A high-pressure fuel pump includes a housing including a chamber, an inlet flow passage to draw fuel into the chamber, and a discharge flow passage to discharge fuel out of the chamber. The high-pressure fuel pump further includes a piston disposed in the housing and configured to compress fuel, a sleeve coupled to the housing and configured to support the piston and form a space for storing fuel, a discharge valve disposed in the discharge flow passage and configured to open when a pressure of fuel stored in the chamber is equal to or greater than a first pressure, and a pressure relief valve disposed in a relief flow passage that communicates with the discharge flow passage and the space. The pressure relief valve is configured to open when a pressure of fuel supplied into the relief flow passage is equal to or greater than a second pressure.

A cam follower assembly includes a cam roller, and a generally cylindrical body having an outer peripheral surface configured to be reciprocally slidable within a bore of an engine component. The cam roller is rotatably mounted on the body and configured to engage with a cam lobe on a camshaft of the engine. The cam lobe is operative to drive the body to a position at which the cam follower assembly causes one of opening of a valve or actuation of a fuel injector of the engine. A groove is formed in the body inset from the outer peripheral surface and extending axially along the outer peripheral surface parallel to the longitudinal axis of the body and aligned with an axial median plane of the cam roller and the cam lobe.

A fuel injection pump includes: a tappet configured to reciprocate by rotation of a cam; a cylinder that supports the tappet to reciprocate; and a plunger configured to reciprocate with the tappet. The tappet includes: a tappet body supported by the cylinder to reciprocate; a pin supported on both sides in an axial direction of the pin by the tappet body; a roller rotatably fitted to an outer peripheral side of the pin; a washer disposed between at least one end surface of the roller in the axial direction and an inner peripheral surface of the tappet body. The washer has at least one protrusion to be in contact with a stopper of the tappet body in either of two rotational directions.

Methods and systems are provided for injector balancing without disabling a cam actuated high pressure fuel pump. In one example, one of a plurality of cam lobes of the pump is selectively and sequentially disabled while a group of injectors are concurrently operated to learn a pressure drop across each injector. The selection of the injectors is based on the identity and stroke timing of the disabled cam lobe.

A fuel pump includes a camshaft that rotates in accordance with operation of an engine and a tappet provided in contact the camshaft. An ECU includes an angle determination unit configured to determine whether a rotation angle from a start of rotation of the camshaft when starting the engine is under a predetermined angle required for forming an oil film on a sliding portion of the tappet, and a control unit configured to, when the rotation angle from the start of rotation of the camshaft is determined to be under the predetermined angle, execute a limit process including at least one of limiting a fuel discharge pressure of the fuel pump or limiting a rotation of the camshaft.

In a high-pressure pump, a relief valve seating surrounds an opening of a relief valve passage of a valve seat main body in a first space, A relief valve member includes a relief valve main body and a relief valve seat portion. The relief valve main body has a rod shape. The relief valve seat portion is integrated with an end of the relief valve main body so as to be capable of contacting the relief valve seat. The relief valve urging member urges the relief valve member toward the relief valve seat. A support portion includes a support main body that slidably supports an outer wall of the relief valve main body so as to guide a reciprocating movement of the relief valve member in the axial direction.

A fuel pump includes a fuel pump housing with a pumping chamber and an outlet valve bore extending along an outlet valve bore axis; a pumping plunger which reciprocates within a plunger bore along a plunger bore axis which is traverse to the outlet valve bore axis; and an outlet valve assembly. The outlet valve assembly includes an outlet valve seat with an outlet flow passage, wherein a first portion of the outlet valve seat is aligned with the pumping plunger in a direction parallel to the plunger bore axis and wherein a second portion of the outlet valve seat is not aligned with the pumping plunger in a direction parallel to the plunger bore axis and an outlet valve member which is moveable between an unseated position which provides fluid communication through the outlet flow passage and a seated position which prevents fluid communication through the outlet flow passage.

A saddle riding vehicle includes: a body frame; a fuel tank; an upright internal combustion engine; a fuel injection device; and a high-pressure fuel pump. The high-pressure fuel pump is configured to be driven by one of an intake-side camshaft and an exhaust-side camshaft. The high-pressure fuel pump is mounted on an upper surface of a cylinder head cover in an attitude inclined rearward toward the other of the camshafts. The high-pressure fuel pump can thus be protected from disturbances from the sides, and the length of a high-pressure pipe for feeding fuel from the high-pressure fuel pump to the fuel injection device can be shortened. The vehicle protects the high-pressure fuel pump from disturbances from the sides, and prevents acceleration of vaporization of fuel by reducing heat which the high-pressure fuel pump receives from the cylinder block.

A housing-includes a pressurizing chamber. A plunger is moved to increase and decrease a volume of the pressurizing chamber, so that the plunger can pressurize the fuel in the pressurizing chamber. A fuel chamber forming portion is placed on a radially outer side of the plunger and forms a fuel chamber that is communicated with the pressurizing chamber. A pulsation damper is placed in an inside of the fuel chamber and is operable to reduce pressure pulsation of the fuel in the fuel chamber. Fixable portions are placed on a radially outer side of the plunger while each of the fixable portions includes a receiving through-hole. The fixable portions are fixed to an engine with bolts, which are provided to correspond with the receiving through-holes, respectively. The fuel chamber forming portion is displaced from axes of the receiving through-holes.

Disclosed herein is a high-pressure fuel pump. The high-pressure fuel pump includes a housing including a chamber provided to compress fuel supplied thereinto, an inlet flow passage that communicates with the chamber to draw fuel into the chamber through the inlet flow passage, and a discharge flow passage that communicates with the chamber to discharge the fuel out of the chamber through the discharge flow passage. The high-pressure fuel pump further includes a piston disposed in the housing and configured to linearly reciprocate to compress the fuel supplied into the chamber; and a discharge valve disposed in the discharge flow passage of the housing and configured to open when a pressure of fuel stored in the chamber is equal to or greater than a first pressure, the discharge valve including an open-and-close member that makes line contact with an inlet of the discharge valve to close the inlet.