Minimum noise with Maximec
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CAV, the diesel injection equipment manufacturing division of Lucas Industries, has announced an addition to its range of in-line injector pumps.
Designed to meet the requirements of larger diesel engines, the Maximec is available in 4-, 6-, 8or 12-cylinder versions and is capable of fuelling engines with an output of up to 75kW per cylinder (100bhp).
Injection pressures, says CAV, are at 1000bar, and the Maximec is said to be suitable for current automotive type diesels which are being uprated as well as for new engine ranges for production in the 1980s.
As an integral part of the Maximec a series of new ancillaries have been developed. These include a servo-assisted governor, a boost control for turbocharged applications and a fuel feed pump.
In concept, the Maximec is based on the established principles of the Majormec which was designed for engines with outputs of 30-38kW (40-50bhp) per cylinder. To reduce exhaust emissions, CAV has increased injection rates and shortened the injection periods on the new pump.
Noise, too, has been reduced, says CAV, so that the Maximec is between 3 and 8 dBA quieter over the load and speed range than other existing pumps with comparable performance. CAV expects the noise levels achieved to be substantially below estimated levels necessary for predicted noise legislation in the 1980s.
Flexibility
To provide flexibility, three camshaft lifts are available, 10, 11 and 12mm (0.39 to 0.51in) which give a range of fuel outputs from 300cumm/stroke (11.8cuin/stroke) all the way up to 400cumm/stroke (15.80cuin/stroke). These together with a range of 12 differing cam profiles on offer, make sure, says CAV, that the Maximec can be matched to engine manufacturers requi rements. • To increase the Maximec's expected working life — CAV anticipates 400,000km (250,000 miles) between major overhauls, even under tough operating conditions — the pump has been designed with a strong pump body as well as profiled tappet rollers and a rigid cambox which allows larger camshaft bearings and tappets of increased size.
Pumping elements can be specified says CAV, with elongated ports to provide an increase in spill rates at the end of pumping, while providing a satisfactory curve of fuel delivery versus speed.