Powertrain Torque Transfer Section Deactivation for Fuel Efficiency
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Solution Overview
Problem
Conventional powertrains in motor vehicles suffer from reduced fuel efficiency in automatic four-wheel drive mode due to constant engagement of the torque transfer section, leading to unnecessary energy consumption and decreased fuel economy.
Innovation Solution
A powertrain design where the torque transfer section is deactuated under normal driving conditions and only rotationally fixedly connected to the secondary axle upon detection of wheel slip, using a control unit to rapidly engage the second clutch, allowing for fast and demand-dependent torque transfer with minimal delay, thereby optimizing fuel efficiency and driving performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the torque transfer section is constantly engaged in automatic four-wheel drive mode, then fast torque transfer to secondary axle is ensured, but fuel economy deteriorates due to unnecessary energy consumption
Solution Approach 1:
The patent applies dynamics by making the torque transfer section switchable between engaged and disengaged states based on driving conditions. The second clutch enables the torque transfer section to be rotationally fixedly connected to the secondary axle only when wheel slip is detected, otherwise it remains disengaged. This dynamic adaptation resolves the contradiction by ensuring fast torque transfer when needed while avoiding unnecessary energy consumption during normal driving.
2Reliability
If the second clutch is closed for fast torque transfer, then driving safety is improved, but energy loss increases due to constant rotation of torque transfer section
Solution Approach 1:
The patent applies preliminary action by using the first clutch to pre-accelerate the torque transfer section before engaging the second clutch. This ensures that when the second clutch closes for fast torque transfer, the torque transfer section is already close to the required speed, minimizing engagement delay while avoiding continuous rotation and energy loss. The preliminary acceleration prepares the system for rapid response without sustained energy consumption.
3Use of energy by moving object
If the torque transfer section is deactuated under normal conditions, then fuel efficiency is enhanced, but torque transfer delay increases when wheel slip occurs
Solution Approach 1:
The patent applies preliminary action by continuously preparing the torque transfer section through the first clutch's acceleration action even when the second clutch is disengaged. This ensures that when wheel slip occurs and the second clutch needs to close, the torque transfer section is already close to operational speed, minimizing the actual torque transfer delay while maintaining fuel efficiency during normal deactuated periods.
Solution Approach 2:
The patent applies dynamics by implementing a dual-clutch system that allows the torque transfer section to be rapidly transitioned from deactuated to engaged state. The first clutch remains active to maintain readiness, while the second clutch provides rapid engagement capability when needed. This dynamic configuration resolves the contradiction by enabling fast response to wheel slip events without requiring continuous engagement that would reduce fuel efficiency.
Data Source
AI summary
The invention relates to a powertrain for a motor vehicle having a permanently driven primary axle, comprising: a drive unit for the generation of a drive torque; a first clutch for the transfer of a variable portion of the drive torque to a secondary axle of the motor vehicle; a second clutch for the deactuation of a torque transfer section of the powertrain arranged between the first clutch and the second clutch when the first clutch is opened; and a control unit for the automatic control of the first clutch, with the control unit being connected to at least one sensor for the detection of a wheel slip at the primary axle; with the control unit being made, starting from a deactuated state of the torque transfer section, to close the second clutch in dependence on a detected wheel slip at the primary axle.