RonJ
Banned
***Knowledge Test: The IACV***
The game and rules:
I got this idea from member EJ6Civic27, who recently created a fun thread that tested members' knowledge about Civic engines. I will do something similar here. The goal is both to have some fun and to learn something. If you don't know the answer to the tech question, please take a guess. The first person to post the correct answer is the winner. The winner is then encouraged to develop the next Civic tech question in some reasonably short period of time to keep the Knowledge Test game going. Let the game begin!
----------------------------
Background information:
The engines of earlier Civic models had a device called the fast idle thermovalve, often referred to as the FITV. The sole purpose of this valve is to bypass air from the throttle body into the intake manifold to increase the idle speed of a cold engine. The FITV is connected to two hoses that circulate coolant through the valve. This is done because cold coolant (=cold engine) opens the valve inside the FITV by contracting a wax plunger whereas, conversely, hot coolant (=hot engine) closes the valve by expanding the wax plunger.
The idle air control valve (IACV) is a second device used to control the engine idle speed through electronic signals sent from the ECU. Therefore, contrary to the FITV, the IACV does not have or need a wax thermovalve to control air bypass from the throttle body to the intake manifold.
Question:
Given that the IACV has no wax thermovalve, then why is the IACV, like the FITV, also connected to two hoses that circulate coolant through it?
The game and rules:
I got this idea from member EJ6Civic27, who recently created a fun thread that tested members' knowledge about Civic engines. I will do something similar here. The goal is both to have some fun and to learn something. If you don't know the answer to the tech question, please take a guess. The first person to post the correct answer is the winner. The winner is then encouraged to develop the next Civic tech question in some reasonably short period of time to keep the Knowledge Test game going. Let the game begin!
----------------------------
Background information:
The engines of earlier Civic models had a device called the fast idle thermovalve, often referred to as the FITV. The sole purpose of this valve is to bypass air from the throttle body into the intake manifold to increase the idle speed of a cold engine. The FITV is connected to two hoses that circulate coolant through the valve. This is done because cold coolant (=cold engine) opens the valve inside the FITV by contracting a wax plunger whereas, conversely, hot coolant (=hot engine) closes the valve by expanding the wax plunger.
The idle air control valve (IACV) is a second device used to control the engine idle speed through electronic signals sent from the ECU. Therefore, contrary to the FITV, the IACV does not have or need a wax thermovalve to control air bypass from the throttle body to the intake manifold.
Question:
Given that the IACV has no wax thermovalve, then why is the IACV, like the FITV, also connected to two hoses that circulate coolant through it?