Caterpillar Inc. of Peoria, Illinois, develops and markets a wide range of heavy machinery designed for use in construction and mining projects. Despite recent financial issues, the corporation still has a heavy research and development presence. In the last three months, Caterpillar earned 170 U.S. patents, a quarterly pace that would see them increase the amount of patents earned in 2015 if maintained. The largest growth cluster of patents appears in control valve technologies and locomotive innovation, with some research and development focused on fuel injectors and engine speed.
One interesting patent is U.S. Patent No. 9086143, which is titled Hydraulic Fan Circuit Having Energy Recovery. It is a hydraulic fan circuit comprised of a primary pump, a motor, a fan driven by the motor, a flywheel configured to rotate with the fan, a supply passage extending from the primary pump to the motor, a return passage extending from the motor to the primary pump and a diverter valve that selectively connects the supply passage to a low-pressure pump. This hydraulic fan circuit used to cool equipment overcomes issues associated with conventional technologies which may recover energy from hydraulic fluid but are quite expensive currently.