Fuel Injection Control System Failure Detection
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Solution Overview
Problem
Existing fuel injection control systems for internal combustion engines equipped with low and high pressure fuel pumps struggle to accurately distinguish between failures in the fuel injection system and vapor generation in the fuel passage, leading to incorrect diagnosis and potential operational issues.
Innovation Solution
The system increases the discharge pressure of the low pressure fuel pump when a discharge failure is detected in the high pressure fuel pump, and then re-evaluates the failure, determining if the cause is a system failure or vapor generation based on the change in fuel pressure sensor measurements, allowing for precise detection and differentiation between the two conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If existing failure detection methods are used, then discharge failure in high pressure fuel pump can be detected, but it is not possible to distinguish between system failure and fuel vapor generation
Solution Approach 1:
The invention changes the operating parameter of the low pressure fuel pump (discharge pressure) to differentiate between failure types. When a discharge failure is detected in the high pressure pump, the system increases the low pressure pump's discharge pressure and re-evaluates the failure condition. This parameter change allows distinction between vapor generation (which resolves with pressure increase) and actual system failure (which persists).
Solution Approach 2:
The system performs a preliminary diagnostic action by temporarily increasing the low pressure pump discharge pressure before making a final failure determination. This preliminary action helps identify whether the initial discharge failure was caused by vapor generation or actual system failure, preventing misdiagnosis.
2Reliability
If the low pressure fuel pump discharge pressure is increased to eliminate vapor, then vapor generation can be resolved, but system failure may be misdiagnosed as vapor generation
Solution Approach 1:
The system uses feedback control by monitoring the high pressure fuel pump discharge failure condition before and after increasing the low pressure pump discharge pressure. If the discharge failure disappears after pressure increase, it feedbacks that vapor generation was the cause. If the failure persists, it feedbacks that actual system failure occurred, preventing misdiagnosis.
Solution Approach 2:
The system dynamically adjusts the low pressure fuel pump discharge pressure based on detected conditions. Rather than maintaining a fixed pressure, the pressure is temporarily increased for diagnostic purposes and then restored to normal operating levels, allowing flexible response to different failure scenarios.
Data Source
AI summary
An object of the invention is to detect, in a fuel injection control system for an internal combustion engine equipped with a low pressure fuel pump and a high pressure fuel pump, a failure in the fuel injection system including the high pressure fuel pump with high accuracy. To achieve the object, in the fuel injection control system for an internal combustion engine equipped with a low pressure fuel pump and a high pressure fuel pump according to the invention, when a discharge failure in the high pressure fuel pump is detected, the discharge pressure of the low pressure fuel pump is increased. Then, it is determined whether a discharge failure in the high pressure fuel pump occurs or not. If occurs, it is concluded that the fuel injection system including the high pressure fuel pump is in failure.