Starter Speed Sensor Assembly for Engine Synchronization
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Solution Overview
Problem
Conventional starters in vehicles with stop-start systems face challenges in efficiently engaging and disengaging the starter motor during frequent start-stop cycles, especially when the engine is still inertially rotating, requiring improved torque transmission and synchronization mechanisms to enhance reliability and energy efficiency.
Innovation Solution
A starter assembly with a magnetic field source, pinion gear, and internal power train that includes a gear set and speed sensor assembly to sense rotational speeds, allowing for synchronized engagement and disengagement of the pinion gear with the flywheel, enabling efficient restarts and reducing energy consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the starter motor engages the pinion gear with the flywheel during frequent start-stop cycles, then the engine can be restarted, but the wear on the gear components increases and reliability decreases
Solution Approach 1:
The speed sensor assembly detects the rotational speed of the flywheel before engagement occurs. The control unit uses this information to determine the optimal timing for pinion gear engagement, ensuring synchronization before contact is made. This preliminary detection and timing adjustment reduces mechanical shock and wear during engagement.
Solution Approach 2:
The speed sensor assembly continuously monitors the rotational speed of the flywheel and provides feedback to the control unit. The control unit adjusts the engagement timing based on this feedback, creating a closed-loop system that optimizes synchronization and reduces mechanical stress on the gear components during frequent restarts.
2Productivity
If the pinion gear engages the flywheel when the engine is inertially rotating, then restart efficiency improves, but synchronization precision must be maintained to avoid damage
Solution Approach 1:
The patent replaces purely mechanical synchronization methods with an electronic control system. The speed sensor assembly and control unit electronically monitor and adjust engagement timing based on detected rotational speed, replacing traditional mechanical linkages and springs that would require precise manufacturing tolerances with an electronic feedback-controlled system.
3Use of energy by moving object
If the starter system operates in high efficiency during cold and warm engine crank environments, then energy consumption reduces, but the complexity of the control system increases
Solution Approach 1:
The speed sensor assembly and control unit serve multiple functions: they detect rotational speed for synchronization timing, determine optimal engagement moments during both cold and warm crank conditions, and control the solenoid actuation. This multi-functionality reduces the need for separate dedicated components for each function, thereby limiting the increase in overall system complexity while achieving high energy efficiency across different operating conditions.
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 enhances the reliability and efficiency of the starter system by ensuring synchronized engagement and disengagement, reducing wear and energy consumption, and improving the driving experience in vehicles with stop-start systems.
Implementation Method 1
the speed sensor assembly is a magnetic flux sensor
Implementation Method 2
a starter motor with an armature and a magnetic field source
Data Source
AI summary
A starter assembly adapted for use with an engine having a flywheel and electronic control unit. The starter includes a motor, magnetic field source and a pinion gear engageable with the flywheel. An internal power train transmits torque from the armature to the pinion gear and includes a gear set dividing the internal power train into a first segment with the armature and a second segment with the pinion gear. During operation the first segment has a faster rotational speed than the second segment. A speed sensor senses the speed of the first segment and communicates it to the electronic control unit. The starter assembly can be used in a vehicle with an automatic start-stop function and facilitates the synchronizing of the pinion gear and flywheel speeds when restarting the engine. The speed sensor can take various forms and is advantageously supported on the field frame assembly proximate the commutator.