Fuel Injection Control System Abnormality Diagnosis
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Solution Overview
Problem
The existing fuel injection systems in engines face challenges in maintaining accurate combustion states due to deviations in fuel pressure sensor readings, leading to potential misfires or engine stalls, especially during partial lift injection when an abnormality occurs in the fuel pressure sensor, as it takes time to diagnose and implement failsafe processes.
Innovation Solution
A control system that employs an electronic control unit to manage fuel injection valves and high-pressure fuel pumps, using partial and full lift injection controls, along with abnormality determination conditions to prevent partial lift injection when sensor abnormalities are suspected, ensuring accurate diagnosis and maintaining engine stability by switching to full lift or port injection modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If partial lift injection is used to achieve precise small-amount injection, then injection-amount accuracy is improved, but combustion state deteriorates when fuel pressure sensor abnormality occurs
Solution Approach 1:
The ECU performs preliminary abnormality determination on the fuel pressure sensor before executing partial lift injection. When an abnormality is detected, the system switches to full lift injection in advance, preventing combustion deterioration that would occur if partial lift injection were performed with inaccurate sensor readings.
2Measurement precision
If abnormality diagnosis of fuel pressure sensor is performed accurately, then diagnosis accuracy is improved, but time consumption increases
Solution Approach 1:
The system performs a simplified preliminary abnormality determination (second abnormality determination condition) that provides sufficient accuracy for injection mode selection without requiring the full diagnostic process. This partial determination enables timely switching to full lift injection without waiting for complete diagnosis.
3Reliability
If full lift injection is used instead of partial lift injection when abnormality is suspected, then combustion stability is improved, but injection-amount precision deteriorates
Solution Approach 1:
The system dynamically selects between partial lift injection and full lift injection based on real-time fuel pressure sensor status. When the sensor is normal, partial lift injection provides precise small-amount control. When abnormality is detected, the system transitions to full lift injection to maintain combustion stability, optimizing performance for each operating condition.
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 approach enhances the accuracy of fuel pressure sensor abnormality diagnosis and prevents combustion deterioration, reducing the likelihood of misfires or engine stalls by prohibiting partial lift injection and adjusting injection modes based on engine load and sensor feedback.
Implementation Method 1
a valve body is opened by current application to a built-in electromagnetic solenoid so as to inject a fuel
Data Source
AI summary
An abnormality flag is set when a first abnormality determination condition is established in an abnormality diagnosis of a fuel pressure sensor and it is determined that an abnormality occurs. In a case where the abnormality flag is kept cleared, when a fuel pressure detection value of the fuel pressure sensor is kept fixed for a prescribed time T2 or more and a second abnormality determination condition is established, a partial lift injection is prohibited, such that an injection control of a fuel injection valve is performed so as to perform a fuel injection without performing the partial lift injection.