Torque Request Shaping for Engine Stall Prevention
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Traditional engine control systems fail to accurately control engine torque output and respond rapidly to driver requests, leading to inefficiencies in torque management and increased fuel consumption.
Innovation Solution
A system that determines minimum propulsion torques based on torque converter clutch states, sets zero pedal torque, and calculates driver axle torque requests using accelerator pedal position and vehicle speed, shaping and converting these requests to ensure optimal torque delivery while preventing engine stall and minimizing fuel consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional engine control systems are used to control engine torque output, then the system structure is simple, but the torque control accuracy is insufficient and response to control signals is slow
Solution Approach 1:
The control system is segmented into multiple specialized modules: minimum torque module (determines minimum propulsion torque based on TCC state), zero pedal torque module (sets zero pedal torque), pedal request module (calculates pedal torque request), driver request module (determines driver axle torque request), shaping module (shapes torque request), conversion module (converts torque values), and final driver request module. Each module handles a specific aspect of torque control, enabling precise control through distributed functionality rather than a monolithic controller.
Solution Approach 2:
The minimum torque module proactively determines minimum propulsion torque values for both locked and unlocked TCC states before they are needed. The zero pedal torque module pre-sets the zero pedal torque equal to the first minimum propulsion torque. These preliminary actions ensure that when torque control is needed, the system can immediately apply pre-calculated values, improving response time without adding computational delay.
2Speed
If traditional engine control systems are used, then the system is easy to operate, but the response rate to control signals is slow
Solution Approach 1:
The control system dynamically adapts its behavior based on real-time TCC state. The minimum torque module selectively determines different minimum propulsion torque values depending on whether the TCC is locked or unlocked. The final driver request module selectively applies the appropriate minimum torque value based on current TCC state, enabling the system to respond optimally to changing operating conditions without requiring complex manual intervention.
Solution Approach 2:
The system continuously monitors the TCC state and uses this feedback to adjust torque control parameters. The minimum torque module receives TCC state information and selectively determines minimum propulsion torque values accordingly. This feedback loop ensures the system maintains optimal response characteristics across different operating modes without requiring complex operator judgment.
3Loss of energy
If minimum torque control is implemented based on TCC state, then fuel consumption is reduced through earlier deceleration fuel cutoff, but torque management complexity increases
Solution Approach 1:
The system changes the torque parameter (minimum propulsion torque) based on TCC state. When TCC is locked, a different minimum torque value is applied compared to when unlocked. This parameter adaptation enables the control system to optimize fuel consumption by allowing earlier deceleration fuel cutoff in appropriate conditions while maintaining drivability, without requiring a completely different control architecture.
Solution Approach 2:
The minimum torque module acts as an intermediary between the TCC control system and the torque management system. It receives TCC state information and translates it into appropriate minimum propulsion torque values, which are then used by the final driver request module. This intermediary layer simplifies the overall system by providing a clear interface between subsystems while enabling complex coordinated behavior.
Data Source
AI summary
A minimum torque module selectively determines a first minimum propulsion torque based on second and third minimum propulsion torques when a torque converter clutch is in unlocked and locked states, respectively. A zero pedal torque module selectively sets a zero pedal torque equal to the first minimum propulsion torque. A pedal request module determines a pedal torque request based on an accelerator pedal position, a vehicle speed, and the zero pedal torque. A driver request module determines a driver axle torque request based on the pedal torque request. A shaping module selectively shapes the driver axle torque request into a shaped driver axle torque request. A conversion module converts the first minimum propulsion torque into a minimum axle torque. A final driver request module sets a final driver axle torque request equal to a greater of the shaped driver axle torque request and the minimum axle torque.