Engine Starter Pinion Engagement Control
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Solution Overview
Problem
Conventional engine starting apparatuses face challenges in accurately detecting engine rotation speed at low speeds, leading to complicated calculations and increased load on the engine control unit, particularly when estimating backward rotation, which can result in excessive engagement noise and abrasion between the pinion and ring gears during restarts.
Innovation Solution
The apparatus detects engine rotation speed and crank angle position during inertial rotation, determining if the crank angle is at an intermediate point between top dead centers to prohibit starter drive within specific time periods, preventing engagement in regions of high backward rotation speed, thereby reducing noise and abrasion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the engine rotation speed is detected using a magnetic disc and electromagnetic pickup, then the rotation speed can be measured, but at low rotation speeds (50 rpm or lower) the pulse period becomes long and the rotation speed cannot be accurately detected
Solution Approach 1:
The patent introduces an intermediary calculation method to determine backward rotation speed. Instead of directly measuring low-speed rotation, the system calculates backward rotation speed by measuring forward rotation speed at intermediate points and using mathematical relationships to infer backward speed, thereby avoiding direct measurement problems at low speeds
Solution Approach 2:
The patent replaces the mechanical electromagnetic pickup detection system with an electronic calculation system. Instead of relying on physical pulse generation from the magnetic disc at low speeds, the system uses electronic computation based on detected forward rotation parameters to determine backward rotation characteristics
2Productivity
If the pinion gear is engaged with the ring gear during backward rotation, then the engine can be restarted, but excessive engagement noise and abrasion in the pinion gear and ring gear are caused
Solution Approach 1:
The patent applies preliminary action by detecting forward rotation speed at intermediate points before backward rotation occurs and using this information to predict and control the backward rotation engagement timing. This allows the system to prepare appropriate starter drive prohibition periods in advance, preventing harmful engagement before it occurs
Solution Approach 2:
The patent changes the control parameter from direct backward rotation speed measurement to forward rotation speed measurement at intermediate points. By measuring and calculating based on forward rotation parameters, the system determines appropriate prohibition periods that prevent engagement during high-speed backward rotation, thereby reducing noise and abrasion
3Object-generated harmful factors
If the starter drive is prohibited for a long period to prevent gear engagement noise and abrasion, then the harmful effects are reduced, but the feeling of sluggishness during restarts increases
Solution Approach 1:
The patent applies dynamics by making the starter drive prohibition period variable rather than fixed. The prohibition period is dynamically adjusted based on the detected forward rotation speed at intermediate points, allowing the system to optimize between preventing harmful engagement and minimizing restart delay for each specific operating condition
Data Source
AI summary
The rotation speed and the crank position of an engine in an engine stopping process are detected; then, in the case where when the detected crank position is at an intermediate point between the top dead center of any one of the cylinders and the top dead center of the cylinder following said one of the cylinders, it is determined that the engine rotation speed is within a predetermined range, drive of the starter is prohibited for a predetermined time period.