Shift control system for automatic transmission

A shift control system for an automatic transmission, which has select position detecting means for detecting a select position of a selector lever among a plurality of gear positions, including a first gear position, when the selector lever is located at a running range, comprising:

• control means for temporally engaging an engaging element to be engaged at a gear position of higher speed side than the first gear position when the select position detecting means detects that the selector lever is operated from a parking range or a neutral range to the running range;
• and
• engine speed detecting means for detecting a revolution speed of an engine,
• wherein said control means increases an oil pressure command value for actuating the engaging element from a start point oil pressure value after reaching a precharge pressure with a predetermined inclination, while changing the start point oil pressure value in accordance with driving environments, and
• wherein the control means lowers the start point oil pressure value when the engine speed is lower than a predetermined value.

A shift control system for an automatic transmission, which has select position detecting means for detecting a select position of a selector lever among a plurality of gear positions, including a first gear position, when the selector lever is located at a running range, comprising:

• control means for temporally engaging an engaging element to be engaged at a gear position of higher speed side than the first gear position when the select position detecting means detects that the selector lever is operated from a parking range or a neutral range to the running range;
• and
• oil temperature detecting means for detecting an oil temperature of the engaging element,
• wherein said control means increases an oil pressure command value for actuating the engaging element from a start point oil pressure value after reaching a precharge pressure with a predetermined inclination, while changing the start point oil pressure value in accordance with driving environments, and
• wherein the control means lowers the start point oil pressure value as the oil temperature increases.

A shift control system for an automatic transmission, which has select position detecting means for detecting a select position of a selector lever among a plurality of gear positions, including a first gear position, when the selector lever is located at a running range, comprising:

• control means for temporally engaging an engaging element to be engaged at a gear position of higher speed side than the first gear position when the select position detecting means detects that the selector lever is operated from a parking range or a neutral range to the running range;
• and
• turbine speed detecting means connected to a torque converter and detecting a turbine revolution speed of the torque converter,
• wherein said control means increases an oil pressure command value for actuating the engaging element from a start point oil pressure value after reaching a precharge pressure with a predetermined inclination, while changing the start point oil pressure value in accordance with driving environments,
• wherein the control means lowers the oil pressure command value immediately after the engaging element is engaged, and
• wherein the control means determines that the engaging element is engaged when the turbine revolution speed is lower than a predetermined value.

A shift control system for an automatic transmission, which has select position detecting means for detecting a select position of a selector lever among a plurality of gear positions, including a first gear position, when the selector lever is located at a running range, comprising:

• control means for temporally engaging an engaging element to be engaged at a gear position of higher speed side than the first gear position when the select position detecting means detects that the selector lever is operated from a parking range or a neutral range to the running range;
• and
• throttle valve opening detecting means for detecting an opening degree of a throttle valve of the engine,
• wherein said control means increases an oil pressure command value for actuating the engaging element from a start point oil pressure value after reaching a precharge pressure with a predetermined inclination, while changing the start point oil pressure value in accordance with driving environments, and
• wherein the control means terminates a control to engage said engaging element to be engaged at the gear position of higher speed side when the throttle valve opening is larger than a predetermined value.