Transcript No Slide Title

EPA 2004 Fuel System
Mike Michalski April 2004
The session which I am about to start will be an
introduction to the EPA 2004 , Woodward MI-04 fuel
system.
Since many of the parts used are so similar to any
prior LPG fuel systems, I am not going to go into the
operational sequences of components such as the
mixer and the regulator , which have been used for
years in LPG systems,. Instead I will attempt to
spend as much time as possible talking about the
components which have not been common as well as
the symptoms and faults we have experienced to date
with this system.
The U.S. Environmental Protection Agency
(EPA) has adopted emission standards for
several types of previously unregulated nonroad engines and vehicles.
The new standard that applies to our forklifts is
regulated by the section which pertains to
spark ignition non-road engines powered by
gasoline , liquid propane or compressed
natural gas and is rated over 25 horsepower.
This presentation will be an overview of the
system CLARK has implemented to meet these
requirements
This regulation will be implemented In two
stages.
The first stage was implemented into engines
manufactured in 2004. We identify this as EPA
2004.
The second stage will take effect in 2007 and is
based on transient testing in the laboratory,
and
will insure the engines will control
emissions when they operate under changing
speed and loads
The second level or “Tier” of emission standards
required by the EPA (Environmental Protection
Agency) Requires that
•
The system meets all of the 2004 emission
requirements
•
The system must have the capability of
maintaining a constant emission level at
steady state operation
•
The system must be able to compensate for
component wear and for fuel variations
•
The system must also be able to alert the
operator if the emission levels exceed the
required levels
The MI-04 fuel control system chosen by
Clark is designed to provide a complete, fully
integrated solution that meets or exceeds the
EPA and CARB requirements for 2004
System Strengths
• Simplicity
– Only one additional fuel system component, the Trim Valve; all remaining
fuel parts are conventional
– Trim valve meters vacuum, not fuel
– Service with fault codes and manual-expensive tools not required
• Proven ECM
– Over 100,000 in use; erratic behavior, failures identified
– Manufactured by Motorola; quality, consistency excellent
• Self-Correcting
– Adaptive Learn allows adjusting for wear, fuel deposits
– Adapts to specific application-truck configuration, altitude, operation
Emission Standards
Emission Levels--Grams per Horsepower-Hour
Exhaust
Certified Results
Emission Requirement Mit 4G-64 Mit 4G-63 GM 4.3
HC + Nox
3.0
2.1
2.1
0.6
CO
37.0
0.4
0.4
0.7
CO %
0.010
0.010
0.010
General Description
The MI-04 system is basically a closed loop system.
However, the system operates in an open loop condition until
the engine has done a certain amount of work insuring that
both the engine and the O2 Sensor are sufficiently warmed
up to stay in control.
General Description
During open loop operation, that is prior to the HEGO
(O2 Sensor) reaching its operating temperature
(Approximately 600 º F) the FTV (Fuel Trim Valve) duty
cycle is based upon a programmed engine speed and load
value.
Once the O2 Sensor is at operating temperature, the
system is in closed loop and the FTV duty cycle is
controlled by the feed back from the O2 Sensor.
General Description
Now that we have established the base parameters of the
system operation, lets start into the system cycle.
General Description
The MI-04 is a closed loop system utilizing a catalytic
muffler to reduce the emissions level in the exhaust gas
O2 Sensor
General Description
In order to obtain the maximum effect from the catalyst,
an accurate control of the air / fuel ratio is required.
In this system, an SECM (Small Engine Control Module)
along with the O2 Sensor is used to monitor exhaust gas
content.
General Description
The SECM controls the air / fuel ratio by modulating
the Fuel Trim Valve.
The Fuel Trim Valve in turn controls the secondary
diaphragm to vary the fuel mixture
General Description
The MI-04 System also uses a Drive By Wire System
connecting the electronic accelerator pedal to an
electronic throttle control. There are no cables.
General Description
The SECM uses several different sensors to gain the
information about the engine performance.
