An arrangement and a method for controlling the braking action of a retarder
Publication Date: 2004-Nov-18
The IP.com Prior Art Database
The oil of a hydrodynamic retarder is usually cooled by means of the ordinary cooling system in a vehicle. Thereby, the available braking effect of the retarder is restricted by the capacity of the cooling system. The capacity of the cooling system depends on, for example, the specific heat CP of the used cooling liquid. In cold climates, a cooling liquid is used containing a mixture of water and glycol. In hot climates, a cooling liquid normally is used containing water and a smaller amount of an antioxidant. The difference in specific heat CP between such cooling liquid mixtures is relatively large. According to the invention, the activation of the retarder is controlled by means of information about the value of the specific heat CP of the cooling liquid mixture, which for the moment is used in the cooling system. Thereby, it is possible to control the activation of the retarder in a more optimally manner without the risk that the cooling system is overheated.