ECU Calibration Memory Dynamic Page Allocation
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Solution Overview
Problem
Electronic control units (ECUs) face memory constraints during calibration, as the available RAM is insufficient to allocate space for large-capacity calibration data, leading to increased costs and inconvenience, especially when external memory is not available due to processor limitations.
Innovation Solution
A calibration memory control method that dynamically allocates a working page based on external calibration requests, mapping a reference page to a working page in a M:M correspondence, and allocating only N working page regions to RAM, where N is less than M, allowing for calibration even when RAM capacity is insufficient, without requiring external memory.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the number of control factors or maps in the ECU is increased to achieve various target performances, then the calibration capability and vehicle performance optimization are improved, but the required memory size is increased beyond available memory capacity
Solution Approach 1:
The patent divides the calibration memory into multiple pages (first page and second page) within the flash memory. The microprocessor can selectively access different pages based on calibration needs, effectively expanding the available calibration memory beyond the initially visible range. This segmentation allows storing more calibration data than what could be accessed in a single memory view.
Solution Approach 2:
The patent introduces a page selection mechanism that adds a dimensional aspect to memory access. By implementing multi-page support with address translation, the system effectively transforms a single-dimensional memory space into a multi-dimensional address space, allowing the ECU to access a larger calibration memory capacity than the physical RAM size would suggest.
2Quantity of substance
If external memory is added to provide sufficient calibration memory space, then the calibration capability is improved, but the ECU cost is increased
Solution Approach 1:
The patent makes the existing flash memory serve multiple functions: it stores both the control program and the calibration data. By implementing multi-page calibration memory support within the flash memory, the system eliminates the need for separate external calibration memory, reducing component count and cost while maintaining adequate calibration capability.
Solution Approach 2:
The patent combines the calibration memory function with the existing flash memory that already stores the control program. By utilizing the flash memory's multi-page capability and address translation features, the system merges storage functions to avoid adding separate external memory components, thereby reducing ECU cost.
3Productivity
If the RAM size is increased to accommodate all calibration data, then the calibration speed and real-time performance are improved, but the ECU cost and device complexity are increased
Solution Approach 1:
The patent implements dynamic page selection where the microprocessor can switch between different calibration pages (first page and second page) based on the calibration requirements. This dynamic access mechanism allows the system to handle large calibration datasets without requiring all data to be simultaneously available in RAM, maintaining calibration speed while avoiding large RAM investment.
Data Source
AI summary
A calibration memory control method of an ECU connected to an external calibration device may include receiving a download command from the external calibration device, checking a sub reference page corresponding to the download command, determining whether a sub working page corresponding to the checked sub reference page is allocated, allocating the sub working page corresponding to the checked sub reference page to a RAM region upon determining that the sub working page is not allocated, and copying data stored in the checked sub reference page to the allocated sub working page. As such, according to the present invention, restrictive memory resources may be efficiently used for calibration.