Photographer: Jason Alden/Bloomberg

VW Bears Blame for Diesel Cheating Scandal, Supplier Bosch Says

  • Internal investigation started a day after VW scandal broke
  • Denner says manufacturers are responsible for car emissions

Volkswagen AG bears the responsibility for its emissions-cheating scandal and not suppliers or diesel technology, according to the head of Robert Bosch GmbH, the world’s biggest maker of auto parts.

State-of-the-art technology means diesel-powered cars are now “air-cleaning machines,” as their emissions are less dirty than the air they take in, Bosch Chief Executive Officer Volkmar Denner said at a press briefing late Tuesday outside Stuttgart, Germany.

“Diesel is a clean, environmentally friendly technology,” Denner said. Engines running on the fuel generate about 20 percent less carbon dioxide than gasoline motors, and other emissions are on a similar level as long as particle filters and selective catalytic reduction systems, which neutralize smog-inducing nitrogen oxides, are installed.

Bosch, which said in September that it supplied control components for VW engines implicated in emissions rigging, started an internal investigation into its role a day after the scandal broke, Denner said, reiterating that the supplier is fully cooperating with authorities. Prosecutors in the U.S. and Germany are looking into whether the partsmaker helped VW cheat on emissions tests. Denner said each car manufacturer is responsible for a vehicle’s emissions, not suppliers who contribute particular parts or component sets to the engine or gearbox.

Regulators’ Reaction

Regulators across Europe have extended probes of the automotive industry since the Volkswagen scandal broke, with investigators in France raiding offices of carmaker Renault SA earlier this month. The French company, which has denied any cheating, subsequently revealed that it’s recalling 15,800 vehicles and will offer systems upgrades to 700,000 diesel-car owners.

Bosch has submitted additional material to authorities beyond what was requested to support technical understanding of the matter, Denner said. Engine-control software is a highly complex field and the documentation can comprise thousands of pages, he said.

The company hasn’t noted a drop in demand for diesel cars, but long-term prospects are uncertain if authorities intensify scrutiny that eventually taints the technology’s reputation, Denner said. Bosch’s diesel-technology operations employ about 50,000 people.

To revive public trust in emissions data, Denner said, the CEO supports independent organizations conducting checks to narrow the gap between laboratory test results and real-world driving.

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