Fuel Injection Control Device for Internal Combustion Engine
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Solution Overview
Problem
In internal combustion engines, a discrepancy between target and actual fuel pressures during reduced engine load can lead to inefficient fuel injection, causing air-fuel ratio deviations and combustion deterioration due to insufficient energization time for the fuel injection valve.
Innovation Solution
A fuel injection control device with an electronic control unit that adjusts the energization time of the electromagnetic fuel injection valve based on the required injection quantity and actual fuel pressure, switching between full lift and partial lift settings to maintain accurate injection quantity and prevent bounce motion-induced variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the energization time is reduced to match the decreased required injection quantity during low load, then fuel efficiency improves, but the injection quantity accuracy deteriorates due to bounce motion
Solution Approach 1:
The patent applies dynamics by making the energization time adaptive rather than fixed. The electronic control unit dynamically adjusts the energization time based on the relationship between required injection quantity and actual fuel pressure. When the required energization time falls below the full lift minimum energization time, the system switches to using the full lift minimum energization time, ensuring the valve body has sufficient time to reach full opening and stabilize, thereby preventing bounce motion while maintaining fuel efficiency under normal conditions.
2Loss of energy
If the target fuel pressure is lowered during low load to reduce injection quantity, then fuel consumption decreases, but the actual fuel pressure cannot follow the target pressure timely causing energization time to fall below minimum
Solution Approach 1:
The patent implements feedback control by continuously monitoring both the required injection quantity and the actual fuel pressure, and comparing the calculated required energization time against the full lift minimum energization time threshold. Based on this feedback, the electronic control unit switches between two energization time setting modes: using the calculated required energization time when it meets the threshold, and using the full lift minimum energization time when it falls below the threshold. This feedback mechanism ensures reliable injection timing while allowing fuel pressure and consumption to be optimized for low load conditions.
3Manufacturing precision
If the full lift minimum energization time is always used to prevent bounce motion, then injection quantity accuracy is maintained, but fuel injection efficiency decreases during low load
Solution Approach 1:
The patent applies parameter changes by switching between two different energization time parameters based on operating conditions. The system calculates the required energization time based on the required injection quantity and actual fuel pressure. When this calculated value is below the full lift minimum energization time, the system changes the parameter being used from the calculated required energization time to the full lift minimum energization time. This conditional parameter switching maintains injection accuracy when needed while allowing more efficient operation during low load conditions where the calculated energization time is sufficient.
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 solution ensures accurate fuel injection by setting the energization time to prevent injection quantity variations, thereby suppressing combustion deterioration caused by discrepancies in fuel pressures and maintaining efficient engine operation.
Implementation Method 1
an electromagnetic solenoid which is opened in response to energization
Data Source
AI summary
A control device for an engine includes an ECU. The ECU is configured to: control an actual fuel pressure supplied to a fuel injector to a target fuel pressure; calculate a required energization time required for fuel injection equivalent in amount to a required injection quantity; set a energization time for each injection based on the required energization time; execute a switching processing for switching a manner in which the energization time is set when the required energization time is shorter than a predetermined time; set the required energization time as a set value of the energization time through the switching processing when a deviation between the actual fuel pressure and the target fuel pressure is equal to or larger than a predetermined value; and set the predetermined time as the set value of the energization time when the deviation is less than the predetermined value.