Fuel injection system for internal combustion engines

Claim 2

In an internal combustion engine, a fuel injection system comprising first fuel pump means for providing a supply of fuel at a first pressure, second fuel pump means for providing a supply of fuel at a second pressure, said second pressure being higher than said first pressure, injection nozzle means for each cylinder for injecting fuel when open into a cylinder of said engine, means for measuring the amount Of fuel to be injected into said cylinder, means for storing fuel to be injected into said cylinder by said injection nozzle means, means for transferring said measured amount of fuel to said means for storing fuel for storage thereby at said first pressure, means for applying fuel from said means for storing fuel to said injection nozzle means at said first pressure to apply an opening bias, means for applying fuel from said second pump means at said second pressure to said injection nozzle means to maintain said injection nozzle closed against the pressure of said fuel at said first pressure, timing means actuated responsive to operation of said internal combustion engine for producing a signal when the time for fuel injection by said injection nozzle means occurs, and means responsive to said timing means signal for increasing the pressure of said stored fuel until it exceeds said second pressure thereby opening said injection nozzle means whereby said stored fuel is injected into said cylinder.

Claim 3

In an internal combustion engine as recited in claim 1 wherein said timing means signal generated by said timing means includes a first signal signifying the time for a pilot fuel injection, followed by a second signal signifying the time for a main injection, said means responsive to said timing means signal includes means responsive to said first timing signal for enabling said means for increasing the pressure of said stored fuel to increase said stored fuel pressure until a predetermined amount of said fuel is injected into said cylinder by said injection nozzle means, and means responsive to said second signal for enabling said means responsive to said timing signal to increase the pressure of said stored fuel until the balance of said stored fuel is injected into said cylinder.

Claim 4

In an internal combustion engine as recited in claim 1 wherein said means responsive to said timing means signal for increasing the pressure of said stored fuel includes a piston having a first surface area, a plunger moveable responsive to motion of said piston and having a second surface area which is smaller than said first surface area, said plunger surface area being in contact with the fuel stored in said means for storing fuel, means for applying fuel from said second fuel pump means to said piston first surface area including a valve means having a closed position wherein it prevents application of fuel from said first fuel pump means to said piston and an open position wherein it enables application of fuel from said second pump means to said piston, yieldable means biasing said valve means to its closed position, and means for applying said timing means signal to said valve means to move it to its open position whereby said piston moves said plunger against said stored fuel to increase its pressure.

Claim 5

In an internal combustion engine as recited in claim 1 wherein said timing means signal generated by said timing means includes a first signal signifying the time for a pilot fuel injection followed by a second signal signifying the time for a main fuel injection, wherein said means responsive to said timing means signal for increasing the pressure of said stored fuel includes, a piston having a first surface area, a plunger moveable responsive to motion of said piston and having a second surface area which is smaller than said first surface area, said plunger surface area being in contact with the fuel stored in said means for storing fuel, means for applying fuel from said first fuel pump means to said piston first surface area including a pilot valve means and a main valve means, both said valve means having a closed position wherein they each prevent the application of fuel from said second pump means to said piston and an open position wherein fuel from said second pump means is applied to said piston, means biasing said pilot valve means and said main valve means to their closed positIons, means for applying said first signal to said pilot valve means to move it to its open position whereby said piston is moved responsive to the application of fuel from said second pump means increasing pressure on said stored fuel sufficiently to open said injection nozzle means to inject stored fuel into said cylinder, means for limiting the amount of fuel applied to said piston through said pilot valve means to a predetermined amount to thereby limit the amount of stored fuel injected into said cylinder to a predetermined amount, and means for applying said second signal to said main valve means to move it to its open position whereby said piston is moved to increase pressure on said remaining stored fuel until it is injected into said cylinder.

Claim 6

In an internal combustion engine, a fuel injection system comprising first fuel pump means for providing a supply of fuel at a first pressure second fuel pump means for providing a supply of fuel at a second pressure which is higher than said first pressure, injection nozzle means for injecting fuel into a cylinder of said engine, when open, means for applying fuel from said second fuel pump means to said injection nozzle means to bias said injection nozzle means closed, means for measuring the amount of fuel to be injected into said cylinder, means for applying fuel from said first fuel pump means at said first pressure to said means for measuring, means for storing at said first pressure fuel measured by said means for measuring and applying said stored fuel to said injection nozzle means to apply an opening bias at said first pressure, pressure intensifier means responsive to the application of fuel from said second fuel pump means for increasing the pressure of said stored fuel when operative, injection control means for enabling the application of fuel from said second pump means to said pressure intensifier means when enabled, means for generating fuel injection timing signals, and piezoelectric valve means responsive to a fuel injection timing signal for enabling said injection control valve means, whereby said pressure intensifier means increases the pressure of said stored fuel until it exceeds said second pressure and is injected into said cylinder.

