Dual Electric Machine Drive for In-Flight Engine Restart
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Solution Overview
Problem
Existing aircraft power plants with combustion engines lack flexibility and redundancy in operating modes, particularly during flight phases, leading to potential engine shutdowns and inefficient restarts.
Innovation Solution
Aircraft equipped with a drive system comprising two electric machines connected to the combustion engine via a kinematic chain, controlled by a management system to operate in various modes, including a superior mode for fast restarts and enhanced functionality during flight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a simplex drive system with one electric machine is used, then the device complexity is reduced, but the reliability and operational flexibility deteriorate because the engine cannot be restarted during flight if it shuts down
Solution Approach 1:
The drive system is segmented into two independent electric machines (first and second electric machines) instead of using a single machine. This segmentation allows each machine to independently control one of the two combustion engines, providing redundancy and the capability to restart engines during flight operations without requiring a complete system redesign.
Solution Approach 2:
Each electric machine is configured with specific local capabilities - the first electric machine controls the first combustion engine while the second electric machine controls the second combustion engine. This local quality assignment allows targeted engine restart capabilities where each machine can independently perform restart functions for its associated engine, enhancing overall system reliability without requiring full system complexity.
2Adaptability or versatility
If the power plant is dimensioned to render a combustion engine inactive during flight, then the operational flexibility is improved, but the reliability deteriorates without an enhanced restart system
Solution Approach 1:
The system performs preliminary action by maintaining the capability to restart combustion engines during flight through the enhanced drive system. The two electric machines are pre-configured to provide restart functionality, allowing the power plant to be dimensioned for fuel efficiency (with engines that can be rendered inactive) while ensuring restart capability is already in place before any shutdown occurs.
Solution Approach 2:
The electric machines are designed with multi-functionality, serving both as primary drive systems during normal operation and as restart systems when engines need to be reactivated. This universal design allows the same components to handle multiple operating modes including active flight, inactive flight, and restart operations, enhancing adaptability without requiring separate dedicated restart systems.
3Productivity
If a single electric machine is used to set the mobile system in motion, then the device complexity is reduced, but the productivity deteriorates during superior operating modes requiring fast restarts
Solution Approach 1:
The restart function is segmented between two electric machines, allowing parallel or coordinated operation to achieve faster restart times. The first electric machine can initiate the restart process while the second electric machine provides additional torque or completes the restart, significantly reducing the time required compared to a single machine performing the entire restart sequence alone.
Solution Approach 2:
The system merges the capabilities of two electric machines to achieve superior restart performance. During fast restart operations, both electric machines can operate simultaneously to provide combined torque to the mobile system, achieving restart speeds and efficiencies that exceed what a single electric machine could deliver, while sharing the operational load.
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
Enhances engine restart capabilities during flight and improves operational flexibility by allowing independent control of each electric machine to meet mechanical power and torque requirements, ensuring redundancy and efficient operation.
Implementation Method 1
an electric machine that is able to operate in an electric motor mode and an electric generator mode
Implementation Method 2
In the electric generator mode, an electric machine is set in motion in order to generate electrical power
Data Source
AI summary
An aircraft provided with a power plant provided with at least one combustion engine mechanically connected to a drive system, the drive system comprising two electric machines each connected to the combustion engine by a kinematic chain, the two electric machines being electrically connected to at least one electrical power source. The aircraft comprises a management system controlling at least a mechanical power or an engine torque delivered by each of the two electric machines as a function of a current operating mode, the management system being configured, during a superior operating mode, to control the two electric machines in order for the two electric machines to deliver different and non-zero mechanical powers or engine torques.