Engine Valve Timing for Torque-Neutral Cylinder Deactivation
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Solution Overview
Problem
Existing internal combustion engines face challenges in smoothly transitioning from full operation to partial operation without torque disruptions, as deactivating cylinders leads to inefficiencies that require compensating for lost torque in the remaining active cylinders.
Innovation Solution
The method involves adjusting the intake and exhaust valve timings using different cams and a phase adjuster to increase the volumetric efficiency of active cylinders, combined with increasing intake manifold pressure, to compensate for the loss of torque during the switch to partial operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If cylinders are deactivated for partial operation to improve efficiency, then fuel efficiency increases, but torque output decreases
Solution Approach 1:
The patent changes the valve timing parameters (opening/closing times) of the remaining active cylinders when switching from full to partial operation mode. This parameter adjustment increases the volumetric efficiency of active cylinders, allowing them to compensate for the lost torque from deactivated cylinders while maintaining fuel efficiency benefits
2Power
If valve timing is adjusted to compensate for torque loss during mode switching, then torque neutrality is achieved, but valve train complexity increases
Solution Approach 1:
The patent implements dynamic valve timing adjustment where the valve train system adaptively changes valve opening and closing times based on the operating mode. This dynamic adjustment allows torque compensation during mode transitions without requiring additional mechanical components, as the system uses existing variable valve timing mechanisms
3Power
If intake manifold pressure is increased to maintain power during partial operation, then torque is maintained, but risk of knocking increases
Solution Approach 1:
The patent coordinates multiple parameter changes including intake valve closing time, exhaust valve opening time, and intake manifold pressure. By optimizing the valve timing parameters first, the system achieves torque compensation with moderate pressure increases, thereby maintaining power output while minimizing the risk of knocking compared to systems that rely solely on pressure increases
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
This approach ensures a torque-neutral transition by rapidly increasing the volumetric efficiency and intake manifold pressure, maintaining drive power and reducing the risk of knocking, thereby enhancing engine efficiency and comfort.
Implementation Method 1
adjusting the timing of the gas exchange valves by changing the cams by means of a phase adjuster
Implementation Method 2
the gas within the combustion chambers formed by these cylinders to be cyclically compressed and expanded
Implementation Method 3
thermodynamic cycles take place in them
Implementation Method 4
thermodynamic cycles are carried out in a first combustion chamber and in a second combustion chamber
Data Source
Figure 1~2
Figure 3
Figure 4~5
AI summary
The invention relates to a method for operating an internal combustion engine, which has an internal combustion motor, which forms at least two combustion chambers, which are bounded by cylinders formed in a cylinder housing and by pistons guided up and down cyclically in said cylinders and in which thermodynamic cycles can be performed during operation of the internal combustion engine, wherein then a gas exchange in the combustion chambers is controlled by means of at least one intake valve (28) and one exhaust valve in the case of each combustion chamber, which valves are actuated by means of cams, and wherein a first operating state is provided, in which the thermodynamic cycles are performed both in a first combustion chamber and in a second combustion chamber and a second operating state is provided, in which the thermodynamic cycles are performed in the first combustion chamber and the thermodynamic cycles are not performed in the second combustion chamber, is characterized in that, in order to switch from the first operating state to the second operating state, a switch is made from the use of a first intake cam to the use of a second intake cam for the actuation of the intake valve associated with the first combustion chamber. Such a method makes it possible to realize a switchover from full operation to partial operation in manner that is as torque-neutral as possible in that the torque component that ceases because of the deactivation of the cylinder or cylinders provided therefor is compensated by the one or more cylinders that continue to actively operate, at least also in that, in the event of the switchover, the delivery ratio, i.e. the ratio of the mass of fresh gas actually contained in the cylinder after the conclusion of a charge cycle to the theoretical maximum possible mass, is increased for said cylinders and, in particular, is set as high as possible.