Abstract: A vehicle engine utilizes adaptive knock retard in which non-volatile memory cells store slowly changed values based on sensed knock to retard ignition timing. Upon engine start, the values in one or more of the memory cells may be reduced in a proportional manner to provide a more advanced engine ignition timing more appropriate to engine warmup. The proportional reduction is based on the sensed engine coolant temperature at the initiation of engine operation, either by itself or through the difference between it and the stored engine coolant temperature from just before the cessation of the last period of engine operation.

Abstract: In a motor vehicle power train including a fuel injected internal combustion engine and a hydraulic automatic transmission, an improved engine fueling control strategy for maintaining proper engine RPM in the presence of an automatic transmission Park or Neutral (P/N) to Drive or Reverse (D/R) range shifting. Communication between the Engine and Transmission Control Modules enables precise anticipation of rapid engine intake manifold absolute pressure (MAP) increases associated with P/N to D/R range shifting. Additional fuel is injected immediately preceding the MAP increase in order to maintain the proper engine air/fuel ratio necessary to prevent RPM sags and engine stalls during the clutch engagement. Once the clutch engagement is complete, the additional fuel is progressively eliminated.

Abstract: A method is described for adjusting the output power delivered by an internal combustion engine to compensate for variations in engine loading induced by a variable capacity refrigerant compressor of a vehicle air conditioning system. This is accomplished by estimating the change in engine loading due to the compressor, based upon an indication of the engine intake air temperature, and then, adjusting the setting of an engine output power control mechanism, in accordance with the estimate. An estimate for the change in engine loading induced when starting or stopping the variable capacity compressor is derived from a schedule of values based upon the temperature of the engine intake air. An estimate for the change in engine loading induced by the off-idle operation of the variable capacity compressor is derived as a function of the difference between the intake air temperature and a retained previous value for the intake air temperature.

Abstract: An ignition timing system activates combustion ignition apparatus in a combustion chamber at times established at least partly in response to a knock retard value. The knock retard value is normally modified in response to a knock signal generated by a knock sensor during a knock window corresponding to a predetermined crankshaft rotational angle in which knock is to be sensed. However, if the knock signal is determined to be present at the beginning of an occurrence of the knock window, modification of the knock retard value in response to the knock signal is prevented during that occurrence of the knock window, since a knock signal already present at the beginning of the knock window is assumed to be noise.

Abstract: A throttle valve diagnostic apparatus monitors the integrity of a throttle valve position sensor in an internal combustion engine using an engine parameter indirectly related to the value position. If the absolute pressure of the air in the intake manifold associated with the throttle valve is less than a predetermined pressure for a predetermined amount of time while the position sensor indicates a valve position greater than a predetermined position, the valve position sensor is assumed to be faulty.

Abstract: A transmission controller in which the throttle position sensor signal is used to determine the throttle position so that proper shift selection may be carried out. In the event that the throttle position sensor malfunctions, a value is calculated for the throttle position based upon the manifold atmospheric pressure, then used in place of the actual value for throttle position. Such a substitution remains in effect until the throttle position sensor is properly functioning once again and the actual value for the throttle position is suitable close to the calculated value so that reversion to the actual value will occur without causing shifts that will surprise the driver who is not expecting any such shift.