Fuel pump drive system

A method of operating a high pressure fuel pump of an engine, the method comprising:

• driving a chain sprocket with a primary timing chain;
• rotating a first housing of a first variable cam timing device and a first bevel gear with the chain sprocket, the first variable cam timing device including a first hydraulic actuator coupled to a first camshaft;
• rotating a drive shaft coupled to the first housing via the first bevel gear, the drive shaft further coupled to a second housing of a second variable cam timing device via a second bevel gear, the second variable cam timing device including a second hydraulic actuator coupled to a second camshaft;
• and
• driving the high pressure fuel pump via a fuel pump drive lobe, the fuel pump drive lobe coupled to the drive shaft.

A fuel pump drive system for a dual overhead cam engine driven by an engine crankshaft, the fuel pump drive system comprising:

• a first variable cam timing device coupled to a first camshaft, the first variable cam timing device having a first hydraulic actuator and a first housing rotatable relative to the first hydraulic actuator via hydraulic fluid;
• a second variable cam timing device coupled to a second camshaft, the second variable cam timing device having a second hydraulic actuator and a second housing rotatable relative to the second hydraulic actuator via hydraulic fluid, the second camshaft being parallel to the first camshaft, and the second camshaft being of a same bank as the first camshaft;
• a drive shaft having a first end coupled to the first housing upstream of the first hydraulic actuator and a second end coupled to the second housing upstream of the second hydraulic actuator, wherein upstream is in terms of a direction of power flow from the engine crankshaft, the drive shaft further including one or more thrust bearings and one or more journal bearings, and the drive shaft being at a right angle with respect to the first camshaft and the second camshaft;
• and
• a fuel pump, coupled to the drive shaft and driven by a fuel pump drive lobe coupled to the drive shaft.