Figure 1 - The 2007 Hyundai Veracruz is equipped with electronically controlled engine mounts.	Figure 2 - Engine vacuum is used to vary the pressure of the intake air chamber in the active control engine mount on a Lexus and Toyota ACM system. (Courtesy of Toyota Motor Corporation)	Figure 3 - Signals are sent from the ECM to the VSV to control the vacuum applied to the engine mount on a Lexus and Toyota ACM system. (Courtesy of Toyota Motor Corporation)	Figure 4 - The 2006 Ford Fusion engine and transmission use three hydromounts to reduce powertrain vibration.

    With changes in vehicle technology, there are more requirements being placed on engine mount performance. Standard hard rubber, passive mounts provide firm support for the engine. However, the use of hard rubber allows engine vibrations to be easily transmitted to the chassis.
    Active engine mount systems overcome these conflicting requirements by combining an engine mount that provides good support properties with an actuator to control engine vibrations, and vibrations from road surface irregularities.
Active systems
    Vehicles that may be equipped with an active engine mount system include, but are not limited to, the 2006 Jaguar XJ, 2007 Hyundai Veracruz, 2007 Lexus RX350, and 2007 Toyota Camry.
    The 2006 Jaguar XJ equipped with a 2.7 twin-turbo diesel features electronically controlled active engine mounts, designed to cancel most of the engine vibration at idle. Because diesel engines generate higher levels of vibration than gasoline engines, electronically controlled active engine mounts are used on all 2006 XJ diesels.
    The 2007 Hyundai Veracruz has electronically controlled engine mounts on both diesel and gasoline engine models (see Figure 1). The Hyundai engine mount system consists of three passive mounts integrated with active controls, to offset vibrations.
    Some Lexus and Toyota models also use an active engine mount system. The engine mount system used on the 2007 Lexus RX350 and Toyota Camry is called the Active Control Engine Mount (ACM) system. On this system, the rear of the engine is attached to the chassis by a fluid-filled mount to control vibration and noise. The front of the engine is attached to the chassis by an electronically controlled active mount that continuously adapts to the driving conditions.
    The ACM system decreases engine vibration at idling using a vacuum-switching valve (VSV). The VSV is controlled by a pulse signal, which is transmitted to the VSV from the electronic control module. The frequency of this pulse signal is matched to the engine speed to decrease engine vibration.
Hydraulic systems
    Some vehicle models, such as the 2006 Ford Fusion, Lincoln Zephyr, and Mercury Milan are equipped with passive hydraulic engine mounts (see Figure 2). A hydraulic engine mount is commonly called a hydromount. These mounts have two chambers filled with a fluid, typically a glycol mixture. A large orifice valve and a small orifice valve connect the chambers. A hydromount produces variable damping as a result of the transfer of liquid from one chamber to another.