Engine Fuel Injection Correction for Reverse Air Flow
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
During a fuel cut in engines, the air-fuel ratio becomes lean due to reverse air flow from the exhaust channel into the combustion chamber, leading to reduced engine torque, drivability issues, and potential misfires, as existing technologies fail to accurately correct the fuel injection amount post-fuel cut.
Innovation Solution
The engine control device performs an increase correction on the fuel injection amount based on the reverse air amount from the exhaust channel, with a greater correction at initial fuel injection post-fuel cut, ensuring the air-fuel ratio remains stoichiometric and preventing lean or rich conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If fuel cut is performed to reduce fuel consumption, then fuel economy is improved, but air-fuel ratio becomes lean causing reduced engine torque and drivability issues
Solution Approach 1:
The control device performs preliminary action by executing a fuel increase correction before the air-fuel ratio feedback control starts after fuel cut. This preliminary correction anticipates the lean condition caused by reverse air flow and compensates in advance, preventing torque reduction and drivability issues before they occur.
Solution Approach 2:
The control device applies preliminary anti-action by counteracting the expected harmful effect (lean air-fuel ratio) before it fully manifests. The fuel increase correction is applied in advance to offset the reverse air flow effect, preventing the adverse condition rather than merely responding to it after detection.
2Reliability
If increase correction is performed on fuel injection amount after fuel cut, then air-fuel ratio is stabilized, but excessive correction causes rich air-fuel ratio condition
Solution Approach 1:
The control device applies dynamics by making the fuel increase correction amount variable based on operating conditions. The correction is dynamically adjusted according to engine load, speed, and temperature conditions, allowing optimal correction without causing excessive fuel injection under varying operating scenarios.
Solution Approach 2:
The control device changes parameters by adjusting the fuel injection amount based on multiple parameters including engine load, speed, and temperature. The fuel increase correction is calculated by changing these parameters dynamically to achieve stable air-fuel ratio without excessive fuel injection.
3Reliability
If fuel increase correction is applied at all fuel injection timings after fuel cut, then air-fuel ratio is maintained, but unnecessary correction at second time onward increases fuel consumption
Solution Approach 1:
The control device applies segmentation by dividing the fuel injection corrections into different phases: initial fuel injection receives fuel increase correction to address reverse air flow, while second time and onward fuel injections use basic fuel supply amount. This segmented approach targets correction only where needed, avoiding unnecessary fuel addition.
Solution Approach 2:
The control device applies partial action by limiting the fuel increase correction only to the initial fuel injection after fuel cut, rather than applying it continuously. This partial correction is sufficient to address the reverse air flow effect without causing excessive fuel consumption in subsequent injections.
Data Source
AI summary
A fuel supply system includes an injector, an air flow meter, and an engine controller. The engine controller includes a fuel supply amount setting unit, a fuel cut controller, a fuel supply amount correcting unit, and an injector controller. The fuel supply amount setting unit sets a fuel supply amount on the basis of an intake air amount. The fuel cut controller executes and ends a fuel cut. The fuel supply amount correcting unit increases, on the basis of a reverse air amount, the fuel supply amount after the fuel cut in at least one cylinder, with respect to a basic supply amount corresponding to the intake air amount. An amount of the increase is greater at an initial fuel supply than in fuel supply at a second time and onward. The injector controller outputs, to the injector, a signal corresponding to the increased fuel supply amount.