The Engineer drives: Mitsubishi Outlander PHEV

Growing interest in electric cars has brought with it a new phrase: ‘range anxiety’. Despite rapidly increasing battery capacities and significant improvements to the charging infrastructure, electric vehicles (EVs) still aren’t ideal if you want to travel from, say, London to Cornwall. That’s not something that most of us do very often, yet that nagging concern about battery range is still a major obstacle to EV adoption, at least in psychological terms.

A plug-in hybrid electric vehicle (PHEV) might just be the best solution to that problem. The theory goes that a PHEV should be able to cover a substantial portion of its day-to-day mileage on electricity alone, while also offering the convenience of a combustion engine for those times when you need to go further afield.

Mitsubishi has championed this approach with the Outlander PHEV. First launched in 2014, it has been the best-selling hybrid vehicle  (and that includes full EVs). During that time, the Outlander PHEV has benefited from a series of significant revisions, the most recent of which came in the summer of 2018. This included a new 2.4-litre four-cylinder petrol engine, which uses a variable cam timing system to switch between the Otto and Atkinson cycles.  At medium-to-high loads, the Otto cycle is used, offering peak outputs of 135PS and 211Nm. Meanwhile, at light loads, the engine switches to the Atkinson cycle, offering higher thermal efficiency in return for a lower peak output.

The petrol engine is connected to a 77kW generator, but it can also be used to drive the front wheels direct. Alongside sits a 60kW AC synchronous permanent magnet electric motor, which provides additional power to the front wheels, while the rear axle has a similar unit, now upgraded to 70kW for the latest model. New cells in the 300-volt lithium ion battery pack – mounted under the floor of the cabin – have seen its capacity rise by 10 per cent to 13.8kWh.

In EV mode, the two motors draw direct from the battery, giving a claimed electric-only range of 28 miles. Once the battery becomes depleted or when additional power is required, the Outlander PHEV switches to Series Hybrid mode. Here, the motors remain the sole source of propulsion, but the engine is engaged to drive the generator. At high speeds, the Outlander PHEV automatically switches to Parallel Hybrid mode, with the engine driving the front wheels direct.

There’s also a Charge mode, which replenishes the battery as quickly as possible and a Save mode that stores energy to use later – handy if you’re approaching a zero emissions zone, such as those planned for London and Oxford.

The Outlander PHEV has been the best-selling plug-in vehicle in Europe for the past four consecutive years

A refined driving experience

Around town, the Outlander PHEV delivers the same impeccable levels of refinement that you’d expect from an EV. The switchover to the internal combustion engine is very smooth – with the radio on you’d be hard pushed to notice it at all. Things do get a bit more vocal if you accelerate hard, and there’s also a touch of wind and road noise at higher speeds. Overall, though, the Outlander PHEV offers a useful step up in refinement compared to its petrol and diesel counterparts.

Performance is fairly sedate in EV mode, but it’s enough to keep up with normal traffic. More importantly, the real-world range figures are pretty close to Mitsubishi’s claims; we managed 23.3 miles on a mixture of town and country roads without driving too studiously. That’s around twice the length of the average UK commute, so it means that some people could feasibly carry out the majority of their day-to-day driving without ever using a drop of fuel. That said, the car will still insist on using the combustion engine once every 90 days in order to preserve the catalytic converter and the fuel injection system.

With household electricity rates hovering at around 12.9 pence per kWh, a full charge will cost you somewhere in the region £1.78. That takes around 5.5 hours from a standard 13-amp plug, although the Outlander PHEV’s onboard charger also allows you to tap into high-power charging points that can bring the time down to as little as 25 minutes. A petrol-only vehicle covering the same 23.3-mile journey at 35mpg would set you back around twice as much in fuel at £3.89.

Quantifying the fuel economy in the hybrid modes is harder, because it covers such a broad spectrum. Driving short distances at low speeds and with a full battery, it is possible to replicate the 100+mpg figures that you hear talked about. And even setting off with the battery depleted we saw upwards of 43mpg on rural roads, which is more than you’d expect from a conventional petrol or diesel car. On the other hand, we found that driving on the motorway would rapidly drain the battery, whereupon that figure could tumble to the mid-30s.

Fuel and tax savings

In short, then, it all depends on the type of driving that you do. For those largely covering short trips and rarely venturing on to motorways, the Outlander PHEV can offer a compelling reduction in running costs, not to mention a more refined driving experience. There are also benefits when it comes to taxation, particularly where company car drivers are concerned.

However, these advantages have to be balanced against the purchase price of a plug-in hybrid. At £39,500, the mid-spec Outlander PHEV 4H retails for over £9,000 more than its petrol equivalent and around £4,750 more than the diesel. Private buyers are going to struggle to recoup that deficit on fuel savings alone.

On the other hand, you could argue that the Outlander PHEV constitutes something of a bargain, offering what is essentially an EV driving experience for a fraction of the cost of most of the electric SUVs on the market.

Many automotive experts predict that plug-in hybrids will be a flash in the pan. Once battery technology becomes cheaper, they argue, it will become unnecessary to lug around what is essentially a whole other powertrain. For now, though, cars like the Outlander PHEV seem to strike a pretty attractive compromise between the convenience of a combustion engine and the benefits of a pure EV.