Advanced Continuous Sensing Technology for Hydraulic Brake Fluid

The Continuous Fluid Level and Quality Indicator (CFLQI) technology is focused on increasing the sampling frequency of brake fluid reservoir volume and detecting specific brake fluid contaminants. CFLQI targets to improve diagnostics detection range and resulting degraded vehicle operation strategies by increasing sensitivity to brake fluid loss and the addition of a fluid quality feature. The theory of CFLQI is to improve future autonomous and highly automated vehicle performance, both of which will have reduced driver input and service schedules, by providing earlier fluid level and fluid health warnings. The two technologies selected to prove theory of operation were ultra-sonic sensor and capacitive sense element technology. Both technologies show initial capability to meet fluid sensing targets with system level ASIL D ASIC design. The CFLQI compliments and improves upon current technology of brake pad wear sensors, leak detection diagnostics and brake fluid level monitoring. The increased data will be used in conjunction with current technology to define if a system fluid weep or contamination exists and the rate in which degraded vehicle operating states should be enacted. The methodology for the design began with defining the necessary diagnostics capabilities and fluid level sensor output strategy during dynamic and static vehicle states. Leading to need of continuous fluid level readouts to provide earlier warnings for previously undetectably low brake fluid leak rates, and ability to use sensor hardware to perform reference checks for monitoring changes in brake fluid composition.