Automatic Engine Stop Control for Piston Positioning
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing automatic internal combustion engine stop devices face challenges in properly setting the piston stop position during idling stop conditions, leading to vibration and prolonged engine startup times, and current solutions like reverse crankshaft rotation or additional stoppers are inefficient or increase component load, respectively.
Innovation Solution
An automatic stop device with a load control unit, load recognition unit, and ignition timing control unit that removes or reduces engine load and retards the ignition timing to stabilize engine speed, ensuring the piston stops at a proper position without excessive time or component stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the piston stop position is set near bottom dead center of the intake stroke, then the in-cylinder volume is increased and a large quantity of air is present in the cylinder, but this causes the air to be heated by the cylinder block and leads to self-ignition and great deal of vibration during restart
Solution Approach 1:
The patent changes the piston stop position parameter from near bottom dead center to near top dead center of the intake stroke. This parameter change reduces the in-cylinder air volume, prevents excessive heating, avoids self-ignition, and eliminates vibration during engine restart, while still maintaining adequate in-cylinder volume for proper combustion.
2Reliability
If the piston stop position is set near bottom dead center of a stroke other than the intake stroke, then no fuel is supplied into the cylinder until the next intake stroke, but this prolongs the time required to start the engine
Solution Approach 1:
The patent optimizes the piston stop position parameter to near top dead center of the intake stroke. This positioning ensures fuel is supplied into the cylinder at the optimal moment during the intake stroke, enabling immediate combustion upon restart without unnecessary delays, thus reducing engine startup time while maintaining reliable fuel supply timing.
3Manufacturing precision
If reverse crankshaft rotation is used to adjust piston stop position, then the piston stop position can be optimized, but this increases the load on auxiliary mechanical components and shortens their life span
Solution Approach 1:
The patent replaces the mechanical reverse crankshaft rotation system with a control-based approach. By using the engine control unit to manage fuel injection timing and ignition based on piston position sensors, the system achieves precise piston stop position control without mechanically reversing the crankshaft, thereby avoiding additional load on mechanical components and extending their service life.
4Manufacturing precision
If a stopper is used to restrict piston stop position, then the piston stop position can be controlled, but this increases the number of components and requires additional stopper attachment steps in assembling the engine
Solution Approach 1:
The patent eliminates the mechanical stopper component by implementing an electronic control system. The engine control unit uses piston position sensors to detect crankshaft angle and controls fuel injection timing and ignition to achieve precise piston stop position control software-based, removing the need for physical stoppers and reducing assembly complexity.
5Ease of operation
If the engine is restarted by supplying fuel to a predetermined cylinder and allowing ignition plug to ignite the fuel, then the engine can be restarted from idling stop state, but improper piston stop position causes great deal of vibration and prolonged startup time
Solution Approach 1:
The patent optimizes the piston stop position parameter to near top dead center of the intake stroke before restart. This positioning ensures that when fuel is supplied and ignition occurs, the piston is at the optimal position for immediate combustion, enabling smooth engine restart without vibration or prolonged startup time, while maintaining ease of operation.
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 effectively stabilizes engine speed and sets the piston at a proper stop position, reducing vibration and startup time while avoiding component stress and additional hardware requirements.
Implementation Method 1
allowing an ignition plug to ignite the fuel
Implementation Method 2
initial combustion is caused by supplying fuel to a predetermined cylinder
Implementation Method 3
transferring the drive power thereof to the engine, namely, by performing a so-called cranking operation
Data Source
AI summary
In an automatic stop device that automatically stops the operation of an internal combustion engine after a predetermined automatic stop condition is satisfied, a load acting on the engine is removed when the automatic stop condition is satisfied. When the automatic stop condition is satisfied, the between the magnitude of the load on the internal combustion engine before and after of the automatic stop condition is satisfied is determined, and an ignition timing retard amount of an ignition plug is decided such that the retard amount is increased as the difference becomes greater. The ignition timing is retarded by the retard amount substantially at the same moment as the load removing operation before the automatic stop control is initiated.