Mazda's new engine vintage: semi-dry - WIP - Brief Article - Statistical Data Included

Automotive Design & Production, Sept, 2002

"We are confident that these small car engines signal a new benchmark for the class." That's Mazda's powertrain deputy manager, Shigeo Mizuno, who, in a rare example of public Japanese braggadocio, is describing his company's all-new inline four-cylinder engines. The 1.3/1.5-liter powerplants represent the second phase of Mazda's new engine series dubbed "MZR" and follow the 2.0/2.3-l offerings that debuted in the MPV and the "6." They will power a yet-to-be-named small car.

Mizuno says that the development team sought to "fully inject Mazda's brand DNA into engine performance" by achieving linear acceleration and a stronger torque response while keeping emissions down. To this end, the engines are fitted with an equal-length 600-mm intake manifold to improve intake efficiency in the low to mid-ranges, and a sequential valve timing mechanism that produces more mid-range torque and a more linear acceleration response. The original intake and exhaust layout has been reversed and equipped with a long-branched 4-1 stainless exhaust manifold to improve flow and increase power and torque.

Noise-vibration-harshness (NVH) levels have been reduced through the use of lightweight pistons and conrods with tighter clearances, and a new highly rigid cylinder block that adds more bending/torsional stiffness and better supports the crankshaft. A re-designed 10:1 compression ratio combustion chamber reduces fuel consumption. And a Tumble Swirl Control Valve in the intake manifold provides for a stable combustion process, reducing emissions.

The production of the new engines represents a milestone because, according to Mazda, it is the first time that any automaker has used semi-dry machining on a large scale in a mass production environment. The semi-dry process greatly reduces the amount of lubricant needed in machining operations by spraying a tiny, targeted amount directly at the tip of the tool, instead of bathing the entire station with fluid as in the conventional method. (Here's the actual magnitude of difference: Mazda sprays 200 l/mm. of turning lubricant at its conventional stations, the semi-dry stations use 0.1 cc/min.) Mazda is applying the process to all machining areas for the aluminum cylinder block except finishing, boring and honing of the cylinder bore. As a result, the amount of lubricant required has decreased 84% over the conventional operation. Further, the automaker has realized a 75% savings in the energy formerly needed to pump all of that lubricant, and an 80% reduction in the waste lubricant that had to be incinerated .