Controlled direct drive engine system

A power producing system which comprises:

• a plurality of first means for producing reciprocating power through a rod from a thermal energy source which may include combustion energy,
• a plurality of linear hydraulic units, one of which is mechanically connected to each said rod,
• a plurality of rotary hydraulic power units which can function as a rotary pump or a motor, one of which units is associated with each said linear hydraulic unit,
• means interconnecting said rotary motor/pumps so that all rotate at the same speed and so that power can be transferred therebetween, and
• a control unit which operates said plurality of first power-producing means complementary to one another and controls the operation said hydraulic rotary power units so as to add power to or subtract power from said individual linear units and in this manner controls said plurality of first reciprocating power-producing means.

A power producing system particularly suited for providing rotary power output, which system comprises:

• first means for producing reciprocating power from a thermal energy source, which may include combustion energy, which includes piston means,
• a hydraulic drive unit mechanically connected to said piston means for controlling said power from said first means to achieve efficient operation by moving said piston means with a desired velocity profile;
• wherein said hydraulic drive unit includes a double-acting cylinder mechanically linked to said first cylinder means by a common rod and to a rotary variable volume hydraulic pump/motor;
• a rotary output shaft from said hydraulic drive unit to achieve efficient rotary power output.