accuracy, allowing the components to
be tested separately and ruggedized
as appropriate. Business as usual.
Meeting the durability demands in
the hydraulics of the SCR system itself
is a little trickier, because employing
the correct acceleration factors during
testing requires a deep understanding
of both the system and the application.
In most cases, working with established
system suppliers who rely on broad
experience and are able to deliver profound data with high confidence is key.
One of the most demanding aspects
comes down to the myriad applications for engines in the off-road markets, ranging from stationary engines in
boats and railways, to mobile application in construction and mining machinery. Each case presents an individual
installation challenge that requires full
mounting freedom for the SCR system.
Systems that provide the needed flexibility use sophisticated sensing technologies at the point of injection and
a suitable pump concept that allows
for large three-dimensional mounting
freedom of the injector.
The use of an SCR system becomes
really tough as the engines get larger.
The high power output engines used
in gen-sets, mining equipment and
other larger machine applications
require DEF injection rates well above
those seen in the largest heavy-duty
trucks. This calls for a dosing system
that is capable of high flow rates while
also delivering a suitable spray for the
required mixing and distribution in the
exhaust. But an isolated scaling up of
the flow is insufficient, and demands
such as increased operating periods
between service intervals conflicts
with existing filter sizes.
It is the task of the engine and
machine manufacturer to deliver the
complete set of requirements and —
if applicable — their correlations. The
task of the SCR system supplier is
then to provide the suitable solution.
By far the most critical problemati-
cal issues are tied to the DEF itself.
The aqueous urea solution can only
bear a limited temperature range.
continued on page 32
DEF In-Tank Combination
Sensor for Concentration,
SSI Technologies Inc. introduces an in-tank combination sensor for accurate, reliable measurement of level, temperature and concentration for SCR DEF tanks to meet legislated mandates for cleaner diesel emissions. CRITICal FEa TuRES: · Detection of 10% water dilution · Detection of contaminants such as diesel, gasoline, oil · Immediate mis-fill notification · 0.4% of full sensing resolution · accurate temp monitoring for DEF tank heat management · Programmable for regular/irregular shaped tanks · J1939 CaN-bus technology for ready system integration · Proven, tested ultrasonic technology · Test samples available for OEMs, systems suppliers
SSI Technologies is a leading Designer/Manufacturer of
automotive and industrial sensors and monitoring systems
installed on millions of vehicles since 1990.
For more information, call 1-888-477-4320 or visit our
web site at www.ssitechnologies.com