Generator Motor Mode for Rail Vehicle Idle Speed Control
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Solution Overview
Problem
Diesel-electrical drive units in rail vehicles face inefficiencies in energy management during braking, as the internal combustion engine can only absorb limited braking energy, leading to increased fuel consumption and mechanical wear when restarting for traction demands.
Innovation Solution
The system operates the generator in a motorized mode during braking, maintaining the internal combustion engine at an idle speed to conserve fuel and reduce wear, allowing it to generate electrical energy for traction motors and other consumers, and switches to generator mode when additional power is needed, optimizing energy distribution and reducing fuel consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the internal combustion engine absorbs braking energy, then kinetic energy is converted to mechanical energy, but the engine can only absorb limited braking energy and requires frequent restarting
Solution Approach 1:
The generator is operated in reverse mode during braking - instead of generating electricity from mechanical input, it acts as a motor driven by electrical energy from the intermediate circuit to maintain the ICE at idle speed, preventing it from stopping and eliminating restart requirements
Solution Approach 2:
The generator serves as an intermediary between the electrical system and the ICE during braking, using electrical energy from the intermediate circuit to drive the ICE and maintain its operation, rather than allowing the ICE to directly absorb braking energy
2Use of energy by moving object
If the internal combustion engine runs at idle speed during braking, then fuel consumption is reduced, but the engine efficiency is low
Solution Approach 1:
The ICE operates in periodic cycles - running at efficient load during traction phases and at idle during braking phases - optimizing overall fuel consumption by matching engine operation to actual power demands of the rail vehicle
Solution Approach 2:
The generator drives the ICE at idle speed using electrical energy from the intermediate circuit, making the engine self-sufficient during braking without requiring external fuel input, thereby reducing overall fuel consumption
3Reliability
If the generator operates in motorized mode during braking, then the internal combustion engine is prevented from stopping, but the generator does not introduce maximum braking energy into the engine
Solution Approach 1:
The generator's function is inverted during braking - it becomes a motor rather than a generator, using electrical energy to drive the ICE instead of generating electrical energy from mechanical input, thereby maintaining engine continuity without maximizing energy absorption
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 energy efficiency by minimizing fuel usage and mechanical stress on the engine, enabling smoother transitions between traction and braking modes while maintaining power supply to other consumers, thus improving overall rail vehicle performance.
Implementation Method 1
the generator is operated as a motor... the generator inverter is connected to the generator via the direct voltage intermediate circuit in order to run the generator in a motorized mode as a motor
Implementation Method 2
a generator/motor system supplies a 3-phase alternating voltage to a pulse rectifier that feeds a direct voltage intermediate circuit
Data Source
AI summary
An assembly for supplying electrical energy to electrical traction motors in a rail vehicle, wherein the assembly includes at least one internal combustion engine, a generator allocated to the at least one internal combustion engine for generating the electrical energy, wherein the generator is mechanically coupled to the internal combustion engine such that it is driven by the internal combustion engine upon generator operation of the generator, a rectifier for rectifying an electrical alternating current generated by the generator, a direct voltage intermediate circuit that is electrically connected to the generator via the rectifier, a generator inverter that is present in addition to the rectifier or that is the rectifier operated in the inverter mode, wherein the generator inverter connects the direct voltage intermediate circuit to the generator in order to operate the generator in a motor mode as a motor, and a control for controlling the motor mode of the generator.