In Europe, things are different. Earlier this year, Peugeot launched the world's first diesel hybrid car, the 3008 HYbrid4.
Positioned to compete between classes, with rivals as diverse as the Mitsubishi Outlander Sport and Ford C-Max, the HYbrid4 uses a 2.0-liter turbocharged diesel to power the front wheels, and a 37-horsepower electric motor for the rear wheels.
Electric range is between 2-3 miles, and the motor is happy to power the car at speeds under around 40 mph. Total system power is just under 200 horsepower, and like many hybrids the 3008 uses an automatic transmission.
Rather than a CVT, electronic CVT or torque converter auto though, it uses a smart fortwo-style automated manual, which can be either left in auto, or operated by steering column-mounted gearshift paddles. A separate selector allows you to choose between Auto, ZEV (electric), Sport and 4WD modes.
In ZEV, or driven gently in auto, the 3008 is as quiet and smooth as any electric vehicle, though with only 37 hp to call upon it's only really suitable for urban use in ZEV mode.
Press the gas pedal a little harder and the engine smoothly fires up and takes over driving duties. Like any modern turbodiesel engine, it's quiet and smooth for much of the time, only becoming raucous when you're accelerating hard.
You won't want to do that often either, despite the useful horsepower and torque outputs. Like the aforementioned smart, the automated manual gearbox is jerky. At lower speeds and under light acceleration this isn't an issue, as the electric motor kicks in during the gearchange pauses for a smooth ride. But driven harder (or above around 40mph), the motor can't keep up, and pauses are long and frustrating.
You can ease this frustration by shifting manually using the paddles (again, like the smart), and it's better in Sport mode, but it'll never be as smooth as a proper automatic or a CVT.
Indeed, the whole hybrid system lacks the polish that you might find in Toyota's hybrids, perhaps as a result of Peugeot being fairly new to the game.
It's all too easy to feel the car switching between its propulsion methods in some situations. We did like the regenerative braking though, which is reasonably strong and means you don't often have to use the friction brakes until you need to shed those final few mph.
Useful, but flawed
In around 200 miles of mixed driving, we averaged 46 mpg in the 3008 HYbrid4. That's not quite Prius-rivaling, nor does it match the optimistic 62 mpg official average, but it's around 7-8 mpg more than we've got in non-hybrid diesel crossovers before, and significantly more than we'd expect from a gasoline crossover.
And academic though it is, with Peugeot not selling cars in the U.S, we were very impressed by the standards of quality and build, and the light, airy cabin was full of high-tech features--notably, a digital head-up display.
In theory, a diesel hybrid should offer the best of both worlds--high gas mileage in city driving, and high mileage on the highway too.
In practice, Peugeot needs a little more work to refine its hybrid system, but the 3008 is still a likeable, economical vehicle.