Control system for determining engagement point for hydrodynamic retarder has electronic circuit connected to electromagnetic oil inlet valve which lets oil into retarder casing

摘要

The retarder control system produces a given relationship between the control current (i) and the braking moment (M) produced by the retarder. At the start of the control procedure M=0. A low current (i off) is produced, followed by a control current (Delta i). A first control procedure involves:- driving the vehicle for a short time Delta t, with a constant drive torque and a constant resistance to motion of the vehicle, estimation of the vehicle or retarder rotor speed for a short future time Delta t z, activation of an actuator for the retarder inlet valve using a small current (Delta i1) and summation of this step in a counter Zj, comparison of forecast and actual speed and determination if they coincide or diverge by more than a given amount, step (c) may be repeated, storage of a counter sum as an individual engagement point of a retarder (i-ret(n)).