Turbo Diesel.

[Squid699]

::zips up flame suit::

I know nearly nothing about diesels except they're 2 stroke and run off compression and heat to combust the gas. Turbo diesels are always boosting, never operating in vacuum.

Query: Do turbo diesels need a BOV?

Discuss....

 

[Big Wang Bandit]

Yeah they do. They just are usually reciruculated if I believe correctly. At lease I THINK i saw a BOV on my dads F250

 

[Topher E]

Ya ummm, they are 4 stroke, and they can operate in vacume. I would imagine they would need a recirculation vavle but thats it.

 

[Wills7MGTE]

They all have BOV's, I worked at my grandpas diesel pump and injector and turbo shop, we only ordered turbos and rebuilt never built a custom or upgraded one. Theres some dodges in town with chips exhaust and get this import style BOV, one runs an hks similar to my hks ssqv, no recirculation. I am pretty sure they are always boosting cuz of the wastegates being different, they only rev to 3500 or 4500 or so so they need boost quick to make torque for towing etc.

 

[Squid699]

Ya ummm, they are 4 stroke

der der........::smacks forehead:: did some reading and watched an animation (i'm slow tonight) makes more sense.


As for the BOV - never looked into a turbo deisel, so I wasn't sure about a bov or not......cool.

 

[Ckanderson]

sooooooooooo much miss information..

99 percent of diesels dont run a throtle body.. thus.. no need for a BOV, thier rev limit is based on a few resons.. speed of ingnition for the fuel.. and the incredible wieght of thier recipricating mass. the never run in vacum (no TB=no vacum), but arnt always boosting. the amount of power they produce is based off how much gas the injectors inject.. too much gas, and the EGT's skyrocket.

 

[Squid699]

interesting. The mis-information is what I'm trying to dispel here.

so if the turbo is not boosting all the time, how can it not be in vacuum.........

 

[Nick M]

interesting. The mis-information is what I'm trying to dispel here.

so if the turbo is not boosting all the time, how can it not be in vacuum.........

Do you know anything about turbochargers? That isn't an insult. Look up some information. Turbochargers are load driven. Diesels are designed for the most part to move a heavy load. And did you read the post above mentioning the misinformation? There is not a throttle plate. You need a plate for vacuum.

A Diesel can be two stroke. Most are 4 stroke.

 

[Squid699]

I know a bit - but trying to learn more. Kinda hard when people treat me like I'm 2, though. Thanks for the info!

 

[Krister]

Diesels doesnt have a throttle body / Butterfly valve, therefore they dont use a BOV.

 

[SupraMario]

I know a bit - but trying to learn more. Kinda hard when people treat me like I'm 2, though. Thanks for the info!

this is why I try and keep my mouth shut around the big boys.
and when I have no clue I dont ask to many questions, Just read alot and fuck with it till it breaks or I figure it out.

 

[Mr.PFloyd]

sooooooooooo much miss information..

99 percent of diesels dont run a throtle body.. thus.. no need for a BOV, thier rev limit is based on a few resons.. speed of ingnition for the fuel.. and the incredible wieght of thier recipricating mass. the never run in vacum (no TB=no vacum), but arnt always boosting. the amount of power they produce is based off how much gas the injectors inject.. too much gas, and the EGT's skyrocket.

CK FTW! In addition, diesels have direct injection vs port injection. Also there is no spark because of the glow plugs. This one time my dad took his 86 Jetta Diesel to Crappy Tire, and they tried fitting spark plugs in spot of the glow plugs :icon_conf that would have blown the stupid shit up as the compression and spark is from the air, then the diesel is added. Yeah he didnt want to take it there, just it was -30 outside, car wouldnt start andCAA then would only tow that little. Diesels are cool, im gonan get a winter beater jetta when winter rolls around.

 

[Squid699]

I had read enough to know about the glow plugs and the direct injection. The glow plugs are only used on cold starts though, right?

 

[Nick M]

The glow plug is to heat the air when the engine is cold.

 

[MDCmotorsports]

Ok every body shooosh for a second and let me edumakate you:

There are 4 ways a diesel ignites its fuel:

-Preheat the air with coils
-Preheat the fuel before injection to the point of combustion
-Heat the combustion chamber (glow plug) untill the chamber is hot enough to self combust
-Compress the incomming fuel to the point of self ignition

99.9% of all diesels (haven't seen one yet, but Im sure there is at least one out there) do NOT HAVE A THROTTLE BODY. The throttle is controlled on how much fuel is injected into the combustion chamber. The turbo itself never sees a vacuum on the compressor side because of this.

Turbo diesel engines do not have BOVS.

Now as for diesel combustion:

1.)Preheated coils. Most commonly found on Cummins applications. There are giant heater coils like the ones you find in a hair dryer, inside the intake plennum. They heat the air so that the fuel can burn inside the combustion chamber. This combustion is ignited by a very sharp dome on the top of the piston. It litterally self detonates.

2.)Preheated fuel. This practice is still in use, but mostly only used in cold climates. Diesel has to be hot or warm to self combust. Again its all about a controlled self detonation.

3.)Heating the combustion chamber. This is the typical glow plug. The glow plug only runs untill the combustion chamber or piston is hot enough to continue to self ignight the incomming mixture.

4.)Ignition by compression. We all know that you can't compress a liquid to a certain degree, and we all know that when you compress a liquid or gas the temp raises. Well this type of ignition is commonly found on the CAT engines around the world. It uses a computer aided cam advance/retard system that helps the pistons from being overly hydrolocked. Again, there is a very sharp machined point in the top of the piston. When the fuel is compressed (we're talking over 300:1 compression at times) it raises quickly in temp, and the top of the piston self detonates the mixture.

LAST:

There are two and four stroke diesels. Most on the road are 4 stroke because of the EPA. Want the biggest baddest diesel engine ever made for over the road trucks? V12 two stroke (might have been a v8 or 6) Detroit Diesel. It was a bad mammerjammer back in the day!

 

[Squid699]

Sweetness MDC - exactly what I was looking for!

 

[Nick M]

There are two and four stroke diesels. Most on the road are 4 stroke because of the EPA. Want the biggest baddest diesel engine ever made for over the road trucks? V12 two stroke (might have been a v8 or 6) Detroit Diesel. It was a bad mammerjammer back in the day!

They still are bad ass.

And they are still in use when not subjected to EPA rapings.

Note the big ass Garrett feeding the blower.

 

[Troyota]

I saw the LARGEST engine I've ever seen. It was on the back of a flat bed pulled behind a diesel Semi Truck. It was HUGE...IIRC it was like 8-12 cylinders (inline). The thing was larger than my car. I'd love to find out what that thing was designed to run. It was stopped at a traffic light, just passing through town. But it was HUGE!!!

 

[Squid699]

I did some work with the Coast Guard when I was in Cadets in Highschool and was always in awe of the big turbo diesels they had on their smaller cutters.........::drool:: Always warm and ready to go in case there was a Search and Rescue Call.

 

[MDCmotorsports]

Ive seen and stood next to diesel engines that you walk inside of to work on.