Fuel injection system and method combining port fuel injection with direct fuel injection

Patent metadata

Field	Value
Publication number	US-9938922-B2
Application number	US-201414561567-A
Country	US
Kind code	B2
Filing date	Dec 5, 2014
Priority date	Dec 5, 2013
Publication date	Apr 10, 2018
Grant date	Apr 10, 2018

Abstract

A system and method for injecting fuel into an engine is provided where a low-pressure fuel pump is connected in fluid communication with at least one port fuel injector and a high-pressure fuel pump is connected in fluid communication with at least one direct fuel injector. The port fuel injector is disposed along an intake path of the engine and the direct fuel injector is disposed adjacent a cylinder of the engine. A lost motion lifter selectively couples the high-pressure fuel pump and the engine. A pump deactivation module switches the lost motion lifter to selectively deactivate the high-pressure fuel pump from the engine in response to partial load operation of the engine. The pump deactivation module may additionally switch the port fuel injector to an activated state and the direct fuel injector to a deactivated state.

First claim

What is claimed is:

1. A fuel injection system for an engine having an intake path leading to at least one cylinder, comprising:
a low-pressure fuel pump for supplying fuel at a first pressure;
a high-pressure fuel pump for supplying fuel at a second pressure that is greater than said first pressure;
at least one port fuel injector connected in fluid communication with said low-pressure fuel pump and disposed along the intake path of the engine;
at least one direct fuel injector connected in fluid communication with said high-pressure fuel pump and disposed adjacent the at least one cylinder of the engine; and
a lost motion lifter selectively coupling said high-pressure fuel pump to the engine in response to full load operation of the engine and decoupling said high-pressure fuel pump in response to partial load operation of the engine, wherein said high-pressure fuel pump supplies fuel to said at least one direct fuel injector when said high-pressure fuel pump is coupled to the engine,
wherein said high-pressure fuel pump includes a pump bore, a fuel passageway that is disposed in fluid communication with said pump bore and said at least one direct fuel injector, an outlet that is disposed in fluid communication with said pump bore, and at least one plunger that reciprocates within said pump bore of said high-pressure fuel pump to pump the fuel through said fuel passageway,
wherein said lost motion lifter includes a cam follower that contacts and is reciprocally driven by a lobe on a camshaft of the engine and an actuator that opens and closes said outlet to switch said lost motion lifter between a coupled state and a decoupled state,
wherein said cam follower is disposed within said pump bore,
wherein said outlet is closed by said actuator when said lost motion lifter is in said coupled state such that fluid in said pump bore between said cam follower and said at least one plunger creates a hydraulic coupling that forces said at least one plunger to move with said cam follower,
wherein said outlet is open and creates a fluid by-pass when said lost motion lifter is in said decoupled state such that the fluid in said pump bore between said cam follower and said at least one plunger is free to enter and exit said pump bore through said outlet, allowing said cam follower to move independently of said at least one plunger.

2. The fuel injection system of claim 1 , further including:
a pump deactivation module connected to said lost motion lifter, said at least one port fuel injector and said at least one direct fuel injector to control said lost motion lifter and activation of said at least one port fuel injector and said at least one direct fuel injector.

3. The fuel injection system of claim 2 , wherein said pump deactivation module receives at least one operating parameter of the engine that correlates with engine load and detects partial load operation and full load operation of the engine based on said at least one operating parameter of the engine.

4. The fuel injection system of claim 3 , wherein said at least one port fuel injector has an activated state for injecting fuel into the intake path of the engine and a deactivated state for disabling port fuel injection.

5. The fuel injection system of claim 4 , wherein said at least one direct fuel injector has an activated state for injecting fuel directly into the at least one cylinder of the engine and a deactivated state for disabling direct fuel injection.

6. The fuel injection system of claim 5 wherein, in response to detecting partial load operation of the engine, said pump deactivation module switches said lost motion lifter to said decoupled state, switches said at least one port fuel injector to said activated state, and switches said at least one direct fuel injector to said deactivated state.

