System for hydraulic transmission regulation of a CVT

A system for generating a signal (Ip) for hydraulically adjusting the transmission ratio of a continuously variable transmission in a motor vehicle, the system comprising:

• a pressure reservoir exhibiting a hydraulic pressure (Ps,act);
• a pressure chamber hydraulically connected to said pressure reservoir;
• a valve for influencing the hydraulic connection between said pressure reservoir and said pressure chamber;
• a control apparatus for generating an electrical signal (Ip) for driving said valve to adjust the transmission ratio of said transmission and said electrical signal (Ip) being generated in such a manner that said electrical signal is limited to maximum and/or minimum values (I max, I min);
• means for determining said maximum and/or minimum values (I max, I min) in dependence upon the hydraulic pressure (Ps,act);
• a pressure sensor for detecting said pressure (Ps,act);
• the hydraulic pressure (Ps,act) being adjusted to a desired value (Ps,des) and being controlled;
• and,
• wherein the maximum and/or minimum values (I max, I min) are determined in dependence upon a comparison or upon the difference between the hydraulic pressure (Ps,act) and the desired value (Ps,des), wherein it is provided that the maximum and/or minimum values (I max, I min) are determined in such a manner that hydraulic connection from the pressure reservoir, which exhibits the hydraulic pressure (Ps,act), to the pressure chamber, is limited when the desired value (Ps,des) exceeds the hydraulic pressure (Ps,act) to a pregivable extent.

A system for generating a signal (Ip) for hydraulically adjusting the transmission ratio of a continuously variable transmission in a motor vehicle, the transmission having a drive end, an output end and a wrap-around part which connects the drive end to the output end;

• the system comprising:
• a pressure reservoir exhibiting a hydraulic pressure (ps,act);
• said output end having a pressure chamber hydraulically connected to said pressure reservoir;
• means for adjusting a pregivable tension of said wrap-around part;
• a valve for adjusting said transmission ratio of said transmission in response to an electrical signal (Ip) driving said valve;
• means for generating said electrical signal (Ip) in such a manner that said electrical signal is limited to maximum and/or minimum values (I max, I min);
• and,
• means for selecting the limitations (I max, I min) in such a manner that the adjustment of the tension is ensured.

A system for generating a signal (Ip) for hydraulically adjusting the transmission ratio of a continuously variable transmission in a motor vehicle, the transmission having a drive end, an output end and a wrap-around part which connects the drive end to the output end;

• the system comprising:
• means for adjusting a pregivable tension of said wrap-around part;
• a valve for adjusting said transmission ratio of said transmission in response to an electrical signal (Ip) driving said valve;
• means for generating said electrical signal (Ip) in such a manner that said electrical signal is limited to maximum and/or minimum values (I max, I min);
• and,
• means for selecting the limitations (I max, I min) in such a manner that the adjustment of the tension is ensured;
• wherein the hydraulic pressure (Ps,act) is adjusted to a desired value (Ps,des) and is controlled;
• a hydraulic pump, which is driven by the vehicle engine, is provided for pumping a hydraulic volume flow and:
• a pumped volume flow (FVS), which represents the instantaneous hydraulic volume flow, is determined at least dependent upon the operating state of the hydraulic pump, in dependence upon the rpm of the vehicle engine;
• a hydraulic volume flow (VS), which is required for the hydraulic pressure supply, is determined at least in dependence of the desired value (Ps,des);
• and,
• the maximum and/or minimum values (I max, I min) are determined in dependence upon a comparison or the difference between the pumped volume value (FVS) and the required hydraulic volume flow (VS).