Intake Manifold Vacuum for Engine Start-Stop Vibration Control
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Solution Overview
Problem
Start-stop operations in internal combustion engines, particularly with belt starter generators, cause high stress and potential damage to vibration damping components due to resonance vibrations during frequent starting, with existing solutions either requiring additional energy or complex designs or resulting in undesirable delays.
Innovation Solution
A start-stop method involving the closure of the throttle device during engine shutdown to maintain negative pressure in the intake manifold, which reduces compression vibrations and minimizes load on vibration-damping components, allowing for quicker engine restart with reduced speed oscillations and minimized resonance damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the engine is frequently started and stopped, then fuel efficiency is improved, but vibration damping components are subjected to high stress and potential damage
Solution Approach 1:
The patent applies preliminary action by maintaining a vacuum in the intake manifold during the standby state (before engine restart) through closing the throttle device. This pre-established vacuum condition reduces compression vibrations during the subsequent starting process, thereby protecting vibration damping components from high stress while enabling frequent start-stop cycles for fuel efficiency.
2Reliability
If additional energy is introduced to mitigate resonance vibrations, then component stress is reduced, but energy consumption increases
Solution Approach 1:
The patent converts the harmful compression vibrations into a beneficial effect by utilizing the vacuum already present in the intake manifold. The negative pressure reduces the air charge during compression, thereby reducing vibration amplitude. This approach eliminates the need for additional energy input while still protecting components from resonance damage.
3Reliability
If the throttle device is closed during starting, then compression vibrations are reduced, but the starting process may be delayed
Solution Approach 1:
The vacuum is established and maintained during the standby state before the engine restart is initiated. This preliminary preparation ensures that when the engine does restart, the vacuum condition is already in place to reduce vibrations, without causing delays in the starting process.
4Reliability
If mechanical coupling of flywheel masses is implemented, then resonance vibrations are reduced, but device complexity increases
Solution Approach 1:
The patent extracts and utilizes the vacuum condition in the intake manifold as a separate, independent mechanism for vibration reduction. This approach avoids the need for complex mechanical modifications to the dual-mass flywheel system, maintaining simpler device architecture while achieving the desired vibration mitigation effect.
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 method reduces the stress on vibration-damping components, minimizes resonance damage, and shortens the starting process by utilizing the stored negative pressure for easier engine reactivation, enhancing fuel efficiency and reducing CO2 emissions.
Implementation Method 1
maintaining a vacuum generated during the switching off process in an intake manifold section between the throttle device and a cylinder
Implementation Method 2
reduces the compression effect occurring at top dead center
Data Source
Figure 1~2
Figure 3
Figure 4~5
AI summary
The invention relates to a start-stop method (21) for an internal combustion engine (3) of a motor vehicle (1), wherein the method comprises: switching off the internal combustion engine (3); closing a throttle device (12); maintaining a vacuum present during shutdown in an intake manifold section (11) between the throttle device (12) and a cylinder (3a-c); starting the internal combustion engine (3); and operating the internal combustion engine (3) with the throttle device (12) at least partially open. The invention further relates to a control unit, an internal combustion engine (3), and a motor vehicle (1) for carrying out such a method (21).