TSI Added to VW's Engine Technologies

Press Release

In addition to TDI, direct injection turbo diesel, FSI, direction injection petrol, Volkswagen now has TSI, a direction injection petrol engine dual-charged with a supercharger and turbocharger.

The European CO2 emissions target for a manufacturer’s overall range of passenger cars by 2008 is an average 140g/km. Whilst the latest generation of direct injection diesel engines are well on their way to reaching these new levels, petrol engines, even the current direction injection types, are not.

Volkswagen says for them the new targets must be met but not at the expense of driving pleasure. They are working on the most effective way to reduce consumption and CO2 emissions by downsizing in capacity. Their new engines must still be compact, durable and suitable for mass production. But smaller engines are not renowned for giving good driving performance, something the customers insists upon otherwise they will not buy them.

The result is TSI that combines an FSI direct injection petrol engine with a supercharger and exhaust driven turbocharger. This technology has been tried before but not successfully as manufacturers could not make the change from supercharged power to turbocharged power seamless.

TSI uses a 1.4-litre FSI engine as its core, which is then dual-charged through a combination of an engine driven supercharger operating at five times crankshaft speed and an exhaust gas turbocharger, arranged in series.

The driving characteristics of the new TSI engine are improved over those of the current FSI unit. The belt-driven supercharger operates at lower engine speeds, with the turbocharger coming in as engine speed increases. To create a seamless progression from one source of boosted power to another, in the mid range at the changeover point the blown air from the supercharger is diverted into the turbocharger for a short period and then the turbocharger takes over completely. This ‘series’ process is continuous and a sealed for life clutch allows the supercharger to switch in and out automatically on demand.

Volkswagen says the result of this is excellent driveability and performance throughout the range with no turbo lag and high maximum torque. It combines the benefits of petrol and diesel engines. Petrol characteristics are low noise and vibration; diesels are good driveability, high torque from low engine speeds and fuel economy.

Key to the TSI’s success is that direct injection allows an abnormally high compression ratio of 10:1 to be used in conjunction with high maximum boost pressure of up to 2.5 bar. This enables the relatively small engine to use very high gearing to provide improved fuel efficiency for a petrol engine, particularly at motorway cruising speeds.  As an additional bonus, the TSI engine produces high power and torque across a rev range from 1,000 to 6,500 rpm.

The new TSI engine has a capacity of 1.4-litres and is available with the choice of two power outputs, either 140 or 170 PS. The 170 PS version has the same peak power as a conventional 2.3-litre petrol unit but with 20 per cent lower fuel consumption, returning 38.2 mpg on the combined cycle. It also produces maximum torque of 177 lbs ft (240 Nm) from 1,750 through to 4,500 rpm.

Depending on the specific model and power output, the 1.4 TSI engines return between 37.7 and 39.2mpg with CO2 emissions between 169 and 180 g/km.

The new 1.4-litre TSI engine replaces in some Volkswagen model the current 2.0-litre, 150 PS/148 lbs ft FSI engine.

All TSI engines drive through a manual six-speed gearbox. A DSG automatic option is also available with the 170 PS engine. This will be offered later in the year with the 140 PS unit.

TSI technology has already received international acclaim, having been named Best New Engine of 2006 in the International Engine of the Year Awards. It also won the 1-litre to 1.4-litre category.

Volkswagen’s Golf is one of the first models in the range to benefit from TSI technology.

It is available in Sport and GT trim with 140 and 170 PS respectively. TSI, 140 PS engines are also available in the Touran and Golf Plus. Volkswagen says the compact engine has been designed for eventual use in other model ranges such as the Polo, Passat and in the new Eos coupe/cabriolet ranges once supplies of the new unit become more widely available.

In the future it is likely TSI engines will be used in the other Volkswagen family brands, Audi, Seat and Skoda.

Speaking at the UK media launch of TSI technology this week, Dr Hermann Middendorf, Volkswagen’s head of Spark Ignition Engine Development said, "In developing our TSI petrol engine our targets were to produce an engine with high torque at low engine speeds, best in class fuel consumption, low fuel consumption at high cruising speeds and of course reliability. In addition we have been able to provide an engine with a very wide and flat torque band from 1,000 rpm right through to 6,500 rpm making the car very flexible and responsive to drive even in high gears."

TSI prices start at £15,995 for the Golf Sport 140 PS three-door model. The Golf GT 170 PS three-door model costs £18,095 with an added £500 for the five-door version. The Golf GT 170 PS with a DSG automated transmission costs £19,925.

As a price comparison, the outgoing Golf three-door with the 2.0-litre FSI engine was priced at £17,275 showing the new TSI engine has a price premium of £820. Volkswagen says there are other changes to the specification of the vehicle so a direct price comparison is not accurately possible.

The Golf Plus Sport 140 PS is priced at £17,215 and Touran 140 PS models start at £17,995.

Volkswagen UK says this year their sales prediction for all Golf models is 60,000 units with the new TSI 140PS and 170PS models each taking around 2 per cent of sales, approximately 2,400 units in total.

For Touran the UK sales this year will be around 11,000 units and the TSI 140PS models will also account for 2 per cent of sales, 220 units.