With CM870
Ambient Air Density Derate
Due to the air handling limitations and stringent emissions regulations, the ISX3 engine family of the ISX with CM870 will be protected more aggressively in altitude than the ISX3 engine family of the ISX with CM570. This aggressive protection, seen as a fueling derate, is necessary to protect the turbocharger from excessive temperatures and turbocharger speed. Not only
is this derate altitude related, it is also ambient air temperature related. The combination of ambient air temperature and barometric pressure is used to calculate the ambient air density. As the air density decreases (ambient air temperature increases or altitude increases), the turbocharger speed increases and a derate is necessary to control the turbocharger speed to under set limits. In INSITE™, the user fueling state will display air density limit state.
The ISX1 and ISX2 engine families of the ISX with CM870 will also encounter this derate, but the derate will be comparable to the pre-Exhaust Gas Recirculation
(EGR) ratings.
Altitude Derate Based On Turbocharger Speed
Due to the turbocharger mechanical limitations, the ISX with CM870 engine will encounter a severe fueling derate if a calibrated turbocharger speed is achieved. This calibrated threshold is set much higher than the turbocharger speed derate threshold described later. This derate is time based and is severe at first. The derate progressively decreases as time elapses. In INSITE™, the user fueling state will display altitude derate.
Turbocharger Compressor Outlet Air Temperature Derate
Due to turbocharger temperature limitations, the ISX with CM870 engine will encounter a charge derate if a calibrated turbocharger compressor outlet air temperature is achieved. This derate is temperature based and will increase in severity as the turbocharger compressor outlet air temperature continues to increase. In INSITE™, the turbocharger compressor outlet air temperature derate will display Active if this derate is active. No loss in power will be felt during this derate, assuming the user fueling state in INSITE™
does not display any type of derate. If the turbocharger compressor outlet air temperature continues to rise and the charge derate becomes severe enough, the exhaust gas temperature could reach a calibrated threshold and a turbocharger fuel control derate could be incurred.
Turbocharger Speed Derate
Due to turbocharger mechanical limitations, the ISX with CM870 engine will encounter a charge derate if a calibrated turbocharger speed is achieved. This calibrated threshold is set much lower than the altitude derate threshold described previously. This derate is speed based and will increase in severity as the turbocharger speed continues to increase. In INSITE™, the turbocharger speed derate will display Active if this derate is active. No loss in power will be felt during this derate, assuming the user fueling state in INSITE™
does not display any type of derate. If the turbocharger speed continues to rise and the charge derate becomes severe enough, the exhaust gas temperature can reach a calibrated threshold and a turbocharger fuel control derate could be incurred.
EGR Flow Derate
Due to EGR valve mechanical limitations, the ISX with CM870 engine will encounter a charge derate if a calibrated engine pressure differential is achieved. The engine pressure differential is defined as the exhaust gas pressure minus the intake manifold pressure. This derate is engine pressure differential based and will increase in severity as the engine pressure differential continues to increase. In INSITE™, the EGR flow derate will display Active if this derate is active. No loss in power will be felt during this derate, assuming the user fueling state in INSITE™ does not display any type of derate. If the engine pressure differential continues to rise and the charge derate becomes severe enough, the exhaust gas temperature could reach a calibrated threshold and a turbocharger fuel control derate could be incurred.
Turbocharger Fuel Control Derate
Due to turbocharger temperature limitations, the ISX with CM870 engine will encounter a fueling derate if a calibrated exhaust gas temperature is achieved. There is no physical sensor in the engine for this temperature. This temperature is calculated by the Electronic Control Module (ECM) and can be monitored in INSITE™. The parameter name is exhaust gas temperature
(calculated). In INSITE™, the user fueling state will display turbocharger fuel control state.
Turbocharger Control Valve – Low Mount
The turbocharger control valve – low mount, enhances the performance of the engine without impacting the emissions level. The control valve modulates air pressure to the variable geometry actuator on the turbocharger as commanded by the ECM. Thus as the signal increases, more air pressure is applied to the variable geometry actuator.
A new engine harness and is required to interface with the ECM, and a new air control line is required to interface with the low mount turbocharger control valve, and the VGT turbocharger.
The turbocharger control valve has two new Fault Codes:
- Fault Code 2384 VGT Actuator Driver Circuit – Voltage Below Normal, or Shorted to Low Source
- Fault Code 2385 VGT Actuator Driver Circuit – Voltage Above Normal, or Shorted to High Source
Engine Protection Derate – Fueling Derate
Several temperatures and pressures in the ISX with CM870 engine have engine protection associated with them. The first phase of engine protection is a fueling derate. This derate is severity based and as the temperature increases, the severity of the fueling derate also increases. Likewise for pressure, as the pressure decreases, the severity of the fueling derate increases. Temperatures that utilize a fueling derate are engine coolant temperature, intake manifold air temperature, EGR temperature, and turbocharger compressor outlet air temperature. The oil pressure is the only pressure that utilizes a fueling derate. In INSITE™, the user fueling state will display engine protection derate.
Engine Protection Derate – Speed Derate
Several temperatures and pressures in the ISX with CM870 engine have engine protection associated with them. The second phase of engine protection is a speed derate. This derate is time based. After a set period of time spent above a calibrated temperature or below a calibrated pressure, the speed derate will ramp into effect. The speed derate will lower the maximum allowed engine speed to a calibrated speed. Temperatures that utilize a speed derate are engine coolant temperature, intake manifold air temperature, engine oil temperature, and EGR temperature. The oil pressure is the only pressure that utilizes a speed derate. In INSITE™, the user fueling state will display engine protection derate. If the engine protection shutdown feature is enabled, the engine will be shut down after a set period of time in speed derate.
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