Dual Mode Engine Using Two or More Fuels and Method for Operating Such Engine

• US 20140032081A1
• Filed: 07/27/2012
• Published: 01/30/2014
• Est. Priority Date: 07/27/2012
• Status: Abandoned Application

• Current Assignee: Caterpillar Incorporated
• Original Assignee: Caterpillar Incorporated
• Inventors: Willi, Martin, Gehrke, Christopher R.
• Application Number:
  US13/559,887
• Publication Number:
  US 20140032081A1
• Time in Patent Office: Days
• US Class Current: 701/104
• CPC Class Codes: F02B 17/005 having direct injection in the combustion chamber
• CPC Class Codes: F02B 23/0672 Omega-piston bowl, i.e. the combustion space having a central projection pointing towards the cylinder head and the surrounding wall being inclined towards the cylinder center axis the surrounding wall being exactly vertical F02B23/0696
• CPC Class Codes: F02B 29/0406 Layout of the intake air cooling or coolant circuit
• CPC Class Codes: F02D 13/0219 by shifting the phase, i.e. the opening periods of the valves are constant
• CPC Class Codes: F02D 19/061 by controlling fuel injectors
• CPC Class Codes: F02D 19/0647 the gaseous fuel being liquefied petroleum gas [LPG], liquefied natural gas [LNG], compressed natural gas [CNG] or dimethyl ether [DME]
• CPC Class Codes: F02D 19/0649 Liquid fuels having different boiling temperatures, volatilities, densities, viscosities, cetane or octane numbers
• CPC Class Codes: F02D 19/0689 for in-cylinder direct injection
• CPC Class Codes: F02D 19/0692 Arrangement of multiple injectors per combustion chamber
• CPC Class Codes: F02D 2041/3052 the mode being the stratified charge compression-ignition mode
• CPC Class Codes: F02D 2200/101 Engine speed
• CPC Class Codes: F02D 41/0025 Controlling engines characterised by use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures
• CPC Class Codes: F02D 41/0027 the fuel being gaseous non-electrical control F02D19/02
• CPC Class Codes: F02D 41/0057 Specific combustion modes combustion modes per se F02D41/3017
• CPC Class Codes: F02D 41/3047 said means being a secondary injection of fuel
• CPC Class Codes: F02M 26/05 High pressure loops, i.e. wherein recirculated exhaust gas is taken out from the exhaust system upstream of the turbine and reintroduced into the intake system downstream of the compressor
• CPC Class Codes: F02M 26/28 with liquid-cooled heat exchangers
• CPC Class Codes: Y02T 10/12 Improving ICE efficiencies
• CPC Class Codes: Y02T 10/30 Use of alternative fuels, e.g. biofuels
• CPC Class Codes: Y02T 10/40 Engine management systems

Abstract

An internal combustion engine includes a first fuel injector configured to inject a first fuel into an engine cylinder in response to a first injection signal, a second fuel injector configured to inject a second fuel into the engine cylinder in response to a second injection signal, and a third fuel injector configured to inject a third fuel into the engine cylinder in response to a third injection signal. The first, second and third fuels have different reactivities. An electronic controller provides, as appropriate, first, second and third injection signals using an engine speed and an engine load signals as primary control parameters such that the engine operates in at least two different combustion modes.

Claims

1. An internal combustion engine, comprising:

a first fuel injector configured to inject a first fuel into an engine cylinder in response to a first injection signal provided to the first fuel injector by an engine controller;

a second fuel injector configured to inject a second fuel into the engine cylinder in response to a second injection signal provided to the second fuel injector by the engine controller, the second fuel having a different reactivity than the first fuel;

a third fuel injector configured to inject a third fuel into the engine cylinder in response to a third injection signal provided to the third fuel injector by the engine controller, the third fuel having a different reactivity than the first and second fuels;

wherein the engine controller is configured to provide, as appropriate, the first, second and third injection signals using an engine speed and an engine load signals as primary control parameters such that the engine operates in at least two different combustion modes.

2. The internal combustion engine of claim 1, wherein the first fuel is injected directly into the engine cylinder, the second fuel is injected directly into the engine cylinder, and the third fuel is provided within an intake port of the engine cylinder and, during operation, is carried into the engine cylinder by incoming air or an air/exhaust gas mixture.

3. The internal combustion engine of claim 1, wherein the first, second and third fuels is selected from the group comprising:

diesel, gasoline, natural gas, petroleum gas, and engine lubrication oil.

4. The internal combustion engine of claim 1, wherein the at least two different combustion modes include reactivity controlled compression ignition (RCCI) and distributed ignition (DI).

