US 9,574,624 B2Granted

Method for a hydraulic system for a dual-clutch gearbox

AssigneeAudi AG

InventorStefan Ammler

Life of this patent

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Abstract

A hydraulic system for an automatic gearbox for a motor vehicle, includes a high-pressure circuit which includes a pressure accumulator, at least one clutch and actuators, and a low-pressure circuit for cooling the clutch, the high-pressure circuit and the low-pressure circuit each containing a hydraulic cooling pump and a hydraulic charging pump that can be driven by a shared electric motor; and a controller which, when it is detected that the pressure accumulator needs to be charged, controls the electric motor to run at a charging setpoint speed, and/or, when it is detected that cooling is needed or another need exists, controls the electric motor to run at a cooling setpoint speed or another setpoint speed. When the pressure accumulator does not need to be charged and there is no need for cooling and no other need, the controller reduces the setpoint speed to zero for a specified period. At the end of the period the controller controls the electric motor to run at least at the test speed.

A hydraulic system for an automatic transmission, in particular a dual-clutch transmission, of a motor vehicle comprising:

a high-pressure circuit comprising a pressure accumulator, at least one clutch, and actuators;
a low-pressure circuit for cooling the at least one clutch,
a cooling hydraulic pump connected to the low pressure circuit;
a charging hydraulic pump connectable to the pressure accumulator and to the low pressure circuit, said cooling hydraulic pump and said charging hydraulic pump being drivable via a shared electric motor;
a control device having a pressure model unit, said control device being configured
to control the electric motor to run at a charging setpoint speed when recognizing a requirement for charging the pressure accumulator
to control the electric motor to run at a cooling setpoint speed or other setpoint speed when recognizing a requirement for cooling or other requirement,
to lower the speed of the electric motor to zero for a predetermined period of time when neither a requirement for charging the pressure accumulator nor a requirement for cooling nor another requirement exists, and
to control the electric motor to run at least at a test speed after expiration of the predetermined period of time,
said pressure model unit during an entire operating time of the hydraulic system detecting actuations of the actuators or other events that influence a pressure of the pressure accumulator, and determining partial pressure differences as a function of the detected actuations of the actuators or other events, said pressure modeling unit modeling a pressure decrease in the pressure accumulator over time during the predetermined period of time as a function of the determined partial pressure differences, and as a function of basic leakage pressure losses of the hydraulic system,
wherein when the modeling of the pressure modeling unit indicates a minimal pressure of the pressure accumulator, the control device controls the electric motor to run at the test speed.

8 more elements

Facts

Application

14/892,953Filed 20 May 2014

Priority

DE 10 2013 008 74023 May 2013

Published

US 2016/0108977 A121 Apr 2016

Granted

21 Feb 2017

Term ends

Not estimatedThe source records don’t support an estimate.

Classification21 codes

F16D 48/062
Control by electric or electronic means, e.g. of fluid pressure: of a clutch system with a plurality of fluid actuated clutches
F16D 13/385
With flat clutching surfaces, e.g. discs: double clutches, i.e. comprising two friction disc mounted on one driven shaft
F16D 21/06
For interconnecting three or more shafts or other transmission members in different ways: at least two driving shafts or two driven shafts being…
F16D 25/10
Fluid-actuated clutches: clutch systems with a plurality of fluid-actuated clutches

Abstract

Claims18