Powertrain Anti-Shuffle Control via Estimated Spring Displacement
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Solution Overview
Problem
Powertrain oscillations, specifically 'shuffle' oscillations, are challenging to control in vehicles with automatic transmissions, particularly at low vehicle speeds, as existing methods either increase parasitic drag or compromise fuel efficiency.
Innovation Solution
A control strategy that estimates the current displacement of a damper spring using a time series of rotational velocities and engine torque values, adjusting engine torque to oscillate between 90 degrees and 180 degrees out of phase with the spring displacement, incorporating both proportional and derivative terms to mitigate oscillations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If energy absorbing components (open torque converter) are used to prevent powertrain oscillations, then oscillation control is improved, but parasitic drag increases and fuel economy deteriorates
Solution Approach 1:
The patent replaces the mechanical energy-absorbing torque converter with an electronic control system that uses sensors to detect oscillations and actuators to apply counteracting forces. This substitution eliminates the continuous parasitic drag of the torque converter while maintaining oscillation control through active feedback control, thereby improving fuel economy while preserving stability.
Solution Approach 2:
The system dynamically changes engine torque parameters in real-time based on detected oscillation conditions. By adjusting torque delivery through the transmission based on feedback from sensors monitoring rotational speeds and accelerations, the system achieves oscillation control without the continuous energy loss associated with mechanical damping components like open torque converters.
2Object-affected harmful factors
If mechanical damping components are used to reduce oscillations, then vibration control is improved, but parasitic drag increases
Solution Approach 1:
The patent replaces passive mechanical damping components with an active electronic control system. Sensors detect oscillations and the controller commands actuators to apply counteracting forces, eliminating the continuous parasitic drag of mechanical dampers while maintaining vibration control through on-demand active compensation.
Solution Approach 2:
The system uses feedback from sensors that continuously monitor rotational speeds and accelerations to detect oscillations. The controller processes this feedback and adjusts engine torque in real-time to counteract detected vibrations, achieving vibration control without the continuous energy loss of passive mechanical damping components.
3Stability of the object's composition
If active torque modulation is used to control oscillations, then powertrain stability is improved, but control complexity increases
Solution Approach 1:
The system uses feedback from sensors that continuously monitor rotational speeds and accelerations to detect oscillations. The controller processes this feedback and adjusts engine torque in real-time to counteract detected vibrations, achieving vibration control without the continuous energy loss of passive mechanical damping components.
Solution Approach 2:
The control system uses the existing sensor infrastructure already present in modern vehicles (crankshaft position sensors, transmission speed sensors) to detect oscillations. By leveraging these existing sensors and the engine's own torque control capabilities, the system achieves powertrain stability without adding significant external components or complexity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Effectively reduces powertrain oscillations by minimizing engine torque variations, improving fuel efficiency and reducing parasitic drag without compromising driver experience.
Implementation Method 1
Some of the components in the power flow path between the engine and the wheels have some degree of torsional compliance. The components also have torsional moments of inertia.
Implementation Method 2
Some of the components in the power flow path between the engine and the wheels have some degree of torsional compliance.
Implementation Method 3
The components also have torsional moments of inertia.
Implementation Method 4
The components also have torsional moments of inertia.
Implementation Method 5
adjusting engine torque based on the estimated current displacement of the spring to reduce a spring displacement oscillation
Implementation Method 6
The controller may also calculate a rate of change of the spring and further adjusting the engine torque based on the derivative
Implementation Method 7
adjusting engine torque based on the estimated current displacement of the spring to reduce a spring displacement oscillation
Data Source
AI summary
Powertrains may include a spring damper between the engine crankshaft and transmission input shaft. In some circumstances, an oscillation known as shuffle may occur in such powertrains. Active adjustment of engine torque is substantially more effective at mitigating shuffle oscillations if the engine torque includes a p-term proportional to displacement of the damper spring in addition to a d-term proportional to the speed difference across the damper. For various reasons, the spring displacement is difficult to measure directly. An observer algorithm is utilized to calculate a current estimated spring displacement based on a crankshaft speed sensor, a transmission input speed sensor, a wheel speed sensor, and past engine torques, using a dynamic model of the powertrain.