Models that employ both measurable engine parameters as well as predictable engine parameters may be used to determine when a thermostat is malfunctioning before the thermostat malfunction results in an engine breakdown. Particular models may be used to provide an estimated coolant temperature and an estimated thermostat position. The estimated coolant temperature can be compared to an actual measured engine coolant temperature. The estimated thermostat position can be evaluated with respect to what the thermostat position should be given a particular engine coolant temperature. In some cases, comparison between a healthy model and a faulty model may be used to ascertain thermostat health.

Models that employ both measurable engine parameters as well as predictable engine parameters may be used to determine when a thermostat is malfunctioning before the thermostat malfunction results in an engine breakdown. Particular models may be used to provide an estimated coolant temperature and an estimated thermostat position. The estimated coolant temperature can be compared to an actual measured engine coolant temperature. The estimated thermostat position can be evaluated with respect to what the thermostat position should be given a particular engine coolant temperature. In some cases, comparison between a healthy model and a faulty model may be used to ascertain thermostat health.

A control system that uses an algorithm to control the fan speed in a cooling system for an engine is disclosed. The algorithm is adapted to maintain a cooling medium at a set temperature instead of an operating temperature range of the cooling medium. The algorithm is also adapted to maintain a cooling medium at a set temperature and to build a cooling safety margin in response to an engine output torque percentage that is below an output torque percentage setpoint.

A control system that uses an algorithm to control the fan speed in a cooling system for an engine is disclosed. The algorithm is adapted to maintain a cooling medium at a set temperature instead of an operating temperature range of the cooling medium. The algorithm is also adapted to maintain a cooling medium at a set temperature and to build a cooling safety margin in response to an engine output torque percentage that is below an output torque percentage setpoint.

A controller includes at least one processor coupled to a memory storing instructions that, when executed by the at least one processor, cause the at least one processor to: determine a target engine outlet coolant temperature for a coolant in an engine system; determine an adjustment to a temperature of the coolant based on a determined engine inlet coolant temperature and the target engine outlet coolant temperature; and, alter a flow of the coolant by controlling a coolant valve in response to the determination of the adjustment to the temperature of the coolant.

Models that employ both measurable engine parameters as well as predictable engine parameters may be used to determine when a thermostat is malfunctioning before the thermostat malfunction results in an engine breakdown. Particular models may be used to provide an estimated coolant temperature and an estimated thermostat position. The estimated coolant temperature can be compared to an actual measured engine coolant temperature. The estimated thermostat position can be evaluated with respect to what the thermostat position should be given a particular engine coolant temperature. In some cases, comparison between a healthy model and a faulty model may be used to ascertain thermostat health.

A control system that uses an algorithm to control the fan speed in a cooling system for an engine is disclosed. The algorithm is adapted to maintain a cooling medium at a set temperature instead of an operating temperature range of the cooling medium. The algorithm is also adapted to maintain a cooling medium at a set temperature and to build a cooling safety margin in response to an engine output torque percentage that is below an output torque percentage setpoint.

A coolant control device includes: first control means for, at warm-up of an internal combustion engine, circulating coolant in a first passage bypassing the engine and stopping coolant circulation in the second passage passing through the engine; second control means for, at engine warm-up and when the quantity of heat required by a heater core is smaller than or equal to a predetermined threshold, circulating coolant in the first passage while adjusting the flow rate of coolant circulating in the first passage and stopping coolant circulation in the second passage; and third control means for, at engine warm-up and when the required quantity of heat exceeds the predetermined threshold, circulating coolant in the first passage without decreasing the flow rate of coolant circulating in the first passage and circulating coolant in the second passage while adjusting the flow rate of coolant circulating in the second passage.

A rail vehicle has a diesel engine, an engine radiator and a cooling circuit that connects the diesel engine to the engine radiator. A cooling liquid is circulated in the cooling circuit, a cooling liquid temperature of the circulated cooling liquid and an outer air temperature of the atmospheric outer air are detected. The outer air temperature is compared with the outer air limit temperature, the cooling power of the engine radiator is set in such a way that the cooling liquid temperature corresponds to a normal operating temperature if the outer air temperature is less than the outer air limit temperature. The cooling power of the engine radiator is set such that the cooling liquid temperature corresponds to a lower operating temperature below the normal operating temperature if the outer air temperature is greater than the outer air limit temperature.

A method for preventing an engine overheat based on a coolant temperature applied to an engine system 1 is provided, in which a controller 50 checks if a coolant coming from an engine 10 is distributed to any one of a heater core 25B and an ATF warmer 25A as a radiator 23 is switched from a distribution blocking state (i.e., radiator closed) at a diagnosis start to a distribution state (i.e., radiator open) during the diagnosis under the control of an opening degree of an ITM valve 40, diagnoses lack of a coolant amount using factors B determined by an inlet/outlet coolant temperature difference T of the engine 10 through first and second water temperature sensors 30A and 30B as a factor cumulative value A, and then controls the ITM valve 40 to a full open state in a state where a coolant temperature increase is predicted.