7. The fuel injection system of claim 5 wherein, in response to detecting full load operation of the engine, said pump deactivation module switches said lost motion lifter to said coupled state, switches said at least one port fuel injector to said deactivated state, and switches said at least one direct fuel injector to said activated state.

8. The fuel injection system of claim 5 wherein, in response to detecting full load operation of the engine, said pump deactivation module switches said lost motion lifter to said coupled state, switches said at least one direct fuel injector to said activated state, and leaves said at least one port fuel injector to said activated state.

9. The fuel injection system of claim 2 , wherein said pump deactivation module controls said lost motion lifter and activation of said at least one port fuel injector and said at least one direct fuel injector.

10. The fuel injection system of claim 1 , wherein said pump bore of said high-pressure fuel pump is disposed within a cylinder head of the engine and wherein said actuator is a hydraulic actuator that is driven by oil pressure from the cylinder head.

11. The fuel injection system of claim 1 , wherein the lobe of the camshaft that drives said cam follower is axially aligned with said cam follower and does not move axially on the camshaft.

12. The fuel injection system of claim 1 , wherein said actuator includes an armature and a coil disposed about said armature, wherein movement of said armature selectively opens and closes said outlet, and wherein said coil produces a magnetic field when said coil is energized that moves said armature to an active position where said armature closes said outlet.

13. The fuel injection system of claim 1 , wherein the fluid in said pump bore between said cam follower and said at least one plunger has a volume that remains free to change when said outlet is open, allowing said at least one plunger to remain in place as said cam follower reciprocates in said pump bore.

14. The fuel injection system of claim 1 , wherein the fluid in said pump bore between said cam follower and said at least one plunger is engine oil.

15. The fuel injection system of claim 1 , wherein the lobe of the camshaft that drives said cam follower also opens and closes at least one intake valve or exhaust valve of the engine.

16. The fuel injection system of claim 1 , wherein the lobe of the camshaft that drives said cam follower is fixed to the camshaft and cannot move axially on the camshaft.

17. The fuel injection system of claim 1 , wherein said lost motion lifter is switched to said coupled state when the engine speed is greater than or equal to a pre-determined value and said lost motion lifter is switched to said decoupled state when the engine speed is less than said pre-determined value.

18. A fuel injection system for an engine having an intake path leading to at least one cylinder and a camshaft, comprising:
a high-pressure fuel pump;
said high-pressure fuel pump including at least one plunger that reciprocates within said high-pressure fuel pump;
said high-pressure fuel pump including a pump bore, a fuel passageway that is disposed in fluid communication with said pump bore, an outlet that is disposed in fluid communication with said pump bore, and at least one plunger that reciprocates within said pump bore of said high-pressure fuel pump to pump fuel through said fuel passageway; and
a lost motion lifter including a cam follower that contacts and is reciprocally driven by a lobe on the camshaft of the engine and an actuator that opens and closes said outlet to switch said lost motion lifter between a coupled state and a decoupled state, wherein said cam follower is disposed within said pump bore, wherein

Assignees

• Avl Powertrain Engineering Inc

Inventors

• Whitaker Paul Andrew

Classifications

• F02D41/32

  of the low pressure type {(F02D41/3082 takes precedence)} · CPC title

• F02D41/38

  of the high pressure type · CPC title

• F02M63/02

  Fuel-injection apparatus having several injectors fed by a common pumping element, or having several pumping elements feeding a common injector; Fuel-injection apparatus having provisions for cutting-out pumps, pumping elements, or injectors; Fuel-injection apparatus having provisions for variably interconnecting pumping elements and injectors alternatively · CPC title

• F02M69/046

  for injecting into both the combustion chamber and the intake conduit · CPC title

• F02M63/0059

  Arrangements of valve actuators · CPC title