Fuel Injection Control System for Engine Acceleration Response
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Solution Overview
Problem
In engines with twin injectors, rapid changes in air supply and engine speed can lead to insufficient fuel delivery to the combustion chamber, especially when the fuel injection ratio of the second injector increases rapidly, causing a delay in fuel reaching the combustion chamber and resulting in low engine output during acceleration.
Innovation Solution
A fuel injection control system that adjusts the fuel injection ratios of both injectors based on engine state, using a memory section with maps to set and compensate the ratios, ensuring the first injector's ratio increases when the second injector's ratio exceeds a predetermined criterion, thereby maintaining adequate fuel supply to the combustion chamber.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the fuel injection ratio of the second injector is increased rapidly in response to driver acceleration request, then the engine driving power can be increased, but the fuel injected from the second injector may reach the combustion chamber at a retarded timing causing low output response
Solution Approach 1:
The control system performs preliminary action by increasing the fuel injection ratio of the first injector (downstream injector) before the fuel from the second injector can reach the combustion chamber. This anticipatory measure ensures that adequate fuel is already present in the combustion chamber when the accelerated fuel arrives, preventing any fuel deficiency during the transition period.
Solution Approach 2:
The control system applies preliminary anti-action by counterbalancing the rapid increase in second injector fuel ratio with a corresponding increase in first injector fuel ratio. This compensatory action prevents the harmful effect of fuel timing delay by ensuring continuous adequate fuel supply to the combustion chamber throughout the acceleration transient.
2Quantity of substance
If the fuel injection ratio of the second injector is increased rapidly, then more fuel can be supplied to increase engine power, but the fuel injection ratio of the first injector decreases rapidly causing insufficient fuel supply to the combustion chamber
Solution Approach 1:
The control system changes parameters by dynamically adjusting the fuel injection ratios of both injectors based on the rate of change of air supply and engine speed. When rapid acceleration is detected, the system modifies the fuel injection ratio parameters to maintain adequate fuel supply, ensuring that the sum of fuel from both injectors meets the combustion chamber requirements throughout the transient period.
Data Source
AI summary
A fuel injection control system is provided. The fuel injection control system comprises a first injector and a second injector positioned upstream of the first injector; a memory section which contains a map for defining a correspondence between a running state of an engine and first and second fuel injection ratios; a fuel injection ratio setting section for setting the first fuel injection ratio as a first set value and the second fuel injection ratio as a second set value; and a fuel injection ratio compensation section for making compensation such that the first set value is greater than a value of the first fuel injection ratio derived from the map, when a condition in which the second fuel injection ratio read out from the map is greater in magnitude than a predetermined determination criterion is met.