Abstract: Oil intensified common rail injectors that combine a common-rail non-intensified injector with an oil-intensified injector. The invention also uses fuel (common rail) pumps that are commercially available since the injector does not rely on this pump for intensification function. Also, since the pressure of the fuel pump is limited to lower than the intensified pressure, the injected pressure is limited to the unit injector; this eases the rail and tube requirements to this lower fuel rail pressure. The injector operates up to this limited pressure with no intensification. Also a separate oil system is configured to operate a hydraulic intensifier. Thus the system is able to achieve very high injection pressure without common rail pump, rail, fitting and jumper tube limits. The oil system does not need to operate or run unless these elevated pressures are required. Embodiments using direct needle control are disclosed.

Abstract: Control method and apparatus for multi-fuel, compression ignition engines. In accordance with the method, a target fuel whose engine operating characteristics are to be duplicated when using fuels other than the target fuel in the engine is selected, and the engine operating characteristics including engine torque versus throttle setting and engine RPM when operating using the target fuel are determined and stored as a desired indicated torque versus throttle setting and engine RPM. Then, when the engine is operating on a fuel, a fuel control input and engine RPM are sensed, the desired indicated torque for that fuel control input and engine RPM is determined, a measured indicated torque for the engine is determined, and a fuel quantity command is adjusted to cause the measured indicated torque to equal the desired indicated torque.