Automatic Transmission Control for Variable Cylinder Engines
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Solution Overview
Problem
Existing automatic transmission control devices for vehicles with variable cylinder engines face challenges in reducing fuel consumption while maintaining driving performance, especially when shifting gears on uphill roads, as they may require switching from cylinder deactivation to full-cylinder operation, leading to inefficient fuel reduction.
Innovation Solution
A control device that detects the current shift position and determines a suitable gear for shift-up based on the vehicle's traveling state, calculates the fuel consumption for each engine operation state, and permits automatic shift-up only when the calculated fuel consumption for the new gear is lower, allowing the engine to switch between full-cylinder and cylinder deactivation operations to minimize fuel consumption without degrading performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If shift-up control is performed quickly to reduce fuel consumption, then fuel consumption amount is reduced, but driving force becomes insufficient and accelerator pedal operation becomes unstable
Solution Approach 1:
The patent implements dynamic shift control that adapts to current driving conditions. The control device determines whether to permit shift-up based on real-time assessment of driving force requirements, vehicle speed, and accelerator operation. This dynamic approach allows the system to optimize fuel consumption while maintaining sufficient driving force by selectively enabling or disabling shift-up control based on current operational context.
Solution Approach 2:
The control device continuously monitors driving conditions including vehicle speed, accelerator pedal position, and engine output to determine whether shift-up control should be permitted. This feedback mechanism ensures that shift-up operations are only executed when driving force requirements are satisfied, preventing instability in accelerator operation while still achieving fuel consumption reduction when appropriate.
2Loss of energy
If shift-up control is performed to reduce fuel consumption in variable cylinder engine, then fuel consumption is reduced, but cylinder deactivation operation cannot be maintained and engine switches to full-cylinder operation
Solution Approach 1:
The control device performs preliminary assessment of driving force requirements before permitting shift-up control. By evaluating whether the vehicle can maintain sufficient driving force after shift-up, the system determines in advance whether shift-up should be permitted. This preliminary action prevents situations where shift-up would force the engine to switch from efficient cylinder deactivation mode to full-cylinder operation, thereby maintaining both fuel efficiency and operational adaptability.
3Force
If shift-down control is performed first on uphill road to secure driving force, then driving force is sufficient, but subsequent shift-up control may cause fuel consumption increase if not properly managed
Solution Approach 1:
The control device uses continuous feedback from vehicle speed sensors, accelerator position sensors, and engine parameters to monitor driving conditions after shift-down operations. This feedback enables the system to determine the appropriate timing for subsequent shift-up control, ensuring that shifts are executed only when driving force requirements are satisfied, thereby preventing unnecessary fuel consumption increases while maintaining adequate driving force on uphill roads.
Data Source
AI summary
For each engine operation state to which a variable cylinder engine can be switched, a fuel consumption amount to be consumed to generate a driving force required to maintain a current traveling state of a vehicle for each of a current gear and a new gear after a possible shift-up is calculated. An automatic shift control of shifting up to the new gear is performed in a condition that a calculated fuel consumption amount of the new gear after the possible shift-up is smaller than a calculated fuel consumption amount of the current gear. In this way, the fuel consumption amount can be optimally reduced and the shift control can be performed without degrading the traveling performance, even in the vehicle equipped with the variable cylinder engine.