Mitsubishi Outlander PHEV Long Term Test Report 4 – Can it really achieve 150mpg in real-life?

Mitsubishi Outlander PHEV Long Term Test Report 4

ECO FACTS

Model/Engine size: Mitsubishi Outlander GX4hs 2.0 PHEV Auto

Fuel: Petrol-Electric Plug-in Hybrid

Fuel economy combined: 156.9 mpg

The Mitsubishi Outlander PHEV (Plug-in Hybrid Electric Vehicle) has an official economy figure of 156.9mpg – so has our long-term test car achieved this in real-life?

Firstly, let’s look at how the 156.9mpg figure is calculated. This is the result of the NEDC fuel economy and emissions test for plug-in hybrids. That means the driving distance is short, the acceleration is gentle, and the test is conducted on a rolling road in a laboratory.

So engineers in car companies around the world have been faced with a challenge: to develop cars that perform well on the NEDC test. And engineers like a challenge.

The result is the plug-in hybrid. Such a powertrain is designed to perform well on the NEDC test – dipping under the 50g/km CO2 barrier, and delivering around 150mpg – or more. The battery capacity is key to all this. To achieve the figures above, the battery needs to deliver around 30 miles of range.

And with the Outlander, along with many other plug-in hybrids that are coming to market, under the bonnet is a petrol rather than a diesel engine. This is usually because of global markets such as North America, where petrol is king, not diesel.

We’re left with the Outlander PHEV, a large petrol 4×4 that weighs 1,845kg, yet it boasts an official economy figure of 156.9mpg. Even city cars struggle to achieve much more than 60mpg. In our experience, many motorists are confused, and they don’t understand how all this works – and you can’t blame them. So what fuel economy have we had from the Outlander in real-life?

The answer to this question is that we’ve had a massive range of fuel economy figures, and the fuel economy that we have experienced – and that you would experience if you bought an Outlander PHEV – completely depends on driving patterns.

The Outlander has an official all-electric range of 32.5 miles. Like the fuel economy figure, this is based on the NEDC test, which we know is flawed. Petrol and diesel cars perform around 20-25% worse in real-life than the official figures, and pure EVs are even further away in terms of real-life range compared to their official figures.

So far we’ve had the Outlander over December and January, in other words the coldest months of the year. This doesn’t help with the EV driving range. The typical electric range of the Outlander after a full recharge is between 18 and 19 miles, although this varies depending on previous driving. This is well down on the official 32.5 mile range, but we would expect this to improve as the weather gets better.

So if you drive around 20-30 miles between charges then you’re likely to enjoy economy figures of over 100mpg. The trouble is, if you only ever drive 20-30 miles between charges, you may as well buy a pure EV rather than a plug-in hybrid such as the Outlander.

We therefore assume that most people will buy the Outlander because they want a driving range that is better than a pure EV, and that they will drive the Outlander more than 20 or 30 miles between charges. And this is the key issue – the more you drive the Outlander beyond its 20-30 mile all-electric range, the more the fuel economy figure will drop.

The Outlander is a large 4×4 weighing almost two tonnes and which has a large frontal area. Weight and aerodynamics are two key factors that influence economy in real-life rather than in the lab. Keep driving the Outlander for hundreds of miles on the motorway without charging and the worst case scenario will be fuel economy dropping towards the 30mpg mark.

So you’re left with a sliding scale that is completely in your hands. Drive the Outlander on electric power most of the time and you’ll achieve or beat the 156mpg official figure. Drive it at 70mph up and down the nation’s motorways on its petrol engine and you’ll see fuel economy head South towards 30mpg. Most people will have a driving pattern somewhere between these two scenarios and will achieve fuel economy in the middle. Which is exactly what we have done.

We have a typical journey each day, the school run. This is 5 miles in the morning and 5 miles in the afternoon. The 10 miles per day can all be achieved on pure electric power with zero tailpipe emissions, using no petrol.

Our other regular journey is a return trip of 22.8 miles, and this was the first journey that we undertook in the Outlander. This should be within the Outlander’s electric range, but it was in mid-December, and the journey involves a large hill, which often demands petrol power to supplement the electric motor. The resulting fuel economy was 203mpg.

We’ve also done longer journeys, and after exactly two months our average fuel economy stands at 60.6mpg. This is short of the 156.9mpg, but is pretty impressive for a two-tonne petrol 4×4.

You can also achieve crazy economy figures such as 856.7mpg, and you can delve into the touchscreen menus to display information such as long-term economy and energy consumption.

We’ve tried to use the Outlander PHEV as it was intended – primarily for driving within its electric range, and if a very long journey needed to be undertaken, we have the use of a diesel car.

That means that the fuel economy is better than it would have been if we didn’t have the use of a second car for longer journeys. However on the other side of the coin, the Outlander has been tested over two months when it has been raining and cold pretty much every day. This has resulted in a key design improvement being identified – it would really benefit from an ‘EV lock’ button. Most mornings, because the car interior needed to get up to temperature, the heating was required. As soon as you put the heating on, the petrol engine invariably starts up, and because here’s no EV lock, there’s no way to prevent this – apart from switching off the heating. The driver still has a heated seat and a heated steering wheel, but this isn’t ideal for all passengers.

There is of course a way round this – there’s an App available for the Outlander to allow you to pre-heat the car before you get into it, while it’s still plugged in, so you’re using mains power rather than petrol to heat the car. The App has been downloaded onto our phone and we’ve attempted to pair the App to the car, but it’s a fairly complex process, including a requirement for the car to be locked and then unlocked 10 times, and so far we’ve failed to get the App working. This is likely to be user error rather than anything to do with Mitsubishi, but the process of pairing doesn’t seem that user-friendly.

However we have tried pre-heating and de-icing the windscreen while the car is plugged in (without using the App), and it seems to take a long time. But the main issue is that even if the car is pre-heated before you drive off, with the amount of rain we’ve had in Manchester over the last two months, once you’re driving, you regularly need to demist the windscreen, and when you do this, the petrol engine fires up, and your zero tailpipe emission driving is at an and.

The Outlander PHEV has been a runaway sales success, and the low official emissions figure is largely responsible for this, as it results in a low Benefit in Kind company car tax rate of just 5%. So company car users are likely to be buying the Outlander and using it for business mileages. If this means driving more than 30 miles between charges on a regular basis, then disappointment in the real-life fuel economy may result. However as our two months (and 2036 miles) with the car have shown, if you do use it carefully, then you can enjoy better economy than a diesel 4×4.

The thing is, Mitsubishi also offers a diesel Outlander, for the same price as the PHEV. If you drive lots of miles without charging, then both ourselves and Mitsubishi would advise you to buy the diesel model rather than the Hybrid. You’ll also enjoy a longer range between fill-ups in the diesel model – with the PHEV, you’ll be refuelling every 300 miles or so.

So, fuel economy of the Outlander PHEV can be impressive, but can it also be capable when off-roading in the snow? Find out in our next report…

Paul Clarke

Mitsubishi Outlander PHEV long-term test report 1 – What do we want to find out?

Mitsubishi Outlander PHEV long-term test report 2 – How does it work?

Mitsubishi Outlander PHEV long-term test report 3 – What’s it like to drive?

Mitsubishi Outlander PHEV long-term test report 5 – Is it any good off-road?

Mitsubishi Outlander PHEV long-term test report 6 – What’s it like to live with?

Mitsubishi Outlander PHEV long-term test report 7 – Charging

Mitsubishi Outlander PHEV long-term test report 8 – The NEDC fuel economy test for Plug-in Hybrids

Mitsubishi Outlander PHEV long-term test report 9 – Can it save you money?