The BVSV/TVV is a vacuum-operated valve controlling the flow of vacuum to the distributor's vacuum advance unit. It regulates the amount of vacuum advance applied to the distributor based on engine temperature. When the engine is cold, the BVSV/TVV restricts vacuum flow to the vacuum advance unit, preventing excessive ignition advance. As the engine warms up, the BVSV/TVV gradually allows more vacuum to reach the vacuum advance unit, increasing the ignition advance to optimize engine performance.
Here's a detailed description of how the BVSV/TVV works:
1. Engine Coolant Temperature Sensor: The BVSV/TVV is controlled by the engine coolant temperature sensor. As the engine coolant temperature rises, the sensor sends a signal to the BVSV/TVV.
2. Vacuum Diaphragm: The BVSV/TVV contains a vacuum diaphragm that responds to changes in vacuum pressure. When the engine is cold, the vacuum diaphragm is relaxed, blocking the flow of vacuum to the vacuum advance unit.
3. Bimetallic Spring: Inside the BVSV/TVV, a bimetallic spring is sensitive to temperature changes. As the engine warms up, the bimetallic spring expands, exerting force on the vacuum diaphragm.
4. Vacuum Flow Regulation: When the engine warms up, the bimetallic spring's expansion gradually allows the vacuum diaphragm to move, opening a passage for vacuum flow. This allows vacuum to reach the vacuum advance unit, increasing ignition advance.
5. Engine Performance: By controlling the amount of vacuum advance applied to the distributor, the BVSV/TVV helps optimize engine performance across different temperature ranges. It ensures proper ignition timing, which affects fuel efficiency, emissions, and overall engine smoothness.
Malfunctions in the BVSV/TVV can cause issues with engine performance, such as rough idling, hesitation during acceleration, or increased fuel consumption. If you suspect a problem with the BVSV/TVV, it is advisable to have it diagnosed and replaced if necessary to restore optimal engine operation.
