Arrangement and method for cooling of coolant in a cooling system in a vehicle

Abstract

An arrangement and a method for cooling coolant in a cooling system in a vehicle: The cooling system includes a first cooling circuit, a first coolant pump (11) to circulate coolant through the first cooling circuit, a first radiator (13) to cool the coolant, and a thermostat (12) which opens to direct coolant to the first radiator (13) when the coolant is above the thermostat's regulating temperature (t2); and a second cooling circuit includes a second radiator (20) to cool coolant. A flow device (23, 29) selectively transfers a portion of coolant from the first cooling circuit to the second cooling circuit, so that this portion of the coolant is cooled in the second radiator (20) when the coolant in the first cooling circuit is within a temperature range defined by a lowest temperature (t1) at which the coolant initially needs cooling and a highest temperature which is equal to the thermostat's regulating temperature (t2).

Description

BACKGROUND TO THE INVENTION AND PRIOR ART[0001]The present invention relates to an arrangement and a method for cooling of coolant in a cooling system in a vehicle according to the preambles of claims 1 and 11.[0002]The coolant in a cooling system for cooling of a combustion engine in a vehicle needs to be at an operating temperature which is usually within the range 80-90° C. The cooling system usually comprises a thermostat which regulates the coolant's temperature in the cooling system. In operating situations where the thermostat finds that the coolant is below the desired operating temperature, it will be in a closed state whereby the coolant is led to the engine without cooling. Operating situations where the thermostat finds that the coolant is above the desired operating temperature will put the thermostat into an operating state in which it directs the coolant to a radiator for cooling before it is led back to the engine. The radiator is usually situated in the vehicle's fr...

AI Technical Summary

Benefits of technology

The present invention provides a cooling system for vehicles that reduces the risk of thermostat opening and closing frequently, which can cause large thermal stresses on the cooling system. This is achieved through a second cooling circuit with a lower cooling capacity than the first circuit, which allows the first circuit to cool the coolant more slowly. The second circuit is activated only when the coolant is circulating through it, via a valve that directs coolant from the first circuit to the second circuit. A control unit monitors the coolant temperature and activates the second coolant pump accordingly. Surprisingly, a valve switch can be quickly and easily switched, while a second coolant pump can be easily regulated. The technical effect of the invention is to reduce cooling system stress and improve vehicle cooling efficiency.

Problems solved by technology

The radiator which cools the coolant in the cooling system of heavy vehicles will have a large cooling capacity and therefore be quite expensive to procure.

Conventional thermostats switch abruptly between the closed state and the open state, subjecting the radiator and connecting units in the cooling system to very rapid temperature changes which cause large thermal stresses on the material of the radiator.

Problems occur in particular if the coolant's temperature begins to oscillate about the thermostat's regulating temperature, a situation which the radiator is very frequently subject to large thermal stresses very likely to shorten its service life.

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