Patent ID: 8296034

Claim:
A vehicle speed limiting system ( 40 ) having a throttle-by-wire mechanism that drives a throttle valve ( 28 ) using a motor ( 30 ), the vehicle speed limiting system comprising: a three-dimensional map ( 46 a ) that is provided to each of gear stages of a transmission ( 60 ) and from which to derive a target throttle valve opening degree (θB) of the throttle valve ( 28 ) on a basis of a throttle grip opening degree (θA) and an engine speed; a throttle valve driving unit ( 47 ) that drives the motor ( 30 ) in accordance with the target throttle valve opening degree, wherein, when a speed of a vehicle ( 1 ) is about to exceed a preset maximum speed, the throttle valve driving unit ( 47 ) drives the motor ( 30 ) in such a manner that the speed of the vehicle ( 1 ) does not exceed the preset maximum speed, irrespective of the target throttle valve opening degree (θB) derived from the three-dimensional map ( 46 a ), speed difference calculating means for calculating a difference between a current speed of the vehicle ( 1 ) and the preset maximum speed; acceleration calculating means for calculating an acceleration of the vehicle ( 1 ); and maximum speed limiter opening degree calculating means ( 43 ) for calculating a first maximum speed limiter opening degree by adding a first predetermined opening degree, a second predetermined opening degree, and a current throttle valve opening degree, the first predetermined opening degree being calculated by multiplying the speed difference by a preset P-term coefficient, the second predetermined opening degree being calculated by multiplying the acceleration by a preset D-term coefficient, wherein the throttle valve driving unit ( 47 ) is configured to drive the motor ( 30 ) on a basis of the first maximum speed limiter opening degree once the calculated first maximum speed limiter opening degree falls below the target throttle valve opening degree (θB) derived on a basis of the three-dimensional map ( 46 a ).