And how does it work? Essentially MDS deactivates the valve lifters in four of the V8's cylinders, resulting in four closed valves and zero combustion in half the cylinders. Fortunately the "dead" cylinders don't drag energy from the working four, due to air being pumped through those cylinders temporarily out of action.
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| MDS deactivates the valve lifters in four of the V8's cylinders, resulting in four closed valves and zero combustion in half the cylinders. (Photo: DaimlerChrysler Canada) |
Chrysler rival Cadillac dabbled in a similar technology in the early '80s with dismal results. While innovative for the era, the 4-6-8 engine delivered poor reliability due to low-tech electronics. Modern technology allows trustworthy operation of this type of system. GM will offer its DOD V8 engine in a variety of multi-brand models later this year.
But so far GM hasn't announced the availability of DOD in any of its car lines, rather focusing on optimizing truck and SUV fuel economy. Chrysler will be first to deliver its cylinder deactivation technology in cars. No doubt Chrysler Group's Dodge and Jeep trucks and SUVs that feature the HEMI V8 will offer the technology in the near future as well.
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| No doubt Chrysler Group's trucks and SUVs that feature the HEMI V8 will offer the MDS at some point in the near future. (Photo: DaimlerChrysler Canada) |
"The MDS was part of the engine's original design," commented Bob Lee, Vice President Powertrain Product Team, Chrysler Group. "This resulted in a cylinder-deactivation system that is elegantly simple and completely integrated into the engine design. The benefits are fewer parts, maximum reliability and lower cost."
Great idea, but can it be trusted? According to Chrysler Group the MDS HEMI has achieved 6.5 million customer-equivalent miles via the automaker's development and durability testing program. What's more, it's covered by the same 84-month, 115,000 km powertrain warranty as its sibling engines.
While savings of up to 20 percent are possible, Chrysler Group is projecting a 10 percent aggregate reduction. According to Chrysler, the gain in fuel economy comes at no compromise in performance.