Engine protection system

Abstract

An engine protection system and protocol is implemented within an electronic engine control module. Various engine fluid parameters, such as coolant level and temperature, oil pressure and temperature, and air intake manifold temperature, are monitored and compared to limit values to determine if a fluid fault condition exists as to one or more of the fluid parameters. The engine performance is derated as a function of the severity of the fluid parameter fault. Two levels of faults are sensed to activate one of two derating schedules. In one schedule, the engine power, or torque as a function of engine speed, is gradually reduced or derated as the fluid parameter moves farther out of normal operating range. With this derate schedule, the engine will still run and the driver can still operate the vehicle, albeit at lower power levels than a healthy engine. In a second schedule for more severe fault conditions, the maximum allowable engine speed is gradually reduced over a certain time period and to a certain percentage of the normal maximum engine rpm. Both schedules permit continued operation of the engine in a 'limp home' mode for the less severe faults, and as required after a more severe fault to bring the vehicle safely to a stop. The engine portection system also stores an array of fault information that can be later access to investigate engine fluid parameter failures.