SPOOL-DASHPOT 4N6407 - Caterpillar

The Electronic Control Module (ECM) monitors engine operation. If a parameter extends outside an acceptable range, the ECM will initiate action. The ECM can cause a warning to occur. The ECM can derate engine power. The ECM can cause an engine shutdown to occur. Not all of the actions are available for all parameters.The Caterpillar Electronic Technician (ET) can be used to select the ECM response. Cat ET can be used to program the level of engine monitoring and the delay times.Separate timers are used in the ECM for each response that is associated with a parameter. Once the trip point is exceeded for an action, the timer for that action is started. For example, if the high coolant temperature warning is set to 102 °C (216 °F) with a five seconds delay, the delay timer starts counting once the coolant temperature exceeds 102 °C (216 °F). If the coolant remained above 102 °C (216 °F) for five seconds, a warning would be issued.Use care when you program the trip point and the delay times. The resulting ECM response must be correct for the application. If the legal range is not exceeded, the engine monitoring system will accept any setting.If the trip point for a shutdown is lower than the trip point for a warning, the engine will shut down. The warning will not be activated.Once a parameter has exceeded the trip point the parameter must drop a certain amount below the trip point before the ECM response will end.If a warning is programmed to 102 °C (216 °F), the temperature must exceed the range in order for the warning to activate. The temperature must decrease below 99 °C (210 °F) for the warning to stop. The variance is the hysteresis. The following table gives the hysteresis for each parameter.
Table 1
Parameter Hysteresis
ECM Voltage 2 VDC
Oil Pressure 20 kPa (2.9 psi)
High Coolant Temperature 5 °C (41 °F)
Low Coolant Temperature 5 °C (41 °F)
Overspeed 100 rpm
Air Inlet Restriction Latched
Altitude N/A
High Exhaust Temperature 10 °C (50 °F)
Oil Filter Differential Pressure 10 kPa (1.5 psi)
Fuel Filter Differential Pressure 10 kPa (1.5 psi)
Crankcase Pressure 0.25 kPa (0.04 psi)
Aftercooler Water Temperature 3 °C (37 °F) Note: The following tables are examples. The values may have changed. Use Cat ET to determine the actual defaults and the specific configuration.
Table 2
Programmable Monitoring System
Parameter ECM Response Default Trip Point Default Delay Time Limits
Range for Trip Point Delay Time
Low High
Low System Voltage On/Off
Warning 20 VDC 10 Seconds 20 VDC 22 VDC 1 to 30 seconds
Low Oil Pressure On/Off
Warning (1) 4 Seconds N/A 1 to 15 seconds
Shutdown (1) 9 Seconds N/A 1 to 15 seconds
High Coolant Temperature On/Off
Warning 102 °C (216 °F) 5 Seconds 90