Is this the car that will save diesel?

Driving a diesel is about to get a lot more exciting – and kinder to the environment – thanks to Bosch. The tech giant has created a highly efficient mild hybrid engine that aims to improve the reputation of diesels – currently under attack from new legislation – and Auto Express has had an exclusive first drive.

While the car has all the hallmarks of a Golf GTD, Bosch’s prototype is no normal Volkswagen. Instead of a 2.0-litre turbodiesel engine packing 181bhp and 380Nm of torque, under the bonnet lies a brand new diesel engine. The 1.7 litre four-cylinder turbo has 148bhp and 340Nm – but it’s far more technical than that. It’s fitted with Bosch’s Boost Recuperation System (BRS).

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The company says the set-up aims to close the large gap between conventional stop/start and hybrid drivetrains, improving CO2 emissions by 15 per cent. It combines brake energy recuperation and torque boost with stop/start and coasting functions. Bosch has also fitted a 48-volt generator (rather than a standard 12-volt set-up) and a drive-by-wire clutch called eClutch.

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Once on the move, apply the brakes and the engine shuts down to coast along. The real development, however, is that the car recoups the braking energy and sends it through the 48-volt generator to the 0.25kWh lithium-ion battery. Put your foot down, and the recouped energy is sent to the BRS – which then effectively becomes an electric motor – giving a surge in torque.

Unlike most other stop/start systems, the engine kicks back into life with no vibrations or noise – and that was even the case when we were coasting along and then planted our foot on the throttle. The eClutch is also a big step forward, as it prevents the possibility of stalling in busy nose-to-tail city driving. Stop and then pull away in first or second gear, and you don’t have to use the clutch – it glides away just like an automatic.

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There’s no word on the incremental cost, but the BRS mild hybrid diesel will be incorporated by mainstream manufacturers within the next two years and is a logical way for mega cities like London to achieve stringent nitrous oxide (NOx) emissions levels. “We are sure this system will be the solution to making the diesel far cleaner and liked again by people who are afraid these engines are bad for cities,” said Dr Michael Krueger, senior vice president diesel systems. 

By 2017/18, London is targeting a cut in harmful NOx emissions by 40 per cent from 2005’s levels – and it’s believed this type of diesel engine will help achieve that. But the view at Bosch is that London and other mega cities will need a scrappage scheme to get old diesels off the roads. Bosch’s prototype Golf could be the type of diesel hatchback you’ll be incentivised to buy in the next few years.

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