I'm thick, so...............

[R1 GTR]

forgive me for asking this but...
am i right in saying that diesel engines do not have spark plugs? and that they have direct injection instead?

[eliot]

yep.
And the dont have a throttle / butterfly like a petrol engine either.

[steve_d]

They rely on much more compression than petrol engines. The heat in the cylinder plus the compression cause the fuel to spontaneously combust. To start from cold they have heaters in the cylinders.

Steve

[1otusfan]

And you have to fill them with Diesel.

[GavinPearson]

eliot said:

yep.
And the dont have a throttle / butterfly like a petrol engine either.

Sorry, most advanced turbo diesels now have a throttle to aid with EGR mix control.

[annodomini2]

R1 GTR said:

forgive me for asking this but...
am i right in saying that diesel engines do not have spark plugs? and that they have direct injection instead?

Not all are direct injection older designs of engines can be indirect injection.

[Pigeon]

Yes, but it's still injection straight into a combustion chamber immediately before/during ignition, not injection into the port like petrol engines usually do.

[vrooom]

If they dont have throttle/butterfly. how they gonna meter the fuel? pour more fuel into diesel, and they go higher rpm?

[apache]

vrooom said:

If they dont have throttle/butterfly. how they gonna meter the fuel? pour more fuel into diesel, and they go higher rpm?

imjection timing, open and close the injector for however long you want

[striker 20v]

hey,

The throttle cable isn't attached to a valve controlling the air going in, but instead the cable is attached to the fuel pump controlling the fuel going in, the air going in is in older diesels non mettered, because it simply doens't need to.

the newer ones create intake vacuum to suck exhaust gas via the EGR tube into the intake plenum.
the volume of fuel deternmines the speed of the engine, not the volume of air which is presented with a burnable fuel. IE a diesle is called fuel-throtteld and a Otto 4stroke gasoline engine is called air-throttled.

so that's how fuel mettering is done. in a nutshell offcourse.

normally a abundance of fuel (overfuling) creates an enourmous amount of power but care should be taken because where a gas engine get's hotter during lean out, a diesel does the opposite, exhaust temps will rocket skyhigh on overfueling killing turbo's and even known to meltdown turbine housings in some apllication

look for Elsbett engine in google, for an explination on the TDI principle. he's the guy that invented it and was screwwed bigtime by VW back in the day over the rights to produce such an engine, funniest thing is that elsbett made this engine to be able to run on vegable fuel instead of Oilbased diesel.

here's a nice link on diesels and very MUCH torque
www.bankspower.com
grtz Thomas

Edited by striker 20v on Thursday 7th December 11:54

[chuntington101]

striker 20v said:

hey,

The throttle cable isn't attached to a valve controlling the air going in, but instead the cable is attached to the fuel pump controlling the fuel going in, the air going in is in older diesels non mettered, because it simply doens't need to.

the newer ones create intake vacuum to suck exhaust gas via the EGR tube into the intake plenum.
the volume of fuel deternmines the speed of the engine, not the volume of air which is presented with a burnable fuel. IE a diesle is called fuel-throtteld and a Otto 4stroke gasoline engine is called air-throttled.

so that's how fuel mettering is done. in a nutshell offcourse.

normally a abundance of fuel (overfuling) creates an enourmous amount of power but care should be taken because where a gas engine get's hotter during lean out, a diesel does the opposite, exhaust temps will rocket skyhigh on overfueling killing turbo's and even known to meltdown turbine housings in some apllication

look for Elsbett engine in google, for an explination on the TDI principle. he's the guy that invented it and was screwwed bigtime by VW back in the day over the rights to produce such an engine, funniest thing is that elsbett made this engine to be able to run on vegable fuel instead of Oilbased diesel.

here's a nice link on diesels and very MUCH torque
www.bankspower.com
grtz Thomas

Edited by striker 20v on Thursday 7th December 11:54

i personal like this one the besT!

www.bankspower.com/DmaxTypeR.cfm

thick its made over 650bhp (f*ck only knows how much torque! lol) and it spinns to about 6500rpm i think! another fine exapmle of where deisel has come to.!

also worth looking in this months Pratical Performance Car. there is a guy in there going to build a diesel wetfield!

thanks Chris.

[eliot]

GavinPearson said:

most advanced turbo diesels

i knew that, but wanted to keep things simple.

Edited by eliot on Thursday 7th December 13:34

[R1 GTR]

steve_d said:

To start from cold they have heaters in the cylinders.

Steve

Hence the glow plug light on the dash?

[steve_d]

R1 GTR said:

steve_d said:

To start from cold they have heaters in the cylinders.

Steve

Hence the glow plug light on the dash?

Yep spot on.
Some are on a timer, you wait for the light to go out. Others you turn the key to just before turn-over which puts the light and heaters (glow plugs) on and wait ten seconds before firing it up.

Steve

[R1 GTR]

I knew i was clever, i think.

[annodomini2]

Pigeon said:

Yes, but it's still injection straight into a combustion chamber immediately before/during ignition, not injection into the port like petrol engines usually do.

Some early engines do.

[bluespanner]

annodomini2 said:

Pigeon said:

Yes, but it's still injection straight into a combustion chamber immediately before/during ignition, not injection into the port like petrol engines usually do.

Some early engines do.

The first ran on coal dust.