So a few weeks ago I visited an engine manufacturing plant in Spain and there I got see firsthand an extremely interesting process called Bore Spray Coating, where a cylinder coating was sprayed directly onto the aluminum block cylinders instead of using traditional cast iron cylinder liners.
This process apparently reduces engine weight and improves efficiency but it also makes the engine non-rebuildable. In response to this, a significant number of viewers commented how this is planned obsolescence and how non-rebuildable engines are bad for the environment.
So in response to that I decided to make this video where I will do two things
1) Explain the different types of cylinder coatings so that we can understand whether this is actually planned obsolescence
2) I will use data from various research papers from reputable sources to measure to quantify the environmental impact of non-rebuildable engines.
Nikasil stands for nickel silicon carbide and Nikasil coating is essentially an electroplating process-
Nikasil was actually perfected by German company Mahle in the late 60s when they were working together with NSU to find a way to make Wankel Apex seals work inside aluminum rotor casings. Porsche was one of the first to implement Nikasil in a piston engine in their 917 and later in the 911 RS. After this it started spreading to motorcycles, it quickly became popular in two stroke motorcycles. In the 90s Nikasil was also implemented in the BMW m52 inline six and m60 v8 as well as Jaguars AJ V8 engine.
What spelled doom for Nikasil is that it’s essentially a slow and labor intensive process which makes it expensive. So what manufacturers decide to do was to find a way to get all the benefits of Nikasil without the labor intensive and expensive manufacturing process. And so they came up with Alusil.
Alusil is essentially an etching process. You cast the entire engine block with a very high content of silicon. Usually around 17%. Once the block is cast you either chemically or mechanically etch away the aluminum in the cylinder and so what remains exposed is a layer of silicon.
This does require some specialized honing to finish the block, but overall the process is much faster and more cost-effective than the electroplating complexities of Nikasil.
But still, manufacturers were not happy so they decided to try and make it cheaper. And what they came up is another acronym. This one was called Lokasil. The whole point of Lokasil is to not cast the entire block with a high content of silicon, because you only need the silicon in the cylinder right?
Now Silitec is just like Lokasil but apparently it’s somehow different enough so that Mercedes didn’t have to pay license fees since Silitec is mostly present on Mercedes engines.
But despite the long-term reliability failure of Alusil, Lokasil and Silitec the performance and efficiency benefits of cylinder coatings remain undeniable so manufacturers decided to try and find a new way to avoid cast iron cylinder liners. And they did. They decided to spray the liner onto the cylinder giving brith to what is known as Thermal Spray Coatings.
We have wires made from whatever metal or combination of metals we want. Usually, it’s a nickel-iron alloy or something similar. You can think of these two wires as welding wires. We pass a ridiculous amount of electricity through these wires. The electricity arcs and creates plasma, a superheated gas. This incredibly hot gas then starts melting and atomizing the wire into tiny droplets. When that starts happening we use compressed air or nitrogen to spray the droplets onto the cylinder.
A special thank you to my patrons:
Daniel
Zwoa Meda Beda
valqk
Toma Marini
Cole Philips
Allan Mackay
RePeteAndMe
Sam Lutfi
Cakeskull
00:00 Nikasil
07:48 Alusil, Lokasil, Silitec
12:26 Thermal Spray Coatings
15:35 Planned Obsolescence?
22:25 Environmental Impact of Non-rebuildable engines
Sources: https://chatgpt.com/
Actual sources:
Life Cycle Energy Consumption and Greenhouse Gas Emissions Analysis of Primary and Recycled Aluminum https://www.mdpi.com/2227-9717/10/11/2299
Aluminum Climate Impact - An International Benchmarking of Energy and CO2 Intensities
https://www.bluegreenalliance.org/wp-content/uploads/2021/04/Aluminumreportdesign-FinalFeb2022.pdf
New car registrations: https://www.acea.auto/pc-registrations/new-car-registrations-13-9-in-2023-battery-electric-14-6-market-share/
EU cars fact sheet: https://www.acea.auto/fact/fact-sheet-cars/
Average mileage driven: https://www.odyssee-mure.eu/publications/efficiency-by-sector/transport/distance-travelled-by-car.html
Coatings 1: https://link.springer.com/article/10.1007/s42247-021-00307-1
Coatings 2: https://ir-api.ua.edu/api/core/bitstreams/ce095876-8a57-4614-b23a-95f75d3da159/content
Alu blocks: https://european-aluminium.eu/wp-content/uploads/2022/11/aam-applications-power-train-2-engine-blocks.pdf
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