Method of controlling cooling water temperature of an engine in which the lower limit value of engine rotation speed is set according to outside air temperature and vehicle speed. When the vehicle starts traveling, a temperature raising-state lower limit rotation speed is set to raise the cooling water temperature to a third threshold value. After the cooling water temperature is raised to the third threshold value, the lower limit value is not set. If the cooling water temperature drops to a second threshold value, a maintaining-state lower limit rotation speed lower than the temperature raising-state lower limit rotation speed is set to raise the cooling water temperature. If the cooling water temperature does not rise but drops to a first threshold value, a temperature re-raising-state lower limit rotation speed lower than the temperature raising-state lower limit rotation speed and higher than the maintaining-state lower limit rotation speed is set.

A thermostat monitoring method includes measuring an engine coolant temperature with an engine coolant temperature sensor a predetermined amount of time after engine startup, determining with a controller one of four zones to determine whether a thermostat will pass or fail, based on the one of four zones determined, accumulate with the controller one a pass index or a failing index, when the pass index reaches a first threshold, reporting a pass with the controller, and when the failing index reaches a second threshold, reporting a fail with the controller.

To estimate an engine cooling water temperature, four learned neural networks (150A, 150B, 150C, and 150D) are stored, in which weights are learned for the four states of whether the grille shutter (50) is opened and whether air blown by the blower (63) circulates through the air-conditioning use heater (65). The engine cooling water temperature is estimated using any one of the learned neural networks selected from among the four learned neural networks (150A, 150B, 150C, and 150D). An abnormality of the engine cooling water recirculation system is detected based on the estimated value of the engine cooling water temperature.

Systems and methods are provided and include an engine temperature sensor, an engine speed sensor, a switching arrangement, a radiator fan control module, and a pulse-width modulation module. The radiator fan control module calculates a required airflow of a radiator fan of the vehicle based on an engine temperature and calculates a required voltage to produce the required airflow of the radiator fan based on a size of the radiator fan. The radiator fan control module generates a control signal to increase a fan motor voltage of a radiator fan motor in response to the required voltage exceeding a battery voltage and generates the control signal to maintain a standard fan motor voltage of the radiator fan motor in response to the required voltage being less than the battery voltage. The pulse-width modulation module controls a switching operation of the at least one switch in accordance with the control signal.

An electronic thermostat may include an internal housing including a partition defining a head chamber communicating with a cylinder head and a block chamber communicating with an engine block and the internal housing of which a head chamber hole and a block chamber hole are formed thereto, an external housing of which an outlet is formed thereto and the external housing covering the internal housing, a thermostat heater disposed to the partition, a first opening/closing portion including a first wax receiving heat from the thermostat heater and selectively closing or opening the head chamber hole and a second opening/closing portion including a second wax receiving heat from the thermostat heater and selectively closing or opening the block chamber hole.

Embodiments of the present invention provide a thermal control method for a vehicle, comprising determining (110), based on a location of a vehicle and digital map data (220), an estimate of at least one vehicle operating condition at one or more future points in time, determining (130), for each of the future points in time, a desired operating temperature for a module of the vehicle based on the associated at least one vehicle operating condition, and controlling (150), in advance of at least one of the future points in time, one or more thermal control means (20) associated with the vehicle to direct an operating temperature of the module to the desired operating temperature at the respective future point in time.

A thermostat misdiagnosis prevention method applied to an engine system of the present disclosure applies high speed/high load and low speed/low load, which are divided by a vehicle speed and an engine output detected from the engine system at an engine warm-up temperature of engine coolant, as monitoring conditions of a thermostat, and determines thermostat fail by primarily determining the thermostat fail with the engine coolant temperature of the engine coolant temperature and the outside air temperature detected from the engine system, then confirming a delay time with respect to the outside air temperature, and secondarily determining the thermostat fail with the engine coolant temperature in a monitoring ECU, thereby corresponding to the enhanced OBD together with preventing the misdiagnosis of the thermostat by the fail-safe according to the primary and secondary determinations.

An engine and cabin thermal management system for use with a vehicle having an engine, a cabin heating system configured to thermally heat a cabin of the vehicle, a coolant system operably coupled to the engine and to the cabin heating system to thermally manage a temperature of the engine and a temperature of the cabin. The coolant system having one or more coolant thermal storage units fluidly coupled with a radiator and heater core of the coolant system forming a coolant loop. The system further having a control system configured to monitor and maintain at least a predetermined coolant temperature at the cabin heating system even during a coolant temperature decrease at the engine stops.

A method for diagnosing the absence of an under-engine protection of a motor vehicle, includes: estimating a temperature of air external to the vehicle, estimating an under-hood temperature, determining whether the external-air temperature value is below the under-hood temperature value, in the affirmative, calculating an absolute value of a difference between the external-air temperature measurement and the under-hood temperature measurement, determining a diagnostic criterion by calculating a difference between the absolute value and a predetermined absolute value, obtained in the presence of the under-engine protection, comparing the diagnostic criterion against a predetermined diagnostic threshold, and emitting a diagnostic signal dependent on the result of the comparison.

A control method for a cooling system includes determining, by the controller, whether the output signal of the ambient temperature sensor satisfies a predetermined an ambient low temperature driving condition, determining, by the controller, whether the output signal of the first coolant temperature sensor satisfies a predetermined first low temperature driving condition when the output signal of the ambient temperature sensor satisfies the predetermined the ambient low temperature driving condition and controlling, by the controller, the operation of the coolant control valve unit to open the first coolant passage and the third coolant passage and to close the second coolant passage when the output signal of the first coolant temperature sensor satisfies the predetermined first low temperature driving condition.