pe and ve
10-31-2005, 07:30 PM
#2
TECH Addict
iTrader: (10)
Join Date: Jun 2004
Location: Commerce Twp, MI
Posts: 2,918
Likes: 0
Received 0 Likes
on
0 Posts
volumetric efficiency - one of the variables in a formula the PCM uses to calculate fueling for various conditions (graphed by rpm vs. manifold pressure).
power enrichment - a fuel adding table for performance/higher load conditions (represented in either EQ or AFR).
Basically, consider your VE table as your foundation. The PCM uses that to achieve the target AFR ratio set, which in our cars is 14.63:1. At this AFR, your EQ is 1.00. PE then takes that AFR and richens it up by the value you have entered for a given rpm. For example, say at 5600 rpms you have an EQ of 1.13. You take 14.63 (AFR) / 1.13 (EQ) = 12.95 (Commanded AFR). I say commanded because there's no way for the PCM to determine whether it's actually producing that AFR in open loop conditions as our O2 sensors are only good for detecting a small AFR range close to 14.63. That help?
power enrichment - a fuel adding table for performance/higher load conditions (represented in either EQ or AFR).
Basically, consider your VE table as your foundation. The PCM uses that to achieve the target AFR ratio set, which in our cars is 14.63:1. At this AFR, your EQ is 1.00. PE then takes that AFR and richens it up by the value you have entered for a given rpm. For example, say at 5600 rpms you have an EQ of 1.13. You take 14.63 (AFR) / 1.13 (EQ) = 12.95 (Commanded AFR). I say commanded because there's no way for the PCM to determine whether it's actually producing that AFR in open loop conditions as our O2 sensors are only good for detecting a small AFR range close to 14.63. That help?
Last edited by SSpdDmon; 10-31-2005 at 07:43 PM.
10-31-2005, 08:45 PM
#3
Moderately Differentiated
iTrader: (4)
Join Date: Nov 2004
Location: Maryland
Posts: 27,408
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by SSpdDmon
volumetric efficiency - one of the variables in a formula the PCM uses to calculate fueling for various conditions (graphed by rpm vs. manifold pressure).
power enrichment - a fuel adding table for performance/higher load conditions (represented in either EQ or AFR).
Basically, consider your VE table as your foundation. The PCM uses that to achieve the target AFR ratio set, which in our cars is 14.63:1. At this AFR, your EQ is 1.00. PE then takes that AFR and richens it up by the value you have entered for a given rpm. For example, say at 5600 rpms you have an EQ of 1.13. You take 14.63 (AFR) / 1.13 (EQ) = 12.95 (Commanded AFR). I say commanded because there's no way for the PCM to determine whether it's actually producing that AFR in open loop conditions as our O2 sensors are only good for detecting a small AFR range close to 14.63. That help?
power enrichment - a fuel adding table for performance/higher load conditions (represented in either EQ or AFR).
Basically, consider your VE table as your foundation. The PCM uses that to achieve the target AFR ratio set, which in our cars is 14.63:1. At this AFR, your EQ is 1.00. PE then takes that AFR and richens it up by the value you have entered for a given rpm. For example, say at 5600 rpms you have an EQ of 1.13. You take 14.63 (AFR) / 1.13 (EQ) = 12.95 (Commanded AFR). I say commanded because there's no way for the PCM to determine whether it's actually producing that AFR in open loop conditions as our O2 sensors are only good for detecting a small AFR range close to 14.63. That help?
nice explanation!