Author Topic: A.P. TECH. QUIZ #2  (Read 641 times)

Offline Skyguns MKII

  • Silver Member
  • ****
  • Posts: 1067
A.P. TECH. QUIZ #2
« on: April 14, 2014, 11:50:29 PM »
On the last quiz we discussed about upper deck and lower deck pressure on the intake system of a turbocharged engine. Now here's something a little more challenging  :banana:... What is the relationship between a fuel injector nozzle and upper and lower deck pressure? which deck pressure is it usually located in? and why? Good luck!  :cheers:

Offline earl1937

  • Gold Member
  • *****
  • Posts: 2290
Re: A.P. TECH. QUIZ #2
« Reply #1 on: April 18, 2014, 09:31:43 AM »
On the last quiz we discussed about upper deck and lower deck pressure on the intake system of a turbocharged engine. Now here's something a little more challenging  :banana:... What is the relationship between a fuel injector nozzle and upper and lower deck pressure? which deck pressure is it usually located in? and why? Good luck!  :cheers:
:banana: Good question! However, I believe, if memory serves me correctly, a fuel injection system, direct into the cylinders, has a metering device, not a carburetor, so the upper and lower deck pressures would be not be a factor. Example, on a Cessna 421 with TSIO-540 engines, if the blowers were hardy enough, you could climb much higher than the service ceiling listed in the POH, but the limiting factor is now the amount of air which can be introduced into the cylinders.
Blue Skies and wind at my back and wish that for all!!!

Offline Skyguns MKII

  • Silver Member
  • ****
  • Posts: 1067
Re: A.P. TECH. QUIZ #2
« Reply #2 on: April 19, 2014, 07:37:15 PM »
:banana: Good question! However, I believe, if memory serves me correctly, a fuel injection system, direct into the cylinders, has a metering device, not a carburetor, so the upper and lower deck pressures would be not be a factor. Example, on a Cessna 421 with TSIO-540 engines, if the blowers were hardy enough, you could climb much higher than the service ceiling listed in the POH, but the limiting factor is now the amount of air which can be introduced into the cylinders.

ah very good! however! notice i said fuel injection system. I didn't mention if it was direct injection OR  :old: CONTINUOUS fuel injection hint! hint!  :bolt:

Offline earl1937

  • Gold Member
  • *****
  • Posts: 2290
Re: A.P. TECH. QUIZ #2
« Reply #3 on: April 20, 2014, 04:38:32 AM »
ah very good! however! notice i said fuel injection system. I didn't mention if it was direct injection OR  :old: CONTINUOUS fuel injection hint! hint!  :bolt:
:uhoh Sorry, this old mind not working like it used to! Still having trouble grasping the heart of the question. "Float" type carbs must be involoved with the question, but not sure how you want answer presented. Help us out on this one, darn good question and subject though!
Blue Skies and wind at my back and wish that for all!!!

Offline Skyguns MKII

  • Silver Member
  • ****
  • Posts: 1067
Re: A.P. TECH. QUIZ #2
« Reply #4 on: April 26, 2014, 10:34:45 PM »
:uhoh Sorry, this old mind not working like it used to! Still having trouble grasping the heart of the question. "Float" type carbs must be involoved with the question, but not sure how you want answer presented. Help us out on this one, darn good question and subject though!

not a float type carburetor. Dont wanna give it all away!  :cheers:

Offline icepac

  • Platinum Member
  • ******
  • Posts: 6979
Re: A.P. TECH. QUIZ #2
« Reply #5 on: April 27, 2014, 01:33:07 AM »
A port fuel injector is located in the lower deck or downstream of the throttle plate.

A "pressure carb" or "injection carb" as used in a merlin is upstream of even the blower inlet.

Offline Skyguns MKII

  • Silver Member
  • ****
  • Posts: 1067
Re: A.P. TECH. QUIZ #2
« Reply #6 on: May 13, 2014, 11:59:28 PM »
A port fuel injector is located in the lower deck or downstream of the throttle plate.

A "pressure carb" or "injection carb" as used in a merlin is upstream of even the blower inlet.


Correct! next one coming soon!