The Hercules Engines 3.7 Series II diesel engine family consists of multiple model four cylinder, in-line configuration, direct injection, liquid cooled, turbocharged, turbocharged/air-to-air inter-cooled, and naturally aspirated versions of 4.00″ (101.6 mm) bore and 4.50″ (114.3 mm) stroke resulting in a displacement of 3.7 liters (226 in3).
The engines were developed to meet 50 state heavy duty emission requirements through 1990 for on-highway applications in Class 2b/3 vehicles (8,500-14,500 lbs/3856-6577 Kg GVW) with ratings up to 125 BHP (93.2 KW) @ 2800 RPM. Other application areas include industrial power units, off highway mobile equipment, military and marine.
This paper presents the technical objectives for the 3.7 Series II, descriptions of significant components/systems, design technical approaches, and development efforts undertaken to meet the performance/durability objectives, and the products application capabilities.