Vehicle Keyless System On-Vehicle Device Power Management
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Solution Overview
Problem
In vehicle keyless systems, the on-vehicle device experiences unnecessary electrical power consumption due to processing of command signals received from other vehicles, as it performs code analysis and processing for each received signal, even if not directed to the own vehicle.
Innovation Solution
The system configures the on-vehicle device to transition to a power-saving state when the ID information in a received command signal does not match the stored ID information, avoiding processing of subsequent signals by intermittently activating the reception unit at different timings than the sub signals and reducing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the on-vehicle device processes each received command signal through code analysis, then it can identify signals directed to the own vehicle, but unnecessary power consumption occurs when processing signals from other vehicles
Solution Approach 1:
The patent applies preliminary action by comparing the ID information in the received command signal with the stored ID information before performing full code analysis. This preliminary ID comparison allows the on-vehicle device to quickly determine whether a signal is intended for its vehicle, preventing unnecessary processing of signals from other vehicles and reducing power consumption while maintaining reliable signal identification
Solution Approach 2:
The patent implements partial action by performing only the necessary ID comparison step rather than complete code analysis on every received signal. When the ID comparison shows a mismatch, the device stops processing that signal immediately, performing only the partial action needed to identify non-target signals and avoiding excessive power consumption from full processing
2Reliability
If the reception unit remains in a ready state to receive RF transmission, then it can always receive command signals, but power consumption cannot be reduced
Solution Approach 1:
The patent applies periodic action by transitioning the reception unit between active and sleep states based on signal reception patterns. The reception unit activates to receive command signals, processes them through ID comparison, and enters sleep mode when no valid signals are present. This periodic activation maintains reliable signal reception capability while significantly reducing power consumption compared to continuous operation
Data Source
AI summary
In a vehicle keyless system 1, an on-vehicle device 10 receives a command signal transmitted from a portable device 2 and controls a predetermined on-vehicle component. The portable device 2 transmits, as a main signal MS, a command signal including ID information unique to the portable device 2, and then transmits a sub signal LP subsequent to the main signal MS. The on-vehicle device 10 transitions to a sleep state when the command signal transmitted as the main signal MS is received and the ID information included in the received main signal MS does not match with ID information stored in an EEPROM 14 as ID information unique to the portable device 2 to which the on-vehicle device 10 is available.