Toyota Prius Plug-in Hybrid (2011) CAR review

The Toyota Prius Plug-in Hybrid is the 911 GT3 of the hybrid world: a more potent, focused, plug-in Prius, for the hardcore who want to sharpen their hybrid’s performance. Not by cutting the 0-62mph sprint, obviously, but by reducing the Prius’s CO2 emissions from 89g/km to less than 60g/km. How does the Toyota Prius Plug-in Hybrid work, and is it an improvement on the standard Prius? Read on for our Toyota Prius Plug-in Hybrid review to find out...

60g/km for the Toyota Prius Plug-in Hybrid? How did they achieve that?

The breakthrough comes from more efficient lithium ion battery cells replacing the regular Prius’s nickel-metal hydride battery pack. Lithium ion cells have a superior energy density and can be recharged more quickly from a socket – hence the plug-in suffix. Toyota claims the cells can be charged in 90 minutes from the UK mains.
With a full charge, the plug-in Prius can drive solely on electric power for 12.5 miles. That’s double the zero-emissions range of the nickel-metal hydride Prius and, with a threshold of 62mph, around twice the maximum speed before the petrol engine joins in. Toyota reckons that 80% of UK car journeys are less than six miles, which means the plug-in Prius could theoretically complete a return trip without the engine stirring.

Toyota Prius Plug-in Hybrid: the updated hybrid tech

The Prius can operate as both a series and a parallel hybrid. In series mode, the electric motor turns the wheels; when more power is needed, the motor works in parallel with the petrol engine. The difference with the plug-in Prius is that it works for longer in series mode. But there’s always the safety net of the petrol engine, which eliminates the range anxiety – the fear of being stranded by a depleted battery – of purely electric vehicles.

Externally, the plug-in looks identical to a regular Prius, save for the flap above the front wheel arch that hides the charging socket. Under the skin the mechanicals are the same. There’s a 134bhp 1.8-litre four-cylinder petrol engine, supplemented by an electric motor yielding 153lb ft. Drive is sent to the front wheels via a continuously variable transmission.

Driving the Toyota Prius Plug-in Hybrid

Trundling around urban areas, you’ll struggle to coax the plug-in Prius out of electric-only mode. You don’t have to accelerate like an asthmatic snail – a decent span of torque will get you up to urban dual carriageway speeds without any drain on the liquid fuel tank. A horizontal bar displays how close you are to triggering the engine, allowing you to back off the throttle to avoid unnecessary emissions. This will be as effective a clamp on un-ecological driving as having a refugee from India’s drought region in the passenger seat. That said, if you stand on the throttle, you can get the engine seamlessly kicking in as low as 40mph. You’d just be missing the point.

Despite driving Priuses for a decade, the novelty never abates of hearing nothing but the tyres’ gentle rumble while on the move. Though with the Mk1 and Mk2 Prius, you /did/ have to accelerate like an asthmatic snail (and a lightly cooked one, as air-con had to be used sparingly) for a moment of silent motoring. The Mk3 has made a big leap forward with its EV range, which the plug-in Prius enhances.

Verdict

There’s one major problem: Toyota does not plan to commercialise the plug-in until it’s completed three years of research into the reliability and optimum size for the bigger, heavier lithium ion battery pack. Currently there are 600 Prius Plug-in Hybrids in a pilot fleet lease programme, and Toyota plans to offer the Plug-in Prius for sale in the second half of 2012. Here’s my instant feedback: get a move on, Toyota. It’s time we plug in, turn on, pop out.