Fuel Pressure Diagnostic Control for Internal Combustion Engine
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Solution Overview
Problem
Existing fuel pressure diagnostic devices are inadequate for accurately identifying errors in high-pressure fuel systems of internal combustion engines with both in-cylinder and intake manifold injectors, as they fail to account for pressure increases due to heat reception when the in-cylinder injector is inactive.
Innovation Solution
A control apparatus that includes a sensor unit to monitor fuel pressure in the high-pressure fuel system, a determination unit to assess if the pressure increase is due to heat reception, and an identification unit to determine if there is no error when the pressure rise is not caused by leakage, ensuring proper error identification in both active and inactive states of the fuel injection mechanisms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If fuel pressure is monitored in the high-pressure fuel system when the in-cylinder injector is inactive, then error detection capability is improved, but false positive errors occur due to pressure increase from heat reception
Solution Approach 1:
The patent applies dynamics by making the diagnostic timing adaptive rather than static. The control unit dynamically selects between two diagnostic approaches: monitoring fuel pressure when the in-cylinder injector is inactive (when port injector is active) or when the port injector is inactive (when in-cylinder injector is active). This dynamic switching resolves the contradiction by avoiding heat-induced pressure increases during diagnostic monitoring.
Solution Approach 2:
The patent changes the operational parameters of the fuel injection system during diagnosis. By switching between different injector configurations (in-cylinder only, port only, or both active), the system alters the thermal state of the fuel system. This parameter change allows the diagnostic system to select a state where pressure increases are due to leakage rather than heat reception, thereby improving measurement precision without false positives.
2Stability of the object's composition
If the in-cylinder injector is kept inactive for diagnostic purposes, then pressure stability is improved, but injection timing accuracy deteriorates
Solution Approach 1:
The system dynamically adjusts injector operation based on diagnostic needs. During diagnostic periods, the relevant injector is kept inactive to ensure pressure stability for accurate error detection. During normal injection periods, the injector operates with precise timing control. This dynamic switching between diagnostic mode and injection mode resolves the contradiction between pressure stability and injection timing accuracy.
Solution Approach 2:
The patent implements periodic switching between diagnostic operation and normal injection operation. The control unit periodically monitors fuel pressure under controlled conditions (with one injector inactive) and periodically performs normal fuel injection with precise timing. This periodic alternation allows both pressure stability during diagnosis and injection timing accuracy during operation to be achieved without compromising either function.
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
Enables accurate identification of errors in the fuel system by distinguishing between pressure increases due to heat reception and actual leakage, thereby preventing erroneous determinations and ensuring reliable operation of internal combustion engines with both in-cylinder and intake manifold injectors.
Implementation Method 1
determining whether pressure of the fuel has risen as a result of the fuel receiving heat from the internal combustion engine
Data Source
AI summary
An engine ECU executes a program including the steps of: when the port fuel injection ratio is 100% (YES at S200), sensing the engine coolant temperature THW (S210); when the engine coolant temperature THW is higher than a threshold value (YES at S220), monitoring fuel pressure P in a high-pressure delivery pipe (S230); and when fuel pressure P rises by the received heat (YES at S240), identifying that there is no error at the high-pressure fuel system.