Method of controlling a transmission of a vehicle in two different modes according to requirements for power and economy

A method of controlling a transmission of a vehicle, said transmission comprising a gear mechanism for providing a series of more than two speed stages having gradually decreasing reduction gear ratios from a lowest speed stage of a largest reduction gear ratio to a highest speed stage of a smallest reduction gear ratio, comprising the steps of:

• detecting a driver's operation of the vehicle to discriminate between the driver's intention to drive the vehicle with a preference for power and a preference for economy performance,
• shifting said gear mechanism in a first mode among said series of speed stages according to a first shift pattern suitable for powerful operation of the vehicle when the discriminated driver's intention is to drive the vehicle with preference on power performance, and
• shifting said gear mechanism in a second mode among a sub-series of speed stages which lacks at least one intermediate speed stage in said series of speed stages according to a second shift pattern suitable for economical operation of the vehicle when the discriminated driver's intention is to drive the vehicle with preference on economy performance,
• wherein, when said first and second shift patterns are expressed in a diagram having an abscissa coordinate for vehicle road speed and an ordinate coordinate for throttle opening, the spacing between each two adjacent speed stage shift lines along the abscissa in said second shift pattern is substantially the same as that in said first shift pattern, with the interval between a speed stage shift line for upshifting from the lowest speed stage to an adjacently higher speed stage and a speed stage shift line for upshifting to the highest speed stage from an adjacently lower speed stage in said second shift pattern being substantially smaller than that in said first shift pattern by an amount corresponding to the reduction of the number of the speed shift lines.