Engine Control Device for Reduced-Cylinder Torque Stabilization
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Solution Overview
Problem
Existing engine control devices face challenges in stabilizing engine torque and improving fuel consumption during the transition from all-cylinder to reduced-cylinder operation due to prolonged switching times, which are exacerbated by hydraulic phase control mechanisms that require high oil pressure and can lead to oil pressure fluctuations.
Innovation Solution
A control device that synchronizes the throttle valve opening with the oil pressure boosting of the hydraulic valve-stopping mechanism, using a hydraulic phase control mechanism to adjust the intake or exhaust valve phase and a control unit to manage the valve-stopping mechanism, thereby reducing switching time and stabilizing torque.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the hydraulic phase control mechanism is used to adjust valve phase, then fuel consumption is improved, but oil pressure fluctuations occur and switching time increases
Solution Approach 1:
The control device performs preliminary action by boosting oil pressure before the hydraulic phase control mechanism operates. This ensures sufficient oil pressure is available when the phase control mechanism needs to adjust valve timing, preventing delays caused by insufficient pressure buildup and reducing overall switching time while maintaining fuel efficiency benefits
2Speed
If the hydraulic valve-stopping mechanism operates simultaneously with phase control, then switching speed is improved, but oil pressure becomes insufficient
Solution Approach 1:
The control device implements preliminary oil pressure boosting before activating the hydraulic valve-stopping mechanism. This sequential approach ensures that sufficient oil pressure is established in advance, allowing the valve-stopping mechanism to operate at high speed without experiencing pressure insufficiency
Solution Approach 2:
The control device uses periodic action by dividing the oil pressure control into distinct phases: first boosting pressure for the phase control mechanism, then maintaining pressure while activating the valve-stopping mechanism. This staged periodic approach prevents oil pressure depletion while achieving rapid switching
3Productivity
If the hydraulic phase control mechanism operates during oil pressure boosting, then valve phase is optimized, but valve stopping is delayed
Solution Approach 1:
The control device completes the oil pressure boosting action preliminarily before initiating the hydraulic phase control mechanism. This ensures that when phase optimization begins, sufficient oil pressure is already available, preventing delays in subsequent valve stopping operations
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively reduces the switching time from all-cylinder to reduced-cylinder operation, improving fuel consumption and stabilizing engine torque by suppressing oil pressure fluctuations and optimizing valve phase changes.
Implementation Method 1
a hydraulic valve-stopping mechanism configured to hold intake valves and exhaust valves of some of the plurality of cylinders (for example, a first and a fourth cylinders of the first to the fourth cylinders) closed
Implementation Method 2
a hydraulic phase control mechanism which makes a phase of the intake valve or the exhaust valve of the engine variable
Data Source
AI summary
A control device for an engine 1 including cylinders, and configured to perform a reduced-cylinder operation by idling some of cylinders. The control device includes a hydraulic valve-stopping mechanism 14b which closes the intake and exhaust valves 41, 51 of the cylinders in response to establishment of the reduced-cylinder operation execution condition, a hydraulic variable valve timing mechanism 19 capable of changing a phase of the exhaust valve 51 of the engine 1, and an ECU 110 which controls the valve-stopping mechanism 14b and the hydraulic variable valve timing mechanism 19. In response to establishment of the reduced-cylinder operation execution condition, the ECU 110 allows the hydraulic variable valve timing mechanism 19 to execute the phase change to the exhaust valve 51, and subsequently allows the valve-stopping mechanism 14b to bring the intake and exhaust valves 41, 51 of the cylinders into closed state.