Media Release

South Africa's Leading International Trade Fair for the Automotive Industry targeting Trade Visitors from the Sub-Saharan Region

6 - 9 May 2015
Johannesburg Expo Centre, Nasrec

15th May 2015

Roger Houghton
Fax          +27 11 494 5004


The South African Diesel Fuel Injection Association (SADFIA) held its Nuts & Bolts conference at Automechanika Johannesburg, taking its members on a journey through the evolution of diesel emission control systems and introducing several other topics of relevance to diesel technicians.

Chris le Roux, SADFIA's chairman, welcomed delegates and thanked the association's director, Louis van Huyssteen, for the leadership example he had set and the role he had played in ensuring that the association's website was kept up to date and informative. Later, Van Huyssteen reciprocated by presenting Le Roux with a recognition award for the dedication he had shown to the association.

SADFIA represents the highly specialised diesel fuel injection sector of the South African motor industry, more specifically the repair and reconditioning of diesel fuel injection pumps for both passenger and commercial vehicles.

A number of SADFIA members were also involved in the supply, installation and maintenance of turbochargers, thanks to the growing popularity of turbocharging technology in vehicles.

One of the key presentations at the conference was delivered by Oscar Oskarsson, a technical and training manager for aftermarket applications at Tenneco.

He addressed the room with enthusiasm and no small amount of concise, clear and valuable information regarding the evolution of diesel emissions control. Citing acoustic contamination as an obvious and initial hurdle, he described in more detail the noxious gases associated with oil burners and petrol engines alike.

Oskarsson listed carbon monoxide, unburned hydrocarbons and nitrogen oxides as gases which, unchecked by catalytic convertors, were harmful to the environment and fatal to people. Particulate matter was another serious problem, kept in check in modern engines by Diesel Particle Filters (DPFs).

Turning attention to exhaust system back pressure, Oskarsson explained that too much – caused by an incorrectly sized pipe or even by a weld – could mean that exhaust gases weren't able to clear the combustion chamber quickly enough, resulting in a loss of power from the engine.

Similarly, too little back pressure – a fault commonly associated with free-flow exhaust systems – meant that much of the air/fuel mixture entering the chamber was invariably ushered out of the exhaust port prematurely at the point of valve overlap.

"Without a correctly adjusted cam profile or timing, all we're getting here is big show and no go," he told the audience. "Imagine that in a normal state of tune, with the standard exhaust in place, that a system injects two drops of fuel vapour per injection cycle into the combustion chamber to achieve the manufacturer's claimed power output.

"Now, with a free-flow system, imagine that while the intake valve is in operation, the exhaust valve is also forced open under load because of lack of back pressure in the system. The unwanted exhaust valve flutter basically robs the engine of power as a tiny amount of fuel vapour escapes through the exhaust port during the combustion stroke," he said.

Oskarsson added that exhaust temperatures that were either too hot or too cold as a result of incorrect back pressure could damage catalytic convertors, DPFs and other costly engine components. On this point his advice to technicians was: "Think logically and read the instructions – and always fit parts that meet OEM specifications."

Background information on Automechanika Johannesburg

Automechanika Johannesburg is part of the global group of Automechanika automotive aftermarket business- to-business trade shows and business events with its portfolio of 15 trade fairs in 14 countries (4 continents).

Automechanika Johannesburg is licensed to SA Shows Messe Frankfurt (Pty) Ltd, part of the Messe Frankfurt Group. It is the largest event of its kind on the African continent and serves South Africa and sub-Saharan Africa since 2009

For more information visit

Background information on Messe Frankfurt

Messe Frankfurt is one of the world's leading trade fair organisers, generating around €550* million in sales and employing more than 2200* people worldwide. The Messe Frankfurt Group has a global network of 28 subsidiaries and around 50 international Sales Partners, allowing it to serve its customers on location in more than 160 countries. Messe Frankfurt events take place at more than 30 locations around the globe. In 2014, Messe Frankfurt organised a total of 120* trade fairs, of which more than half took place outside Germany.

Comprising an area of 578,000 square metres, Messe Frankfurt's exhibition grounds are home to ten exhibition halls. The company also operates two congress centres.

The company is publicly owned, with the City of Frankfurt holding 60 per cent and the State of Hesse 40 per cent.

Further information on the company can be found at
* preliminary numbers (2014)

Oscar Oskarsson, a technical and training manager for aftermarket applications at Tenneco.

For more information contact:

Roger Houghton on 012 998 1771 or at

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