EGTs for school project. Turbo guys please help!
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EGTs for school project. Turbo guys please help!
Hi all,
I am a student in engineering and as part of senior design project I need to know some information for my project model. Pretty much what it comes down to is I need to know the difference in temperature of exhaust gas before and after the turbo. Let's assume we are talking about cruising speed of 60 in overdrive in standard conditions (approximately 70 F), what ever that rpm may respond to. I know, it changes based on turbo and from car to car, but I just need a decent estimation to see if the project idea is worthwhile. So if some of you run gages pre-turbo, please let me know what kind of temperatures you are seeing. Same for post turbo. I have a cummins truck, and normally I see temps of 550-650 F at the conditions specified pre-tubro, is it similar to a car set up?Any useful information is great.
The help is really appreciated. Thank you!
I am a student in engineering and as part of senior design project I need to know some information for my project model. Pretty much what it comes down to is I need to know the difference in temperature of exhaust gas before and after the turbo. Let's assume we are talking about cruising speed of 60 in overdrive in standard conditions (approximately 70 F), what ever that rpm may respond to. I know, it changes based on turbo and from car to car, but I just need a decent estimation to see if the project idea is worthwhile. So if some of you run gages pre-turbo, please let me know what kind of temperatures you are seeing. Same for post turbo. I have a cummins truck, and normally I see temps of 550-650 F at the conditions specified pre-tubro, is it similar to a car set up?Any useful information is great.
The help is really appreciated. Thank you!
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Re: EGTs for school project. Turbo guys please help!
Wow, loaded question.
How about this for a start, EGTs on the diesel will be lower than a gas engine, and not exactly follow the same pattern. They will in general go up under higher load, but otherwise will be different since a gas engine is throttled by controlling airflow, diesel by controlling fuel delivery. On a diesel, as boost goes up temperature goes up with pressure, but as you move more air through the engine exhaust temps go down. On a gas engine, temp goes up with pressure, and temp goes up with airflow untill you blow the engine up. Adding fuel will typically lower temps in a gas engine, and raise them in a diesel (within reason, at some point if fuel ends up burning off in the exhaust it will go up in both. Actually, this pretty much applies across the board, if you push any condition far enough some thing strange could happen).
Part throttle is harder to answer than WOT, and typically you're not hurting things on a gas engine till you get over about 1400*, where with diesels you're typically a few hundred degrees cooler.
You'll also see a few hundred degrees drop across the turbine.
But all of this changes with design, materials, distances from the port to the turbine, turbine size and design, exhaust after the turbine, pressure ratio, fueling, emissions consideration...
How about this for a start, EGTs on the diesel will be lower than a gas engine, and not exactly follow the same pattern. They will in general go up under higher load, but otherwise will be different since a gas engine is throttled by controlling airflow, diesel by controlling fuel delivery. On a diesel, as boost goes up temperature goes up with pressure, but as you move more air through the engine exhaust temps go down. On a gas engine, temp goes up with pressure, and temp goes up with airflow untill you blow the engine up. Adding fuel will typically lower temps in a gas engine, and raise them in a diesel (within reason, at some point if fuel ends up burning off in the exhaust it will go up in both. Actually, this pretty much applies across the board, if you push any condition far enough some thing strange could happen).
Part throttle is harder to answer than WOT, and typically you're not hurting things on a gas engine till you get over about 1400*, where with diesels you're typically a few hundred degrees cooler.
You'll also see a few hundred degrees drop across the turbine.
But all of this changes with design, materials, distances from the port to the turbine, turbine size and design, exhaust after the turbine, pressure ratio, fueling, emissions consideration...
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