And what the heck is 'stratified' injection anyway?
What does Volkswagen TSI stand for? In the automotive world, acronyms are as common as strippers with the name Tiffany, and Volkswagen is particularly fond of using a few short letters to represent something complex. For example, the term Turbocharged Direct Injection - the name applied to common rail diesel engines from Volkswagen - is identified by the acronym TDI.
Many incorrectly assume that the TSI acronym represents Turbocharged Supercharged Injection, but although there was a 1.4-liter TSI engine with both a turbocharger and a supercharger, the truth is that, while the T does represent Turbocharged, the S does not mean Supercharged. The I stands for Injection as it does in TDI. So what is a TSI?
The S in the VW TSI car acronym refers to the word Stratified. The 2.0 TSI engine in cars like the Volkswagen Golf makes use of stratified charge, which means that the charged air entering the combustion chamber includes injected fuel vapors that are so well mixed with the air that the fuel is effectively arranged in uniform, stable layers, or strata, helping to initiate ignition and promoting complete combustion. This means that the VW TSI engine, which is a 2.0-liter four-cylinder, can run with slightly higher compression ratios without the risk of pre-detonation, otherwise known as engine knock. In addition, the engine can run a leaner air/fuel ratio, making it more efficient.
Simply put, stratification in engines is a type of fuel injection. Remarkably, while this design is more complex, it's also more affordable to produce, making the end product - whether that's an Atlas or a humble Golf - cheaper to produce.
For those with a little more nerdery in their makeup, the VAG TSI engine may call to mind its predecessor, the TFSI. Like a regular TSI Volkswagen, the T, S, and I refer to turbocharging, stratification, and direct injection. As a predecessor to the TSI engine, the earlier name represented the same thing but was slightly more cumbersome, as the F simply means Fuel. Volkswagen likely decided that the F was redundant, and dropping it must have saved a noticeable pile of money on badge production alone. It may seem inconsequential on a single car, but removing one letter from the badges on fenders, trunks, and engine covers will have saved millions over the years.
Hopefully, this article has contributed to your general knowledge in a clear and concise manner, and the next time you're asked, "What does VW TSI stand for?" you can answer in a similar fashion.
With that done, we can't help but wonder: Will Volkswagen's EVs be subjected to the same unusual acronyms, or will things get simpler? Since VW will produce electric drive systems in-house, we suspect it will trademark the names of those motors too.
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