Abstract: An adaptive method of detecting a lamp outage condition is implemented in a vehicle flasher system including a plurality of lamps. The method includes the steps of: a) initializing an adaptive flasher current variable when the vehicle flasher system is powered on; b) monitoring the vehicle flasher system to detect a driver flasher signal request; c) measuring current output from the plurality of lamps in the vehicle flasher system; d) determining whether the level of measured current is indicative of a lamp outage condition by comparing the measured current to the adaptive flasher current variable; e) setting the adaptive flasher current variable equal to the measured current if the measured current falls within a predetermined learning range, thereby compensating for resistance changes in the flasher system over time to allow lamp outage detection; and f) returning to step b).

Abstract: A circuit for sensing the loss of a signal ground in an automotive electronic system having a source of electrical power and both a signal ground and a power ground, includes a first sensor coupled to the power ground and between the signal ground and the source of electrical power for generating a first signal responsive to the voltage on the signal ground differing from the voltage on the power ground by more than a first predetermined limit. A latching semiconductor switch is coupled to the first sensor and between the signal ground and the power ground for latching the electrical coupling of the signal ground to the power ground responsive to receiving the first signal.

Abstract: The rich or lean status of an air/fuel control system is determined according to the difference between the time period that the normalized air/fuel ratio is greater than an upper limit and the time period that the normalized air/fuel ratio is less than a lower limit in equal number of successive rich and lean cycles when in closed-loop fuel operation. The degree of rich or lean of the system is proportional to the time period difference. An adaptive learning control correction factor is incremented or decremented by an adaptive amount proportional to the time period difference.

Abstract: An engine idle speed control (ISC) method includes fully opening an idle speed control valve during an engine crank mode and opening the idle speed control valve to a fixed position during a diagnostic mode. The normal idle speed control mode includes selecting an open-loop idle speed control mode or a closed-loop idle speed control mode as a function of dashpot preposition, dashpot control, Pre-RPM control, RPM control, and RPM lockout protection. In the open-loop idle speed control, the duty cycle is the sum of a base duty cycle, a dashpot action adder, an engine coolant temperature compensation adder, a time-since-engine-start compensation adder, and other duty cycle adders for additional loads, such as air-conditioner. In the closed-loop idle speed control, the duty cycle is adjusted at the proper time and with an appropriate amount to maintain the idling speed at the desired speed.

Abstract: A hybrid air charge calculation system for an internal combustion engine in which the air charge is obtained by using either the mass airflow sensor readings or the engine speed and throttle angle information. A decision logic selects either means based on the engine speed, throttle angle, and the mass airflow rate.