Driving system of motor vehicle

A driving system of a motor vehicle, comprising:

• a driving power source that generates power;
• a belt-and-pulley type continuously variable transmission that transmits the power received from the driving power source to a drive wheel while changing a first speed of rotation of an input shaft thereof to a second speed of rotation of an output shaft thereof;
• and
• a speed changing mechanism provided between the driving power source and the continuously variable transmission so as to increase or reduce a speed of rotation of the driving power source during forward running of the vehicle, wherein the speed changing mechanism comprises at least one planetary gear set, and has a forward-drive/reverse-drive switching function of establishing a selected one of a cut-off mode in which power transmission is cut off, a forward drive mode in which the vehicle runs forward, and a reverse drive mode in which the vehicle runs backward, wherein:
• the driving power source comprises a diesel engine;
• and
• the speed changing mechanism transmits the power generated by the diesel engine to the continuously variable transmission while increasing a speed of rotation of the diesel engine during forward running of the vehicle, wherein:
• speed ratio at which the speed changing mechanism changes the speed of rotation of the driving power source is determined so that a maximum torque applied from the diesel engine to the continuously variable transmission is substantially equal to or smaller than a maximum torque applied from a gasoline engine producing the same power as the diesel engine.

A driving system of a motor vehicle, comprising:

• a driving power source that generates power;
• a belt-and-pulley type continuously variable transmission that transmits the power received from the driving power source to a drive wheel while changing a first speed of rotation of an input shaft thereof to a second speed of rotation of an output shaft thereof;
• and
• a speed changing mechanism provided between the driving power source and the continuously variable transmission so as to increase or reduce a speed of rotation of the driving power source during forward running of the vehicle, wherein:
• the driving power source comprises a diesel engine;
• and
• the speed changing mechanism transmits the power generated by the diesel engine to the continuously variable transmission while increasing a speed of rotation of the diesel engine during forward running of the vehicle, wherein:
• a speed ratio at which the speed changing mechanism changes the speed of rotation of the driving power source is determined so that a maximum torque applied from the diesel engine to the continuously variable transmission is substantially equal to or smaller than a maximum torque applied from a gasoline engine producing the same power as the diesel engine.