EVA - emergency relief valve

It is an emergency braking assistant.

If the speed at which the brake pedal is depressed exceeds a certain threshold, the inertia-controlled valve of the so-called emergency valve (EVA) immediately "opens", allowing outside air to enter the brake booster chamber. This instantly increases the braking force until the ABS is activated.

If the driver removes his foot from the brake, the “power amplifier” is immediately canceled.