Cars

Subaru hybrid: Boxing clever

A hybrid version of Subaru's famous boxer engine is coming our way. William Scholes samples pre-production XV and Forester e-Boxer models

Subaru XV e-Boxer
Subaru XV e-Boxer Subaru XV e-Boxer
Subaru Forester e-Boxer
Subaru Forester e-Boxer Subaru Forester e-Boxer

HERE at Drive, we are great admirers of Subaru, writes William Scholes.

Few cars, in any price bracket, convey the depth of their engineering and independence of thought with as much authority as the products from the left-field Japanese manufacturer.

A commitment to low-slung boxer configuration engines - so-called because of the way the horizontally-opposed pistons appear to punch and counter-punch each other - is part of the Subaru story.

So too is all-wheel-drive. Subaru was offering family cars with four driven wheels long before it became fashionable.

Strong and safe, dependable and durable, a Subaru is also built to last. In a world where even some cars can feel disposable, a Subaru has an air of permanence. If Rathlin Island was a car, it would be a Subaru.

To those who 'get' Subarus, they are brilliant things. Others wonder what the fuss is all about.

These people will point out that Subarus tend not to be the prettiest vehicles in the car park and that the model range is relatively limited.

Subaru XV e-Boxer
Subaru XV e-Boxer Subaru XV e-Boxer

And they'll remind you that the in-car tech traditionally isn't at the cutting edge, and that any car with an automatic gearbox - Subaru favours a continuously variable transmission - shackled to four-wheel-drive and a boxer engine is never going to be the most frugal way of getting the family from A to B.

With emissions and fuel economy an ever-increasing part of the conversation around cars, Subaru has spent a lot of time and money considering that last point.

It used to offer a rather fine diesel engine - a boxer, naturally - but this has been quietly dropped, leaving a bunch of relatively thirsty petrol units to carry on.

But things are soon to improve considerably with the imminent arrival of Subaru's first electrified drivetrain, which it dubs e-Boxer.

It's a mild hybrid system, meaning it uses a relatively small battery and motor-generator arrangement to provide brief bursts of electric-only driving as well as electrical assistance to the engine.

The chief goal of these set-ups is to increase fuel economy and cut emissions. Refinement and smoothness can also be improved.

A mild hybrid offers less electric range than a regular 'full' hybrid system, but because it doesn't need such a large battery, it is also significantly lighter.

Both mild and full hybrids have lower electric-only ranges than plug-in hybrids, such as the Mitsubishi Outlander PHEV featured on these pages recently, but apart from the weight penalty, Subaru seems to have reckoned that its punters couldn't be bothered with the faff of plugging-in.

Affordable pure electric cars which can do heavy-duty off-roading to Subaru's standard and pull a heavy trailer are still some way off.

The e-Boxer will arrive later this year in the XV and the all-new Forester, and I have had the opportunity to drive pre-production versions of both cars in Northern Ireland.

I'll get to try the cars in final showroom specification next month, but impressions gleaned from the pre-production versions were very positive.

The e-Boxer is a mild hybrid system, meaning it uses a relatively small battery and motor-generator arrangement to provide brief bursts of electric-only driving as well as electrical assistance to the engine

The car feels more responsive, with sharper acceleration than before. It's also smoother and refined, with the lack of engine noise and vibration - for example, when pulling away from traffic lights - almost eerie compared to a regular Subaru.

That's best experienced with the gentlest of throttle movements. A lap of Lisburn town - sorry, city - centre gave me a chance to feel the difference between a soft right foot and a heavy right foot.

Even a moderate press on the accelerator, led to the engine kicking in - this happened instantly and very quietly, but perhaps the car's computers were also too quick and too willing to resort to petrol power.

It's more an observation than a complaint, because the system goes about its business so smoothly that it doesn't really matter; in any case, production cars may be less eager to activate the petrol engine before it really needs to be called upon.

Subaru Forester e-Boxer
Subaru Forester e-Boxer Subaru Forester e-Boxer

The switch between battery and petrol power is very well managed. A little graphic display on the dashboard tells you what the drivetrain is up to - whether the battery is being recharged, for example, or sending its energy to the motor.

The general idea is that at a cruise, the petrol engine drives the car but also recharges the battery. Boot the throttle, and you get both power sources at once.

The e-Boxer also harvests energy that would ordinarily be lost when braking or free-wheeling, using it to recharge the battery.

The car looks after all of this automatically - you can't push a button to force it to run under battery power alone, for example.

It's thought the mild hybrid system weighs around 110kg. This is split roughly half-and-half between the front and back of the car, with the battery pack sitting under the boot floor and over the rear axle, and the motor-generator dovetailing with the gearbox at the front of the vehicle.

A superb view out, consistent and well-weighted controls, an abundance of grip and supple suspension all play their part in helping these practical family cars so satisfying to drive

The extra weight doesn't feel burdensome enough to affect the car's dynamics. Both the XV and Forester flowed along familiar roads around Lisburn, Moira and Hillsborough - the preview drive was based at Desmond Eastwood Motors in Lisburn - with that same sense of easy pace that I so enjoy about Subarus.

Their outright power and torque figures may not always be the highest, but they have an uncanny way of maintaining momentum that allows them to cover ground with deceptive pace.

A superb view out, consistent and well-weighted controls, an abundance of grip and supple suspension all play their part in helping these practical family cars so satisfying to drive.

Continuously variable transmissions can be awful droney and noisy affairs, but Subaru's version - called Lineartronic - is one of the better ones, only sending the engine into a constant moan when provoked with very heavy, sustained acceleration - and how often do you do that?

The e-Boxer drivetrain has simply been added to the XV, Subaru's crossover, but the Forester is an all-new car.

It might look very similar to the current Forester, but the new version is longer and wider. That means more space for passengers and luggage.

The most obvious change inside the car is a step up in quality and technology; the Forester has always been well-built in the sense that it felt like it would survive a nuclear war, but now everything looks and feels that bit more upmarket.

On first acquaintance, then, the Subaru e-Boxer is an admirable effort at adding a mild hybrid system to some of the most distinctively engineered cars on the road.

Far from detract or interfere with the traditional Subaru driving experience, it enhances it with a welcome injection of smoothness and refinement.

Whether it delivers meaningful CO2 and fuel consumption benefits remains to be seen. A final verdict will have to wait until I've spent time with a proper production version of the e-Boxer XV or Forester.

The signs, however, are promising.

Subaru XV e-Boxer
Subaru XV e-Boxer Subaru XV e-Boxer
Subaru Forester e-Boxer
Subaru Forester e-Boxer Subaru Forester e-Boxer
Subaru Forester e-Boxer
Subaru Forester e-Boxer Subaru Forester e-Boxer
Subaru Forester e-Boxer
Subaru Forester e-Boxer Subaru Forester e-Boxer
Subaru XV e-Boxer
Subaru XV e-Boxer Subaru XV e-Boxer
Subaru Forester e-Boxer
Subaru Forester e-Boxer Subaru Forester e-Boxer