TSI (Turbo Stratified Injection) engines installed in Volkswagens, Seats, and Skodas, and TFSI (Turbo Fuel Stratified Injection) engines in Audis are turbocharged successors to FSI (Fuel Straight Injection) engines. All these engines share a key feature – a cutting-edge gasoline fueling method developed by Volkswagen AG for spark ignition engines – direct fuel injection. The concept of direct gasoline injection involves creating the fuel-air mixture directly in the combustion chamber. To achieve this, an electromagnetic injector is placed in the chamber, and only air is admitted through the intake valve, similar to diesel engines. The fuel is injected under high pressure, ranging from 50 to 120 bars, generated by a special pump.
When this leading German car manufacturer from Wolfsburg introduced the FSI engine in 2002, the technology was hailed as a true revolution. Direct fuel injection allows for greater power output and lower gasoline consumption compared to the multi-point injection systems used at the time. Additionally, thanks to the turbocharging system and (from the second generation onwards) stratified injection, these engines are very dynamic and flexible, meaning that their maximum torque is achieved over a very broad range of revolutions. TSI and TFSI units are still considered some of the most fuel-efficient gasoline engines globally. The 1.8 and 2.0 TSI/TFSI engines are available in various power variants from 160 to 272 horsepower and are continuously being updated and improved, with the fourth generation now in production.
The excellent performance combined with low fuel consumption has made the 1.8 and 2.0 TSI/TFSI engines the most popular power units in Volkswagen Audi Seat Skoda vehicles in recent years, gradually replacing the popular TDI.
With rising diesel prices compared to gasoline, the popularity of TSI is even more understandable. Additionally, cars with gasoline engines are cheaper to buy and later service than their diesel counterparts. Cars with TSI units do not have clogging particulate filters, often faulty exhaust gas recirculators, or the very costly to repair or replace and unfortunately prone to failure injectors and common-rail pumps. Moreover, these vehicles are considered very environmentally friendly, which means they do not face the same restrictions as Diesels in entering city centers in Western European countries. In some countries, they also benefit from significantly lower road tax than Diesels.
Unfortunately, TSI/TFSI engines, especially those from the early years of production, have various serious design flaws that lead to significant failures, and their rectification often requires a costly engine overhaul. The need for expensive repairs at low mileage has led to extremely negative opinions about these engines.
The first-generation engine, designated EA113, is essentially an FSI engine equipped with a turbocharger. Similar to Volkswagen's popular Diesels and older gasoline engines, the timing drive is implemented by a toothed belt, which drives the exhaust camshaft and the coolant pump. Drive to the intake camshaft is transferred from the exhaust camshaft by a short chain located at the back of the camshafts. Under the drive shaft (in the oil pan), a balancing shaft module with an oil pump is placed, similar to those known from 2.0 TDI engines. Unfortunately, like in Diesel engines, this module can fail due to natural wear at around 200,000 km (in practice, in engines mainly used in urban traffic, it can happen sooner). The result of module failure is a lack of engine lubrication leading to engine seizure. The cost of overhauling such a seized engine (depending on the actual wear of its most important components) can reach several thousand PLN.
The second-generation engine, designated EA888, produced from late 2007, is a completely different design from its predecessor. Both camshafts are driven by a single timing chain. The balancing shaft (in this engine, there is only one) is located in the engine block at mid-height and is driven by a second chain, with a pulley at its end driving the coolant pump. A third chain drives the oil pump. The problem described above from older generation engines does not occur here. Unfortunately, these engines have another problem – after just tens of thousands of kilometers, they begin to consume large amounts of oil, and over time, the consumption intensifies. The only effective way to eliminate oil burning is a fairly costly engine overhaul.
The third-generation engine is a modified EA888. It differs from its predecessor in that it features variable timing control through variators on both camshafts. Additionally, modified pistons are installed in these engines. The problem of excessive oil consumption does not occur as quickly as in the second-generation engines.
