Engine Control Unit Cylinder Deactivation Strategy
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Solution Overview
Problem
Existing control apparatuses for internal combustion engines and automatic transmissions fail to determine whether cylinder deactivation is executable based on the rotation speed conditions of the engine output shaft and automatic transmission input shaft, leading to limited fuel consumption improvement and inexecutable cylinder deactivation.
Innovation Solution
A control apparatus comprising an engine control unit and a transmission control unit that determine whether cylinder deactivation is executable by comparing the rotation speeds of the engine output shaft and automatic transmission input shaft against predetermined lower limit speeds, allowing for cylinder deactivation control by stopping some cylinders based on a cylinder deactivation control table.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If cylinder deactivation control is executed without considering input shaft rotation speed, then fuel consumption improvement is limited, but the control system complexity increases
Solution Approach 1:
The patent combines engine control and transmission control into a unified control system that jointly determines cylinder deactivation execution. The engine control unit receives input shaft rotation speed information from the transmission control unit, merging previously separate control functions to enable comprehensive decision-making for cylinder deactivation based on both engine and transmission states.
Solution Approach 2:
The engine control unit is enhanced to perform multiple functions: it not only controls engine operations but also integrates transmission state information (input shaft rotation speed) to make cylinder deactivation decisions. This multi-functional approach allows the control unit to optimize fuel consumption by considering the combined state of both engine and transmission systems.
2Measurement precision
If cylinder deactivation is determined based only on engine rotation speed, then the determination accuracy is insufficient, but the measurement requirements increase
Solution Approach 1:
The patent merges engine rotation speed detection with input shaft rotation speed detection to form a comprehensive determination basis for cylinder deactivation. By combining these two measurement parameters from different sources (engine and transmission), the system achieves more accurate determination of appropriate deactivation conditions without requiring additional complex sensors.
3Use of energy by moving object
If cylinder deactivation control is performed without considering transmission state, then fuel consumption improvement is limited, but the control complexity increases
Solution Approach 1:
The transmission control unit acts as an intermediary that provides input shaft rotation speed information to the engine control unit. This intermediary role enables the engine control system to make informed cylinder deactivation decisions by incorporating transmission state data, achieving fuel consumption improvement through coordinated control without requiring direct complex integration of all transmission components.
Data Source
AI summary
If the rotation speed of the output shaft of an engine exceeds a lower limit engine rotation speed, and the rotation speed of an input shaft exceeds a lower limit input shaft rotation speed, the control apparatus of this invention executes cylinder deactivation control of decreasing the number of operating cylinders by stopping the operations of some of a plurality of cylinders based on a cylinder deactivation upper limit engine torque set by referring to a cylinder deactivation control table corresponding to the gear range of an automatic transmission.