Engine Airflow Control for Low-Speed Stability
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Solution Overview
Problem
Internal combustion engines face instability at low speed and light load due to residual burnt gases, with existing solutions either increasing costs or compromising high-speed, high-load performance.
Innovation Solution
A method involving a motorized butterfly valve in the air inlet pipe to temporarily reduce air flow during the engine cycle at low speed and light load, creating a negative pressure for better air filling and expelling burnt gases, without additional components or increased fuel consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the air inlet pipe flow regulation means temporarily reduce air flow during the engine cycle at low speed and light load, then engine stability is improved through better air filling and burnt gas expulsion, but the air flow rate is reduced during intake stroke
Solution Approach 1:
The patent applies periodic action by temporarily reducing air flow during specific phases of the engine cycle (intake and compression strokes) and then restoring normal flow during power and exhaust strokes. This periodic modulation of air flow creates negative pressure cycles that enhance air filling during intake while maintaining overall engine stability without compromising long-term productivity
Solution Approach 2:
The patent implements preliminary action by reducing air flow before the intake valve closes, creating negative pressure upstream of the intake valve. This preliminary pressure reduction enhances the suction effect and improves air filling during the subsequent intake stroke, preparing the combustion chamber for better combustion conditions before the actual intake phase completes
2Reliability
If fresh air is injected into the exhaust to maintain rich air/fuel mixture, then three-way catalytic converter operates effectively, but additional injection means and manufacturing cost are required
Solution Approach 1:
The patent applies self-service by using the existing air inlet pipe and its flow regulation means to achieve the desired air/fuel mixture management. Instead of adding separate injection systems into the exhaust, the system utilizes and optimizes the existing intake air flow control to create negative pressure and improve air filling, thereby maintaining catalytic converter effectiveness without additional injection components
Solution Approach 2:
The patent demonstrates universality by making the air inlet pipe's flow regulation means perform multiple functions: it not only regulates overall air flow to the engine but also temporarily reduces flow during specific cycles to create negative pressure for better air filling. This multi-functionality eliminates the need for dedicated exhaust injection systems while maintaining catalytic converter operation
3Stability of the object's composition
If the combustion chamber shape is adapted to encourage turbulence for better scavenging, then engine stability at low speed and light load is improved, but performance at high speed and high load is compromised
Solution Approach 1:
The patent applies dynamics by making the air flow regulation dynamic rather than static. Instead of permanently modifying the combustion chamber shape, the system dynamically adjusts air flow timing and pressure using the existing flow regulation means. This dynamic control creates negative pressure cycles that improve low-speed stability through better air filling, while maintaining the original combustion chamber geometry that supports high-speed performance
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
Improves engine stability at low speed and light load without affecting performance at other operating points, optimizing combustion and efficiency through software modifications.
Implementation Method 1
creates, upstream of the intake valve, a negative pressure which then encourages better filling with air upstream of the intake valve by creating a suction effect
Implementation Method 2
creates a suction effect when the means for regulating the flow of air in the inlet pipe return to a position that allows for a higher air flow rate
Data Source
AI summary
Disclosed is a method for controlling combustion in an internal combustion engine including, on the one hand, an air inlet pipe provided with an air flow regulator in the pipe and, on the other hand, a single cylinder associated with the regulator, and including the following steps: determining the engine speed and/or load; and when the speed is below a predetermined value and/or the engine load is below a predetermined value, the air flow regulator in the inlet pipe is operated in such a way that the air flow is temporarily reduced during the engine cycle compared with the position that the butterfly-type throttle valve occupies during the other strokes of the engine cycle, while an intake valve that lets air from the inlet pipe into the corresponding cylinder is open.