Dual-Clutch Transmission Hydraulics With Valve Spread Diagnosis
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Solution Overview
Problem
The existing hydraulic systems for double-clutch transmissions rely on complex sensors to detect malfunctions in the accumulator charging valve, which can lead to unreliable operation due to issues like spring failures or dirt deposits, increasing the risk of valve malfunction and requiring extensive sensor technology.
Innovation Solution
A diagnostic module within the control unit performs valve spread and changeover time diagnoses using a pressure sensor to determine actual valve spread and pressure thresholds, allowing for the detection of errors with reduced sensor technology effort by monitoring hydraulic pressure and current consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If complex sensors are used to detect malfunctions in the accumulator charging valve, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent uses the existing pressure sensor to detect both the accumulator pressure for normal operation and for diagnostic purposes. Instead of adding complex dedicated sensors for valve malfunction detection, the system creates a diagnostic copy of the pressure measurement data, analyzing it to infer valve status. This allows accurate detection of valve malfunctions using the same pressure sensor that is already part of the system.
Solution Approach 2:
The pressure sensor serves multiple functions: it monitors accumulator pressure for normal hydraulic system operation and simultaneously provides data for diagnostic analysis of the accumulator charging valve status. By making the pressure sensor multi-functional, the system eliminates the need for additional dedicated sensors while maintaining accurate malfunction detection capability.
2Reliability
If the accumulator charging valve is monitored continuously with multiple sensors, then reliability is improved, but loss of substance increases due to higher energy consumption
Solution Approach 1:
The diagnostic module performs valve status analysis at specific intervals or under specific conditions rather than continuously monitoring with additional sensors. The system periodically evaluates the accumulator pressure data already being collected to determine valve malfunction, reducing energy consumption while maintaining reliability through timely detection.
Solution Approach 2:
The system uses feedback from the existing pressure sensor measurements to continuously assess valve status. By analyzing the relationship between accumulator pressure and expected pressure patterns, the system provides continuous monitoring and early warning of valve malfunctions using minimal additional energy, avoiding the need for continuous operation of multiple dedicated sensors.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enhances the operational reliability of the accumulator charging valve by simplifying error detection and reducing sensor requirements, ensuring accurate diagnosis and maintenance of hydraulic system functionality.
Implementation Method 1
a pressure sensor to determine an actual valve spread and actual changeover times
Implementation Method 2
a charging hydraulic pump that pumps hydraulic fluid into the hydraulic system during a charging process in order to increase the accumulator pressure
Implementation Method 3
a pressure accumulator for providing an accumulator pressure in the hydraulic system
Data Source
Figure 1~2b
Figure 2a
Figure 3
AI summary
The invention relates to a hydraulic system for an automatic transmission, more particularly a dual-clutch transmission, of a motor vehicle, comprising a high-pressure circuit (H), in which a pressure accumulator (25), at least one clutch (K1, K2), and gear selectors (G1 to G4) are connected, and comprising a low-pressure circuit (N) for cooling the clutch (K1), wherein the high-pressure circuit (H) and the low-pressure circuit (N) have at least one hydraulic pump (53), which can be driven by means of an electric motor (57), and comprising a control unit (39), which activates the electric motor (57) of the hydraulic pump (53) when a need to charge the pressure accumulator is identified, wherein the high-pressure and low-pressure circuits (H, N) are connected by means of a bypass line (67), which has an integrated accumulator charging valve (71), which fluidically connects the hydraulic pump (53) to the low-pressure circuit (N) in a non-charging position (K) and fluidically connects the hydraulic pump (53) to the high-pressure circuit (H) in a charging position (L), wherein the accumulator charging valve (71) independently switches from the charging position (L) to the non-charging position (K) at a first switching time (tU1) if the accumulator pressure (pS) in the high-pressure circuit (H) exceeds an upper pressure threshold value (pmax) and independently switches from the non-charging position (K) to the charging position (L) at a second switching time (tU2) if the accumulator pressure (pS) falls below a lower pressure threshold value (pmin). According to the invention, the control unit (39) has a diagnostic module (79), by means of which a valve spread diagnosis is performed, in which an actual valve spread (Δpist) between the lower and the upper pressure threshold values (Pmin, Pmax) can be determined.