What will the fleet car of the future be like?

With diesel engines dogged by pollution woes and pure electric vehicles too impractical, the intelligent petrol mild hybrid could be the popular choice for the reps of tomorrow.

by Hilton Holloway
Last Updated: 31 Aug 2016

Illustrations by Muti - Folio Art

Never mind all the talk of pure electric vehicles like pricey Teslas or the Nissan LEAF. The real-world fleet car of 2020 will be the petrol mild hybrid, and it will use internet-enabled 'swarm intelligence' to optimise everything from fuel consumption and traffic information to route planning and road safety.

It may sound like a cigar from the 1970s but the petrol mild hybrid is the car industry's mass-market response to the more esoteric full-on EVs and the much hyped arrival of semi-autonomous vehicles. Much cheaper and simpler than a full-on hybrid, more practical than a full-on BEV and considerably less polluting than the under-pressure diesel engine, the petrol mild hybrid will most likely be the repmobile of choice before very long.

National and local governments are now in agreement: diesel is causing serious air pollution problems that in turn are causing serious health issues and shortening lives. The era of the diesel vehicle thus looks to be coming to an end. According to a study by King's College London, there are as many as 9,500 'premature' deaths in the UK capital because of high levels of diesel-sourced pollution. Both very fine particulates (known as PM2.5) and nitrogen dioxide (NO2) are said to be behind these health risks.

And other large cities are encountering similar issues. Paris has just banned pre-1997 vehicles from the city centre, and its mayor has spoken of making the French capital 'diesel-free' by 2020. London's new mayor is also planning to ban older vehicles from central London and wants to create a stringent low-emissions zone inside the capital's north and south circular routes.

Across Western Europe, just over 51% of newly registered vehicles in 2015 had diesel engines. It's a figure that's been steadily rising since 1990, when under 14% of new cars were diesel. (A BMW study into customer usage found that, of all the company's vehicles, the one that was driven furthest and fastest was the 320d - the definitive business driver's express.)

It's perfectly true to say that EU regulations have demanded engines that emit ever lower pollution. 'Euro' categorisations have been upgraded regularly (Euro 4 in 2005, Euro 5 in 2009 and Euro 6 in 2014). A Euro 6-rated diesel engine, for example, is allowed to emit just 80mg/km of nitrogen oxides. However, recent real-world testing - as opposed to the standard lab-based tests - of Euro 6-rated diesel engines by the ICCT (International Council on Clean Transportation) found that, on average, NOx emissions were seven times higher than demanded by regulations.

In a seeming admission that diesel engines are not able to meet these strict Euro 6 requirements, the European Commission announced last year that diesel vehicles will be allowed to exceed the Euro 6 NOx limits by 110% for new models launched in 2017 and by 50% for new models launched in 2020.

Diesel is a busted flush, in the medium term at least. And while the downstream disadvantages of diesels are not of much concern to hard-nosed fleet managers, residual values do determine the leasing costs of diesel vehicles. If carmakers find that there's an increasing reluctance for private buyers to purchase threeand four-year-old diesel vehicles, residuals will fall and petrol-powered vehicles will again become a more economic proposition for fleets.

Trouble is, most of today's petrol engines can't touch diesel for real-world fuel economy. Diesel turns around 45% of the energy in the fuel into mechanical energy to propel the vehicle. Few petrol engines are better than 35% efficient, which is where diesel gets its clear fuel economy advantage. But diesel engines are expensive and it's difficult to ensure they'll offer low pollution over a lifetime of as much as 15 years.

However, carmakers have to meet stringent EU vehicle 'fleet' CO2 targets. Regulations demand a pretty tough average fuel economy of 95g/km - or 79mpg - for cars (it varies between 85g and 105g/km depending on the individual maker) by 2021. Even tougher targets for 2030 are in the pipeline. And then there's the new Worldwide Harmonized Light Vehicles Test Procedure (WLTP) that will test economy in real world driving conditions rather than in artificial lab tests which can be gamed, or even cheated completely as in the VW scandal

So where now? Conventional hybrid vehicles, such as the Toyota Prius and the original Honda Insight, remain relatively expensive and are only now matching the best of real-world diesel economy (though they are far, far, less polluting). Pure electric vehicles are also relatively expensive, difficult to use as longer distance business vehicles and are much less efficient in cold weather.

Fortunately, some automotive engineers have had the vision to look beyond the age of diesel and come up with an alternative, combining the familiar practicality of the internal combustion engine with many of the expensive advantages of full-on hybrids. Dubbed the 'mild hybrid', this future drivetrain is in many ways less complex than both modern diesels and full hybrid engines.

One of the things that makes a Prius expensive is the unique hybrid transmission, which includes two electric motors and a complex epicyclic transmission (a kind of giant version of a Sturmey-Archer three-speed bicycle hub gear).

The mild hybrid is all about avoiding such costly complexity, by combining a conventional petrol engine and regular automatic transmission with a small battery pack and simplified electrical assistance, in the form of either an electrically driven turbocharger or a very large starter motor, which doubles as a generator. The philosophy is simple. A mild hybrid car can recuperate otherwise-waste energy when braking or coasting along, storing it in the small (and relatively light and inexpensive) battery pack. And when the engine needs extra oomph - via the turbocharger or starter motor/generator - the stored energy from the battery pack is called into play.

