Why do new cars smoke?
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Patman
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I try to go full throttle often in my Corvette but a few weeks ago I had driven a few days without doing so, and when I pulled onto the highway and put my foot down I noticed a small cloud of black smoke briefly. That's the only time I've actually noticed that. I do notice my tailpipes get rather black, and I need to clean them frequently.
Yep, black smoke is rich mixture. Not oil burning.
And to the guy who commented about Mitsubishis - in my mind, every Mitsubishi ever made, burns oil and smokes like a chimney. Heck, I'm sure those Zeros smoked on their way to Pearl Harbor.
And to the guy who commented about Mitsubishis - in my mind, every Mitsubishi ever made, burns oil and smokes like a chimney. Heck, I'm sure those Zeros smoked on their way to Pearl Harbor.
On the DI engines, particularly the ones without port injection incorporated, it is soot. The soot is from the combustion process and a good hard throttle application clears a lot of it out the exhaust. On the ecoboosts, it is why the nice chrome exhaust tips are often black, and why I have a sooty spot on my garage floor from the cold exhaust dripping on the concrete. Definitely not oil.
One of the big reasons many engines are going to dual direct and port injection is to reduce this phenomena. An instance of where the DI engines got ahead of the emissions standards...
One of the big reasons many engines are going to dual direct and port injection is to reduce this phenomena. An instance of where the DI engines got ahead of the emissions standards...
My Cherokee will puff out black smoke. And it's port injected gas.
Originally Posted By: demarpaint
It must be a DI thing in gas engines.
That's what I've noticed. Diesel is a totally different animal, and not really a fair comparison.
How is it different? These gas engines are high (er) compression, with direct fuel injection. Getting pretty close to diesels technology wise.
Originally Posted By: demarpaint
It must be a DI thing in gas engines.
How is it different? These gas engines are high (er) compression, with direct fuel injection. Getting pretty close to diesels technology wise.
The ones that have sooty exhausts are usually turbocharged with direct injection. Two reasons contribute to this:
1) DI only engines are prone to higher particulate emissions at low load part throttle operation. This is the main reason behind manufacturers going dual injection using both port and direct injectors, it is more to curb particulate emissions with cleaner intake valves as a byproduct.
2) Turbos also get real hot under full load, so manufacturers tune the fuel mapping to run much richer at high loads to help with cooling the exhaust gasses. This contributes to more particulates when accelerating hard, but helps the turbos run cooler with higher reliability.
The current crop of dual injection turbo engines with integrated exhaust runners in the cylinder head run much cleaner than previous iterations.
1) DI only engines are prone to higher particulate emissions at low load part throttle operation. This is the main reason behind manufacturers going dual injection using both port and direct injectors, it is more to curb particulate emissions with cleaner intake valves as a byproduct.
2) Turbos also get real hot under full load, so manufacturers tune the fuel mapping to run much richer at high loads to help with cooling the exhaust gasses. This contributes to more particulates when accelerating hard, but helps the turbos run cooler with higher reliability.
The current crop of dual injection turbo engines with integrated exhaust runners in the cylinder head run much cleaner than previous iterations.
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