Method for control of engine torque during gear changing

A method in an automatic computer controlled control system for changing gears in a mechanical stepped gear box in a vehicle powered by a combustion engine for reducing the torque delivered by the engine in connection with the disengagement of a gear, which method comprises the steps of:

• (a) measuring the acceleration of the engine a.sub.m ;
• (b) determining an acceleration factor M.sub.a as a function of the measured engine acceleration a.sub.m ;
• (c) before disengagement of a gear reducing the torque delivered by the engine to a zero-torque level M.sub.0 which is a function at least of the acceleration factor M.sub.a ;
• (d) disengaging the gear;
• and
• (e) after disengagement of the gear, accelerating the engine to a value corresponding to the engines instantaneous value of acceleration of the engine before disengagement of the gear, wherein during torque reduction before gear disengagement, the acceleration factor M.sub.a is continuously corrected on the basis of any engine acceleration changes and wherein the acceleration factor M.sub.a is the product arrived at by multiplying an inertia factor J, which depends on the engine's moment of inertia, by the engine acceleration a.sub.m.

A method in an automatic computer controlled control system for changing gears in a mechanical stepped gear box in a vehicle powered by a combustion engine for reducing the torque delivered by the engine in connection with the disengagement of a gear, which method comprises the steps of:

• (a) measuring the acceleration of the engine a.sub.m ;
• (b) determining an acceleration factor M.sub.a as a function of the measured engine acceleration a.sub.m ;
• (c) before disengagement of a gear reducing the torque delivered by the engine to a zero-torque level M.sub.0 which is a function at least of the acceleration factor M.sub.a ;
• (d) disengaging the gear;
• and
• (e) after disengagement of the gear, accelerating the engine to a value corresponding to the engines instantaneous value of acceleration of the engine before disengagement of the gear, wherein the zero-torque level M.sub.0 is also a function of a friction factor M.sub.f which corresponds to the internal friction of the engine and which depends on the torque required for the engine to run at constant speed in no-load conditions.

A method in an automatic computer controlled control system for changing gears in a mechanical stepped gear box in a vehicle powered by a combustion engine for reducing the torque delivered by the engine in connection with the disengagement of a gear, which method comprises the steps of:

• (a) measuring the acceleration of the engine a.sub.m ;
• (b) determining an acceleration factor M.sub.a as a function of the measured engine acceleration a.sub.m ;
• (c) before disengagement of a gear reducing the torque delivered by the engine to a zero-torque level M.sub.0 which is a function at least of the acceleration factor M.sub.a ;
• (d) disengaging the gear;
• and
• (e) after disengagement of the gear, accelerating the engine to a value corresponding to the engines instantaneous value of acceleration of the engine before disengagement of the gear, wherein the zero-torque level M.sub.0 is also a function of a power take-off factor M.sub.pto which depends on the additional torque required for powering at least one power take-off driven by the engine while maintaining the engine at a constant speed in otherwise no-load conditions.