I believe Toyota GDI engines and probably others now have two injectors per cylinder. The ECU directs the fuel intermittently through a second intake manifold injector to keep the back of the valves clean.
( edited to correct misinformation)
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More complex with more parts to fail. Seems like a Rube Goldberg design to me. All because of carbon deposits on valves.
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Get 1 ? or 2 ? mpg more but when something breaks youâll pay back the savings in gasoline and a lot more $$$$$
That has absolutely nothing to do with being ânormally aspiratedâ. Normally aspirated means the engine does not have a turbocharger or supercharger. The injectors in the intake manifold is port injection.
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A number of manufacturers have successfully solved this DI engine intake valve carbon buildup problem in recent years. As other have noted, two injectors are often used. I believe the 2nd injector is in the intake manifold and sprays only enough fuel to keep the intake valve clean.
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Direct injection is more efficient, I suppose. More power, better MPGâs. Port injection keeps the valves cleaner. Realistically, most people arenât going to worry about valve deposits or try to remove them. So, I get why the manufacturers added the port injection. Although, yeah, it is more parts to fail. Add to that turbos, variable timing, cylinders that shut down under light loads, etc. I read an article about the 2.7 (if I recall) 4 cylinder in the Silverado. That thing soundedâŠpretty complex.
There is an issue with DI - particulates. Maybe the combination of the two allows makers to better meet particulate limits.
There are companies that make catch cans that go in the PCV system and catch the oil that goes back into the intake. I put one on my 2020 Ford with a 3.5L DI engine, and collected about 8 oz of oil in 2500 miles. This is oil that is now not going back into the intake to get onto the tops of the valves.
Ford told me to take it off or void the engine warrantyâŠ
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This study suggests that even removing the PCV stream from the intake does not reduce intake valve deposits:
Iâve read that reverse flow of gases from combustion chamber to intake during beginning of the intake stroke are the source of IVDs.
Iâd rather not send harsh chemicals and dissolved crud through my engine, and on to the cat converter.
When itâs time for a cleaning, the intake manifold will be taken off and valves will be cleaned directly.
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Omg! That looks like the outcome when my wife makes French Toast.
Without getting into the weirdness of CIS fuel injection; it was not uncommon for CIS cars to hydrolock on gasoline now and then.
The fuel injectors spray continuously (the C in CIS) with no pulse and when something goes goofy in the fuel distributor the injectors may spray wide open with the throttle at idle. The fuel drowns the spark plugs and soon fills the cylinders. Next step; tow truck and a silent prayer.
Our wives must be cousins. Once, one of our smoke alarms just went off for no reason. My daughter called out from her room âIs Mom cooking again?â
I donât recommend CCleaner for OSâs beyond Vista, itâs not needed for Win7/10/11 IMHO. Also if youâre using a SSD, defragging is pointless and just adds unnecessary write cycles, I havenât had a mechanical drive in any of my PCâs in years. Malwarebytes is legit though.
Itâs handy, the smoke alarm letâs you know when dinner is ready
A response to a 12 year old post.
Oops. I should probably start reading the dates on these posts.