gas engine output in an eCVT or electrically continuously variable transmission mode...

Low extended range is technically an “input split” style of eCVT. In this mode the large motor MGB is driving the vehicle through PG 2 to the wheels with the PG 2 ring gear locked together with the mechanical power from the gasoline engine on PG 1 and the electrical power generated by MGA on PG 1. By adjusting the power generated by and used by the two motors the engineers can put the ICE at its most efficient operating point.

Of course, the Honda is a pure hybrid, not an EV, but several articles seem to imply it is a series hybrid to reduce friction losses, and not a parallel hybrid. I thought that an e-CVT parallel hybrid would always give better city mpg than a series hybrid. The 2019 insight is EPA rated at 55mpg city mpg; 49mpg highway.

https://www.caranddriver.com/reviews/2019-honda-insight-first-drive-review
...
Honda’s layout saves weight and space by skipping a conventional transmission completely. The traction motor is geared directly to the drive wheels and provides all of the low-speed propulsion. At moderate speeds and loads, the system works as a series hybrid with the gasoline engine turning a generator that, in conjunction with the battery, feeds power to the traction motor. Under low loads and moderate speeds, the gas engine is geared directly to the drive wheels, but if full load is requested, like say in a quarter-mile run, the engine is assisted by the traction motor and whatever charge is in the battery.