As electrical power requirements in medium and heavy-duty trucks continue to grow, manufacturers of alternators are responding with a range of high-output, high-efficiency units that are designed to increase component performance and life while improving fuel economy.

Robert Bosch Corp. puts long life and reliability at the top of the list of demands currently driving truck alternator design, along with higher power output. The 100-amp alternators of a few years ago, the company says, are no longer sufficient to run all the devices in today's vehicles, such as the a/c compressor, heated seats, power windows and doors, sophisticated stereo systems and even satellite equipment. At the same time, new emissions regulations for diesel engines and fuel economy concerns are also driving change in component design.

Bosch is currently developing a long-life alternator called the LI-L that will be offered in 14- and 28-volt models, with a 42-volt version scheduled for production at a later date. With output ranges from 140 to 200 amps, the LI-L will increase power by up to 40%; lower horsepower requirements will give it an efficiency rating of up to 76%, for reduced fuel consumption and lower emission levels.

Leece-Neville/Prestolite concurs that higher output alternators, especially at low idle, are a continuing trend in alternator design due to the extensive range of comfort features fleets are spec'ing in their cabs and sleepers. The manufacturer recently introduced a 160-amp brushless alternator. While previous brushless models sacrificed low-end performance for reduced maintenance, Leece-Neville has overcome this problem with the 160-amp alternator, which provides over 100 amps at idle.

Leece-Neville also offers alternators with standard size brushes and newer, longer-length brushes that provide extended life. A new directional high-flow fan is designed to pull more air through the alternator to keep the component cooler at higher engine temperatures.

The way alternators are mounted in the engine compartment is also changing for the future. Some engine manufacturers — Detroit Diesel, for example — have already switched from traditional swivel mounts to the new pad mounts, also called “4 Point” mounts or quadramounts. The enhanced design, Leece-Neville explains, enables the alternator to be mounted tighter to the engine to reduce vibration and extend component life.

Denso Sales of California has also introduced a new brushless alternator model for Class 3-8 trucks that replaces its SAE J180 mount with the new pad mount design. The 12V/130A alternator has a variety of terminal options. Meanwhile, Denso continues to work on securing greater output from alternators, while exploring ways to use power more efficiently, including developing more effective means of charging batteries.

Responding to the increased demand for products with extended service life, Delco Remy has introduced 33SI and 34SI brushless alternators, as well as the 34SI QuaDRAmount model that's designed to withstand increased levels of vibration found in high-horsepower diesels, specifically the Detroit Diesel Series 60.

To satisfy higher electrical load requirements in today's diesel-powered vehicles, Delcro Remy has also designed its new alternators to respond to true battery voltage. The company notes that select models of 33SI and 34SI alternators are available with a Remote Sense Terminal, which monitors battery system voltage at either the batteries or a similar location where voltage can be read. The 33/34SI alternator with remote sensing capabilities not only enables fleets to maintain a higher state of charge in the battery, but also can increase component life by not overcharging batteries and overworking alternators when higher output is not needed.

According to Delco Remy, a low-voltage disconnect (LVD) is another fairly new product that's becoming popular in the truck market. The LVD, which allows drivers to run appliances and other comfort items without idling the truck, is basically an on/off switch that shuts down nonessential electrical loads in the truck cab or bunk when battery voltage drops below a pre-set limit. The advantage is that batteries cannot be run down accidentally due to a power drain by non-safety related items such as dome lights, radios, and VCRs. By avoiding battery depletion, which makes them more difficult to recharge, fleets can also extend the life of the alternator.

Robert Bosch Corp. 330
www.boschusa.com

Delco Remy 331
www.delcoremy.com

Denso Sales of California 332
www.densocorp-na.com

Leece-Neville/Prestolite 333
www.prestolite.com