5. The internal combustion engine of claim 4, wherein the engine controller provides one first signal and a plurality of second signals for each combustion event to create stratified regions of air/fuel ratios having different reactivities within the engine cylinder when the engine is operating in the RCCI mode.

6. The internal combustion engine of claim 4, wherein the engine controller provides at least one of the first and second signals and a single third signal for each combustion event to create a relatively uniform region of air/fuel ratio that contains at least one of the first and second fuels within the engine cylinder, which relatively uniform region of air/fuel ratio ignites using droplets of the third fuel as an ignition source.

7. The internal combustion engine of claim 1, wherein an operating range of the engine includes a set of operating points, each operating point being characterized by a particular engine speed and a particular engine load, wherein a first operating mode of the two different operating modes is present when the engine is operating under a first subset of the set of operating points and wherein a second operating mode of the two different operating modes is present when the engine is operating under a second subset of the set of operating modes.

8. The internal combustion engine of claim 7, wherein the first and second subsets are discrete.

9. The internal combustion engine of claim 7, wherein the first and second subsets overlap along a third subset.

10. The internal combustion engine of claim 7, wherein the first subset encompasses operating points having relatively low engine speed and relatively low engine load, and wherein the second subset encompasses operating points having relatively high engine speed and relatively high engine load.

12. The internal combustion engine of claim 1, wherein the first, second and third fuels is selected from the group comprising:

diesel, gasoline, natural gas, petroleum gas, and engine lubrication oil.

11. An internal combustion engine, comprising:

an engine cylinder formed in a cylinder case and at least partially defining a variable volume, the variable volume being in selective fluid connection with an air source via an intake port;

a first fuel injector configured to inject a first fuel directly into the variable volume;

a second fuel injector configured to inject a second fuel directly into the variable volume, the second fuel having a different reactivity than the first fuel;

a third fuel injector configured to inject a third fuel into the intake port, the third fuel having a different reactivity than the first and second fuels;

a speed sensor configured to provide an engine speed signal;

a load sensor configured to determine and provide an engine load signal;

a controller configured to receive and analyze the engine speed and load signals and provide a first injection signal to the first fuel injector, a second injection signal to the second fuel injector, and a third injection signal to the third fuel injector such that the engine operates in a first mode or a second mode as determined by the engine speed and load signals.

13. The internal combustion engine of claim 11, wherein the first mode is a reactivity controlled compression ignition (RCCI) combustion mode that is carried out only on the first and second fuels, and wherein the second mode is a distributed ignition (DI) combustion mode that is carried out using at least one of the first and second fuels, and the third fuel.

14. The internal combustion engine of claim 13, wherein the controller is configured to command the first and second fuel injectors to operate such that stratified regions of air/fuel ratios having different reactivities within the engine cylinder when the engine is operating are created.

15. The internal combustion engine of claim 13, wherein the controller is configured to command at least one of the first and second fuel injectors, and the third fuel injector, such that a relatively uniform region of air/fuel ratio that contains at least one of the first and second fuels is created within the engine cylinder, which relatively uniform region of air/fuel ratio ignites using droplets of the third fuel as an ignition source.

16. The internal combustion engine of claim 11, wherein an operating range of the engine includes a set of operating points, each operating point being characterized by a particular engine speed and a particular engine load, wherein the first mode is present when the engine is operating under a first subset of the set of operating points and wherein the second mode is present when the engine is operating under a second subset of the set of operating modes.

17. The internal combustion engine of claim 16, wherein the first and second subsets are discrete.

18. The internal combustion engine of claim 16, wherein the first and second subsets overlap along a third subset.

19. The internal combustion engine of claim 16, wherein the first subset encompasses operating points having relatively low engine speed and relatively low engine load, and wherein the second subset encompasses operating points having relatively high engine speed and relatively high engine load.

20. A method for operating an internal combustion engine, comprising:

monitoring engine speed and engine load signals;

determining a then-present operating point of the engine;

analyzing the then-present operating point of the engine;

determining whether at least a first operating mode or a second operating mode is desired based on the then-present operating point of the engine; and

when it is determined that the first operating mode is desired, sending appropriate commands to fuel injectors of the engine to inject fuels such that stratified regions of air/fuel mixtures having different reactivities are set up within an engine cylinder during operation, and

when it is determined that the second operating mode is desired, sending appropriate commands to fuel injectors of the engine to deliver a desired quantity of one or more than one fuel into the engine cylinder, and sending an appropriate command to an additional fuel injector to provide an ignition substance into an air inlet port of the engine cylinder.