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In the second of our series of dealer view articles, Victoria Stubbs from Volkswagen retailer group Vindis explains the technology behind the company’s TDI engines, as used in the new Polo SE and SEL 1.6 TDIs

If you’re comparing engine options on Volkswagen models, you probably asked yourself at some point ‘What is a TDI engine?’ Well, TDI stands for Turbocharged Direct Injection. TDI engines are Volkswagen’s advanced diesel engines, and are more powerful (with faster acceleration and smooth performance), more economical, produce less CO2, and will require less maintenance and servicing. To find out why, read on.

You need oxygen to burn fuel in an engine, and as only 21% of our atmosphere is oxygen, huge amounts of air are needed for an effective engine. The TDI’s turbocharger squeezes air tightly into the engine’s cylinders (where the combustion takes place) and then cools it so it shrinks further. The injection system then adds fuel (also under high pressure) into the compressed air. This compressed mix burns better but uses less fuel.

The knock-on effect of this more efficient combustion technique is an engine that is powerful even at low revs, and burns less fuel whether at low or high speeds.

More about turbochargers
A turbocharger has two turbines; the first is powered by the exhaust gas and drives the second, which sucks in the air with the oxygen needed for combustion. The air is compressed and then cooled to compress it still further before it is mixed with the fuel and burnt.

A traditional problem with turbochargers is that if the engine is running at low revs then there will be less exhaust gas and therfore less power to drive the turbines. VW uses a nifty feature called Variable Turbine Geometry to overcome this problem. Vanes are used to create a smaller area of airflow through the exhaust turbine, increasing the speed of flow and making the turbine work as if the engine were running at a higher speed.

More about fuel injection
The key factor here is the fuel pressure. The more pressure you can put the fuel under, the finer the spray will be that gets injected into the cylinder, and the quicker and more thoroughly it will mix with it the compressed air. This means you get more power – and less emissions – from the same amount of fuel.

Volkswagen use Piezo crystal injectors, which are lighter and twice as fast as the solenoid valves traditionally used. This speed increase means the injector valve can adjust the rate of fuel injection five times faster. This means smoother, quieter and more efficient combustion.

The latest weapon in the war to increase fuel pressure is the ‘Common Rail’ direct injection system. This separates the pressure generation and the fuel injection processes, meaning each can be more efficient. The common rail is the name given to the high-pressure fuel reservoir to which all the injectors are connected. Each injector receives an uninterrupted supply of fuel at the same high pressure from the common rail.

Finally, as well as burning less fuel, the TDI engines also produce less emissions, thanks to VW’s diesel particulate filters. These not only trap even the smallest particles of soot produced by burning fuel, but need no additives to run, meaning they need little or no maintenance. In fact VW recommend the first inspection at 150,000km.

Victoria Stubbs, Vindis
Vindis are retailers for all Volkswagen models including used Volkswagen Passat

Read the PoloDriver first drive of the 74bhp Polo SE 1.6 TDI and the rest of the fifth-generation Polo range here

Following our recent first drive of the turbocharged Polo SEL and in the first of a new series of articles, Victoria Stubbs from Volkswagen retailer group Vindis explains the technology behind the company’s TSI engines, as used in the new Polo GTI

If you’re looking into buying a new Volkswagen you might have wondered what a TSI engine is, and what the difference is between a TSI and TDI. Simply put, TSI are Volkswagen’s petrol engines and the TDIs are diesel. However there’s a bit more to it than that; the TSI engines actually take features from the diesel TDIs and normal petrol direct injection engines and mix them together.

The 1.4-litre TSI unit is a ‘hybrid’ engine that combines petrol direct injection with what VW call ‘twincharging’ – a turbocharger and supercharger working together. The result is a compact yet powerful engine that scores highly for both performance and economy, runs smoothly and quietly, and produces less CO2.

The following features are at the heart of the TSI formula:

First, a smaller and lighter engine. Decreasing engine size means less power is lost through friction, and reducing weight means the engine has less to move.

Second, direct petrol injection and twincharging. Engines run by burning fuel (combustion). The more efficient the combustion, the higher the power output and the lower the fuel consumption. VW’s twincharging system means a turbocharger and supercharger working together. The supercharger is powered via belt drive from the crankshaft, giving optimum pulling power even at very low revs. At higher speeds the turbocharger (a system that uses the energy from exhaust gases to power the air intake that is essential for combustion) joins in, making the system more energy-efficient.

Volkswagen have used a number of design tricks to make the TSIs even more efficient. These include redesigning moving parts to use less materials (and therefore be lighter) and optimising the fuel injection. This second point needs a little more explanation.

Two of the key factors in engine design are pressurising and cooling air in the cylinder (because oxygen is needed for combustion and air is only 21% oxygen), and pressuring fuel so that it can be injected into the cylinder as a fine spray and mix as quickly and evenly as possible with the compressed air prior to combustion. The TSI’s turbocharger has its own separate air cooler, which means that the volume of air held in the system to charge the cyclinder with has been halved. The pressure required for combustion can build up far more quickly, meaning further efficiency savings all round.

