Semi-Automatic Powershift Transmission Shift Control

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Solution Overview

Problem

Manually triggered shifts in semi-automatic powershift transmissions experience significant delays between the shift command and the change in engine rotational speed, leading to a non-spontaneous and sluggish response perceived by the driver.

Innovation Solution

The method involves simultaneously executing the charging, overlap, and engine rotational speed alignment phases during a manually triggered shift, with the termination of charging based on a pressure sensor signal, to minimize delay and jerk.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If charging, overlap and engine rotational speed alignment are carried out sequentially one after the other, then shift comfort is improved, but the response time to manual shift command increases significantly

Engineering Contradiction:

Improveshift comfortVSAvoiddelay between shift command and rotational speed change

Core Design Contradiction:

Ease of operationVSLoss of time

Solution Approach 1:

The patent merges the charging phase, overlap phase, and engine rotational speed alignment phase into a single simultaneous execution period. The control unit initiates all three phases at the same time in response to a manual shift command, eliminating the sequential delays between phases while maintaining shift comfort through coordinated control of multiple clutches and engine torque management.

Inventive Principle:

Principle #5Merging (Combining)

2Loss of time

If charging and overlap phases are executed quickly to reduce delay, then response time is improved, but jerk increases making the shift less smooth

Engineering Contradiction:

Improvedelay between shift command and rotational speed changeVSAvoidjerk during shift

Core Design Contradiction:

Loss of timeVSObject-generated harmful factors

Solution Approach 1:

The patent employs dynamic control of the charging process where the charging rate is continuously adjusted based on real-time monitoring of clutch state and system conditions. The control unit modulates the charging speed of the engagement clutch and the emptying speed of the disengagement clutch to optimize the balance between response time and jerk minimization, adapting the control strategy during the simultaneous execution of all phases.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes multiple parameters simultaneously including clutch pressure, engine torque, and shift timing to achieve rapid response without excessive jerk. By coordinating the adjustment of these parameters during the simultaneous phase execution, the system achieves fast response while maintaining smooth transition through optimized parameter trajectories.

Inventive Principle:

Principle #35Parameter changes

3Loss of time

If all shift phases are executed simultaneously to reduce delay, then response time is improved, but the complexity of control increases

Engineering Contradiction:

Improvedelay between shift command and rotational speed changeVSAvoidcontrol coordination complexity

Core Design Contradiction:

Loss of timeVSDevice complexity

Solution Approach 1:

The patent implements comprehensive feedback control where the control unit continuously monitors the state of both clutches, engine rotational speed, and shift progression. Based on this feedback, the control unit dynamically adjusts the charging and emptying rates of the clutches to maintain coordinated simultaneous execution of all phases. The feedback mechanism ensures that despite the increased control complexity, the system remains stable and achieves the desired rapid response.

Inventive Principle:

Principle #23Feedback

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 reduces the delay in perceived engine rotational speed change to less than 200 ms, providing an immediate and spontaneous response to the driver's shift command while minimizing jerks, particularly in sports cars.

Implementation Method 1

the charging is terminated on the basis of a pressure sensor signal

Methodology Applied

Scientific EffectPressure sensor detection:

Data Source

PatentUS8864624B2Method for shifting a semi-automatic powershift transmission

Publication Date: 2014.10.21 DR ING H C F PORSCHE AG

AI summary

A method for shifting a semi-automatic powershift transmission used in a motor vehicle during a manually triggered traction upshift involves the shift phases of the charging of an actuator of a clutch to be engaged, an overlap of the charging of the actuator of the clutch to be engaged and the emptying of an actuator of a clutch to be disengaged, and also involves an engine rotational speed alignment. The charging, the overlap and the engine rotational speed alignment are carried out simultaneously. In the shift process during a manually triggered shift, the driver perceives a change in engine rotational speed with only a minimal delay after the shift command.