초록 ▼

A method and device are disclosed for determining and checking a state or condition of a hydraulic fluid contained in a brake system, including a state of hydration and/or age such that the fluid boiling point is reduced. The boiling point or a characteristic value of the fluid which depends on the

A method and device are disclosed for determining and checking a state or condition of a hydraulic fluid contained in a brake system, including a state of hydration and/or age such that the fluid boiling point is reduced. The boiling point or a characteristic value of the fluid which depends on the boiling point, on the one hand, and the instantaneous temperature value of the fluid, on the other hand, are measured by means of sensor elements. These two values represent a range of permissible comparative temperature values, including a thermal reserve which is within that same range and is determined for further permissible heating of the fluid. A warning signal is released when a predetermined minimum value of the thermal reserve is reached. The sensor elements have hollow spaces with open walls permitting fluid flow-through and have such a design as to ensure that, after heating-up, there comes about a stable cellular convection in a temperature range lying below the boiling temperature. The cellular convection is used as an indication of the condition or the state of the fluid.

대표청구항 ▼

A method for determining the state or condition of a fluid contained in a hydraulic brake system, in a vehicle wherein said fluid has a boiling point, a temperature and a characteristic value in relation to the boiling point, said characteristic value being a resistance value measured according to a

A method for determining the state or condition of a fluid contained in a hydraulic brake system, in a vehicle wherein said fluid has a boiling point, a temperature and a characteristic value in relation to the boiling point, said characteristic value being a resistance value measured according to a current and being determinable by means of a sensor element in said system, the method comprising determining an instantaneous thermal state of the fluid with sensor elements located in said system, measuring the instantaneous temperature and the characteristic value, determining from a comparison of said measurements of the instantaneous temperature and characteristic value, an instantaneous thermal reserve of the fluid in the system, said instantaneous thermal reserve being a value that is the difference between a predetermined stored temperature value of the fluid and the actual temperature of the fluid during braking operation, and emitting a warning signal when said instantaneous thermal reserve coincides with a predetermined minimum value.