Press Information
Tokyo, March 24, 2010 - Mitsubishi Heavy Industries, Ltd. (MHI) has completed a mass production system for lightweight, high-strength "hollow-head" engine valves employing proprietary forging technology that enables hole-forming from the valve stem to head in one process. The new forging technology was achieved based on the company's unique production knowhow in hollow valves for aircraft engines. With hollow valve heads, overall valve weight can be reduced by up to 20% compared with solid valves. The technology has also cut hollow-head valve production costs significantly. MHI expects demand for this valve type to increase going forward, and is targeting shipments of 1.5 million units in 2014, mainly for the automobile industry as a key measure to improve fuel efficiency as CO2 emission controls become increasingly tighter worldwide.
As MHI's production method performs consecutive forming of the hollow-head valve from cylindrical metal material mainly during cold-forging, a significant reduction in processing time is achieved. To realize maximum benefit from hollow valves, the company analyzed various factors - shape of the hollow, valve strength, generated stress, etc. - and studied how to form shapes that conventional machines have been unable to form.
Because hollow valves can add to cooling efficiency through improved thermal conductivity by encapsulating sodium (natrium) in the hollow, the heat resistance of exhaust valves can also be increased, enabling accommodation of the higher exhaust temperatures associated with high-efficiency engine combustion. Coupled with reduced friction loss due to weight reduction, hollow valves can boost fuel efficiency substantially, thereby contributing to reduced CO2 emissions.
MHI's Machine Tool Division has already established a production structure capable of producing 25,000 hollow-head valves per month. It has also started shipments of samples mainly to automobile manufacturers, and launched development of customized products reflecting the diversified needs of users and the results of their evaluation testing.
As a measure to combat global warming, CO2 emission controls, especially for automobiles, are becoming more stringent. In response, automobile manufacturers around the world are fiercely competing to develop more fuel-efficient cars and electric vehicles. In parallel with these initiatives, stepped-up efforts are being made to reduce auto engine weight further, lower friction loss and enhance combustion efficiency.
MHI views hollow-head valves as a differentiated product that can contribute largely to enhancement of automobile engine efficiency. Going forward the company will aggressively conduct marketing activities of the new valves by offering a lineup of metals - ranging from heat-resistant steel to nickel alloy - for not only the automobile industry but other potential users as well.
About MHI Group
Mitsubishi Heavy Industries (MHI) Group is one of the world’s leading industrial groups, spanning energy, smart infrastructure, industrial machinery, aerospace and defense. MHI Group combines cutting-edge technology with deep experience to deliver innovative, integrated solutions that help to realize a carbon neutral world, improve the quality of life and ensure a safer world. For more information, please visit www.mhi.com or follow our insights and stories on spectra.mhi.com.