Abstract: A method of minimizing torque disturbances in an internal combustion engine for a vehicle having a lean NOx trap that is periodically purged. The method includes the steps of generating feedforward values of first engine characteristics as a function of desired engine torque and generating feedback values of second engine characteristics as a function of intake manifold pressure. Target values are then calculated for predetermined engine variables based on the first and second engine characteristics. Engine variables are then set to the target values to compensate for torque disturbances resulting from the lean NOx trap purge cycle. According to the disclosed method, the feedforward path schedules the throttle, fuel rate and spark timing based on an engine model to produce a demanded engine torque. The feedback path then uses the values of fuel rate and spark timing to compensate for torque variations.

Abstract: A method of controlling intake manifold pressure during startup of a direct injection engine permits a decrease in instantaneous cylinder pressure by reducing intake manifold pressure thereby increasing the time available for fuel injection during the compression stroke, which allows sufficient fuel to be injected at the lower fuel pressures present during starting of this engine.

Abstract: A tire diagnostic system and method for detecting an inflation condition of a pneumatic tire on an automotive vehicle includes a method for estimating the inevitable pressure loss of the tire. The method creates the estimate based on a combination of a time since the tire was last set to a nominal value and an operating condition of the vehicle. For example, the estimate can be based on a combination of time and distance traveled since the tire was last set to a nominal value.

Abstract: A system and method that monitors four wheel sensors of an automotive vehicle to determine changes in the effective rolling radii of any wheel and a low pressure tire condition. Certain vehicle operating conditions, such as excessive or very low speeds, driven wheel torque, braking, and turns, are determined from the sensor outputs and are used to prevent erroneous detection of changes in effective rolling radius. Data from the sensors that is determined to be acceptable is accumulated over time as displacement values for each wheel. When the displacement values exceed a predetermined value, a metric function is used to compare differences detected in accumulated displacement values for the front pair of wheels and for the rear pair of wheels. If the difference between compared pairs of wheels is excessive, as compared with a predetermined baseline metric value, a low tire condition is detected.

Abstract: A sensing method and system for generating an output signal indicative of an estimated mean value of an input signal is provided. A sensor samples the input signal for N (N=2, 4, 8, 16, . . . ) input signal samples and determines a current twice mean value of the N input signal samples. The current twice mean value is equal to one-half of the summation of two terms, the first being twice the mean value of the first N/2 input signal samples (called the previous twice mean value) and the second being twice the mean value of the last N/2 input signal samples. The sensor then compares the current twice mean value to a previous twice mean value.

Abstract: A tire diagnostic system for detecting an inflation condition of a pneumatic tire on an automotive vehicle includes a sensor cooperating with each wheel to sense a distance related parameter of each wheel and a global positioning receiver for receiving position signals from a global positioning system. A distance related parameter of the vehicle based on the position signals received from the global positioning receiver is calculated so that a desired distance related parameter of a wheel having a predetermined inflated pneumatic tire may be calculated. The system then compares each sensed distance related parameter of each wheel with the desired distance related parameter to determine whether each tire is properly inflated.

Abstract: A system and method that monitors four wheel sensors of an automotive vehicle to determined changes in the effective rolling radii of any wheel and a low pressure tire condition. Certain vehicle operating conditions, such as excessive or very low speeds, braking, and turns, are determined from the sensor outputs and are used to prevent erroneous detection of changes in effective rolling radii. Data from the sensors that is determined to be acceptable is accumulated over time as displacement values for each wheel. When the displacement values exceed a predetermined value, a metric function is used to compare differences detected in accumulated displacement values for the front pair of wheels and for the rear pair of wheels. If the difference between compared pairs of wheels is excessive, as compared with a predetermined baseline metric value, a low tire condition is detected.