Hybrid Engine Torque Control via Intake Cam Timing
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Solution Overview
Problem
In hybrid vehicles, frequent switching between EV and HEV modes results in insufficient engine torque during transitions, leading to temporary non-constant transmission input torque and vehicle impacts due to the delayed activation of the intake cam, which affects system efficiency and driver demand.
Innovation Solution
A method to control engine torque by determining the point of intake cam activation based on engine oil pressure, limiting demand torque before activation, and maximizing it after activation to maintain constant transmission input torque and system efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the engine is frequently turned on and off during mode switching, then fuel efficiency is improved, but transmission input torque becomes non-constant causing vehicle impacts
Solution Approach 1:
The intake cam is activated in advance based on predicted engine operating conditions before the engine actually needs high torque. By monitoring parameters such as engine speed, load, and oil pressure, the system proactively adjusts valve timing to ensure the engine can quickly generate required torque when mode switching occurs, preventing transmission torque fluctuations and vehicle impacts while maintaining frequent engine shutdowns for fuel efficiency.
2Stability of the object's composition
If high engine torque is requested during mode switching, then transmission input torque is maintained constant, but system efficiency decreases due to operating outside optimal range
Solution Approach 1:
The intake cam activation timing is dynamically adjusted based on real-time engine operating conditions including engine speed, load, and oil pressure. The system continuously monitors these parameters and adapts the valve timing strategy to match current demands, allowing the engine to operate efficiently under normal conditions while quickly transitioning to high-torque mode when needed for mode switching, thus balancing transmission torque stability with overall system efficiency.
3Power
If the intake cam is activated early, then engine torque is sufficient during mode switching, but oil pressure may be insufficient causing cam activation failure
Solution Approach 1:
The system implements continuous feedback monitoring of engine oil pressure, temperature, and flow conditions to determine the optimal moment for intake cam activation. By reading oil pressure sensor data and engine operating parameters in real-time, the control system ensures the cam is activated only when sufficient oil pressure is guaranteed, preventing activation failure while still enabling timely torque delivery for mode switching operations.
Data Source
AI summary
The present invention provides a method for controlling engine torque in a hybrid vehicle, in which a point of time when an intake cam is activated is determined such that an engine demand torque is controlled to a level at which system efficiency is maximized within a limited engine output range before activation of the intake cam and the engine demand torque is controlled to a level at which the system efficiency is maximized after activation of the intake cam.