FILTERS BALDWIN

Catalog Baldwinfilters for tractors

Auto Parts / Amplified Common Rail System CLEAN FUEL IS VITAL
(ACRS) generates 50 percent of its
injection pressures with a high- One of the key preventive
pressure pump, and amplifies that
maintenance strategies for any of
pressure at the injector itself. The idea these fuel injection systems involves
here is to limit the stress on the fuel
the related filtration of fuel, since the
lines and pump, as well as offering higher pressures also can deliver
more precise control at the nozzle.
the tiny abrasive particles that can
Common rail systems deliver injection braise poppets and valves.
pressures that are “infinitely variable “The orifices and the tolerances all
and totally programmable. You can do inside the pump and the injector are
anything you want with the fuel much tighter,” Gollub explains. “For
system,” Shick says, noting how the common rail system, any little
Navistar is using its approach to particle larger than, say, .25 mm in
generate less NOx within the cylinder.
size or something like that, can
The peak pressures are not that cause problems.”
different than those generated by an
The related damage can manifest
electronic unit injector. But the
nozzles will open and close within 0.4 itself in a number of ways. When fuel
first begins to run back into the tank,
milliseconds, offering five injections
per combustion event, notes Gene there will be a marginal affect on the
engine’s fuel economy. “The first
Gollub, a supervisor in Denso’s
technical services department. thing you see is you’re a couple of
tenths off on (mpg),” Shick says. As
“Even those two (extra) injections the situation worsens, the electronic
per combustion event help with the fault codes begin to emerge,
cleanliness,” he says. complete with a loss of power that
Each injection event performs a slightly can occur under extreme situations.
different role. In the case of the five It all makes the condition of fuel filters
injections, the “pilot” injection allows more important than ever. Service
the fuel and air to mix before injection. technicians should be watching over
That is followed by the “pre” injection all levels of filtration, such as the units
that helps to shorten the delay of that filter out water and the largest
ignition during the “main” injection that debris (Shick calls these “rock
follows – reducing NOx, noise and catchers”), and the engine-mounted
vibrations in the process. The “after” filters that catch the finer material.
injection re-burns particulate matter
that may remain, and the “post” Clogged fuel filters or a bad fuel pump
injection helps to manage the in the low-pressure rail that circulates
temperature of exhaust gases, making fuel to the unit injectors can present a
exhaust gas recirculation (EGR) number of challenges, Gollub agrees.
systems more effective. “It’s going to be misfires, it’s going to
be rough idle, surges, lack of power,
The systems also use different lagging, stumbling, hard start, no
technologies to control the actual start… you’re going to have your early
injection, adds ProDiesel vice indicators.”
president of production, Joe Hutto,
referring to solenoids, electromagnetic High injection pressures also can
force and ceramic-based Piezo present other maintenance challenges.
technology, with is three times as fast Saxman, for example, refers to issues
as its counterparts. such as cracked alternator mountings

1264 / Auto Parts

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