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US 5,665,024 AGranted
Method of detecting deterioration of automatic transmission fluid
AssigneeChrysler Corporation
InventorsMaurice B. Leising, Hans Dourra, Howard L. Benford
Life of this patent
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AssigneeChrysler Corporation
InventorsMaurice B. Leising, Hans Dourra, Howard L. Benford
Estimating the term…
A method of determining the deterioration of automatic transmission fluid by detecting shudder during the EMCC portion of air conditioner clutch engagement. Shudder is detected by calculating the acceleration of the turbine during EMCC slip with the following equation: .SIGMA..alpha..sub.t =.SIGMA..alpha..sub.t (i-1)+.alpha..sub.t where .alpha..sub.t represents the absolute value of turbine acceleration. In a preferred embodiment, the turbine acceleration is summed for twenty-eight periods of 7 msec each after the start of EMCC and the determination that shudder occurred made if the resulting value exceeds a predetermined number. In a further preferred embodiment, the method is used to modify the air conditioner compressor clutch engagement sequence. Once it is determined that shudder is occurring during the EMCC portion of the air conditioner compressor clutch engagement sequence, the EMCC portion of the air conditioner clutch engagement sequence is eliminated or bypassed.
In a motor vehicle having an automatic transmission and air conditioner, the automatic transmission having a converter clutch and a turbine, the air conditioner having a compressor, the compressor having a clutch, the compressor clutch being engaged by an engine controller to which it is coupled, the transmission coupled to a transmission controller, the compressor clutch engaged by a sequence of engine controller and transmission controller steps wherein the engine controller sends a message to the transmission controller that the compressor clutch is to be engaged, the transmission controller starts electronic modulation of its converter clutch (EMCC) and, upon detecting slip, sends a message to the engine controller to engage the compressor clutch, the engine controller engaging the compressor clutch upon receipt of the message to do so from the transmission controller, a method of determining that the automatic transmission fluid has deteriorated by detecting whether shudder occurs during an initial period of EMCC slip.
In a motor vehicle having a transmission, the transmission having a turbine, a transmission controller, an air conditioner compressor, the air conditioner compressor having a clutch, a method of engaging the air conditioner clutch to reduce the occurrence of disturbances upon engagement of the clutch, comprising the steps of:
Dependencies are inferred from the claim text.