Fuel Injection Control Device for Direct-Injection Engines
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Solution Overview
Problem
In direct-injection internal combustion engines, fuel injection errors occur due to overlapping fuel injection periods with fuel inflow periods, leading to inconsistencies in fuel injection quantity and pressure, which can affect combustion stability and efficiency.
Innovation Solution
A fuel injection control device that adjusts the fuel injection period based on the fuel injection quantity and pressure in the accumulator, prioritizing changes to the advance side to ensure proper mixing and reduce errors, while also considering the combustion stabilization range to minimize combustion deterioration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the fuel injection period is set based on the fuel injection quantity and pressure before injection, then the fuel injection quantity can be controlled, but the injection period may overlap with the fuel inflow period causing pressure changes and injection errors
Solution Approach 1:
The control device determines whether the set injection period overlaps with the fuel inflow period in advance, and if overlap is detected, it changes the injection period before injection occurs. This preliminary detection and adjustment prevents the harmful overlap from occurring, ensuring reliable injection quantity control.
Solution Approach 2:
The injection period is made dynamically adjustable based on the detected overlap condition. When overlap with the fuel inflow period is detected, the control device changes the injection period timing (to advance or delay side) to eliminate the overlap, making the system adaptive to varying fuel supply conditions.
2Manufacturing precision
If the injection period is changed to eliminate overlap with fuel inflow period, then injection quantity error is reduced, but the injection timing may affect combustion stability
Solution Approach 1:
The injection period timing is dynamically adjusted based on the overlap detection result. The control device changes the injection period to the advance side or delay side depending on the specific condition, optimizing both injection precision and combustion stability for each operating condition.
Solution Approach 2:
The control device changes the timing parameter of the injection period when overlap is detected. By adjusting the injection period timing (advance or delay) and potentially the injection duration, it maintains precise fuel quantity delivery while ensuring proper combustion characteristics.
Data Source
AI summary
A high-pressure pump section pumps fuel in a fuel tank into a delivery pipe. An injector injects the fuel in the delivery pipe directly into a combustion chamber of an engine. An ECU calculates fuel injection quantity based on an operation state of the engine and calculates fuel injection time based on the fuel injection quantity and pressure of the fuel in the delivery pipe. The ECU calculates fuel injection start timing based on the operation state of the engine. The ECU sets the fuel injection time and the fuel injection start timing as a base injection period. When a fuel inflow period, in which the high-pressure fuel flows into the delivery pipe with the fuel pumping by the high-pressure pump section, overlaps with the base injection period, the ECU changes the base injection period to eliminate or reduce the overlap.