O2 Sensor
Engine Speed - VR Sensor
Intake Manifold Air Temperature and
Absolute Pressure - TMAP
Throttle Position - TPS
Engine Coolant Temperature -ECT
Accelerator Position - APP
Oil Pressure Switch
Exhaust Gas - O2 Sensor
The Rest of the MI-04
Components
CA 55 Mixer
CA 55 Mixer
The Model N- CA-55 -500TR mixer uses a piston type air
valve assembly to operate a gas metering valve inside the
mixer.
The gas metering valve is normally closed (spring loaded),
requiring a negative pressure (vacuum) signal, from a
cranking or running engine to open.
The gas metering valve controls the amount of fuel to be
mixed with the incoming air at the proper ratio.
CA 55 Mixer
The only adjustment that can be made to the N-CA55500 TR mixer is the idle adjustment setting
The idle mixture screw is an air bypass port, adjusting
the screw inward blocks off the port and enriches the
idle mixture
• There are 2 ways to set the idle mixture
adjustment. The first is with a Multi-Meter
which has a % duty cycle feature.
• The second is with a cable and a laptop.
This is the only adjustment required on the entire system
and should only be required if the mixer is changed.
This page is found in the EPA
2004 Manual located in Parts
PRO/pdf/Truck
Troubleshooting/ EPA 2004
Service
Fuel Lock Off
This Fuel Lockoff is a spring loaded electric
solenoid in a normally closed position.
+12 VDC power is supplied to the lockoff when the
key is activated with the SECM providing the
ground connection.
It has a stall safety shutoff feature built into the
system, closing the lockoff if the SECM detects a
STALL condition.
The SECM actually monitors 3 engine conditions:
•CRANK: When any engines are detected
•STALL: Key on but no engines revolutions after 5
seconds
•RUN: When pre idle RPM is reached (700 RPM)
Electronic Throttle
The Bosch DV-E5 electronic throttle is an
automotive based unit consisting of :
•Throttle valve
•Throttle Valve Activator (DC Motor)
•Throttle Position Sensor (TPS)
The throttle valve position is determined
by the SECM based on engine load and
input from the Accelerator Pedal.
Electronic Throttle
TPS Gear Drive Pick up
TPS Potentiometer Contacts
Electronic Throttle
The SECM calculates the correct throttle opening that
corresponds to the accelerator input.
It then makes adjustments needed for adjusting to the
engines current operating condition and then generates an
electrical signal to the throttle valve activator.
Feed back from the TPS continually informs the SECM of
the throttle valve position.
The default position for the throttle plate is approximately
7 % open if power is removed for any reason.
Fuel Trim Valve
The Fuel Trim Valve is a Bosch 2way electric solenoid valve and is
controlled by a pulse width
modulated signal provided by the
SECM.
It meters air valve vacuum into the
atmospheric side of the regulator
secondary diaphragm.
Fuel Trim Valve
The MI-04 System is calibrated to run “rich” without the
FTV.
By increasing the amount of times the FTV opens,
(Modulation or Duty Cycle) causes the air / fuel mixture to
become leaner, decreasing the duty cycle enriches the air
fuel mixture…….
When the pressure is reduced on the regulators secondary
side the secondary valve will close and reduce the fuel flow
which leans out the air / fuel mixture
Temperature / Manifold Air Pressure
Temperature Manifold Air
Pressure
The SECM self-calibration and cross checking of the TPS
is accomplished by comparing the TPS signal to a
calculated throttle position in the SECM software
(Predicted TPS)
In addition to the throttle position sensor, a Temperature /
Manifold Absolute Pressure Sensor (TMAP) is used to
monitor intake manifold temperature and pressure.
Heated Exhaust Gas Oxygen Sensor ( HEGO)
The zirconium type oxygen sensor has a
hollow internal element made of a
ceramic material (zirconium dioxide,
ZrO2) which is also coated with a layer
of micro-porous platinum
The outer layer is exposed to the exhaust
gas stream
The inner layer is vented to atmosphere
and attached to a wire that connects to
the SECM.
Heated Exhaust Gas Oxygen Sensor ( HEGO)
The O2 Sensor (SECM) generates a voltage signal proportional to
the amount of oxygen is the exhaust.
If the exhaust mixture is lean, the O2 voltage is below the set point
and the FTV duty cycle decreases to allow more fuel. If the
mixture is rich , the sensor voltage is above the set point and the
FTV duty cycle increases to allow less fuel.
