Fuel accumulator and fuel system using the same

A fuel rail for use in a direct injection engine fuel system having a predetermined restart pressure and a fuel system controller that starts and stops said direct injection engine fuel system on command, said fuel rail comprising:

• a fuel inlet for receiving fuel;
• a fuel outlet for dispensing fuel;
• and
• a fuel accumulator, said fuel accumulator comprising:
• a central guide post with a fuel passage therethrough;
• a cup shaped, closed ended plunger slidably disposed on said central guide post;
• a seal means operable between said plunger and said central guide post to create a substantially sealed fuel chamber within said plunger;
• a biasing means operable to urge said plunger onto said central guide post to pressurize said fuel chamber;
• and a fuel admission valve located between said central guide post and said fuel rail to selectively provide fluid communication between said fuel passage and said fuel rail in response to said fuel system controller;
• whereby when said fuel system controller commands a system stop, said fuel admission valve is opened to admit pressurized fuel through said fuel passage into said fuel chamber, thereby compressing said biasing means until the fuel pressure within said fuel chamber rises to at least said restart pressure, said fuel admission valve is then closed and said biasing means maintains said restart pressure in said fuel chamber;
• and whereby when said fuel system controller commands a system start, said fuel admission valve is opened to admit pressurized fuel into said fuel rail from said fuel chamber.

A direct injection engine fuel system having a predetermined restart pressure and a fuel system controller that starts and stops said direct injection engine fuel system on command, said direct injection fuel system comprising:

• a fuel tank for storing fuel;
• a fuel pump for supplying fuel from said fuel tank to a fuel rail;
• and
• a fuel accumulator, said fuel accumulator comprising:
• a central guide post with a fuel passage therethrough;
• a cup shaped, closed ended plunger slidably disposed on said central guide post;
• a seal means operable between said plunger and said central guide post to create a substantially sealed fuel chamber within said plunger;
• a biasing means operable to urge said plunger toward onto said central guide post to pressurize said fuel chamber;
• and a fuel admission valve located between said central guide post and said fuel rail to selectively provide fluid communication between said fuel passage and said fuel rail in response to said fuel system controller;
• whereby when said fuel system controller commands a system stop, said fuel admission valve is opened to admit pressurized fuel through said fuel passage into said fuel chamber, thereby compressing said biasing means until the fuel pressure within said fuel chamber rises to at least said restart pressure, said fuel admission valve is then closed and said biasing means maintains said restart pressure in said fuel chamber;
• and whereby when said fuel system controller commands a system start, said fuel admission valve is opened to admit pressurized fuel into said fuel rail from said fuel chamber.