Fuel injection system

A fuel system for supplying fuel to a multi-cylinder compression ignition engine comprising:

• a fuel injection nozzle for each engine cylinder;
• a reciprocable plunger cam actuated pump means for each engine cylinder for supplying fuel to a respective nozzle;
• an electromagnetically operable valve means for each engine cylinder for controlling flow of fuel to a respective nozzle;
• and
• a control unit for controlling said electromagnetically operable valve means for each engine cylinder;
• said pump means comprising,
• a body having a hollow interior,
• a step in said hollow interior of said body,
• a pump barrel in said hollow interior of said body having a flanged portion engaging against said step, a first end and a second end,
• a bore in said pump barrel having a first end and a second end,
• a pumping plunger slidably mounted and extending in said bore and having a first end and a second end, said first end being adjacent said first end of said bore,
• resilient means in said hollow interior of said body between said body and said pumping plunger for biasing said plunger outwardly toward said first end of said bore,
• means engageable with said pumping plunger for effecting inward movement of said plunger toward said second end of said bore,
• means for supplying fuel to said bore during outward movement of said plunger,
• a mounting block having a first part extending within said hollow interior of said body,
• a first valve block and a second valve block in said hollow interior of said body between said pump barrel and said mounting block,
• engaging surfaces between said pump barrel, valve blocks and mounting block,
• means for securing said mounting block to said body for producing a clamping force between said engaging surfaces of said barrel, valve blocks and mounting block,
• a spill valve in one of said valve blocks,
• said electromagnetically operable valve means being mounted on said mounting block and being operatively connected to said spill valve for controlling the operation of said spill valve,
• a fuel outlet on said mounting block,
• a fuel delivery channel communicating said second end of said pump barrel with said fuel outlet, and
• a fuel delivery valve in said fuel delivery channel for controlling the flow of fuel through said fuel delivery channel,
• said spill valve comprising a spill valve bore in said one of said valve blocks and having a first end and second end,
• a valve seat defined at said first end of said spill valve bore,
• a spill valve member slidably mounted in said spill valve bore and having a first end and a second end, said spill valve member being shaped at said first end thereof to conform to and cooperate with said valve seat,
• a reduced diameter portion on said spill valve member at said first end thereof defining a chamber between said spill valve member and said spill valve bore,
• a spill passage having one end opening into said spill valve bore and a second end communicating with said pump barrel bore, said valve seat surrounding said first end of said spill valve bore between said spill passage and said chamber,
• restricted flow passage means extending between said spill passage and said second end of said spill valve bore, and
• means for communicating said second end of said spill valve bore with said electromagnetically operable valve, said electromagnetically operable valve being arranged so that when energized fuel is prevented from escaping through said second end of said spill valve bore whereby said spill valve member moves into engagement with said valve seat to prevent flow through said spill passage, and when de-energized fuel escapes through said second end of said spill valve bore whereby said spill valve member moves out of engagement with said valve seat to allow flow of fuel through said spill passage.