Heated Exhaust Gas Oxygen Sensor ( HEGO)
OK …..lets get technical for a moment.
The HEGO (O2 Sensor) target voltage is 500 mVolts and changes
as a function of speed and load. When it sends a voltage slightly
less than 500mVolts, the SECM interprets the air/fuel ration to be
lean and it decreases the FTV duty cycle which lowers the amount
of vacuum to the regulator which will then richen the air/fuel
mixture.
Conversely, if the SECM receives a higher than 500mVolts from
the HEGO, it interprets the mixture as too rich and increases
duty cycle of the FTV and leans out the mixture.
Catalytic Muffler
All exhaust gases pass through a catalyst inside the muffler.
The catalyst is a dense honeycomb structure coated with
precious metals.(Platinum, Palladium & Rhodium) the
chemical reaction converts pollutants into less harmful gases.
Catalytic Muffler
In a nutshell……. The catalytic muffler has a reduction cycle
and a oxidation cycle.
Reduction Catalyst reduces NOx to nitrogen and carbon
dioxide (NOx > N2 + CO2)
Oxidation Catalyst reduces the unburned hydrocarbons and
carbon monoxide by oxidizing (burning) them over platinum
and palladium which reduces them to water and carbon
dioxide. (HC + CO > H2O +CO2)
Catalytic Muffler
In Summary,by using the signal from the O2 Sensor the SECM
can increase or decrease the amount of oxygen in the exhaust
by modulating the FTV.
This makes sure the engine is running close to stoichiometric.
Stoichiometric Mixture: Definition is ….just enough air to
theoretically burn all of the fuel , with no oxygen or unburned
fuel left after combustion. Also commonly referred to as
“Stoich”.
SECM
(Small Engine Control Module)
SECM
While in open loop, the FTV duty cycle is based on tables using
engine speed, load and temperature.
Once the O2 Sensor is at operating temperature , the fuel
management goes to closed loop for all steady state conditions,
from idle through full throttle. In closed loop, the FTV duty
cycle is based on feed back from the O2 Sensor.
Accelerator Control
The accelerator pedal uses 2 potentiometers (APP1 & APP2) to detect pedal
position.
The SECM uses these inputs to calculate the throttle position required.
Ignition Control
The MI-04 System uses a distributor based system for the Mitsubishi 2.0 &
2.4 Liter engine along with a 30-5 Variable Reluctance signal. (The GM
engines use the GM EST System)
The distributor does not use any internal advance mechanism.
The timing is calculated by the SECM based on RPM ,TPS; & TMAP
Ignition Control
The SECM can read RPM as low as 50 RPM with the 30-5 system.
This allows the SECM to synchronize the input faster creating shorter crank
time, more accurate timing and better cold starting
The VR Sensor is mounted on a crank case bracket. The set up gap is
adjustable and it provides all of the speed (RPM) feedback to the SECM.
7
Ignition Control
The MI-04 system for 2.0L/2.4L engines use a single coil
which incorporates the ignition driver circuitry inside the
coil itself.
The SECM signals the “smart coil” when to begin its dwell
cycle then the coil waits for the trigger signal from the
SECM.
The “smart coil” eliminates the need for a driver circuit
inside the SECM or externally from the coil. Using a single
VR sensor and “smart coil” eliminates multiple sensors and
coil packs used in more complex ignition systems.
Ignition Timing
Using the timing indicator on the
crankshaft pulley, set the engine
on 0 (zero) degrees Top Dead
Center (TDC) of number 1
cylinder
Ignition Timing
Verify that the distributor
rotor is lined up with number 1
cylinder on the distributor cap.
Remove the distributor rotor
and dust cover so that the
internal VR sensor and signal
rotor gear are visible.
Ignition Timing
The internal VR sensor inside the
distributor is not used by the
SECM for a speed reference with
the 2.0L/2.4L engine and it’s
wiring harness does not connect
to the system.
The distributors internal VR
sensor is only used as an
alignment reference point for
setting the correct distributor
position.
