Rotating Electrical Machine for Cold Engine Starting
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Solution Overview
Problem
Existing power transmission systems for vehicles struggle to start an internal combustion engine in cold states due to increased lubricant viscosity and decreased friction coefficient between V-belts and pulleys, leading to slippage and failure in transmitting rotation driving force.
Innovation Solution
A power transmission apparatus with a rotating electrical machine is designed, where the rotor is coupled to the output shaft of the internal combustion engine, and a stator is fixed to a non-rotating member with a gap, allowing reliable transmission of rotation driving force even in cold states without using a V-belt and pulley, and integrating both power generation and engine start functions into one machine.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a V-belt and pulley system is used to transmit rotation driving force from the alternator to the internal combustion engine, then the structure is simple and cost-effective, but the friction coefficient decreases in cold states leading to slippage and failure to transmit driving force
Solution Approach 1:
The patent replaces the V-belt and pulley mechanical transmission system with a rotating electrical machine (starter generator) that directly couples to the engine crankshaft. This substitution eliminates the friction-dependent belt-pulley interface, allowing reliable cold-start through direct electromagnetic-to-mechanical force conversion without lubricant viscosity interference.
Solution Approach 2:
The rotating electrical machine serves dual functions: as a generator during engine operation and as a starter motor for cold-start. This multi-functionality consolidates the alternator and separate starter motor into one integrated component, eliminating the need for V-belt/pulley systems while maintaining both power generation and engine starting capabilities.
2Reliability
If a separate starter motor is added to handle cold-state engine starting, then cold-start reliability is improved, but device complexity and space requirements increase
Solution Approach 1:
The patent merges the alternator and starter motor functions into a single rotating electrical machine. The starter generator integrates the field winding and armature winding in one structure, eliminating the need for separate starter motor components and reducing overall system complexity while maintaining cold-start reliability.
Solution Approach 2:
The rotating electrical machine is designed to perform both power generation and engine starting functions. By utilizing the same core structure for dual purposes, the patent avoids adding extra components and achieves space efficiency while solving the cold-start problem.
3Reliability
If a rotating electrical machine is used to replace V-belt and pulley, then cold-start reliability is improved, but the apparatus complexity increases
Solution Approach 1:
The rotating electrical machine is segmented into distinct functional windings: field winding for generating magnetic flux and armature winding for producing electromagnetic force. This segmentation allows independent optimization of each winding's characteristics, simplifying the overall design while maintaining cold-start reliability.
Solution Approach 2:
The patent employs a nested structure where the armature winding is positioned within the magnetic field generated by the field winding. This nested arrangement of concentric cylindrical windings optimizes space utilization and simplifies the mechanical structure, reducing apparent complexity while achieving reliable cold-start performance.
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 solution enables reliable engine starting in cold conditions, reduces costs and space by eliminating separate starter motors and V-belt/pulley components, and extends apparatus lifespan by avoiding brush-related issues, ensuring quiet operation and reduced maintenance.
Implementation Method 1
a rotating electrical machine that includes a rotor coupled to a synchronous rotating member that rotates synchronously with the output shaft of the internal combustion engine
Data Source
AI summary
A power transmission apparatus, which is disposed on a power transmission path from an output shaft of an internal combustion engine to a transmission in a vehicle, is provided with a rotating electrical machine including a rotor and a stator. The rotor is coupled to a synchronous rotating member that rotates synchronously with the output shaft of the internal combustion engine, and takes a central axis of the output shaft of the internal combustion engine as a rotating shaft. The stator is fixed to a fixing member on a non-rotating side with respect to the synchronous rotating member, and faces the rotor with a first gap therebetween.