The TSI engine has been well-received by motor critics worldwide, and the 1.4-litre twincharger unit has won the International Engine of the Year award in the 1.0-1.4 litre category every year since 2005. It also won Best Green Engine in 2009. A 1.2-litre TSI engine is also available, fitted with a turbocharger only.

Victoria Stubbs, Vindis
Vindis are retailers for all Volkswagen models including the ever-popular secondhand VW Golf

It’s the news we’ve not been waiting for. While the Polo GTI with 178bhp will be speeding into the junior hot hatch market later this year, the much-rumoured Polo R will not be following it. At least that’s the story according to UK motoring weekly Auto Express, which states that bosses at the German giant’s new performance division have vetoed a new 200bhp-plus Polo to take on the Renaultsport Clio 200, the current junior hot hatch king. We’d heard it rumoured, but didn’t want to believe it.

The confirmation comes as VW launches its new performance division, Volkswagen R GmbH. Set to be what M Division is to BMW and AMG to Mercedes-Benz, the new company will focus on producing the hottest versions of regular models. The new engineering-focused division already bears fruit; the 269bhp Golf R and 264bhp Scirocco R (pictured above) are both products of the R team. R-Line models with cosmetic upgrades but no mechanical tweaks will also originate from the newly-created division.

Based not far from Volkswagen’s huge Wolfsburg corporate headquarters at Warmenau, Volkswagen R GmbH has more than 350 staff, meaning that super-performance-focused cars can be developed and built from the ground up. Future projects include a production version of the Detroit 2009 motor show wowing BlueSport roadster, but not, it would seem, an ultimate performance Polo.

Lower consumption and emissions combine with higher driving dynamics

Currently the Polo’s most powerful engine until the GTI comes along in the summer, the 1.2-litre TSI unit is one of the family of Volkswagen’s TSI powerplants that have been awarded the environmental commendation certified by TÜV Nord. The Life Cycle Assessment on which the commendation is based confirms that the TSI engines have significantly improved environmental characteristics compared with the predecessor models throughout their life cycle thanks to their smaller engine size and lower fuel consumption – while at the same time evidencing higher driving dynamics.

It’s not the first time Volkswagen has won awards for its engine and gearbox technology; last year the automotive giant won three prestigious ‘Engine of the Year Awards’. After the DSG dual-clutch transmission, the TSI engine tech, the second of the three basic technologies in the BlueMotion Technologies brand, has confirmed its outstanding Life Cycle Assessment. BlueMotion Technologies is the Volkswagen umbrella brand for all environmentally-friendly, energy-efficient products and technologies. Thanks to a reduction in engine capacity, the TSI engines significantly lower fuel consumption and CO2 emissions.

For commendation, a 1.4 TSI engine with 120bhp was compared with a 1.6 FSI engine with 114bhp, while a second test compared the Polo’s 1.2 TSI unit with 104bhp and a 1.6 MPI engine with 100bhp. The environmental commendations, which are based on Life Cycle Assessments pursuant to ISO 14040/44, investigate the environmental characteristics of vehicles or technologies throughout their entire life cycle, from manufacture through use to recycling. The environmental commendation is only issued if the overall performance of the new development is better than that of the respective predecessor.

Environmental protection is the top priority for Volkswagen: new campaign for efficient driving and environmental awareness

Volkswagen launched its new ‘Think Blue’ campaign on 27 February, using and building on its BlueMotion tag for its greenest and lowest-polluting models. The company says that ‘protecting the environment is simple and everyone can help in their everyday lives,’ and that along with BlueMotion, it is ‘sending out a new signal for sustainable mobility.’ Marketing puff maybe, but the newest incarnation of the Polo BlueMotion is set to play a major part in the Think Blue marketing campaign.

Fielding press and TV advertisements, brochures, web specials and the Think Blue Challenge game for both the iPhone and iPod Touch, all the marketing strands feature a focus on potential savings, sustainability and environmental awareness. The popular interactive Volkswagen Polo Challenge game for example, seems to have been adapted to become the Think Blue Challenge app, where gamers drive more environmentally to use less fuel. In all materials for the campaign, the predominant colour is – ironically for a green campaign – blue, again underpinning the BlueMotion philosophy. The company’s goal is to establish Think Blue as an expression of its corporate mindset and a firm feature of its ecologically sustainable activities.

Linking its future with its past, Volkswagen is pillaging its archives to come up with the launch advertisement, featuring the infamous ‘Think Small’ strapline, which trumpeted the international success of the Beetle in the 1960s. ‘The “Think Small” slogan symbolises Volkswagen’s achievement in democratising mobility the world over. The challenge of the future lies in achieving efficient and sustainable mobility for everyone. This is expressed by the campaign: “Think Small” has become “Think Blue”,’ Luca de Meo, Head of Marketing at Volkswagen Passenger Cars explains.