Abstract:
A method for detecting and isolating an actual fault in a fuel delivery system having a fuel pump and a fuel pump motor, includes monitoring fuel pressure, pump current, and pump voltage. Each of a plurality of fault triggers are designated as one of flagged and un-flagged based on at least one of the fuel pressure, the pump current and the pump voltage. The actual fault in the fuel delivery system is isolated from a plurality of possible faults when a condition respective to one of the possible faults is satisfied based on at least one of the plurality of fault triggers designated as flagged and un-flagged.
Abstract:
A method of estimating a tire-road friction coefficient includes determining when the slope of a tire characteristic curve relating a utilized longitudinal friction of a tire to longitudinal slip of the tire is linear and non-linear. When the slope of the tire characteristic curve is linear, then the tire-road friction coefficient is estimated by correlating the slope of the tire characteristic curve to the tire-road friction coefficient. When the slope of the tire characteristic curve is non-linear, indicating that the tire is near or at saturation, then the tire-road friction coefficient is estimated by calculating a current utilized longitudinal friction of the tire.
Abstract:
A cooperative diagnostic and prognosis system for generating a prognosis of at least one component in a vehicle. An in-vehicle diagnostic unit determines a diagnostic signature of the component each time an occurrence of a condition is triggered and transmits the diagnostic signature to an off-board diagnostic unit. The off-vehicle diagnostic unit determines a SOH of the component and a rate-of-change in the SOH of the component. The off-vehicle diagnostic unit determines whether the rate-of-change in the SOH is greater than a threshold. The off-vehicle diagnostic unit requests additional information from the vehicle in response to the rate-of-change in the SOH being greater than the threshold. The additional information relating to operating parameter data associated with the component. The off-vehicle diagnostic unit receives the requested information and predicts a time-to-failure of the component.
Abstract:
A method to control a vehicle includes monitoring desired vehicle force and moment, monitoring real-time corner constraints upon vehicle dynamics which includes monitoring corner states of health for the vehicle, and monitoring corner capacities for the vehicle. The method further includes determining a desired corner force and moment distribution based upon the desired vehicle force and moment and the real-time corner constraints, and controlling the vehicle based upon the desired corner force and moment distribution.
Abstract:
A vehicle acceleration wheel slip control system monitors wheel slip and when a wheel slip condition becomes excessive as wheel slip increases during vehicle acceleration, engine torque output is initially reduced in accord with the rate of change in wheel slip. This derivative adjustment produces a significant correction to the engine torque output before the slip condition becomes very large. Thereafter, when the slip condition represents recovery from the excessive slip condition, the engine torque output is controlled in accord with the error in wheel slip from a desired value. This proportional adjustment maintains a desired slip value while maintaining stable acceleration slip control.
Abstract:
A method for determining a state of health (SOH) value for an electric power steering (EPS) system in a vehicle includes estimating a first Self-Aligning Torque (SAT) value using a tire dynamics model, which includes modeled dynamics in the linear region of a lateral force acting on the vehicle tires. The method also includes estimating a second SAT value using an extended state observer and nominal parameters for the EPS system, and calculating a variance between the first and second SAT values. The controller monitors a progression of the calculated variance over a calibrated interval using the controller to thereby determine the SOH value, and automatically executes a control action using the SOH value. An EPS system for a vehicle includes a steering wheel, torque and angle sensors, a rack and pinion assembly, a steering motor, and the controller. A vehicle is also disclosed having the same controller.
Abstract:
A controller of an active rear steering (ARS) control system includes a processor and a software module. The software module includes instructions that, when executed by the processor, cause the processor to determine rear steering angles, determine a vehicle state, determine shaping functions, and determine a rear steering command.
Abstract:
An electric motor is configured to provide mechanical power to a fuel pump. A method for monitoring the fuel pump includes estimating a pump speed and a nominal pump motor current in relation to a pump motor control signal and a fuel pressure. An armature resistance and a back-emf constant for the electric motor are determined corresponding to the estimated pump speed, a monitored pump motor current, and the pump motor control signal. A nominal armature resistance and a nominal back-emf constant for the electric motor are adjusted in relation to a pump motor temperature. A plurality of residuals are calculated based upon the adjusted nominal armature resistance, the adjusted nominal back-emf constant for the electric motor, the estimated armature resistance and the estimated back-emf constant for the electric motor. The residuals are compared with corresponding thresholds. A fault in the electric motor is detected based upon the comparisons of the residuals with the corresponding thresholds.
Abstract:
A method to control a vehicle having a plurality of wheels includes monitoring desired vehicle dynamics, determining a desired corner force and moment distribution based upon the desired vehicle dynamics and a real-time closed form dynamics optimization solution, and controlling the vehicle based upon the desired corner force and moment distribution. The real-time closed form dynamics optimization solution is based upon a minimized center of gravity force error component, a minimized control energy component, and a maximized tire force reserve component.
Abstract:
A method for allocating forces among the corners of a vehicle having a redundant actuator suite includes determining a set of desired forces at the center of gravity of the vehicle, and allocating the set of desired forces among the corners of the vehicle as virtual control commands using a controller. The method also includes mapping the virtual control commands at the corners to actual or true control commands at the corners, and controlling a plurality of actuators at the corners using the actual or true control commands. The actuators may include friction brakes and wheel motors. Mapping the virtual control commands may include using a Least Squares formulation. Control of the actuators may be prioritized with respect to each other using weighting matrices. A vehicle includes a controller having actuators and a controller configured for executing the above method.