Diesel breakthrough

● Tech reduces NOX emissions to nearly a 10th of new limits

Bosch reveals clever tech that cuts NOX emissions

REVOLUTIONARY new diesel emissions technology capable of cutting harmful nitrogen oxide (NOX) output to almost a tenth of future limits will ensure that “there’s a future for diesel”, according to its maker.

The system, developed by Bosch, enables diesel cars to emit just 13mg/km (milligrams per kilometre) of NOX in mixed real-world driving conditions. This dramatically undercuts RDE2 emission limits being introduced in 2020, which permit up to 120mg/km of NOX to be produced in real-world driving conditions.

Announcing the breakthrough at the firm’s annual conference in Stuttgart, Bosch’s chief executive, Dr Volkmar Denner, said: “We want to put a stop, once and for all, to the debate about the demise of diesel technology.”

Bosch’s system works by moving the emissions-busting selective catalytic reduction (SCR) system and diesel particulate filter (DPF) closer to the engine, allowing them to operate at optimal temperatures.

A faster-spooling turbo is also fitted to improve operating efficiencies and the exhaust gas recirculation system is modified to keep hot air pointed at emissions-reduction components. The set-up includes improvements to the fuel injection, Adblue dosing equipment and engine management software, while the development car’s engine capacity was reduced from 2.0 litres to 1.7 litres without any loss of power.

Even in town driving, where lowspeed, stop-start traffic means diesels can’t always reach the 200 degrees Celsius needed by SCR, Bosch’s tech allows for average NOX emissions of just 26mg/km. Fuel economy and Adblue consumption are said to be largely unaffected by the tech, but a Bosch engineer said in “extreme cases” of heavy stop-start traffic in winter, cars fitted with the kit could use between three and five per cent more fuel.

Bosch used a Volkswagen Golf to show off its system to journalists, but the firm’s head of powertrains, Dr Rolf Bulander, said the comprehensive changes meant “this is not a VW motor, this is a generic motor”.

While the tech can’t be retrofitted to old vehicles, it is available for car makers to order now. But the hardware changes needed mean the complete system is unlikely to be integrated into production lines for around two years.

“Bosch tech works by moving catalytic reduction system and DPF closer to the vehicle’s engine”