Predictive Engine Torque Control for Smoother Transmission Shifts
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Solution Overview
Problem
Conventional vehicle powertrain systems experience delays in communicating shift requests from the transmission control module (TCM) to the engine control module (ECM), leading to poor shift quality and performance due to CAN delays and engine actuator response times, which are challenging to address especially when the TCM and transmission are provided by a third-party supplier and internal signals are not accessible.
Innovation Solution
A predictive transmission shift request and engine torque control system that uses engine torque actuators to prepare the engine for upcoming shifts by adjusting air and spark settings based on predictive shift requests from the TCM, accounting for known time delays such as CAN latency and engine actuator delays, ensuring smooth and timely torque delivery during transmission shifts without requiring hardware changes or additional sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional engine control systems wait for actual shift requests from TCM before adjusting torque, then the control system remains simple and reliable, but shift quality deteriorates due to CAN delays and actuator response time
Solution Approach 1:
The ECM receives and processes predictive shift requests from the TCM before the actual shift occurs. By anticipating the shift event and pre-adjusting engine torque parameters, the system eliminates the delay caused by CAN communication latency and actuator response time, thereby improving shift quality without adding complex hardware
2Measurement precision
If the ECM requests additional information from the TCM to optimize shift control, then shift precision improves, but system complexity increases due to additional communication protocols
Solution Approach 1:
The solution utilizes the existing CAN communication interface between ECM and TCM, making it multi-functional by enabling both conventional torque control and predictive shift management through the same hardware channel. No additional sensors or communication protocols are required, reducing system complexity while improving shift timing accuracy
3Reliability
If engine torque actuators are adjusted in advance to create torque reserve, then shift smoothness improves, but emissions control becomes more challenging due to altered combustion characteristics
Solution Approach 1:
The system dynamically adjusts engine torque parameters (such as ignition timing and fuel injection) in response to predictive shift requests, creating a flexible control strategy that optimizes both shift smoothness and emissions performance based on real-time operating conditions rather than fixed pre-programmed values
Data Source
AI summary
Predictive transmission shift request and engine torque control techniques include transmitting, from an engine control module (ECM) to a transmission control module (TCM), engine torque information and receiving back a predictive shift request for a transmission generated based on a set of known time delays and the engine torque information, controlling, by the ECM, engine torque actuators in response to and based on the predictive torque request to prepare the engine for the transmission shift operation, receiving, from the TCM, an actual shift request indicative the TCM and the transmission beginning to execute transmission shift operation, and controlling, by the ECM, the engine torque actuators in response to and based on the actual shift request to adjust a torque output of the engine during the transmission shift operation to provide a faster and smoother transmission shift.