Today we're going to talk about interim tier 4, or iT4 for engine emission control.
There are more than a few differences in iT4 engines, so there will be many
guidelines and numbers to remember. Please refer to your operator's manual
for the specific information that we will be discussing. The emission control
is mandated by the EPA and affects 75 horsepower and above engines. The iT4
mandate requires changes to the engine on a fuel intake side, and on the exhaust
outlet side. On the fuel intake side, there's a high-pressure common-rail fuel
distribution system. There's also a new fuel filter with a water separator,
crankcase breather filter, fuel cooler, and supply pump. The fuel system on the
engine requires special tools and knowledge to troubleshoot and repair. See
your Bobcat dealer for a qualified technician with the proper training and
tools to keep your engine and emission systems operating properly. It's very
important to use high-quality, ultra-low sulfur fuel with iT4 engines. The sulfur
content should be less than 15 parts per million. Biodiesel can be used but only
up to a five percent ratio. Check the operator's manual and follow the
specific guidelines for biodiesel. The engine oil must meet API CJ4
standards, which reduces ash buildup in the diesel particulate filter or DPF. On
the exhaust side of the engine, there is a diesel particulate filter which is
used to trap and collect soot. The DPF will heat up internally in the canister
when the machine is being worked steadily, and the soot will be burned off
from the system. This process of collecting and burning the suit is
called regeneration. There are four types of regeneration. Passive, when the engine
exhaust is that adequate temperature. Active, where the engine control unit or
ECU control's the process of generating enough heat in the DPF to burn the soot.
Parked, when the operator initiates regeneration using the optional
boat parked regeneration kit. And service, when the Bobcat dealer uses specialized
equipment to perform a service regeneration. Passive regeneration is the
most common and it occurs when the engine is operating at a load that can
provide a high enough exhaust temperature and the DPF so regeneration
occurs naturally. Active regeneration is controlled by the ECU. By injecting fuel
into the DPF to raise the temperature at approximately 40 to 60 hour intervals.
When this is happening, you'll hear one beep and the D rate override switch will
illuminate. You won't need to stop working or shut down the machine, it's
just a reminder that regeneration is occurring. If the ECU cannot complete the
regeneration or the DPF remains restricted, a level two active
regeneration cycle will begin. You'll hear a two beep alarm, the D rate override
switch will flash, and the engine will derate by 25 percent. Pushing the top of
the switch will override the engine d rate and the light will stop flashing
and remain on. But, if you choose to override this process, the machine should
be operated above half throttle and under a load that will facilitate
regeneration or soot will build up in a DPF. The D rate override switch will
flash every 10 minutes if the load is not sufficient. You should continue to
operate until a level 2 regeneration is completed. If all goes well, the switch
will return to the normal position and the light will turn off once the
regeneration is finished. In certain applications, you may not want
regeneration occurring so there's an optional kit available. It contains a DPF
inhibit switch that replaces the D rate override switch. After it's been
installed, simply press the bottom of the switch to activate it. When DPF
regeneration is being inhibited, the switch will light up. Service codes M
8551 and M 8552 will appear and will continue to prevent regeneration
until the machine is turned off. Automatic regeneration will return the
next time the machine is turned on. But remember, inhibiting regeneration will
cause continued soot to build up in a DPF, so it's important to allow regular
regeneration to occur to help maintain along the service life of the DPF.
Service codes m8551 and 8552 will occur when the DPF system is inhibited from
automatically performing an active regeneration. You can also inhibit the
machine from reverting back to automatic the next time it turns on by holding the
bottom of the DPF inhibit switch for four seconds. The operator can re-enable
the regeneration to occur by pressing the top of the DPF inhibit switch. In the
inhibit mode the same to active service codes will occur, stopping it from
automatically performing an active regeneration. But if too much soot is
allowed to accumulate, because of the short periods of operation, while the DPF
inhibits which is left and inhibit position too long, a level 3 remote
regeneration may be necessary. Service codes M 8551 and M 8552 will occur when
the DPF system is inhibited from automatically performing an active
regeneration. When this happens, a to beep alarm will sound, the DPF d e f icon will
be flashing, the inhibit switch will be on, the engine will derate by 25 percent,
and the code M8553 will be on a display. At this stage, you can use the
part regeneration kit to initiate a regeneration well outside the operator
compartment. To perform it, be sure there's enough fuel for one hour of
operation. When using the remote regeneration kit, safety precautions have
been put in place such as locking out the operator control
from the cab and applying the parking brake so it is safe for the engine to
run without an operator in the seat. After it's performed the remote
regeneration, the machine will shut down automatically. However, you must turn off
the remote key before the machine can be operated normally. If you've continued to
operate the machine without regeneration happening, an alert to the next level
will occur. A two beep alarm will sound, the DPF d e f icon will be flashing, the
switch will be flashing, the engine will be rate to fifty percent, and an M8554
service code will appear. At this point, a dealer with special tools must be called
to perform a service regeneration. The final level of monitoring is for DPF
cleaning. If this is required, a two beep alarm will sound, the DPF d e f icon will
be flashing, and the general warning icon will be flashing. An M8555 service code
will be visible. At this point, the DPF will need to be removed by a trained
Bobcat service technician, and taken to a cleaning station to have the ash removed.
As a general rule, make sure regular regeneration is taking place so the DPF
does not become plugged and have to be removed and cleaned. Operating under
normal conditions with regeneration occurring as necessary, you can get over
3,000 hours of use before the regular removal maintenance needs to be
performed on the DPF. Bobcat loaders equipped with the iT4 engines are
another example of Bobcat Company building products to meet the needs of
our environment and our customers in the marketplace. If you need or want more
information, contact your local Bobcat dealer. They can also offer training or
perform service work for your Bobcat machine and are your source for genuine
Bobcat parts.