Cutaway of the Cat 3500 Series B engine.

Caterpillar Engine Division has introduced three additions to its 3500 family of industrial engines. The new engines, identified as the 3500 Series B, feature mechanical enhancements and advanced electronic control systems that combine to offer significant improvements in fuel efficiency and emissions control, while increasing power ratings and improving responsiveness.

The electronic control module (ECM) of the 3500 Series B engines collects operating condition information from engine sensors, analyzes that information, and constantly adjusts injection timing and duration to optimize fuel efficiency and while meeting Tier I/Stage I emissions standards. This level of control is also responsible for the engine's virtually smokeless operation even during startup and rapid acceleration. Fuel consumption can be reduced by as much as 15%.

The 3500 Series B engines retain the familiar, field-proven 3500 engine structure. In addition to a number of mechanical improvements, new iron and updated electronics help take full advantage of combustion efficiency benefits available through electronic control for these large engines.

Larger, more aggressive camshafts provide increased injection pressure and shorter injection duration. New, electronically controlled unit injectors combine 150 MPa (22,000 psi) injection pressure with highly developed injector spray tip geometry to improve fuel atomization and injection timing pressure. A new deep-crater piston design helps increase turbulence in the combustion chamber for better air/fuel mixing. Reduced crevice volume - due to the piston's higher crown perimeter - minimizes wasted charge air by keeping more air in the combustion chamber. A lower aftercooler water temperature and streamlined exhaust manifolds also contribute to engine efficiency.

Three electronic protection strategies - alarms, deratings, and shutdowns - are programmable by the equipment operator to help prevent serious downtime incidents without interfering with safe machinery operation. With the derating feature selected, the engine will automatically derate itself gradually in steps as little as 2-3% if it enters a dangerous operating zone resulting from air inlet restriction, insufficient cooling, high exhaust temperature, overspeed, or any other cause. Automatic derating does not occur if the operator reacts first to move the engine out of the dangerous operating zone.

For more information, visit www.cat-industrial.com