Brushless Starter Pinion Pre-Engagement Control
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Solution Overview
Problem
Existing engine starter systems face inefficiencies in power consumption and noise during auto-start events, particularly when using a permanently-engaged starter motor with a one-way clutch or dual-tandem solenoid configurations, which can lead to suboptimal gear meshing and increased noise, vibration, and harshness (NVH).
Innovation Solution
An electric starter system incorporating a brushless starter motor, a pinion gear, and a solenoid device, controlled by a controller that uses pulse-width modulation (PWM) signals to selectively engage and disengage the pinion gear with the flywheel, reducing power consumption and maintaining engagement with a lower holding current, thereby minimizing NVH issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a permanently-engaged starter motor with one-way clutch is used, then the starter motor is always ready to engage, but power consumption increases and NVH issues worsen
Solution Approach 1:
The starter system transitions from a permanently-engaged static configuration to a dynamic engagement system where the pinion gear is selectively engaged only when needed for starting. The control module dynamically controls the engagement state based on engine speed conditions, reducing power consumption while maintaining rapid response capability.
Solution Approach 2:
Instead of continuous engagement, the system employs periodic or event-driven engagement of the pinion gear with the flywheel. The control module activates the pinion engagement only during specific start events when engine speed is below the threshold, eliminating continuous power consumption while preserving immediate response when required.
2Reliability
If dual-tandem solenoid configuration is used, then engagement control is achieved, but device complexity and manufacturing cost increase
Solution Approach 1:
The invention extracts or removes one solenoid from the dual-tandem configuration, retaining only the necessary engagement solenoid. This simplification maintains the core functionality of reliable pinion engagement while eliminating the redundant second solenoid, thereby reducing device complexity and manufacturing cost.
Solution Approach 2:
The control module integrates the solenoid control functionality directly, eliminating the need for separate dual-tandem solenoid mechanisms. The single solenoid system works in conjunction with the control module to achieve reliable engagement control, simplifying the overall system architecture while maintaining functional reliability.
3Reliability
If peak current is delivered continuously to solenoid, then pinion gear engagement is maintained, but overheating and power consumption increase
Solution Approach 1:
The control module applies peak current to the solenoid only during the brief period when pinion engagement is being achieved or maintained during active starting. When the engine starts or during idle periods, the peak current is discontinued, allowing the solenoid to cool down and significantly reducing overall power consumption and thermal stress.
Solution Approach 2:
The system dynamically changes the current parameter delivered to the solenoid based on operational requirements. Peak current is applied only when engagement is needed, otherwise lower or zero current is supplied. This parameter modulation maintains engagement reliability when required while preventing overheating and reducing power consumption during non-operational periods.
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 solution reduces power consumption and noise during engine start/stop events by maintaining the pinion gear engagement with reduced current levels, ensuring efficient engine starting while minimizing overheating and NVH issues.
Implementation Method 1
a solenoid device, where the solenoid device translates the pinion gear into meshed engagement with the flywheel of the engine and the planetary gear system of the brushless starter motor in response to a requested engine start event
Implementation Method 2
a brushless starter motor, where the solenoid device translates the pinion gear into meshed engagement with the flywheel of the engine and the planetary gear system of the brushless starter motor
Data Source
AI summary
An electric starter system is used with an engine. The starter system may include a solenoid device coupled to a pinion gear, a brushless starter motor connectable to the engine via the pinion gear during a requested engine start event, and a controller. In response to the start event, when the engine speed is less than a threshold speed, the controller delivers a control current to the solenoid device at a peak current level sufficient for translating the pinion gear into contact with the flywheel. The control current is reduced to a holding current level less than the peak current level after the pinion gear is engaged with the flywheel. Motor torque is commanded from the starter motor, through the pinion gear, and to the flywheel while maintaining the holding current level, and held for a duration sufficient for starting the engine.