Engine Crank Permission Logic for Invalid Gear Reporting
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Solution Overview
Problem
Current engine cranking systems in vehicles with electronic transmission range selection lack efficient mechanisms to permit cranking when the actual gear range is invalid or not reported correctly by the transmission control module, leading to potential engine starting issues.
Innovation Solution
A crank permission system comprising first and second permission modules and a crank module, which generate permission signals based on the engaged gear range, stored gear range, and requested gear range to determine if engine cranking is permitted, allowing cranking even when the actual gear range is invalid or not reported as park or neutral.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the engine cranking system relies solely on the actual gear range reported by the transmission control module, then the system structure remains simple, but the engine may fail to crank when the actual gear range is invalid or not reported correctly
Solution Approach 1:
The system stores the requested gear range in memory before the ignition system transitions to crank mode. This stored information is preserved even when the transmission control module fails to report the actual gear range, enabling the cranking decision to be made based on pre-stored valid data rather than relying solely on real-time reporting.
Solution Approach 2:
The patent introduces a intermediary cranking permission system that acts as a mediator between the transmission control module and the engine cranking system. When the actual gear range is invalid or not reported, this intermediary system uses the stored requested gear range to determine whether cranking should be permitted, thus resolving the contradiction between system simplicity and cranking reliability.
2Reliability
If the system uses multiple permission modules to determine cranking permission, then cranking reliability improves, but the control logic complexity increases
Solution Approach 1:
The cranking permission determination is segmented into two independent permission modules: the first permission module checks the actual gear range from the transmission control module, while the second permission module checks the stored requested gear range. This segmentation allows each module to operate independently with its own validation logic, improving overall reliability while keeping individual module complexity manageable.
Solution Approach 2:
The system implements a fallback mechanism where the second permission module provides an alternative validation path when the first permission module cannot confirm valid gear range. This partial action approach ensures that cranking permission can still be determined through the second module even when the primary validation path fails, enhancing reliability without requiring complete redundancy of the entire control system.
Data Source
AI summary
A crank permission system includes first and second permission modules and a crank module. The first permission module selectively generates a first permission signal, based on a first gear range engaged within a transmission, when an ignition system transitions to crank. The second permission module selectively generates a second permission signal, based on (i) the first gear range stored when the ignition system last transitioned to off and (ii) a second gear range of the transmission requested by a driver using a transmission range selector, when the ignition system transitions to crank. The crank module begins cranking an engine via a starter, in response to the generation of at least one of the first and second permission signals, when the ignition system of the vehicle transitions to crank.