New designs address durability issues
One of the challenges facing alternator manufacturers is that of designing a product that takes up less space under the hood, yet also meets the ever-increasing demand for higher power output.
The sloping hood that's been incorporated into more aerodynamic vehicle design for greater fuel efficiency also means less room under the hood for packaging of components, including the alternator. At the same time, vehicle electrical load requirements are increasing. As Leece-Neville points out, the average output requirement for alternators on heavy-duty trucks today is closer to 130 amps, while just five years ago the norm was 105-110 amps.
According to Denso Sales California, heavy-duty alternators of the future will feature smaller, more compact designs, provide higher output, be vibration-resistant, and be able to withstand high-temperature environments. Fleets will continue to demand products with increased longevity, and specifically longer belt life.
In response to demands for equipment that lasts longer, alternator manufacturers developed brushless units. By eliminating the brush - which ultimately wears out - they were able to add considerably to the longevity of the alternator.
Although brushless-style alternators are generally more expensive, they are also more cost-effective in the long run. Delco Remy, Denso, and Leece-Neville all produce brushless alternators for the heavy-duty market.
Leece-Neville introduced a 140-amp, 12V brushless model last fall. Based on the company's VR-Series 110-55 brushed alternator, the BLD (J180) and BLB (pad-mount) brushless units are rated at 5,000 rpm and exceed 65% of rated output at 1,800 rpm. Fleets can choose standard or SmartChek self-diagnostic regulators.
Denso Sales California also offers a series of long-life brushless alternators for heavy-duty commercial vehicles. The alternators, which have the SAE J180 mount, are available in 90-, 105-, and 130-amp models, and feature integrated circuit-type regulators.
Delco-Remy's 34-Quadramount brushless alternator for Class 8 trucks features a sturdy pad-mount design for added durability and vibration-resistance.
The trend to pad-mount reflects the industry's effort to 0design an alternator that is more durable than the more conventional hinge-mount units. With hinge-mount units, technicians have to loosen the alternator bolts in order to change the belt. If the bolts aren't put back correctly, the result is an unstable alternator. As Delco-Remy explains, with pad-mount models "that maintenance variable is engineered out" of the alternator design.
Delco Remy is introducing the Road Gang System in April. It features an alternator modification that eliminates the voltage drop between battery and alternator, and thus improves battery recharging. Remote voltage sensing enables the regulator to know when to regulate voltage, and at what level. Voltage regulators ensure that the alternator doesn't run at a speed that will ultimately cause engine damage.
The system's low-voltage disconnect (LVD) is a device that will start shutting down non-essential loads (refrigerator, computer, etc.) if the battery charge reaches a predetermined minimum level. This avoids running the battery down so low that the alternator can't recharge it. LVD works while the truck is on the road as well as when the engine is off.
Another feature involves temperature compensation. By bringing this factor into the mix, more voltage will be available to recharge batteries when it's cold, and less when it's hot, for a more efficient recharge procedure.
In brush-type alternators for medium- and heavy-duty applications, Leece-Neville points to its long-life brushes and Robert Bosch to its quick-brush change models.
C.E. Niehoff (CEN), whose market is military, transit, mining, and emergency vehicles, has designed "smart voltage regulators" for some of its alternators to protect engines from low-speed mechanical load damage. CEN anticipates the day when vehicle computers will also talk to alternators, and be able to signal voltage regulators to shut alternators down temporarily if the engine needs to provide all available horsepower. CEN currently has this capability.
