Crankshaft Torque Control Using Multiple Actuators
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Automatic transmissions face challenges in achieving shorter shift times and a greater range of torque authority during upshifts, as existing methods relying on spark retardation can negatively impact fuel economy and are limited in torque reduction capabilities.
Innovation Solution
A method utilizing multiple torque actuators, including spark, air, and fuel torque actuators, to control crankshaft torque modification during transmission shifts, allowing for more precise and efficient torque management by determining appropriate actuator types and timing based on shift metrics and events.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If spark retard is used for torque reduction during a shift, then torque control is fast and finely tuned, but fuel economy deteriorates due to wasted combustion energy
Solution Approach 1:
The torque reduction function is segmented across multiple actuators: spark retard provides fast initial torque reduction, while airflow actuators (throttle, turbo/supercharger) provide sustained torque management. This segmentation allows each actuator to operate in its optimal performance range, with spark handling rapid response and airflow handling energy-efficient sustained control.
Solution Approach 2:
The system dynamically selects and combines different torque actuators based on real-time operating conditions, shift phase, and torque requirements. The controller transitions between spark-only mode, airflow-only mode, and combined mode to optimize both response speed and fuel economy under varying conditions.
2Device complexity
If only spark retard is used for torque reduction, then the system is simple, but the range of torque authority is limited
Solution Approach 1:
The control system integrates multiple torque actuators (spark, airflow/throttle, turbo/supercharger) that can individually or collectively provide torque reduction. This multi-functional approach enables the system to achieve a broader range of torque authority while maintaining adaptability to different operating conditions and shift scenarios.
3Adaptability or versatility
If airflow torque actuator is used, then greater torque modification is achieved, but response time increases due to inherent delay
Solution Approach 1:
The controller anticipates the need for torque reduction and begins modulating airflow actuators in advance of the actual shift event. By pre-positioning the airflow actuators, the system reduces the effective response delay and ensures torque control is already in progress when the shift begins.
Solution Approach 2:
The system merges the fast-acting spark actuator with the high-capacity airflow actuators, using spark for immediate torque reduction and airflow for sustained and greater overall torque modification. This combination compensates for the airflow actuator's slower response by overlapping its action with the faster spark actuator.
Data Source
AI summary
A method of controlling engine crankshaft torque on a vehicle requests crankshaft torque modification using multiple types of torque actuators prior to and during a single commanded shift, such as an upshift. Appropriate levels of torque modification for the request, as well as appropriate times to make determinations regarding actuator type and make crankshaft torque reduction requests are determined in light of timing of key events during the shift.