Delphi Multec 3.5, Руководство по применению

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Multec 3.5 Fuel Injector Application Manual Software
Delphi Energy and Chassis Systems Revision: 11/05-1 5-15
when the air/fuel ratio is close to stoichiometric. Integral correction is a
slower (several milliseconds and smaller) step change. The amount of
correction increases in relation to the length of time that the error exists.
The ability of both of these systems to correct and control the air/fuel ratio
depends on the control system’s loop time, the optimization of calibration
and the performance of the components.
The adaptive multiplier, also called the long-term fuel trim, corrects
durability, engine tolerance, system tolerance and flow or output shifts
that occur over time, such as changes caused by wear. The corrections are
based on a block-partitioned graph of engine speed (RPM) versus engine
load (throttle position). The long-term fuel trim has corrections for each
block.
Note Limits should exist on short term and long-term authority. The limits
should be picked to avoid driveability or emission problems, while
comprehending normal system tolerances. The customer must define the
limits for each given application.
Fuel system component limit testing is encouraged to evaluate the
control system response. Components with flow and pressure set at the
limits of production and durability tolerances in order to create lean and
rich limit conditions should be evaluated with the production engine
control system as part of production validation. (See section 8.4.13)
In lieu of building limit components, modifications to the flow calibration
software tables can be made to simulate these conditions.
5.2.5 Fuel Injection Timing
Previously, Figure 5-1 illustrated the different injector firing schemes.
ASDF, SDF and SSF systems provide the greatest variation in fuel
preparation and residence time. Open intake valve fuel injection cannot
be avoided for these firing schemes.
Sequential firing schemes allow for optimizing fuel injection timing to
maximize fuel at intake valve residence time and avoid most cases of open
intake valve fuel injection. Figure 5-3 below is an example of optimum
timing for a representative emissions test operating condition.