The Direct Injection Story

Nowadays Direction Injection technology is becoming more and more common news in today’s mainstream cars. Such technology is still not widely offered in our local market due to the usual circulating stories about the high sulphur content in the fuel used here. The technology is not new and has been commonly used in diesel engines and is offered in the Japanese market for quite sometime, until lately we started witnessing it reaching into other markets such as the US & Europe.

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Direct Injection is quite impressive, allowing car makers to produce engines with more efficient combustion which yield to a more generous power output & less fuel consumption.


Direct injection allows engines to be run at higher compression ratios, the fuel mixture is atomized more efficiently into the combustion chamber compared to the average multi-port fuel injection which also leads to thermal efficiency within the combustion chamber.
Here is a diagram of a combustion chamber where you can see that the fuel injector is actually a common rail fuel line atomizer that feeds fuel directly into the combustion chamber compared to the regular multi-port injection system:

 

Close up on direct injection atomizer:

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Below is a picture of Ford’s 3.5 Duratec V6 engine with direct injection. The fuel pump is sits above cylinder head and is driven by the camshaft as it feeds the fuel injections that are connected to the direct injection atomizers:

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The technology is ever changing the way engines are built coupled with complex electronic management systems & Variable Valve Timing technologies these engines pave a way for a brighter & perhaps more promising future for the conventional internal combustion engine.

Though the question remains is whether these engines, will be commonly sold at our local dealers.
The issue comes as follows:
Direct injection engines are sold in the US & Europe, though the fuel quality there is poor compared to that of Japan. And producing high-quality, low sulphur content fuel will mean more costly fuel.

– It is said that poor quality fuels (98ron & below) will cause sludge builds up in the atomizers which can be permanently damaged. Circulating recommendations is that people with DI engines or GDI (gasoline direct injection, as the technology was adopted ages ago in Diesel Engines) using low quality fuel to keep the an eye on keeping the fuel system clean, from injectors, to fuel pump & the throttle body.
– GDI Engines run lean but have specially engineered combustion chambers designed in a fashion to efficiently compress and combust the fuel without any knock yet such method does produce plenty of NOx emissions, hence GDI engines use a special type of catalytic converter to deal with such emissions. The issue is that higher sulphur content is the fuel can also potentially damage such catalytic converters.

These are some reasons why we don’t see such engines in our market. The good news is carmakers have already methods to counter such problems and are still figuring stuff out also laws and regulations in the near future will be more strict about the quality of fuel sold in several markets world wide. I will keep you posted about updates and news about this chapter as our beloved 86 comes with direct injection.

For those that believe that turbo charging is an issue with such high compression ratio engines here is ford is using direct injection in their Eco Boost engines, here is their Story.

One thing forsure, such engine would be a whole different thing for tuners to deal with, I am trying to find out what Greddy has in store soon for such engine, as they the first few to get their hands dirty with the 86.

As a matter of fact here is some good news, Subaru is going to consider producing a Turbocharged version of the BRZ.

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http://www.mycarforum.com/index.php?showtopic=2645702
http://www.autozine.org/technical_schoo … etrol1.htm
http://www.arunautogas.co.uk/lpg_and_fs … ngines.htm

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