Engine Air Metering for Vibration Control and Fast Restart
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Solution Overview
Problem
In vehicles with start/stop technology, there is a conflict between achieving fast engine restart and comfortable engine shutdown, as fast restart requires high air in the cylinders while comfortable shutdown requires minimal air, leading to engine vibrations.
Innovation Solution
An air metering device adjusts air supply to the internal combustion engine by reducing it during shutdown and increasing it before restart, using a rotational speed threshold to prevent unwanted vibrations and ensure a quick restart, with fuel injection before the intake stroke to create an ignitable mixture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the air supply to the internal combustion engine is reduced during shutdown to minimize vibrations, then the engine run-down becomes comfortable with low vibrations, but the engine restart becomes slower due to insufficient air charge in the cylinders
Solution Approach 1:
The air metering device dynamically adjusts the air supply quantity based on the engine's operational state. During shutdown, it reduces air supply to minimize vibrations, and during restart, it increases air supply to ensure rapid engine starting. This dynamic adjustment resolves the contradiction between comfortable shutdown and fast restart.
Solution Approach 2:
The control device preliminarily increases the air supply quantity shortly before the engine comes to a standstill, ensuring that the cylinders are adequately charged with air before restart is needed. This preliminary action prepares the engine for rapid restart while maintaining low vibrations during the actual shutdown period.
2Speed
If the air supply is increased early during shutdown to ensure fast restart, then the engine can restart quickly, but the engine experiences noticeable vibrations and shaking during run-down
Solution Approach 1:
The system dynamically controls the air metering device to adjust air supply based on real-time engine conditions. It maintains low air supply during shutdown to prevent vibrations, then rapidly increases air supply when restart is detected, resolving the contradiction between fast restart and vibration reduction.
Solution Approach 2:
The control device monitors engine operational state and provides feedback to adjust the air supply quantity accordingly. When engine shutdown is detected, it reduces air supply to minimize vibrations; when restart is detected, it increases air supply to enable fast restart, thus resolving the contradiction through feedback-based dynamic control.
3Object-affected harmful factors
If the throttle valve is closed during engine run-down to suppress vibrations, then outlet roughness is reduced, but the air filling in the cylinders is reduced which conflicts with fast restart requirements
Solution Approach 1:
The air metering device dynamically adjusts the air supply quantity based on engine operational state. During shutdown, it reduces air supply to minimize vibrations and outlet roughness, then rapidly increases air supply when restart is detected, ensuring adequate air charging for fast restart.
Solution Approach 2:
The control device preliminarily increases the air supply quantity shortly before the engine comes to a standstill, ensuring that the cylinders are adequately charged with air before restart is needed. This preliminary action resolves the contradiction between reducing outlet roughness during shutdown and maintaining sufficient air filling for fast restart.
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 minimizes engine vibrations during shutdown and enables fast restarting by ensuring an adequate air-fuel mixture, balancing the need for low air during shutdown with high air for quick restarts.
Implementation Method 1
the increased air filling acts as a gas spring, which exerts a strong restoring torque on the inlet cylinder ZYL2 of a crankshaft
Implementation Method 2
with fuel injection before the intake stroke to create an ignitable mixture
Implementation Method 3
the amount of air supplied to the internal combustion engine is first reduced when the internal combustion engine is running down
Data Source
Figure 1
Figure 2a~2c
Figure 3
AI summary
The invention relates to a method for stopping an internal combustion engine, wherein an amount of air which is supplied via an air metering device of the internal combustion engine, in particular a throttle flap (100), is reduced after a stopping order has been detected. According to the invention, the amount of air which is supplied via the air metering device of the internal combustion engine is again increased when the detected speed (n) of the internal combustion engine falls below a predefinable speed threshold value (ns), wherein an intake cylinder (ZYL2) to which the amount of air is supplied does not enter any working cycle after the amount of supplied air has been increased.