METHOD FOR OPERATING AN OIL FILTER SYSTEM
First Claim
1. A method for operating an oil filter system for transmission oil of a transmission assembly having a clutch or a brake, as well as a filter circuit having at least one oil filter and a hydraulic pump with an electric drive or an electrically superimposed drive and controller, wherein the drive of the hydraulic pump is controlled and turned on by the controller, the method comprising the steps of:
- providing a contamination model for indirectly determining an actual contamination level Va (%) of the transmission oil via a relationship
Va (%)=Vstart(IW %)−
A (%)+B (%)+C (%),whereinVstart (IW %) is a starting contamination value based on an initial original contamination value IW % that is freely selectable for an initial system startup during manufacture/final inspection,A (%) is an oil cleaning level percentage that is a function of a hydraulic pump flow rate,B (%) is an oil contamination level percentage that is a function of a clutch energy input, andC (%) is an oil contamination level percentage that is a function of a transmission performance;
initializing the contamination model with the initial starting contamination value Vstart (IW %);
decrementing the initial starting contamination value Vstart (IW %) by A (%) and incrementing Vstart (IW %) by B (%) and C (%) to compute the actual contamination level Va (%);
defining a contamination level threshold value Vs (%) and comparing the contamination level threshold value Vs (%) with the actual contamination level Va (%);
when the actual contamination level Va (%) exceeds the contamination level threshold value Va (%), switching the drive of the hydraulic pump on and controlling the drive of the hydraulic pump until the actual contamination level Va (%), as computed by decrementing with A (%) in the contamination model, is equal to or less than the contamination level threshold value Va (%) minus a fixed hysteresis value VH (%);
storing the actual contamination level Va (%) in a nonvolatile memory of the controller; and
using the stored actual contamination level Va in a subsequent system startup;
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Abstract
A transmission assembly has a clutch or brake, an oil filter, an electrically driven hydraulic pump and a controller controlling the pump. In the method for operating an oil filter system for transmission oil, the actual contamination level Va (%) of the transmission oil is determined indirectly by a contamination model Va (%)=Vstart(IW %)−A (%)+B (%)+C (%), wherein Vstart (IW %) is a starting contamination value, A (%) depends on the hydraulic pump flow rate, B (%) depends on a clutch energy input, and C (%) depends on a transmission performance. When a contamination threshold value Vs (%) is exceeded, the hydraulic pump is switched on, until the actual contamination level Va (%), after decrementing by A (%) in the contamination model, is equal to or less than the contamination level threshold value Va (%) minus a fixed hysteresis value VH (%).
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Citations
9 Claims
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1. A method for operating an oil filter system for transmission oil of a transmission assembly having a clutch or a brake, as well as a filter circuit having at least one oil filter and a hydraulic pump with an electric drive or an electrically superimposed drive and controller, wherein the drive of the hydraulic pump is controlled and turned on by the controller, the method comprising the steps of:
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providing a contamination model for indirectly determining an actual contamination level Va (%) of the transmission oil via a relationship
Va (%)=Vstart(IW %)−
A (%)+B (%)+C (%),wherein Vstart (IW %) is a starting contamination value based on an initial original contamination value IW % that is freely selectable for an initial system startup during manufacture/final inspection, A (%) is an oil cleaning level percentage that is a function of a hydraulic pump flow rate, B (%) is an oil contamination level percentage that is a function of a clutch energy input, and C (%) is an oil contamination level percentage that is a function of a transmission performance; initializing the contamination model with the initial starting contamination value Vstart (IW %); decrementing the initial starting contamination value Vstart (IW %) by A (%) and incrementing Vstart (IW %) by B (%) and C (%) to compute the actual contamination level Va (%); defining a contamination level threshold value Vs (%) and comparing the contamination level threshold value Vs (%) with the actual contamination level Va (%); when the actual contamination level Va (%) exceeds the contamination level threshold value Va (%), switching the drive of the hydraulic pump on and controlling the drive of the hydraulic pump until the actual contamination level Va (%), as computed by decrementing with A (%) in the contamination model, is equal to or less than the contamination level threshold value Va (%) minus a fixed hysteresis value VH (%); storing the actual contamination level Va (%) in a nonvolatile memory of the controller; and using the stored actual contamination level Va in a subsequent system startup; - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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Specification