Deceleration Fuel Cutoff Control Using Engine Speed Rate of Change
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Solution Overview
Problem
Traditional engine control systems for internal combustion engines lack precision in controlling engine output torque and fail to provide rapid responses to control signals, leading to inefficient fuel consumption during vehicle deceleration events, especially when traveling down inclines.
Innovation Solution
A system comprising a rate of change module, a period estimation module, and a deceleration fuel cutoff (DFCO) module that determines the rate of change of engine speed and estimates the period of a next DFCO event to selectively generate a DFCO signal, cutting off fuel to the engine based on this estimation rather than relying solely on a predetermined minimum engine speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If traditional engine control systems use fixed minimum engine speed thresholds for fuel cutoff, then the control system is simple to implement, but fuel consumption is inefficient during deceleration events
Solution Approach 1:
The patent applies dynamics by transitioning from static fixed thresholds to dynamic predictive timing. The system calculates the rate of change of engine speed and estimates the time to next deceleration event, allowing fuel cutoff timing to adapt dynamically to varying driving conditions. This enables optimal fuel economy while maintaining simple implementation through straightforward computational algorithms.
2Speed
If traditional engine control systems respond to control signals with standard processing speed, then the system is easy to implement, but the response time is insufficient for rapid torque control
Solution Approach 1:
The patent applies preliminary action by predicting the time to next deceleration event in advance and preparing fuel cutoff timing accordingly. The system calculates engine speed rate of change and estimates when deceleration will occur, allowing the control system to respond proactively rather than reactively. This predictive approach enables rapid response to control signals while maintaining relatively simple implementation through straightforward temporal estimation algorithms.
3Measurement precision
If the engine control system uses fixed throttle area adjustments for torque control, then the control mechanism is simple, but torque control precision is insufficient
Solution Approach 1:
The patent applies feedback by continuously monitoring engine speed and its rate of change, using this information to dynamically adjust fuel cutoff timing. The system measures actual engine behavior and compares it with predicted deceleration patterns, making real-time corrections to control decisions. This feedback mechanism enhances torque control precision while maintaining simplicity through straightforward sensor-based measurement and computational comparison.
Data Source
AI summary
A system for a vehicle includes a rate of change module, a period estimation module, a deceleration fuel cutoff (DFCO) module, and an injection control module. The rate of change module determines a rate of change of an engine speed. While an engine is being fueled, the period estimation module determines an estimated period of a next DFCO event based on the rate of change of the engine speed. The DFCO control module selectively generates a DFCO signal based on the estimated period. The injection control module cuts off fuel to the engine when the DFCO signal is generated.