Fuel Injection Control Device with Upper Guard Value
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Solution Overview
Problem
Existing injection control devices face challenges in accurately correcting the energization time for fuel injection valves, leading to potential overcorrection and abnormal control, especially during overlapping injection intervals in multi-cylinder engines.
Innovation Solution
The proposed injection control device employs a microcontroller and control IC with a booster circuit and drive circuit configuration, which calculates and sets an upper limit guard value for energization time correction, using a booster circuit to manage boost voltage and current, and a drive circuit to control the solenoid coil, ensuring precise energization time adjustments while preventing overcorrection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If energization time correction is applied to improve injection precision, then manufacturing precision is improved, but overcorrection occurs leading to control instability
Solution Approach 1:
The control device applies preliminary anti-action by detecting the actual energization time and comparing it with the instructed energization time before making corrections. The correction amount is calculated based on the time difference, and an upper limit value is set to prevent overcorrection. This preliminary detection and limitation mechanism prevents control instability while maintaining injection precision.
Solution Approach 2:
The invention implements feedback by continuously monitoring the actual energization time of the fuel injection valve and using this information to adjust subsequent energization instructions. The control device calculates the difference between actual and instructed energization times, applies correction amounts within predetermined limits, and repeats this process to maintain precise control without causing overcorrection or instability.
2Measurement precision
If energization time correction is increased to improve injection accuracy, then measurement precision is improved, but abnormal control occurs during overlapping injections
Solution Approach 1:
The control device detects overlapping injection conditions in advance and applies preliminary anti-action by setting appropriate upper limit values for correction amounts during these conditions. This prevents the correction from causing abnormal control while still maintaining measurement precision for energization time.
Solution Approach 2:
The invention applies dynamics by making the upper limit value for correction amounts variable based on injection conditions. During overlapping injections, different upper limit values are applied compared to non-overlapping conditions. This dynamic adjustment allows precise measurement and correction while preventing abnormal control specific to overlapping injection scenarios.
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 enables accurate and efficient correction of energization times, preventing overcorrection and abnormal control, thereby ensuring proper fuel injection and maintaining engine performance without compromising fuel efficiency.
Implementation Method 1
a solenoid-type fuel injection valve (2) which is opened and closed by energizing a solenoid coil (2a)
Data Source
AI summary
When injecting fuel from a fuel injection valve by energizing thereof, an energization time correction amount calculator performs an area correction of an electric current flowing in the fuel injection valve, and calculates an energization time correction amount. An injection instruction state determiner determines an inter-cylinder injection instruction interval among cylinders which inject fuel in series or determines an injection instruction overlapping state. An upper guard value setter sets an upper guard value of the energization time correction amount based on the inter-cylinder injection instruction state determined by the injection instruction state determiner.