On-axis Brushless Starter Assembly Wear Reduction
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Solution Overview
Problem
Conventional electric starters for internal combustion engines using brushed motors suffer from wear and tear of physical contacts, leading to reduced torque near the upper speed range and limited durability, as well as inefficiencies in stop-start systems for fuel conservation.
Innovation Solution
An on-axis brushless electric starter assembly featuring a partial planetary gear set, a brushless electric motor with a multi-phase stator assembly, and a solenoid assembly that allows the starter pinion gear to slide along an axis for engagement with the engine's ring gear, utilizing a control processor and power electronics assembly for precise torque application and reduced wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If contact brushes are used to conduct current between stator and rotor, then electrical connection is achieved, but physical wear occurs leading to reduced durability and torque
Solution Approach 1:
The patent replaces the mechanical contact brush system with a brushless DC motor design where electrical current is transmitted through the rotor windings without physical contact. The stator generates a rotating magnetic field that interacts with the rotor magnets to produce torque, eliminating wear from friction and contact degradation while maintaining reliable electrical connection and current conduction between stationary stator wires and moving rotor parts.
Solution Approach 2:
The patent introduces magnetic fields as an intermediary to transfer energy and generate motion without mechanical contact. The stator windings create a magnetic field that interacts with permanent magnets on the rotor, enabling torque transmission and rotational motion without the need for physical contact brushes, thereby eliminating wear while maintaining electrical connection functionality.
2Speed
If brushed motor is used, then simple construction is achieved, but torque delivery near upper speed range is substantially zero
Solution Approach 1:
The patent replaces the brushed motor system with a brushless DC motor where electronic commutation replaces mechanical brush contact. The electronic controller manages current flow to the stator windings, enabling precise control of the magnetic field to maintain optimal torque production across the entire speed range, including at high speeds where brushed motors fail.
Solution Approach 2:
The patent implements dynamic electronic control of the motor commutation process. The electronic controller continuously adjusts the timing and magnitude of current flow to the stator windings based on rotor position feedback, enabling the motor to maintain optimal torque characteristics across varying speeds. This dynamic control allows the motor to deliver substantial torque even near the upper bound of its speed range.
3Productivity
If conventional starter system is used, then simple operation is achieved, but efficiency in stop-start systems is reduced
Solution Approach 1:
The patent incorporates feedback mechanisms through the electronic controller that monitors motor performance, battery state, and vehicle operating conditions. This feedback enables the system to optimize energy management during stop-start operations, adjusting motor operation to minimize energy consumption while ensuring reliable engine restarts, thereby improving overall system efficiency and reducing energy loss.
Solution Approach 2:
The patent enables efficient periodic operation for stop-start systems where the motor alternates between idle state and active restart operation. The electronic controller manages the periodic engagement and disengagement of the motor, optimizing energy usage by keeping the motor ready for rapid restart when needed while minimizing energy consumption during extended idle periods between restarts.
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
The brushless starter assembly enhances durability and torque delivery across the speed range, reduces wear, and improves the efficiency of stop-start systems by enabling precise control and efficient energy use in hybrid and conventional vehicles.
Implementation Method 1
The brushless electric motor includes a multi-phase stator assembly arranged inside the motor casing concentrically with respect to the first axis and a rotor assembly arranged for rotation inside the stator assembly
Implementation Method 2
a partial planetary gear set operatively connected to a starter pinion gear configured to slide along a first axis
Implementation Method 3
a solenoid assembly having a pinion-shift solenoid arranged on a second axis that is parallel to the first axis. The pinion-shift solenoid may be configured to shift or slide the starter pinion gear along the first axis
Data Source
AI summary
A starter assembly includes a partial planetary gear set connected to a pinion gear slidable along a first axis. The starter also includes a motor casing housing a brushless electric motor and having a first bearing. The motor includes multi-phase stator and rotor assemblies arranged inside the casing concentrically relative to the first axis. The rotor assembly has a rotor with a shaft supported by the first bearing and connected to a sun gear engaging the gear set, and a rotor position and speed sensor target. The starter additionally includes a motor end-cap for mating with and enclosing the motor casing and having a second bearing supporting the shaft. The starter also includes an electronics cover with a power connector for mating with the end-cap and housing an electronic commutator assembly. The commutator assembly includes power electronics, and control processor electronics arranged between the end-cap and the power electronics.