Two-Stroke Engine Spark Control for Rapid Deceleration
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Solution Overview
Problem
Two-stroke engines experience slow engine deceleration when transitioning from full load to minimum load conditions, leading to poor responsiveness to user controls.
Innovation Solution
A method for controlling spark ignition internal combustion engines that involves monitoring the throttle valve opening degree and engine speed, preventing spark generation when the throttle valve is nearly closed and engine speed is above a certain threshold, allowing the engine to decelerate quickly due to inertia, and adjusting the air-fuel ratio based on throttle position and ionization current to optimize performance and emissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the throttle valve is closed to reduce engine load, then the engine speed should decrease, but the engine deceleration is slow and unresponsive
Solution Approach 1:
The control unit suspends fuel injection in advance before the throttle valve is fully closed, and suspends ignition timing even earlier based on crankshaft position sensing. This preliminary interruption of energy supply to the combustion chamber enables rapid engine deceleration when the throttle valve is closed, significantly improving responsiveness to user controls without requiring mechanical changes to the throttle system.
2Speed
If fuel injection is suspended to reduce engine speed, then engine deceleration improves, but combustion interruption timing must be precise to avoid harmful effects
Solution Approach 1:
The control unit senses the crankshaft position and rotation speed, using this feedback information to precisely determine when to suspend fuel injection and ignition timing. The system continuously monitors engine parameters and adjusts the timing of fuel and ignition suspension accordingly, ensuring reliable combustion control while achieving rapid deceleration. This feedback mechanism prevents harmful effects by maintaining precise synchronization between throttle valve position and energy supply interruption.
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 method significantly improves engine deceleration speed and responsiveness to user controls by preventing spark generation when the throttle valve is nearly closed and optimizing the air-fuel ratio for efficient engine operation and reduced pollutant emissions.
Implementation Method 1
The airflow which flows along the Venturi pipe generates a vacuum which, through the dispensing nozzle, intakes the fuel from the containment chamber and mixes it with the air flowing towards the combustion chamber
Implementation Method 2
a spark plug which is cyclically controlled to generate a spark which ignites the combustion of the air and fuel mixture
Implementation Method 3
the combustion of the air and fuel mixture, producing exhaust gases - in quick expansion - which cause the movement of the piston
Implementation Method 4
The piston is mechanically connected to a crankshaft by means of a connecting rod, so that the linear movement of the piston is transformed into a rotary movement of the crankshaft and vice versa
Data Source
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AI summary
Herein described is a method for controlling the operation of a spark ignition internal combustion engine (100), wherein the engine (100) comprises: a combustion chamber (115), an intake duct (155) suitable to place the combustion chamber (115) in communication with the external, a throttle valve (165) arranged inside the intake duct (155), a carburettor (170) suitable to introduce fuel into the intake duct (155) to form a mixture of air and fuel intended to be intaken into the combustion chamber (115), and a spark plug (235) arranged inside the combustion chamber (115) to generate a spark suitable to ignite the combustion of the air and fuel mixture; the method comprising the steps of: monitoring the opening degree (G) of the throttle valve (165), monitoring the speed (V) of the engine (100), preventing the spark plug (235) from generating the spark, if the opening degree (G) of the throttle valve (165) drops below a first opening degree threshold value (GM) and the speed (V) of the engine (100) is greater than a first engine speed threshold value (VF).