Cooling system for an internal-combustion engine of a motor vehicle having a thermostatic valve

Claim 1

A cooling system for an internal-combustion engine of a motor vehicle comprising: a thermostatic valve which controls the quantity of coolant which flows through at least one of a short-circuit pipe and a coolant radiator from an engine outlet to an engine inlet, and which thermostatic valve is switched by means of a signal depending on at least one of operating parameters of the internal-combustion engine and environmental parameters from a higher control level for the coolant temperature to a lower control level for the coolant temperature, and a fan which is assigned to the coolant radiator and which is switched by means of a fan control circuit, wherein the fan control circuit has a temperature comparison step which compares the actual temperature of the coolant with a first desired value and, when the first desired value is exceeded, generates a temperature signal which is applied to a first input of an AND-element, and the switching signal of the thermostatic valve being applied to a second input of the AND-element, which AND-element generates a switch-on signal for the fan.

Claim 20

A method for controlling a cooling system for an internal-combustion engine of a motor vehicle having a thermostatic valve which controls the quantity of coolant which flows through at least one of a short-circuit pipe and a coolant radiator from an engine outlet to an engine inlet, which thermostatic valve is switched by means of a switching signal depending on at least one of operating parameters of the internal-combustion engine and environmental parameters from a higher control level for the coolant temperature to a lower control level for the coolant temperature, and having a fan which is assigned to the coolant radiator and which can be switched by means of a fan control circuit, said method comprising the steps of: comparing the actual temperature of the coolant with a first desired value, generating a temperature signal when the actual temperature of the coolant exceeds the desired value, applying the temperature signal to a first input of an AND-element, applying the switching signal of the thermostatic valve to a second input of the AND-element, and generating a switch-on signal for the fan from the AND-element when said temperature signal and said switching signal are simultaneously applied to said first input and said second input, respectively.

Claim 21

A method for controlling a cooling system for an internal-combustion engine of a motor vehicle having a thermostatic valve which controls the quantity of coolant which flows through at least one of a short-circuit pipe and a coolant radiator from an engine outlet to an engine inlet, which thermostatic valve is switched by means of a switching signal depending on at least one of operating parameters of the internal-combustion engine and environmental parameters from a higher control level for the coolant temperature to a lower control level for the coolant temperature, and having a fan which is assigned to the coolant radiator and which can be switched by means of a fan control circuit, said method comprising the steps of: comparing the actual temperature of the coolant with a first desired value, generating a temperature signal when the actual temperature of the coolant exceeds the desired value, applying the temperature signal to a first input of an AND-element, applying the switching signal of the thermostatic valve to a second input of the AND-element, and generating a switch-on signal for the fan from the AND-element when said temperature signal and said switching signal are simultaneously applied to said first input and said second input, respectively.