Truck alternators have had to work harder, not only to keep up with increasing electrical loads in today's trucks and tractors, but also to meet the demands of lower-emissions engines that have created a hotter environment under the hood. Alternator manufacturers are now speculating what 2010 emissions regulations will hold in store for them.

Tim Barnes, aftermarket product manager, Delco Remy, says to face the challenges ahead, “early studies indicate up to 20 to 30 more amps output may be required over today's production alternator. The Delco Remy 28SI and 40SI models [rolled out by Delco over the last year] are prepared to meet those requirements with an industry-best durability and performance rating.”

The Delco Remy 28SI and 40SI high output series alternators, rated at 125 deg. C., are designed to beat the heat and exceed any application's electrical load requirements, says Barnes. In addition, they are high-efficiency designs, meaning they can do their job with a minimal amount of electrical loss during operation. The 28SI 180- and 200-amp models, as well as 40SI 240-, 275- and 300-amp models, feature Delco Remy's Remote Sense technology, which improves battery charge time by 50%.

Since the alternators require less horsepower to operate, they offer fleets better fuel economy. “The fuel savings are measurable and significant. Based on real-time operating data collected for a typical linehaul tractor, operating a high-efficiency alternator can exceed $700 per 500,000 mi. per truck. The fuel savings for a fleet operating numerous trucks can be unbelievable and help with improving the bottom line,” says Barnes.

Eric Karr, national account manager with Mitsubishi Electric Automotive America (MEAA), notes: “Our alternators currently in the field have experienced a warranty failure rate of less than 1%, so MEAA's strategy is to continue with the same core technologies and philosophies as we look towards the upcoming EPA 2010 emissions requirements. Those strategies include one-piece molded regulator and rectifier assemblies, low maintenance brushless designs, dual rectifiers, increased fuel economy and reduced heat generation through optimized electromagnetic design and tight control over manufacturing tolerances and quality.”

MEAA is developing a heavy-duty alternator to exceed 2010 requirements for the heavy-duty market. The main change, the company says, is increased output requirements based on the need for a urea heater in engines operating in colder temperatures with SCR systems.

According to Bosch's Fred Padgett, group product manager, starting & charging products, the Bosch Long Haul alternator (AL9960LH) for heavy-duty vehicles is specifically built to withstand hotter running engines. It also provides greater electrical power and efficiency on the road or at idle, he notes. “This is the ideal alternator for the higher temperatures experienced by today's hard-working heavy trucks. It is, in fact, designed to keep generating electrical power even when temps climb to as high as 257 deg. F [125 deg. C].”

The Bosch Long Haul alternator produces 160 amps operating output and 80 amps at idle. The higher charge rate at idle, Padgett explains, prolongs battery life by reducing deep cycling. He says that also incorporated into the design of the Long Haul are dual internal cooling fans and Bosch's Self Protection Regulator technology, which automatically reduces output when under-hood temperatures reach 257 deg. F. and returns to normal output when temperatures drop again.

According to Padgett, the Long Haul alternator can save fleets as much as $400 in fuel over 100,000 mi. on the road. “This powerful alternator, which operates at more than 70% efficiency, transforms energy into power rather than performance-robbing heat, saving fleets fuel every mile. In fact, it may well pay for itself in the first year it's installed, and as fuel costs continue to soar, this could be an increasingly important factor,” he explains.

Recent product releases from Leece-Neville Heavy Duty Systems Div. of Prestolite Electric include a 270-amp alternator featuring a regulator design that allows for multiple alternators to be installed on a single application. The design allows it to share the dynamic load of the vehicle for 1,040 total system amps. The only thing required to create this load-sharing capability is the installation of a single transmit/receive wire between the alternators.