Claim 7

In an internal combustion engine, a fuel injection system comprising first fuel pump means for providing a supply of fuel at a first pressure second fuel pump means for providing a supply of fuel at a second pressure which is higher than said first pressure, injection nozzle means for injecting fuel into a cylinder of said engine, when open, means for applying fuel from said second fuel pump means to said injection nozzle means to bias said injection nozzle means closed, means for measuring the amount of fuel to be injected into said cylinder, means for applying fuel from said first fuel pump means at said first pressure to said means for measuring, means for storing at said first pressure fuel measured by said means for measuring and applying said stored fuel to said injection nozzle means to apply an opening bias at said first pressure, pressure intensifier means responsive to the application of fuel from said second fuel pump means for increasing the pressure of said stored fuel when operative, injection control means for enabling the application of fuel from said second pump means to said pressure intensifier means when enabled, means for generating fuel injection timing signals, and piezoelectric valve means responsive to a fuel injection timing signal for enabling said injection control valve means, whereby said pressure intensifier means increases the pressure of said stored fuel until it exceeds said second pressure and is injected into said cylinder.

Claim 8

In an internal combustion engine as recited in claim 5 wherein said injection control valve means includes a pilot injection control valve means for enabling a limited application of fuel from said second pump means to said pressure intensifier to enable injection of a predetermined amount of stored fuel into said cylinder, a main injection control valve means for enabling further application of fuel from said second pump means to said pressure intensifier to enable injection of the remainder of stored fuel into said cylinder; wherein said means for generating fuel injection timing signals includes means for generating a pilot timing signal followed by a main timing signal, said pilot injection control valve means includes biasing means for enabling response to said piezoelectric valve means when activated in response to a pilot timing signal, and said main injection control valve means includes biasing means for enabling response to said piezoelectric valve means only when activated in response to a main timing signal.

Claim 9

In an internal combustion engine as recited in claim 5, wherein said second fuel pump means comprises a first chamber, an annular disc in said chamber, first spring means biasing said annular disc toward one end of said chamber, a second chamber coaxial with said first chamber, a piston in said second chamber, a fuel chamber means for delivering fuel to said fuel chamber from said first fuel pump means, plunger means extending between said fuel chamber and said piston for applying pressure to the fuel in said fuel chamber in response to motion by said piston in one direction, means for biasing said plunger means in a Direction so as not to apply pressure to the fuel in said fuel chamber, means within said first chamber for biasing said piston toward said one direction, means coupling said piston and said annular disc motion together after said piston has been moved a predetermined distance in a direction opposite to said one direction, and means for applying gas from a cylinder of said internal combustion engine to said second chamber to drive said first piston in a direction opposite to said one direction.

Claim 10

In an internal combustion engine, as recited in claim 7 wherein said means coupling said first piston and said annular disc comprises an annular piston surrounding said piston, said annular piston having an internal abutment therein for being engaged by said piston after said piston has moved a predetermined distance in a direction opposite to said one direction, and said annular piston abutting said annular disc at one end for moving said annular disc in a direction opposite to said one direction with motion of said annular piston and having its other end extending into said chamber.

Claim 11

In an internal engine as recited in claim 7, wherein said first chamber includes in the walls thereof a gas pressure relief valve means for venting gas above a predetermined pressure out of said first chamber.

Claim 12

In an internal combustion engine as recited in claim 5 wherein said means for measuring the amount of fuel to be injected into said cylinder includes a hollow chamber, a moveable shuttle within said chamber, means for alternately directing fuel from said first fuel pump means into opposite ends of said chamber while removing fuel from the end of said chamber opposite to the one into which fuel is being directed, said shuttle being moved by the pressure of fuel being directed into one end of said chamber to force fuel out of the other end of said chamber, and means for controlling the travel of said shuttle in response to fuel pressure including wedge means positionable to control the travel of said shuttle, valve means actuable for determining the position of said wedge means, means for generating a fuel signal representative of the quantity of fuel desired, means for generating a position signal representative of the position of said wedge means, means for comparing said fuel signal and said position signal to generate a difference signal, and means for applying said difference signal to said valve means to actuate it responsive thereto.