Dual Starter Engine Starting System Noise Reduction
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Solution Overview
Problem
The existing engine starting techniques generate excessive noise during cranking due to the prolonged operation of the starter, which is caused by the switching between the ring gear and pinion, and are unable to stop the starter early enough to reduce this noise effectively.
Innovation Solution
An engine starting system utilizing a first starter connected to the crankshaft and a second pinion enmeshing starter, controlled by a controller that determines if the engine can pass the first compression top dead center based on torque conditions, allowing the second starter to be stopped earlier and transitioning to the first starter's operation before reaching this point.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the starter operation is stopped after fuel injection is started and the first TDC is passed, then the engine can be reliably started, but the driving time of the starter cannot be shortened and the engine starting sound cannot be minimized
Solution Approach 1:
The patent applies preliminary action by determining whether the engine can pass the first TDC before actually reaching that point. The controller evaluates torque conditions (required passage torque > engine starting torque) in advance during cranking, and if the condition is met, stops the starter early before fuel injection starts and before the first TDC is reached. This prevents the ring gear and pinion from meshing unnecessarily, minimizing the engine starting sound while ensuring reliable engine start through the belt-driven starter.
2Object-affected harmful factors
If the starter operation is stopped early to reduce noise, then the engine starting sound is reduced, but the engine may not have enough time to pass the first TDC reliably
Solution Approach 1:
The patent implements feedback by continuously monitoring engine cranking state and calculating torque conditions in real-time. The controller determines whether the required passage torque exceeds the engine starting torque based on actual cranking parameters, and uses this feedback information to make the decision of when to stop the starter. This closed-loop control ensures the starter is stopped early enough to reduce noise while maintaining sufficient cranking time for reliable engine start.
Solution Approach 2:
The controller performs preliminary evaluation of the torque condition during cranking, before the engine reaches the critical first TDC point. By assessing whether the required passage torque will be sufficient before actually needing it, the system can confidently stop the starter early without compromising reliability, thus minimizing noise from gear meshing.
3Object-affected harmful factors
If a one-way clutch is used to switch between ring gear and pinion, then the starter can be stopped after fuel injection starts, but the one-way clutch reengages before the starter is stopped generating noise
Solution Approach 1:
The patent extracts the noisy gear meshing mechanism from the starting process by using a belt-driven starter that directly rotates the crankshaft without engaging the ring gear and pinion. The one-way clutch and gear meshing are completely removed from the starting path, eliminating the source of collision noise between ring gear and pinion while maintaining efficient engine starting through direct belt-driven rotation.
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 approach reduces the operational time of the second starter, minimizing the noise generated by the ring gear and pinion meshing, thereby decreasing the engine starting sound during cranking.
Implementation Method 1
The first starter is a motor generator having a function of an electric generator and a function of an electric motor
Implementation Method 2
The one-way clutch transmits torque in only one direction from the motor to the pinion, and thus blocks torque transmission from the pinion to the motor
Implementation Method 3
The solenoid device has a function of moving the pinion in the axial direction and a function of starting/stopping (turning on/off) power supply to the motor
Data Source
AI summary
A first controller includes a start control section and a passage determination section. After activating a second starter to start cranking, the start control section stops the operation of the second starter and starts the motor operation of the first starter at a predetermined timing. The passage determination section determines whether a predetermined passage conditional expression holds after cranking is started by the second starter. The start control section stops the operation of the second starter and starts the motor operation of the first starter if the passage conditional expression holds before the engine passes the first compression top dead center, regardless of whether the engine has passed the first compression top dead center.