Is the throttle valve closed at idle?
2 Answers
At idle, the throttle valve is not completely closed, leaving a very small gap that allows a minimal amount of air to flow through into the engine for combustion, thereby maintaining idle operation. Introduction to the throttle valve: The throttle valve is a controllable valve that regulates the entry of air into the engine. After entering the intake pipe, the air mixes with gasoline to form a combustible mixture, which then ignites to generate power. It connects the air filter at the top and the engine block at the bottom, often referred to as the "throat" of the automobile engine. Classification of throttle valves: Throttle valves are categorized into traditional cable-type and electronic throttle valves. In traditional engines, the throttle valve's operating mechanism works via a cable or linkage rod, connecting the accelerator pedal at one end and the throttle linkage plate at the other. Electronic throttle valves primarily use a throttle position sensor to adjust the throttle valve's opening angle based on the engine's energy requirements, thereby regulating the intake air volume.
The throttle isn't completely closed at idle. Imagine the engine needs to breathe even at low speeds, so the throttle leaves a small gap for air intake. Older vehicles used idle speed control valves for adjustment, while modern electronic control systems directly regulate the throttle's slight opening to maintain airflow around 2.5 cubic meters per hour. Once after cleaning the throttle, my engine RPM fluctuated wildly because it was closed too tightly without sufficient gap. Electronic throttle systems automatically adjust the opening based on coolant temperature - during cold starts, the opening can reach up to 10%.
