ENGINE POWER DERATING MAP
ACCORDING TO ATMOSPHERIC PRESSURE ACCORDING TO ATMOSPHERIC PRESSURE
ATMOSPHERIC PRESSURE IN kPa ATMOSPHERIC PRESSURE IN kPa P E
Atmospheric pressure measurement by the sensor provides an altitude reference for the purpose of Automatic Altitude Compensation.
The graph shown here describes how derating on a typical 3406E starts at 7500 ft. and continues linearly to a maximum of 17000 ft. Other 3406E engines may start as low as 4000 ft. depending on the application.
The advantage of the EUI system is that the engine always operates at the correct derating setting at all altitudes. The system continually adjusts to the optimum setting regardless of altitude, so the engine will not exhibit a lack of power or have smoke problems during climbs or descents to different altitudes.
NOTE:
NOTE: The EUI The EUI system has an system has an advantage over a mechanical advantage over a mechanical fuelfuel system which is derated in "altitude blocks" (i.e. 7500 ft., 10000 ft., system which is derated in "altitude blocks" (i.e. 7500 ft., 10000 ft., 12500 ft.).
12500 ft.). EUI derating EUI derating is continuous is continuous and automatic. and automatic. Therefore, aTherefore, a machine operating in the lower half of the block is not penalized with machine operating in the lower half of the block is not penalized with low power
low power. . Conversely, a machine operating in Conversely, a machine operating in the upper half of thethe upper half of the block will not overfuel with the EUI system.
block will not overfuel with the EUI system.
S
¥¥ CalcuCalculatilations aons are usre useded to determine gauge to determine gauge pressure
OIL PRESSURE SENSOR OIL PRESSURE SENSOR ATMOSPHERIC PRESSURE SENSOR
ATMOSPHERIC PRESSURE SENSOR INLET AIR TEMPERATURE SENSOR INLET AIR TEMPERATURE SENSOR
F
FUUEEL TL TEEMMP SP SEENNSSOORR EEXXTTEENNSSIOION TN T O RO REEMMOOTTEE FILTER (D400E) FILTER (D400E) COOLANT TEMPERATURE SENSOR
COOLANT TEMPERATURE SENSOR
HIGH SPEED/TIMING SENSOR HIGH SPEED/TIMING SENSOR
OIL PRESSURE SENSOR OIL PRESSURE SENSOR
CRANKING CRANKING SPEED/TIMING SENSOR
SPEED/TIMING SENSOR TIMING CALIBRATIONTIMING CALIBRATION CONNECTOR CONNECTOR
Two pressure sensors are used for the measurement of oil (gauge) pressure:
- Oil Pressure Sensor - Atmospheric Pressure Sensor
PRESSURE CALCULATIONS PRESSURE CALCULATIONS M
MEEAASSUURREEMMEENNTT MMEEAASSUURREED D BBYY RREESSUULLTT Oil pressure [oil press (A) - atmospheric (A)] = oil pressure (GP)
These measurements are used to determine oil pressure for the ET service tool, Caterpillar Monitoring System and to alert the operator that an abnormal condition exists. The sensor operating range is 0 to 690 kPa (0 to 100 psi) (A).
NO
NOTETE: : (A(A)) = = ababsosolulute te prpresessusurere (G
(GP)P) = = gagauguge e prpresessusurere
S
¥¥ DeterDeterminemines cs correorrectct pressure for all rpm pressure for all rpm
¥¥ Low Low oil oil presspressureure OIL PRESSURE MAP OIL PRESSURE MAP
1900
Engine oil pressure varies with engine speed. As long as oil pressure increases above the upper line after the engine has been started and is running at low idle, the ECM reads adequate oil pressure. No faults are indicated and no logged event is generated.
If the engine oil pressure decreases below the lower line, the following occurs:
- An event is generated and logged in the permanent ECM memory.
- A Category 3 Warning (alert indicator, action lamp and alarm) is generated on the Caterpillar Monitoring System (if so equipped).
- The engine is derated (if so equipped) to alert the operator.
The two lines are sufficiently separated to prevent multiple alarms and events or a flickering lamp. This pressure separation is referred to as
"hysteresis."
S
¥¥ TurbTurbo outo outlet prlet pressuressuree sensor
sensor
¥¥ BoBoost prost pressessururee calculation calculation
¥¥ Air/Air/fuel rfuel ratio catio controntrolol
J2
OIL PRESSURE SENSOR OIL PRESSURE SENSOR
TURBO OUTLET PRESSURE SENSOR TURBO OUTLET PRESSURE SENSOR ATMOSPHERIC PRESSURE SENSOR ATMOSPHERIC PRESSURE SENSOR INLET AIR TEMPERATURE SENSOR INLET AIR TEMPERATURE SENSOR
F
FUUEEL TL TEEMMP SP SEENNSSOORR EEXXTTEENNSSIOION TN T O RO REEMMOOTTEE FILTER (D400E) FILTER (D400E) COOLANT TEMPERATURE SENSOR
COOLANT TEMPERATURE SENSOR
HIGH SPEED/TIMING SENSOR HIGH SPEED/TIMING SENSOR
TURBOCHARGER OUTLET PRESSURE SENSOR TURBOCHARGER OUTLET PRESSURE SENSOR
CRANKING CRANKING SPEED/TIMING SENSOR
SPEED/TIMING SENSOR TIMING CALIBRATIONTIMING CALIBRATION CONNECTOR CONNECTOR
The Turbocharger Outlet Pressure Sensor measures absolute pressure downstream of the aftercooler. Boost (gauge) pressure can be read with the service tools. This measurement is a calculation using the
Atmospheric Pressure and the Turbocharger Outlet Pressure Sensors.
A failure of this sensor can cause the ECM to reduce power by as much as 60% when the ECM defaults to a zero boost condition.
The primary function of the sensor is to enable the Air/Fuel Ratio Control which reduces smoke, emissions and maintains engine response during acceleration. The system utilizes boost pressure, atmospheric pressure and engine speed to control the air/fuel ratio. Engine fuel delivery is limited according to a map of gauge turbo outlet (boost) pressure and engine speed. The Air/Fuel Ratio Control setting is not adjustable in 3406E machine applications.
INSTRUCTOR
INSTRUCTOR NOTE: NOTE: The The pressure pressure calculations and calculations and purposes of purposes of these calculations for all sensors are tabulated on the next page.
these calculations for all sensors are tabulated on the next page.
¥¥ CalCalculculatiationonss determine gauge determine gauge pressure pressure
PRESSURE CALCULATIONS PRESSURE CALCULATIONS
M
MEEAASSUURREEMMEENNTT MMEEAASSUURREED D BBYY RREESSUULLTT
1.Atmospheric pressure atmospheric sensor = ambient press (absolute)
2. Air filter differential Atmospheric - turbo inlet = filter ∆ pressure
3. Boost turbo outlet - atmospheric = boost ( gauge press)
4. Manifold press. absolute turbo outlet sensor = boost ( absolute press)
5. Oil pressure oil press - atmospheric = oil press ( gauge press)
These measurements are used to determine:
1. Automatic Altitude Compensation
2. Automatic Air Filter Compensation and Restriction Indication (if so equipped)
3. ET Boost Measurement
4. Caterpillar Monitoring System Oil Pressure Indication (Lubrication)
5. Altitude
NOTE:
NOTE: ∆pressure = differential pressurepressure = differential pressure S
STTMMG 77112G 2 8811 --- - 11/99
11/99
70 70