Cooling control systems described herein detect decreased operation of a cooling system of a vehicle, restrict movement of the vehicle without stopping movement responsive to decreased operation of the cooling system, and restrict movement of the vehicle by preventing the vehicle from traveling at a speed and/or power output for a non-zero designated period of time. This can allow for the vehicle to continue moving for a temporary period of time to avoid blocking traffic. Other control systems determine predicted distances and/or times that the vehicle can continue moving before coolant in the cooling system decreases below a designated threshold. Movement of the vehicle can be changed responsive to an upcoming distance and/or time that the vehicle is to travel exceeding the predicted distance and/or time. Other control systems modify a coolant flow rate based on differences between designated and ambient conditions.

Cooling control systems described herein detect decreased operation of a cooling system of a vehicle, restrict movement of the vehicle without stopping movement responsive to decreased operation of the cooling system, and restrict movement of the vehicle by preventing the vehicle from traveling at a speed and/or power output for a non-zero designated period of time. This can allow for the vehicle to continue moving for a temporary period of time to avoid blocking traffic. Other control systems determine predicted distances and/or times that the vehicle can continue moving before coolant in the cooling system decreases below a designated threshold. Movement of the vehicle can be changed responsive to an upcoming distance and/or time that the vehicle is to travel exceeding the predicted distance and/or time. Other control systems modify a coolant flow rate based on differences between designated and ambient conditions.

Methods are provided for engine coolant system diagnostics. In one example, engine coolant system malfunction is indicated based on an engine coolant temperature inference model, whereas in another example engine coolant system malfunction is indicated based on a time-based monitor, where the inference model is enabled at ambient temperatures above a predetermined threshold, and where the time-based monitor is enabled at ambient temperatures below the predetermined threshold. In this way, accurate engine coolant system diagnosis may be accomplished under ambient temperature conditions wherein the engine coolant temperature inference model may be compromised.

Systems and methods for monitoring the temperature of a liquid are disclosed herein. Systems can include a thermistor in contact with a liquid coolant and circuitry configured to measure a temperature of the thermistor by applying a nominal current through the thermistor and detecting a voltage drop across the thermistor. The circuitry may be further configured to apply a current pulse greater than the nominal current through the thermistor, detect a transient thermistor response to the current pulse, and compare the detected transient thermistor response to an expected transient response. The circuitry may be capable of determining if the thermistor is immersed in a fluid or at least partially located within a fluid-free region based on comparing the detected transient thermistor response to the expected transient response.

Systems and methods for monitoring the temperature of a liquid are disclosed herein. Systems can include a thermistor in contact with a liquid coolant and circuitry configured to measure a temperature of the thermistor by applying a nominal current through the thermistor and detecting a voltage drop across the thermistor. The circuitry may be further configured to apply a current pulse greater than the nominal current through the thermistor, detect a transient thermistor response to the current pulse, and compare the detected transient thermistor response to an expected transient response. The circuitry may be capable of determining if the thermistor is immersed in a fluid or at least partially located within a fluid-free region based on comparing the detected transient thermistor response to the expected transient response.

A method for operating an engine cooling system is provided. The method includes monitoring a coolant temperature profile after engine shut-down and indicating a low coolant level based on the coolant temperature profile determined after engine shut-down.

A method for operating an engine cooling system is provided. The method includes monitoring a coolant temperature profile after engine shut-down and indicating a low coolant level based on the coolant temperature profile determined after engine shut-down.

The present invention relates to a cooling control apparatus which performs control for cooling an internal combustion engine by causing an electric pump to circulate cooling water and causing an electric fan to supply cooling air to a radiator. The cooling control apparatus comprises an electric pump for circulating a coolant through a coolant passage formed in the internal combustion engine, and a radiator and a radiator fan which are for cooling the coolant. When the internal combustion engine stops after completion of warming-up, the radiator fan and the electric pump are driven to cool the internal combustion engine, and when a temperature of the coolant decreases to less than a temperature at a time of engine stop, the radiator fan is stopped in a state in which the electric pump is operated.

A fuel property determination apparatus for an internal combustion engine is applied to an internal combustion engine that is equipped with an ignition plug and an ignition timing controller. An electronic control unit provided in the fuel property determination apparatus executes a determination process of making a determination on a property of a fuel supplied to the internal combustion engine based on an ignition sufficiency ratio, during a predetermined period after startup of the internal combustion engine. The electronic control unit is configured to determine that the property of the fuel is heavy when a determination index value that is obtained by subjecting the ignition sufficiency ratio to a smoothing process is equal to or larger than a predetermined threshold. The electronic control unit is configured to set a smoothing coefficient to a value corresponding to each of a first period, a second period, and a third period.

A fuel property determination apparatus for an internal combustion engine is applied to an internal combustion engine that is equipped with an ignition plug and an ignition timing controller. An electronic control unit provided in the fuel property determination apparatus executes a determination process of making a determination on a property of a fuel supplied to the internal combustion engine based on an ignition sufficiency ratio, during a predetermined period after startup of the internal combustion engine. The electronic control unit is configured to determine that the property of the fuel is heavy when a determination index value that is obtained by subjecting the ignition sufficiency ratio to a smoothing process is equal to or larger than a predetermined threshold. The electronic control unit is configured to set a smoothing coefficient to a value corresponding to each of a first period, a second period, and a third period.