When Ford launches its global 3-cylinder gasoline engine family for MY2011, it will bring more than just a powerplant with improved fuel efficiency and lower emissions. The program, code-named Fox, will employ a bold new machining strategy that offers significant energy cost savings and environmental benefits.
The strategy is Minimum-Quantity Lubrication (MQL) machining. Ford has proved it out at numerous transmission plants in the U.S., the U.K., and Europe in recent years. The Fox engine marks the first time MQL (also known as dry or “green” machining) is being used extensively on an all-new, high-volume engine program.
Total Fox production volume from the two initial plants, Cologne, Germany (the lead plant) and Craiova, Romania, is expected to reach approximately 700,000 engines annually. The 1.0-L engine, to be offered in 75-125-hp (56-93 kW) ratings, will be used in a wide range of Ford passenger and light-commercial vehicles.
In MQL machining, an atomized mist of high-viscosity oil delivered to the tip of the cutting tool performs the same basic function as the white flood coolant typically used in wet machining. The air/oil aerosol is created by combining oil pumped from a reservoir tank with a stream of compressed, turbulent air (3-5 bar; 44-73 psi) inside the tool, which resembles a giant fuel injector.
The dual-channel supply system allows high-precision quantities of the mist to be delivered into the cutting path.
Ford’s experience using MQL in transmission production “helped us lay the foundation to implement it on the Fox engine program,” said an engineering manager who asked not to be identified.
For the Fox triple, the MQL process is being configured to handle machining of camshaft bores, valve seats and guides, and fuel-injector bores, as well as deep-hole drilling on the crankshaft, among other tasks. Development of the process is continuing, with engineers investigating the drilling of oil galleries using MQL, as well as drilling and tapping of the block and head. The process has proved successful with tools as small as 3-mm (0.118-in) diameter.
Ford’s MQL experience to date shows total oil consumption per component to be 5-15 mL (0.17-0.51 oz), depending on the workpiece geometry and machining task being performed. The metal chips generated by the machining process are vacuum-extracted from the machining cell and shipped directly to the foundry. Ninety percent of the filtered air inside the machine is recycled.
Ford Powertrain engineers expect MQL to do for the company’s engine plants what it did for Ford transmission plants, in terms of dramatically changing the appearance and smell of the shop floor. For decades powertrain machining plants were among the nastiest industrial work environments, with slippery, odorous flood coolant omnipresent in most work spaces.
Implementing MQL on Fox engine production will pay off in much cleaner, safer work environments while saving the company millions in cylinder block and head machining, according to engineers involved with the program.
Ford currently consumes more than 5 million gal (19 million L) of the approximately 600 million gal (2.3 billion L) of flood coolant used annually by various industries worldwide. The company current spends millions annually on the liquid and its filtering, daily treatment against bacteria, waste treatment (the chips have to be cleaned and dried before being recycled), energy consumption (energy is 33% the cost of flood coolant and is expected to rise to 50%), and related health and safety issues.
Coolant-related costs equal 10-20% (approximately $2 per part) of Ford’s manufacturing costs per component. Using MQL eliminates flood-coolant tanks, chillers, and all related ductwork in the machining areas of the plant.
The Fox program is part of Ford’s long-term strategy to roll out MQL across its global machining facilities. In the U.S., Ford currently has more than 200 MQL machining centers, including four dedicated to crankshaft production. Cologne and Craiova each are equipped with 60-100 machines on their engine-machining lines, and the Dagenham, U.K., plant is also in the vanguard of MQL use.
By all metrics Ford currently leads the global auto industry in its “green” machining capacity. In 2007 its MQL development team placed first in SAE International’s Environmental Excellence in Transportation Award for Stationary Energy & Emissions & Process Innovations. Ford’s SAE technical paper on the subject of “green” machining is number 2007-01-1338.
Some German OEMs are also ramping up their MQL activities in search of the same results. Mercedes pioneered the process on aluminum suspension knuckles a decade ago, and in 2008 launched a hybrid (wet and dry) cylinder block and head machining process at the Unterturkheim plant that builds Mercedes’ world diesel. Volkswagen is installing an MQL line in Germany that will support a 2011 product launch.