Injection Timing Determination Without Camshaft Sensors
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Solution Overview
Problem
In four-stroke combustion engines, determining the correct timing of the injection cycle relative to the operating cycle is challenging without using expensive angular position sensors on the camshaft, leading to potential phase shifts and disagreeable engine operations for vehicle occupants.
Innovation Solution
A method that adjusts two engine operating parameters - injection period and ignition advance - to compensate for changes, ensuring smooth engine operation if timing is correct, and allowing for detection of out-of-synchronism timing by monitoring engine torque, thereby reducing passenger discomfort.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an angular position sensor is installed on the camshaft to determine correct injection timing, then timing precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent extracts the timing determination function from the camshaft sensor system and relocates it to the crankshaft sensor system. By using the crankshaft's angular position signals combined with cylinder identification logic, the system determines injection timing without requiring camshaft sensors, thus reducing device complexity while maintaining precision.
Solution Approach 2:
The patent introduces an intermediary calculation layer that processes crankshaft angular position signals and cylinder identification data to derive the correct injection timing. This intermediary logic layer translates simple crankshaft sensor data into accurate timing information, eliminating the need for direct camshaft sensing.
2Difficulty of detecting and measuring
If engine operating parameters are changed to determine timing correctness, then timing detection capability is improved, but engine operation smoothness deteriorates
Solution Approach 1:
The patent performs preliminary timing determination during engine operation by monitoring torque variations, but only implements permanent timing changes after correct timing is confirmed. This preliminary detection phase allows timing accuracy to be verified without permanently disrupting engine operation, maintaining smoothness during the detection process.
Solution Approach 2:
The patent uses torque feedback from the engine to determine timing correctness. By monitoring torque variations in response to parameter changes, the system receives feedback about timing accuracy and adjusts accordingly, allowing detection without requiring disruptive manual intervention or permanent parameter changes.
Data Source
AI summary
The invention concerns a method for determining the timing of an injection cycle relative to an operating cycle of a four-stroke engine (ECH, ADM, COMP, DET), the timing being possibly correct or wrong, the method including the step of operating the engine while modifying a first operating parameter of the engine adapted to bring about on the engine operating effects which are different depending on whether the timing is correct or wrong; it consists in simultaneously modifying a second operating parameter of the engine adapted to bring about on the engine operating mode effects which compensate the effects modifying the first operating parameter of the engine when the timing is correct, and which do not compensate the efforts modifying the first operating parameter of the engine when the timing is wrong.