Normally, an engine needs to be running at a certain speed and generating a certain volume of exhaust gases for a conventional turbocharger to work its magic. Using a turbocharger driven by a high-speed electronic motor means the engine gets a performance boost at very low revs and very low speed.

Likewise, the motor/generator is connected to the engine's crankshaft by a conventional rubber drive belt and can assist the engine at low speeds.

Such electrical assistance means that the engine can also be smaller than normal - say, a 1-litre three-cylinder engine instead of a 1.4-litre, four cylinder - further improving real-world economy without sacrificing useful performance. Large engines are only really needed for acceleration and decent uphill progress. At a steady motorway cruise, your car might need as little as 40 bhp to maintain 75 mph.

The upshot is that, by using energy recovery and storage, mild hybrid technology helps the petrol engine get close to the diesel engine's fuel efficiency, but without all the NOx and particulate pollutants to deal with.

Ironically, one of the first carmakers to go down the mild hybrid route will be a post-Dieselgate Volkswagen. The technology will appear on its new Audi A8 next year, before filtering down to all its new vehicles over the next decade.

Other companies' simplified hybrids are also close, including the Hyundai Ioniq, which is about to go on sale in the UK.

Like other mild hybrids, the Ioniq uses an otherwise conventional petrol engine and dual-clutch transmission, assisted by a small electric motor. Crucially, Hyundai's chief engineer says the Ioniq's new drivetrain has the same factory build cost as a Euro 6b diesel engine.

Volvo is heading down a similar route for its new range of smaller vehicles. The Compact Modular Architecture (CMA) family is being developed with Chinese owners Geely and will underpin a series of smaller models include a crossover and Golf-sized hatch. The CMA platform will feature a small electric motor that assists the engine by clutching onto one of the gearbox mainshafts.

But there's another, arguably even more important development on the horizon, which will reduce fuel consumption and further drive down the costs of running fleet vehicles.

So-called swarm intelligence will make use of huge amounts of local information hoovered up by vehicles and uploaded to the cloud, where it will be collated and sent back down to vehicles in the form of super-accurate traffic and weather reports. Combined with super-accurate mapping and topographical information, this will enable the next generation of cars to switch their engines on and off automatically, allowing a car to coast downhill, for example. Your driving instructor might not have liked it, but it will help to make significant fuel savings.

Last year, Audi, Mercedes and BMW bought Nokia's HERE mapping division as the basis of this new super-intelligence. HERE has mapped most of Western Europe with hyper-accurate LIDAR cameras, using laser scanning to create a kind of '3D cave', a virtual image of the road and its immediate environs, inside which the car drives. It is many magnitudes more accurate than Google Maps, and neither does it need to use GPS to fix a vehicle's position, with all the issues around satellite visibility in built-up areas that entails.

You might wonder what useful information can be gathered by a car simply driving along. The HERE mapping connectivity protocols seen by MT are an eye-opener. They include actual speed, wiper speed, fuel tank status, road temperatures and headlamp status (low beam, high beam, fog lights, hazard lights). Vehicles will also upload accurate information about when traction control and anti-lock braking systems are triggered. This, for example, would allow HERE to send warnings about icy road surfaces to drivers.

Equally, super-accurate 'swarm' information about weather and visibility - built from the wiper speeds and headlamp status of hundreds of vehicles in a small area - can also be created. The safety benefits of live micro weather reports can be huge.

The HERE protocol assumes a 'connected' vehicle will have satnav, which will allow more information to be collated, including the direction the vehicle is heading in from three different GPS sources. HERE is also expecting data from - potentially - millions of cars on road curvatures and slope inclines. This, along with the hyper accurate mapping and location info is partly to prepare for autonomous driving technology, but it also means that a connected car will have a remarkable 'understanding' of its surroundings.

This is useful on a number of levels. Any vehicle equipped with HERE mapping and connected to the swarm intelligence generated by the HERE Cloud, has enough information to, for example, automatically idle its engine on a long downhill stretch or switch the engine off as it approaches a red light. It can also change down a gear in anticipation of uphill sections of road.

Audi's new Q7 e-tron hybrid SUV is production proof of this concept. It can already shuttle between various transmission modes (electric motor only, engine only, engine and motor together and engine-off coasting) to extract the maximum fuel consumption, and even reserve its battery power for passing through towns and villages on its route in pure EV mode. Audi's new Quattro Ultra 4x4 system uses similar information so that fuel-sapping all-wheel drive is only engaged when the conditions demand it.

It's this kind of 'drivetrain autonomy' that will almost certainly prove to be more important than self-driving technology. It helps ensure that low-pollution petrol hybrids are much more economical than diesel engines and opens the way for them to meet more stringent future CO2 regulations.

Swarm intelligence and car-to-car communication will -along with automatic braking technology - also drastically reduce the number of accidents and collisions. Not to mention being a godsend for insurance companies and, perhaps, fleet managers who want to monitor driving styles.

While the downsides of diesel might not play on a fleet manager's mind (or spreadsheet), pressure from governments, environmentalists and the used car trade will inevitably start to sideline diesel. The good news is that intelligent petrol mild hybrids equipped with swarm intelligence connectivity will be a far better solution - both for reducing fuel use and running costs and making driving far safer.


Find this article useful?

Get more great articles like this in your inbox every lunchtime

Upcoming Events