injection versus ignition time

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metal_miner

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What is a good rule of thumb for one to safely assume as to the time difference between injection versus ignition of diesel?

Is this something to really worry about with street trucks versus race trucks?

From research fuel quality plays a part, but is that somewhat alleviated at the rail pressures common rails operate?
 
It is very difficult to measure on a high speed diesel. You can look at peak pressures based on crank angle and see the point of injection and then the following ignition delay. There will always be a delay, how long that delay will be depends on (as you mentioned) fuel quality, atomization and even cylinder heat. It is some what predictable with most pumped fuel. Just not exactly sure how you would eb able to measure it on a highspeed diesel to adjust for it. I think the gains would be minimal regardless.

We do this often with medium and slow speed diesels. Mostly to check the performance of the injection equipment and to balance the engines. In the future I believe you will see common rial engines that will do this automatically. I have already seen medium speed natural gas engines that could do this. The problem is the pressure sensors located in the cylinder heads don't last too long. They have been developing a new sensor that uses fiber optics and a steel membrane to measure cylinder pressure. This technology appears to be very promising in regards to reliability.
 
Torque Monkey said:
It is very difficult to measure on a high speed diesel. You can look at peak pressures based on crank angle and see the point of injection and then the following ignition delay. There will always be a delay, how long that delay will be depends on (as you mentioned) fuel quality, atomization and even cylinder heat. It is some what predictable with most pumped fuel. Just not exactly sure how you would eb able to measure it on a highspeed diesel to adjust for it. I think the gains would be minimal regardless.

We do this often with medium and slow speed diesels. Mostly to check the performance of the injection equipment and to balance the engines. In the future I believe you will see common rial engines that will do this automatically. I have already seen medium speed natural gas engines that could do this. The problem is the pressure sensors located in the cylinder heads don't last too long. They have been developing a new sensor that uses fiber optics and a steel membrane to measure cylinder pressure. This technology appears to be very promising in regards to reliability.
Click to expand...

What part of the industry are you in?

Monkey Fist Rage
 
metal_miner said:
What is a good rule of thumb for one to safely assume as to the time difference between injection versus ignition of diesel?

Is this something to really worry about with street trucks versus race trucks?

From research fuel quality plays a part, but is that somewhat alleviated at the rail pressures common rails operate?
Click to expand...

are you attempting to quantify an optimum cutoff ratio??
 
Julius....I might just have to have you tune my grey truck!

Sent from my DROID4 using Tapatalk
 
an engineer's mind is a valuable thing... use that mind to calculate a potential tuning change and try it out. At some point you just gotta load it up and see what happens, but you've got the mind to load up calculated changes. best of all worlds!
 
cquestad said:
Julius....I might just have to have you tune my grey truck!

Sent from my DROID4 using Tapatalk
Click to expand...

You have to get it running first!

I haven't had time to play around with UDC too much with my new injectors yet. As a baseline I'm wanting to start out at a same performance level as with my Flux 2 results. Even though the new injectors are double in size than before, I'm finding that so far cutting my UDC duration in half on the top end and backing off timing accordingly (based on spreadsheet model) is still more SOP power than before.

I guess this would make sense in terms of extracting more energy from the amount of fuel being injected at the right time versus over a longer period of time and fighting the movement of the piston????
 
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