Load: Difference between revisions

From S4wiki
Jump to navigation Jump to search
No edit summary
No edit summary
 
(17 intermediate revisions by the same user not shown)
Line 1: Line 1:
;Engine load: Also known as relative cylinder charge. It represents the percentage of air (compared to standard density) in each of the cylinders. 100% load means each cylinder has the mass of air as an equivalent volume at standard density. Ingested air mass is calculated from [[MAF]] value (mass/time) divided by RPM (1/time), divided by two to yield a mass. Standard mass is calculated by engine displacement (volume) times standard density (mass/volume). The ratio of the two masses is load. It is used in real time to determine all other values including boost, timing, and fueling. In normally aspirated motors, load will rarely exceed 100%, but in forced induction motors, load exceeding 100% is expected.
;Engine load: A number extrapolated from the [[MAF]] value with some minor corrections. It is used in real time to control all other values including boost and fueling.


{{Load}}
;Engine load specified: Target load based on programmed values (and throttle pedal input?). i.e. [[ME 7]] strives for a specific [[MAF]] number at a certain RPM point.
=ECUx definitions=


Actual ME7 FR definitions in parenthesis.
;Engine load corrected specified: Adjusted target load based upon a number of internal and external values, two externals being ambient temerature and pressure. Internals are usually due to engine wear trims.

;EngineLoadSpecified (<code>rlmx_w</code>): The maximum target load, depends only on RPM. Misnomer, should really be something like "EngineMaxLoad"

;EngineLoadCorrectedSpecified (<code>rlmax_w</code>): Adjusted maximum target load based upon <code>rlmx_w</code> corrected by a number of internal and external values, two externals being ambient temperature and pressure. Instantaneous ignition retard due to knock control might also affect maximum specified load. Misnomer, should really be something like "EngineMaxLoadCorrected"

;EngineLoadRequested (<code>rlsol</code>): Target load based on the accelerator pedal position. It is capped by EngineLoadCorrectedSpecified (<code>rlmax_w</code>) and will never exceed that value.

Latest revision as of 20:02, 10 July 2019

Engine load
Also known as relative cylinder charge. It represents the percentage of air (compared to standard density) in each of the cylinders. 100% load means each cylinder has the mass of air as an equivalent volume at standard density. Ingested air mass is calculated from MAF value (mass/time) divided by RPM (1/time), divided by two to yield a mass. Standard mass is calculated by engine displacement (volume) times standard density (mass/volume). The ratio of the two masses is load. It is used in real time to determine all other values including boost, timing, and fueling. In normally aspirated motors, load will rarely exceed 100%, but in forced induction motors, load exceeding 100% is expected.

ECUx definitions

Actual ME7 FR definitions in parenthesis.

EngineLoadSpecified (rlmx_w)
The maximum target load, depends only on RPM. Misnomer, should really be something like "EngineMaxLoad"
EngineLoadCorrectedSpecified (rlmax_w)
Adjusted maximum target load based upon rlmx_w corrected by a number of internal and external values, two externals being ambient temperature and pressure. Instantaneous ignition retard due to knock control might also affect maximum specified load. Misnomer, should really be something like "EngineMaxLoadCorrected"
EngineLoadRequested (rlsol)
Target load based on the accelerator pedal position. It is capped by EngineLoadCorrectedSpecified (rlmax_w) and will never exceed that value.