| 摘要 |
A method and apparatus for modifying a shift map of an automatic transmission in a vehicle having a gasoline or diesel engine. A calibrator uses the shift map to determine launch ratio from a plurality of speed ratios and is responsive to ambient pressure and/or ambient temperature. The calibrator may be further responsive to engine speed, engine temperature, transmission temperature, gradient and direction of gradient. The method includes determining a first numerical factor in the range 50-100 relating ambient pressure and ambient temperature, the first factor having the lowest numerical value for high temperature and low pressure, and highest numerical value for low temperature and high pressure, determining a second numerical factor relating the first factor and gradient in a range -30% to +20%, the second factor being indicative of a minimum vehicle engine speed at which a lower launch ratio is permitted, and commanding launch in the lower launch ratio should engine speed be less than the numerical value of the second factor. |
