4-16 POWER TAKE-OFFS E UROCARGO Euro 4/5 4.6.3.1 Changes to the torque curve, final rotation speed and steepness of the final limiter For mechanical power take-off protection, it is possible to limit: a) engine torque delivery as a protection against overload b) engine rpm, as a protection against over-speed The diagram in Figure 4.8 shows this qualitatively by means of a toque/engine RPM curve (defined by 16 points), a horizontal section (representing torque limitation) and a sloping section (representing over-rev adjustment). Figure 4.8 Rpm [rpm] 114514 1. Resultant curve - 2. Maximum torque straight limitation line - 3. Out of rev curve - 4.
Curve points After setting a maximum for engine RPM and a variation mode (slope 3), we obtain a point of intersection X with the straight line of the set torque and therefore the maximum RPM compatible with this torque on the x-axis. In other words: As the engine RPM increases, the control unit uses the lowest torque value between those on curve 1 and those on straight line 2 and then, for speeds greater than that determined by point X, causes the over-revving adjustment device to cut in and thus reduce the torque. PTO management Base - January 2008 Print 603.93.431