Advanced Automotive

The use of P/M parts in automobiles can only increase due to the influence of the Partnership for Next Generation Vehicle (PNGV) program. The PNGV program is a "network" between the government, the car manufacturers (USCAR: Chrysler, Ford, and GM) and Suppliers/Universities/Others with Government funding currently at greater than $100 million per year. In summary, the goal of the PNGV program is to have all of the features of today's car, with three times the fuel efficiency, affordability, manufacturability, repairability, and recyclability (greater than 80% of the vehicle to be recyclable). Clearly, this fuel efficiency must come mainly from a vehicle weight reduction, with the body and chassis potentially showing the greater weight reductions.

In Japan, a number of automotive components have been targeted by the Japanese Titanium Society for possible titanium use. In this regard, a comparison of the manufacturing costs of low-cost titanium BE parts with wrought titanium and current steel parts is shown in Fig. 12. The material developed requires little machining and is cost competitive with current steel parts.

Current steel pans (CSP}

Ti wrought Deve loped MMC

Tt wrought Developed MMC

Relative manufacturing oost per part

Raw material

Machining + surface treatment

; Powder (C): Compacting (S): Sintering (m) : Machining




Raw material

(Mj + Surface treatment

Pari B

Fig. 12 Comparison of manufacturing costs of low-cost titanium BE composite parts with conventional wrought titanium and current steel parts

Use of spray-formed and extruded parts have proven to be cost effective for use in the rotors of the high-efficiency Mazda Miller cycle automotive engine (Ref 31, 32, 33, and 34). This engine results in a reduction in fuel consumption of about 20%. Future plans are to use sprayed aluminum-silicon in the connector rods, cylinders, and air-conditioning compressor of the Mazda EUNOS 800 (XEDOS 9), featuring a V-6 Miller cycle engine (Ref 31, 32, 33, and 34).

Aluminum alloy MMCs have been introduced in various automotive engine components, and applications are steadily increasing. Examples include Toyota diesel engine pistons selectively reinforced with 5% short alumina fiber (Ref 35), where the MMC leads to a weight reduction of 5 to 10%, wear reduced by four times, and seizure stress doubled; Honda cast aluminum cylinder blocks locally reinforced with 12% short alumina fiber and 9% C (Ref 36). Particulate-reinforced aluminum alloy MMCs, containing typically 15 to 30% SiC, are poised for automotive use, with promising applications including brake discs, drums, and calipers. The new Lotus Elise sports car has aluminum MMC discs for both front and rear brakes. Disc weight is reduced by about 50% compared with the alternative cast iron, and better thermal diffusivity gives increased resistance to overheating of the friction surfaces.

0 0

Post a comment