Porsche Active Motor Mounts
Over the years, motor mounts have evolved from when they were just an item to mount the engine to the frame or unibody.
Diagnosing Active Motor Mounts On Asian Vehicles
Many automakers, including Toyota and Honda, have changed their lineup of engines to improve fuel economy and emissions. Gone are the high-revving 1.8L and 2.0L four-cylinder engines. Replacing them are engines with displacements ranging from 2.3L to 2.5L. These engines are more efficient and produce more power lower in the power band. But, these new engines increase the stroke and not the bore, making for some unique vibration conditions the motor mounts have to minimize.
Diagnosing And Servicing Active Motor Mounts
Engine vibration is usually most noticeable when the engine is idling, especially if the engine has an odd fire configuration as some V6 engines do. Four cylinder engines, as well as diesels, can also produce a lot of vibration at idle. Vibrations can be amplified even more when high-load belt-driven accessories, such as the A/C compressor, are engaged while the engine is idling.
Diagnosing And Servicing Active Motor Mounts
For many years, auto makers relied on solid rubber motor mounts to support the engine. The natural flexibility in rubber allows the mounts to absorb vibration. However, if the rubber is too compliant, the engine may experience excessive motion under load that could stress and crack exhaust pipes and connections. And with such tight clearances under the hood, there’s a risk of something rubbing against something else and causing additional noise or problems. So the rubber in the mounts has to be relatively stiff to limit compliance so the engine does not rock excessively when it is under load.
Tech Feature: Active Motor and Trans Mounts
Motor mounts serve an important function: They support the weight of the engine and transaxle (or transmission), and also isolate engine vibration from the rest of the chassis. With so much emphasis on controlling noise, vibration and harshness in late model luxury vehicles, it was inevitable that sooner or later motor mounts would go electronic.
New Motor Mount Technology
Engine speed is the primary input that determines the stiffness of the mount.
VIDEO: Honda’s ACM Active Motor Mount System
Jason Stahl discusses active motor mounts, specifically Honda’s ACM system, and how it communicates with the BCM. Sponsored by Intermotor.
Motor Mount Logic
Engines have noticeably changed in the past decade. Fewer cylinders, more power at lower RPM and more detectable vibration at idle are just a few of the differences in today’s engines. With these changes, it should be no surprise that engine and transmission mounts have taken on new importance. New technologies are being used that access information from the engine to anticipate vibration before it reaches the driver.
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