Common Rail Injection Timing Control via Plausibility Checks
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Solution Overview
Problem
Existing methods for determining the start and end of injection in internal combustion engines with common rail systems and individual accumulators suffer from inaccuracies due to interfering frequencies in the measurement signals, leading to incorrect interpretation of injection events.
Innovation Solution
A method that uses stored individual accumulator pressure values to determine an evaluation window for each injection event, allowing for the precise calculation of representative and trial injection starts and ends, which are then checked for plausibility to set accurate control variables for the engine's automatic control system, enabling adjustment for injector changes and ensuring continued operation even if the rail pressure sensor fails.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If raw individual accumulator pressure values are used to determine injection start and end, then the determination process is simple, but interfering frequencies cause incorrect interpretation and reduce accuracy
Solution Approach 1:
The patent applies preliminary action by determining an evaluation window before calculating injection parameters. The method first identifies a relevant time window based on expected injection duration and timing, then processes pressure values only within this window. This preliminary step filters out interfering frequencies that occur outside the injection event, allowing accurate determination of injection start and end points even in noisy environments.
2Device complexity
If a single determination method is used for injection events, then the control system is simple, but it cannot handle sensor failures or injector aging
Solution Approach 1:
The patent implements feedback by checking the plausibility of determined injection parameters against expected physical constraints and operational ranges. The method verifies whether the calculated injection start and end times, duration, and pressure changes are reasonable based on pre-stored injection characteristics and current operating conditions. If parameters fall outside plausible ranges, the system can detect potential sensor failures or injector aging and trigger appropriate responses, enhancing reliability without requiring complex redundant sensor systems.
Data Source
AI summary
A a method for automatically controlling an internal combustion engine, in which an individual accumulator pressure (pE) of a common rail system is detected in a measurement interval and stored; in which an evaluation window is determined for the stored individual accumulation pressure (pE), within which window an injection was brought about; in which, in a first step, both a representative injection start and a trial injection end are determined in this evaluation window as a function of the detected pressure values, and, in a second step, both a trial injection start and a representative injection end are determined in this evaluation window as a function of the detected pressure values; in which the representative injection start is checked for plausibility against the trial injection start; and in which the representative injection end is checked for plausibility against the trial injection end.