PSD Engine Model, PSDEM (Preliminary Results)
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From: Fulltime RVer
PSD Engine Model, PSDEM (Preliminary Results)
Objective: Model the end-to-end flow path from the atmosphere, through the air filter, and out the tail pipe. Use input data, and model output parameters that can be verified by measurements, estimates, and obtained from specifications.
Preliminary Results: My measurements to date are from acceleration runs where my gauge readings are constantly changing, which limits their accuracy. However the results below are agreeing pretty well with those measurements. When I hit the road in two weeks I'll get much better data, and I also have a long way to go on the model to increase its sophistication in a number of areas. As time permits, I'll give detailed write ups on each part of the model, and some of my lessons learned.
If the 7 spreadsheet pics below loaded in the sequence I hoped for, you should see from top to bottom, Information Tables and Model Output Tables for the following 3 output parameters. 1) AFIVAF=Air Filter Inlet Volume Air Flow, ft3/min=cfm. Included here is a Table of turbo, IC, and inlet manifold temps that is the same for the other two outputs. 2) HPRR=Horse Power Rear Wheel vs RHPRR=Required Horse Power Rear Wheel to climb various grades, and 3) MPG=Miles Per Gallon when climbing various grades.
Output #1, gives CFM into the air box vs RPM & BP. I overlaid my CFM measurements using my new AFAFG= Air Filter Air Flow Gauge, and they agree pretty well with the model. Output #2, gives max RWHP vs RPM & BP. I overlaid colored tags to show combinations of HP & MPH for various grades. For example, at 0% grade 255 HP at 3200 RPM & 15 psi BP gives 103 MPH. I'm not encouraging this experiment, but if anyone has already done it I'd be curious how close this model (for an early 99) comes to a correct prediction? It predicts my truck has a HP limited top speed of about 105 MPH! Output #3 gives MPG at max HP, and overlays combinations of HP & MPH for various grades. The model shows that at a AFR=30, the HP is sufficient to cruise at 60 MPH on the flat at 15 MPG which seems about correct.
Well, the site only lets me upload 3 files, I'll try to load the #2 & #3 Outputs later, maybe below as replies to my own post.
Preliminary Results: My measurements to date are from acceleration runs where my gauge readings are constantly changing, which limits their accuracy. However the results below are agreeing pretty well with those measurements. When I hit the road in two weeks I'll get much better data, and I also have a long way to go on the model to increase its sophistication in a number of areas. As time permits, I'll give detailed write ups on each part of the model, and some of my lessons learned.
If the 7 spreadsheet pics below loaded in the sequence I hoped for, you should see from top to bottom, Information Tables and Model Output Tables for the following 3 output parameters. 1) AFIVAF=Air Filter Inlet Volume Air Flow, ft3/min=cfm. Included here is a Table of turbo, IC, and inlet manifold temps that is the same for the other two outputs. 2) HPRR=Horse Power Rear Wheel vs RHPRR=Required Horse Power Rear Wheel to climb various grades, and 3) MPG=Miles Per Gallon when climbing various grades.
Output #1, gives CFM into the air box vs RPM & BP. I overlaid my CFM measurements using my new AFAFG= Air Filter Air Flow Gauge, and they agree pretty well with the model. Output #2, gives max RWHP vs RPM & BP. I overlaid colored tags to show combinations of HP & MPH for various grades. For example, at 0% grade 255 HP at 3200 RPM & 15 psi BP gives 103 MPH. I'm not encouraging this experiment, but if anyone has already done it I'd be curious how close this model (for an early 99) comes to a correct prediction? It predicts my truck has a HP limited top speed of about 105 MPH! Output #3 gives MPG at max HP, and overlays combinations of HP & MPH for various grades. The model shows that at a AFR=30, the HP is sufficient to cruise at 60 MPH on the flat at 15 MPG which seems about correct.
Well, the site only lets me upload 3 files, I'll try to load the #2 & #3 Outputs later, maybe below as replies to my own post.