Loosen the distributor, hold down
nut and rotate the distributor so
that the signal rotor gear tooth of
the #1 cylinder (tooth opposite the
flat side of the distributor shaft)
lines up with the sensor pickup.
Ignition Timing
To correctly set the distributor,
align the center of the #1 cylinder
tooth with the leading edge of the
VR sensor pickup. Keep in mind
that the distributor rotates in a
clockwise direction.
Ignition Timing
Once the proper alignment
is obtained, lock the
distributor in place by
tightening the hold down
nut to the specified torque
value and re-install the
rotor, dust cover and rotor
cap.
Lock the distributor in
place by tightening the hold
down nut to the specified
torque value.
After you have completed
setting the distributor
alignment you will need to
adjust the VR sensor used
by the SECM for speed
reference.
Ignition Timing
Rotate the crankshaft pulley so that
one of the gear teeth on the timing
wheel aligns in the center of the VR
sensor.
Using a feeler gauge loosen the sensor
retaining bolts and adjust the gap
between the sensor and the gear tooth
from 1.25mm to 1.5mm.
Rotate the crankshaft pulley 180°
degrees and align a timing gear tooth
in the center of the VR sensor pickup.
Verify that the sensor gap is still
within 1.25mm to 1.5mm.
MI-04 Fault Action
Descriptions
Fault Action Description
Each fault detected by the SECM is stored in memory FIFO (First In First Out) and
has a specific action or result that takes place.
ENGINE SHUTDOWN
The most severe action is an Engine Shutdown. The MIL will light and the engine
will immediately shutdown, stopping spark with the fuel lock-off closing.
LIMP HOME MODE ( POWER LIMITING)
The Limp Home Mode reduces the lift truck power, but will provide to enable the
operator to move the truck safely , but not use for normal operation.
MIL ONLY ( STORED CODE)
The MIL will light by an active signal provided by the SECM indicating a fault
condition but no further action will take place.
The following are some examples of these action modes:
Fault Action Description
ENGINE SHUTDOWN
Fault Action Description
Low Oil Pressure Shutdown
On the Clark Gen2 trucks, this is a function of the Instrument Panel not the fuel
system and is evident by a dash icon for the oil pressure being illuminated and the
flashing along with the dash alarm.
However, on the CMP Models this becomes a function of the fuel system. This will be
an engine shutdown displaying a 52 code in the MIL system.
Fault Action Description
High Water Temperature Shutdown
On the Clark Gen2 trucks, this is also a function of the Instrument
Panel not the fuel system and is evident by the over temperature
sequence and the flashing along with the dash alarm. ( Remember ,
the Gen 2 series does not have a 16 code in the MIL system)
However, on the CMP Models this becomes a function of the fuel
system. This will be an engine shutdown displaying a 16 code in
the MIL system.
Fault Action Description
LIMP HOME (POWER LIMIT)
Fault Action Description
STORED CODE
MI-04 Basic Troubleshooting
Basic Troubleshooting
The MI-04 Systems are equipped with built in fault diagnostics.
Note: Older units may have the Air Restriction symbol
as the MIL
Items such as fuel level, plugged fuel lines, clogged fuel filters and
malfunctioning pressure regulators may not set a fault code by the
Small Engine Control Module (SECM).
Methods for troubleshooting plugged fuel lines, fuel filters, vapor lines
and cylinder tank problems apply to the MI-04 system as they did
with a Tier I system.
Basic Troubleshooting
Detected system faults can be displayed by the Malfunction Indicator
Lamp (MIL) as Diagnostic Fault Codes (DFC) or flash codes, or
viewed in detail with the use of the service tool software.
When the ignition key is turned ON the MIL will perform a self-test,
illuminate once and then go OFF. If a detected fault condition exists,
the fault or faults will be stored in the memory of the small engine
control module (SECM).
If an Active Fault occurs while the engine is running the MIL will
illuminate and remain ON. This signals the operator that a fault has
been detected by the SECM.
