In a direct cylinder admission air starting...

In a direct cylinder admission air starting...

Question 1 of 2707066636eef28f7522a1c51fa3a

In a direct cylinder admission air starting system, once the engine begins to fire, the air starting check valve illustrated, is closed by __________. Illustration MO-0107

Question 1 of 27070

Q

In a direct cylinder admission air starting system, once the engine begins to fire, the air starting check valve illustrated, is closed by __________. Illustration MO-0107

No Illustration

This question does not have an illustration

🔍 Key Concepts

• Operation of a direct cylinder admission air starting valve during start and after firing • Function of a non-return (check) valve in a starting air line • Forces acting on the valve disc: spring force, starting air pressure, and cylinder pressure

💭 Think About

• When the engine is cranking on starting air, which direction is the force from the starting air acting on the valve, and does that tend to open or close it? • After the cylinder fires and its internal pressure rises above the starting air manifold pressure, which forces now act to push the valve back onto its seat? • Looking at the illustration, do you see any cams, bellows, or external mechanisms connected to the valve element, or is it operated purely by pressure and a spring?

✅ Before You Answer

• Confirm that a check valve in a starting air system must automatically prevent backflow of hot combustion gases into the starting air manifold. • Verify from the diagram what element is trying to keep the valve on its seat even when there is no pressure (look for the spring). • Make sure the closing force you select could exist right at the end of starting, when starting air is being removed and the cylinder has just begun firing.