Comment by rootusrootus
8 hours ago
The Volt is not an EREV, it is a plug-in hybrid. GM wanted to make it a series hybrid (EREV) but due to the inefficiency at highway speeds it does engage the engine mechanically to drive the wheels.
(Interestingly, the wikipedia page for EREV incorrectly cites the Volt as an example of an EREV, but the actual page for the Volt correctly identifies it as a plug-in hybrid.)
As an unrelated aside, it also has been abandoned altogether by GM and the only way to fix the battery is to find a third-party repair shop to work on it. Batteries are not available, and for the cars remaining under warranty coverage a battery failure results in GM buying back the car since they cannot fix it. Caveat emptor; IMO the resale value right now is much too high given that risk.
Off the top of my head, the only example I can think of for an EREV that actually reached production status (in the US at least, China excepted) is the BMW i3.
The Volt Gen 1 used the engine primarily to run the generator, although the mechanical coupling ability existed in Gen 1 as well. Gen 2 optimized the system to couple the engine to the wheels whenever it is efficient to do so, when an engine mode is selected or the battery is run out.
However, besides from the formal classification debates, I submit that the Volt meets the primary customer visible "EREV" behaviour: it drives like an electric car with the full available power (the engine never comes on) until the battery is depleted or a different drive mode is explicitly selected. All other PHEVs use the gas engine to assist when full power is called for by default, unless the "EV" mode is explicitly selected. The Volt, as far as I know, is the only EREV/PHEV that had that behaviour.
The only other example of a series EREV I know of where the engine is small and fully decoupled from the mechanical drive train is the Mazda MX-30R, which never made it to the US and was discontinued in EU and Japan after a short two year lifespan.