Basic Troubleshooting
Turn the key on without cranking the engine
Depress the accelerator to the floor 3 times within 5 seconds
This will begin the fault display process
Basic Troubleshooting
Reading Diagnostic Fault Codes
All fault codes are 2 digit
When the fault codes are retrieved (displayed) the MIL will flash for each
digit with a short pause ( .5 seconds) between digits and a long pause (1.2
seconds) between fault codes
There will be a 12 code to start and a 12 code will indicate the end or that it
restarting
Basic Troubleshooting
Turn the key on without cranking the engine
Depress the accelerator to the floor 10 times within 5 seconds
This will the clear the faults
MI-04 Basic Troubleshooting
What have we found so far…..
31 Code
The 31 code only is found on units with an
SECM with RBAE Software or newer
The unit will set a 31 code anytime the truck
cuts out with the key on. This includes running
out of fuel or turning the key back to off before
the truck starts.
This can also be the result of a SECM reset due
to electrical interference. In order to verify this
fault, a cable and crypt token is required. The
MotoViewer will record occurrences in the test
screen/ SECM / Reset Counter
This is the page from the latest Service Manual which is
still in Draft form.
31 Code
If you are experiencing a symptom of intermittent
shutdown or, an extreme fluctuation of RPM, maybe
described as stuttering, it could be a 31 code .
First verify that you have a good chassis ground.
If you do not have a Cable set, temporarily relocate
the SECM from its current location on the chassis to
a loose mount (wire tie) under the floor board. If the
shutdowns stop, contact us for instructions.
If you have a cable set, download RBAE or newer
software into the SECM. It will then record 31 codes
if that is what the the problem is.
31 Code
If a 31 code is verified , either by elimination of the
shutdown or by use of a cable which allows you to
see the number of SECM resets in the Test Screen.
A new SECM part number is available and
incorporates a capacitor to eliminate the voltage
spikes causing the shutdown.
Smelly Exhaust
We have found that out of the few complaints
we have had, they were the result of the mixer
washer cracking and causing the mixer piston to
operate too slow. This causes the mixer to
remain rich too long and thus creating either
an ammonia or rotten egg smell
The checkout is…………………..
It is not necessary to remove the air horn.
You only need to remove the fuel lines and
air inlet, disconnect the elec. plug, then the
4 mounting 5 mm bolts to access the bottom
of the mixer. Then remove the 4 torx
screws to remove the piston..
Requires torx t-25 security bit to remove the
5MM ball end Metric Allen required
4 screws to access the mixer piston
4 bolts
Use extreme caution to not damage this o ring
when removing and reinstalling the mixer. Hold the
throttle assembly as it does not need to be lifted up.
Only the mixer and adapter.
See Page 2 for
inspection
Remove Mixer
Inspect disc for cracks
Remove the piston
68 Code
C152 Cushion only
Accelerator pedal assembly will slip past
the stop under certain conditions and
throw a 68 code momentarily . It does not
affect the truck operation after the pedal is
returned to the up position. While the code
is active, the truck will experience reduced
performance because it is an error in the
pedal input.
Fix is a rework of the pedal until a
redesign is completed by the vendor
Pedal 8033089 will cause a 68 code due to incorrect voltage. This
apparently is caused when the pedal is depressed with a left to right
depression effort, the pedal misses the stop and slides to the right and
travels beyond the stop allowing the voltage to go beyond limits.
Rework consists of removing the rubber stop and drilling
through and inserting a bolt to stop pedal travel at same
height as the stop rim..
Pedal in up position
Pedal depressed against the stop
Pedal depressed but,missed stop
No Code
Complaint of slow starting. We have observed
the following items:
If you start cranking before the fuel lock off
opens and the throttle plate test cycles, the
truck will not start until these cycles are
completed. You can hear the 2 clicks. Crank
time appears to range between 1 1/2 to 4
seconds depending on several factors.
If battery voltage drops below 9.0 volts, the
lockoff will not open and the truck will not
start. If it does not start in about 5 seconds ,
recycle the key switch.
We are presently working with the vendor to
reduce the crank time.
No Code
Complaint of intermittently truck will not
accelerate after initial start up.
Insure that the operator is not stepping on
accelerator while cranking, it will default the
pedal . Pedal will have to be recycled prior to
initial acceleration.
Installing Laptop System
Software
934427
USB - Can Converter Cable
Dealer Net = $645.00
934428
Tier 2 Software Package
Dealer Net = $405.00
The Mototron CD included with part
number 934428, has instructions
for loading onto your laptop,
however, the CD also is self guided
through the installation process. Just
follow the guide instructions.
