| 摘要 |
<p>A method and system of controlling a maximum start gear ratio of an automated mechanical transmission system is disclosed. To protect the clutch under conditions of level ground up to a mild grade, a maximum starting gear is determined by the system when a valid Gross Combination Weight (GCW) of the vehicle is known. The maximum starting gear is defined as the highest starting gear ratio that will provide adequate startability without having to put excessive energy into the clutch during the start. The system will force a downshift if insufficient vehicle acceleration is detected by the system. If the GCW of the vehicle is not known, the maximum start gear will be limited to that for a fully laden vehicle. To protect against too much power being transmitted through the clutch, the power through the clutch is determined and the engine torque and/or engine speed is limited to values resulting in power through the clutch below a preset value. The power through the clutch is determined by the transmission input speed, the engine speed and the torque at the flywheel.</p> |
