Vehicle Engine Stop Control Device Using Dual Speed Thresholds

The patent segments the vehicle speed threshold into two distinct levels: a first threshold for initial coast stop permission and a second, lower threshold for subsequent stop permission. This segmentation allows the system to differentiate between initial high-speed coasting conditions and subsequent low-speed congested conditions, enabling frequent engine stops in congestion without triggering excessive stops during normal driving.

The patent implements dynamic threshold selection based on driving conditions. The system dynamically switches between the first threshold (higher) and second threshold (lower) depending on whether the vehicle is in initial coasting mode or subsequent low-speed operation mode. This dynamic adaptation allows the system to optimize fuel economy in congested conditions while maintaining driver comfort during normal driving.

The control logic is segmented into distinct modes: initial coasting mode governed by the first threshold and subsequent operation mode governed by the second threshold. This segmentation simplifies the control architecture by creating clear, manageable decision branches rather than requiring complex continuous optimization algorithms.

The system changes the threshold parameter from a single fixed value to two distinct values selected based on operating mode. This parameter change approach maintains simplicity by using basic threshold comparisons rather than complex control algorithms, while still achieving frequent engine stops for fuel economy in congested conditions.