Saturn Corporation

Rimas S Milunas

Larry T Nitz

William J Bolander

Susan L Rees

James Kevin Mainquist

Nader Motamedi

Matthew Alan Schroeder

Charles A Gray

Internal combustion engine ignition timing is adjusted in response to a sensed knock condition and in response to a determination of engine knock propensity through application of fuzzy logic, wherein an inference engine comprised of a predetermined knowledge rulebase generates a set of truths in response to application of a set of input signals from a set of membership functions. The set of truths are combined according to both relative and absolute strength in indicating engine knock propensity.

Knock control using fuzzy logic

Timing of delivery of a determined fuel injection quantity is adapted for engine operating conditions including current conditions and likely future conditions under which the fueling requirement may vary significantly from fueling event to fueling event. Parameters are sensed indicating the actual engine operating condition and indicating any current or potential transients, and a fuel injection timing value referenced as a function of the parameters to account not only for the current engine condition, but for likely future conditions.

Fuel injection timing control

Automotive internal combustion engine air/fuel ratio control accuracy improvement is provided through correction of engine cylinder volumetric efficiency to account for variation in engine intake air temperature away from volumetric efficiency calibration intake air temperature, and to account for heating of the intake air passing through engine intake air passages prior to entry to the engine cylinders. Change in air density and change in airflow dynamics occurring in engine intake air passages are accounted for in the volumetric efficiency correction so that engine control commands more accurately account for actual engine cylinder intake air mass.

Internal combustion engine control

Internal combustion engine cylinder volumetric efficiency is corrected for deviations in cylinder combustion temperature away from volumetric efficiency calibration combustion temperature to account for engine cylinder intake air and fuel dynamics under conditions deviating away from calibration conditions. The significance of the combustion temperature deviation on cylinder intake air and fuel heating is evaluated in accord with engine intake mass airflow information. The corrected volumetric efficiency is applied for improved cylinder intake air mass determination and for precise cylinder air/fuel ratio control.

A motor vehicle has a manual transmission and means for indicating to the operator a point in operation for upshifting to the next higher gear from the present gear. A method of determining the shift point is provided based upon actual operating parameters of the motor vehicle effecting current wheel torque and predicted wheel torque in the next higher gear. Calibration to a single value representing the ratio of predicted wheel torque to current wheel torque allows simple balancing between fuel economy and performance.

Upshift indicator for manual transmission

A traction control approach provides for smooth and precise control of engine output torque to reduce slip of the driven wheels during acceleration thereof through an integrated control of engine ignition timing and engine fueling in automotive vehicles regardless of the type of transmission used in the vehicle. In the presence of a slip condition at the vehicle driven wheels, ignition timing is adjusted to attempt to alleviate the condition. If limits on ignition timing authority, established for catalytic converter overtemperature protection, are being approached or exceeded, a single fuel injector is disabled, ignition timing is advanced to buffer the significant fuel-based torque loss, and the timing authority is increased. Further injectors may be sequentially disabled in this manner if ignition timing again approaches or runs out of authority. Recovery from a compensated slip condition is provided through sequential enabling of any disabled injectors, with appropriate reduction in ignition authority and retarding of ignition timing following each re-enabled injector. Accommodation is made for the effects of any transmission shifting that may occur.

Integrated traction control system

A shift pattern control for a multiple speed ratio transmission wherein an inference-based control overrides the normal shift pattern to automatically achieve manual pulldown operation under conditions for which such operation would be advised and expected. The inference-based control is achieved with a fuzzy logic technique by which vehicle parameters influencing the desirability of manual pulldown operation are measured or estimated, and used to establish an aggregate measure of the overall need for engine braking and downshifting. In the preferred embodiment, the fuzzy logic parameters include vehicle speed, grade load, engine throttle position, time of braking and time of deceleration. The parameters are applied to membership functions to indicate the truthfulness of the specified conditions, and logical combinations of the truth indications are formed, weighted to reflect their criticality, and combined to form an aggregate measure of the overall need for pulldown operation.

Inference-based manual pulldown control of an automatic transmission

A traction control system provides coordinated use of axle torque management via engine spark, engine fuel, and transmission gear ratio. Primary torque management is provided by retarding the ignition timing to reduce engine torque. When the spark retard reaches a determined limit value, the vehicle automatic transmission is upshifted which reduces axle torque and engine speed, thus reducing the amount of spark retard required to control a slip condition, thereby increasing the authority of the spark retard system. The limit spark retard threshold is established as a function of the temperature of the catalytic converter so as to prevent an overtemperature condition. Further, fuel control is ultimately used if control of ignition timing is incapable of bringing the acceleration slip under control. This condition may exist, for example, when the spark system authority of control is insufficient due to limitations placed upon its authority in response to a sensed hot catalytic converter condition.

