Internal Combustion Engine Valve Timing for Torque Response
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Solution Overview
Problem
Existing internal combustion engine operation methods, such as the Miller method, often result in longer load step times and higher fuel consumption due to the need for increased intake manifold pressure, which can delay the completion of torque increase requests from drivers.
Innovation Solution
Implementing a method that switches between two operating modes: one that closes the inlet valve later during a load step and another that closes it earlier, using a variable valve drive to actuate the inlet valve device according to different control times, allowing for efficient fuel use and rapid torque response by switching to the Miller method post-load step.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the Miller method is used to operate the inlet valve device, then fuel consumption is reduced, but the load step time increases and torque response becomes slower
Solution Approach 1:
The patent applies dynamics by making the valve control strategy changeable over time. The control unit switches between the Miller method (for fuel efficiency during steady-state operation) and a non-Miller method (for rapid torque response during transient load steps). This dynamic adaptation allows the system to optimize for different operational requirements at different times, resolving the contradiction between fuel consumption and torque response speed.
2Use of energy by moving object
If the inlet valve device is closed earlier (Miller method), then fuel consumption decreases, but the time to complete load steps increases
Solution Approach 1:
The control unit performs preliminary action by detecting driver requests or anticipated load changes before they fully manifest. When a load step is anticipated, the system pre-switches from the Miller method to a non-Miller method, ensuring the inlet valve remains open longer to facilitate rapid torque buildup. This preliminary detection and proactive switching prevents time loss during actual load transitions while maintaining fuel efficiency during steady-state operation.
3Speed
If the inlet valve device is operated according to non-Miller control times during load step, then torque increases rapidly, but fuel consumption increases
Solution Approach 1:
The patent applies periodic action by implementing alternating control strategies based on operational phases. During transient phases (load steps), the system uses non-Miller control times with later valve closure to achieve rapid torque increase. During steady-state phases, it switches to Miller method with earlier valve closure for fuel efficiency. This periodic switching between control modes ensures optimal performance for each operational phase without the penalty of continuous suboptimal operation.
Data Source
AI summary
An internal combustion engine may have an intake valve device. A sudden load variation may be carried out in which a torque provided by the internal combustion engine is increased from a first value to a second value which is higher than the first value. While the sudden load variation is being carried out, the intake valve device may be operated according to an operating method different from the second operating method and is thereby closed later than in the second operating method. After the sudden load variation has been carried out, and while the internal combustion engine provides the torque having the second value after the sudden load variation has been carried out, the internal combustion engine may be switched over from the first operating method different from the second operating method to the second operating method.