If you are unsure, cancel the installation , go to the file pull down and click
open. From the menu, click on MotoService Install Info.pdf, it will give you
the information regarding the installation
NOTE: Once this CD is loaded to your laptop, it will not be required
again. Place it in a safe storage place. ALSO………. If it has been loaded
for Either Clark or Daewoo, it is not necessary to load it again,
Once the installation is complete, you will need
to download the necessary program files from
Clark Intranet. These files are in PartsPro / Truck
Troubleshooting/ EPA 2004 System Service/EPA
2004 Program Files.
pdf
Now you will need to down load the
files from Clark PartsPRO. These
files are found in pdf.Files
First, open and read the EPA 2004
Program Instructions
Now , open the EPA 2004 Program
Files
These files will have to be
downloaded for installation in your
laptop
File transfer from the Parts PRO system will
vary depending on the capability of your
laptop and the operating systems available to
you.
Therefore I will not cover this but if you
experience any problem in the downloading of
your files please feel free to call me
Mike Michalski @ 859-422-6423
The MotoViewer requires a display file to operate. These are labeled as MI_4 Diagnostic_Display_revxx.dis. You
will only need the latest revision level of this file. This file needs to be placed into the directory
C:\ECUFiles\Displays.
Display files to Displays folder
ECU Files
The next file is VARSPEED????.dll with the question marks being replaced by the versions of software
available. There is a .dll file for each version of the software. You should load all the .dll files in the directory.
These files need to be placed into the directory C:\ECUFiles\Tdbdll. NOTE: You must have a .dll file for
every software version used. Do Not delete any of these files.
dll files to TDBDLL folder
ECU Files
The next file is VARSPEED????_??_?_???_?_???.mfu, again with the question marks replaced with the
versions of the software. These files are required only if a newer version of software is required for trucks
already in the field. These fles are used by Moto-Update to bring the SECM in a field truck update to the
latest factory standards. The structure of these files , VARSPEEDXXXX, the letters replaced by the X’s is
the software version. It will match the .dll files. The rest of the numbers and letters designate the software for
each truck model. All of these files need to be placed into the directory C:\ECYFiles\Updates
mfu files to Updates folder
ECU Files
NOW we are ready to use the cable
You may have already created a
shortcut to your MotoUpdate and
MotoViewer as described in the
Instructions found on the CD. If not
you will need to click on the Start
Icon and then enter the Program
Files and then select MotoService/
MotoViewer
After clicking on the MotoViewer
Icon, With the Ignition Key on, you
will get this screen. Note that it says
(Clark Service Dept) at the top.
Click on File and then on Open
If it says Unlicensed, You are not
properly connected or do not have
the correct crypt token. Back up and
verify all connections , insure key is
on etc.
Now you will click on the newest Rev
Level, which in this case is Rev F
MI-04 Troubleshooting
Downloading new Software
There may be occasions when new software
will be installed into your existing SECM.
The following is the procedure to do this
using a cable and crypt token with your
laptop.
You may have already created a
shortcut to your MotoUpdate and
MotoViewer as described in the
Instructions found on the CD. If not
you will need to click on the Start
Icon and then enter the Program
Files and then select MotoService/
MotoUpdate
This is the first screen you will get….click
on Next>
Then you will get this screen which will advise what
software is in the SECM….First highlight the
software to install, in this case it is
VARSPEEDRBAG_01_2.5 cnf_000. Then click Next
>
Next you will get this advisory, insure your laptop
is not in low battery warning when you click OK to
start the download.
You will get the download screen ……..
Successful download!
Click Finish
MI-04 Troubleshooting
Using the Chart Function
I usually rename the RUN SCREEN.log to either the
truck serial number or the reason I am charting. Then
Click OK
Right click on selected
function to chart
3
1
2
Repeat for all items to be monitored
Chart is running
This is an example of the data we can retrieve with a chart
This is an example of the data we can retrieve with a chart
We have had some preset charts developed by Woodward
for examination of a specific check.
For example:
Cold Start
Cold Running