A power shutdown sequence provides for an orderly power shutdown for master and slave processors sharing a single power supply while at the same time allowing the master and slave processors to retain all the information learned regardless of failures. If the master senses a shutdown condition, it sends the slaves a power down signal confirming its intention to power down the system and commanding the slaves to initiate shutdown procedures, including the storing of variables to memory. In addition, the master also initiates shutdown procedures, and after a minimum time determined sufficient to allow the slave to complete their shutdown procedures, the master powers down the system. The slaves may also initiate their own powerdown procedures if a failure in the communications link with the master is sensed.

Multiple microprocessor single power supply system shutdown

A transmission shift control having both multiple shift pressure moding and adaptive pressure schedule adjustment. A predetermined pressure schedule is used to develop an open-loop pressure command for the post-fill phase of the on-coming clutch in each upshift. Regardless which shift mode is selected, the controller measures the duration of the shift and compares the measured duration to an expected duration which will occur if the shift progresses as desired. The deviation, if any, is used to develop an adaptive correction amount, which is applied to shift mode dependent tables. In the base (Normal) mode, the pressure is determined in accordance with the pressure command from the predetermined pressure schedule, adjusted by an adaptive correction amount from a Normal mode correction table. In the Performance mode, the pressure command from the predetermined schedule is adjusted by adaptive correction amounts from both the Normal mode correction table and a Performance mode correction table. The Performance mode correction table is initialized at a minimum value which maintains at least a minimum pressure differentiation between the Normal and Performance modes so that a switch from the Normal mode to the Performance mode will always result in a firmer, sportier shift feel.

Multiple mode adaptive pressure control for an automatic transmission

An improved powertrain control which recognizes the occurrence of engine speed flare during low torque upshifting, and effectively converts the shift to a power-off upshift via an override of the normal engine torque management controls. The engine spark timing is retarded by a predetermined amount during every power-on upshift for the reasons described above. However, when the occurrence of engine flare is detected, the control increases the spark retard to a maximum valve, substantially eliminating the transmission input torque. As the on-coming element smoothly applies and decelerates the input, the flare condition terminates, and the spark timing is returned to the predetermined amount for completion of the shift.

Engine torque management for engine speed flare suppression for

An open-loop clutch-to-clutch shift control system wherein the overlap between off-going and on-coming clutches in an upshift is regulated in accordance with a confidence term determined through a self-estimation by the control system of its ability to accurately determine the on-coming clutch fill time, and thus, its ability to effect a precise exchange of the off-going and on-coming clutches with little or no overlap. Under certain conditions, the confidence level is assumed to be low, and the clutches are controlled to result in a relatively high level of overlap. As the level of confidence improves, the timing of the clutch exchange is adjusted to reduce the level of overlap. When the level of confidence is high, the exchange of clutches is effected with almost no overlap.

Open-loop clutch-to-clutch upshift control having clutch overlap

An adaptive pressure control for an automotive transmission in which the fluid pressure developed by an electro-hydraulic actuator is directed to a plurality of fluid operated torque establishing devices, wherein adaptive pressure corrections occasioned by actuator variability do not impair shift quality in operating regions known to be substantially free of actuator variability. Separate adaptive correction amounts are provided for each torque establishing device, and the amounts are compared to determine the portion, if any, occasioned by actuator variability. Such portion is utilized as a correction to an open-loop scheduled pressure to a degree which depends on the magnitude of the scheduled pressure.

Adaptive shift pressure characterization of an electronically controlled

An adaptive transmission pressure control based on a measured interval of speed ratio progression includes a closed-loop control which compensates for factors that tend to extend the speed ratio progression. The control detects the rate of speed ratio progression during a first portion of the inertia phase of the shift, and employs closed-loop pressure control to maintain the detected rate of progression through completion of the shift. This ensures that the measured progression interval will accurately reflect the relationship between the scheduled pressure and the resulting shift ratio progression, regardless of factors which would otherwise influence the measured shift progression interval. Consequently, the correlation between shift quality and the measured shift progression interval is preserved.

Adaptive transmission shift pressure control with closed-loop

An improved method of scheduling ratio shifting in a vehicle transmission adaptively adjusts the normal shift schedule to avoid shift-related overheating of the torque transmitting devices of the transmission. In normal operation, transmission shifting is scheduled by comparing measured vehicle speed and engine throttle position values with predefined load data. In the background, the transmission controller determines the cumulative thermal energy stored in the torque transmitting devices. If excessive energy is indicated, the normal shift schedule is modified to allow extended operation in the lower speed ratios. When the cumulative energy indication returns to a normal level, normal shift scheduling is resumed.

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Royal Oak, MI, United States of America

Rimas S Milunas