Optimized fuel management system for direct injection ethanol enhancement of gasoline engines

Patent metadata

Field	Value
Publication number	US-11359559-B2
Application number	US-202117500322-A
Country	US
Kind code	B2
Filing date	Oct 13, 2021
Priority date	Nov 18, 2004
Publication date	Jun 14, 2022
Grant date	Jun 14, 2022

Abstract

Fuel management system for enhanced operation of a spark ignition gasoline engine. Injectors inject an anti-knock agent such as ethanol directly into a cylinder. It is preferred that the direct injection occur after the inlet valve is closed. It is also preferred that stoichiometric operation with a three way catalyst be used to minimize emissions. In addition, it is also preferred that the anti-knock agents have a heat of vaporization per unit of combustion energy that is at least three times that of gasoline.

First claim

What is claimed is:

1. A fuel management system for a spark ignition engine, comprising:
at least one direct injector;
at least one port injector; and
an electronic control unit configured to control use of the at least one direct injector and the at least one port injector,
wherein the fuel management system is configured to use both the at least one direct injector and the at least one port injector to introduce a mixture of ethanol with gasoline into a spark ignition engine during at least a part of a drive cycle,
wherein both the at least one direct injector and the at least one port injector are configured to operate at a highest torque value at which the spark ignition engine is operable at different speeds,
wherein the fuel management system is further configured such that the at least one direct injector provides an octane enhancement relative to the at least one port injector in the spark ignition engine due to evaporative cooling from direct injection by the at least one direct injector,
wherein the fuel management system is further configured to provide a stoichiometric or substantially stoichiometric air/fuel ratio in the spark ignition engine in at least a part of the part of the drive cycle in which both the at least one direct injector and the at least one port injector introduce the mixture of ethanol with gasoline into the spark ignition engine,
wherein the fuel management system is further configured such that the at least one direct injector is inoperable to provide direct injection of the mixture of ethanol with gasoline when torque decreases below a selected value, the selected value being dependent on engine speed, and
wherein the fuel management system is further configured to prevent undesired autoignition of end gas in at least one cylinder in the spark ignition engine.

2. The fuel management system of claim 1 , wherein the fuel management system is further configured to determine the selected value of torque by employing open loop control using predetermined information that includes information about a dependence of an occurrence of undesired autoignition of end gas near a wall in at least one cylinder of the spark ignition engine upon engine torque.

3. The fuel management system of claim 2 , wherein the fuel management system is further configured such that an octane enhancement from ethanol in the mixture of ethanol with gasoline that is introduced by the at least one direct injector increases at a rate of at least four octane numbers for every 20% energy fraction of the mixture of ethanol with gasoline that is provided by the ethanol, the octane enhancement relative to gasoline being due to both higher evaporative cooling than gasoline and a higher octane number than gasoline.

4. The fuel management system of claim 1 , wherein the fuel management system is further configured such that an octane enhancement from ethanol in the mixture of ethanol with gasoline that is introduced by the at least one direct injector increases at a rate of at least four octane numbers for every 20% energy fraction of the mixture of ethanol with gasoline that is provided by the ethanol, the octane enhancement relative to gasoline being due to both higher evaporative cooling than gasoline and a higher octane number than gasoline.

5. The fuel management system of claim 1 , wherein the highest torque value at which the engine is operable varies with engine speed.

6. The fuel management system of claim 1 , wherein the fuel management system is further configured to provide a uniform fuel distribution during at least a part of the part of the drive cycle in which both direct injection and port injection are used to introduce the mixture of ethanol with gasoline into the spark ignition engine.

7. A fuel management system for a spark ignition engine, comprising:
at least one direct injector;
at least one port injector; and
an electronic control unit configured to control use of the at least one direct injector and the at least one port injector,
wherein the fuel management system is configured to use both the at least one direct injector and the at least one port injector to introduce a mixture of ethanol with gasoline into a spark ignition engine during at least a part of a drive cycle,
wherein both the at least one direct injector and the at least one port injector are configured to operate at a highest torque value at which the spark ignition engine is operable at different speeds,
wherein the fuel management system is further configured such that the at least one direct injector provides an octane enhancement relative to the at least one port injector in the spark ignition engine due to evaporative cooling from direct injection by the at least one direct injector,
wherein the fuel management system is further configured to provide a stoichiometric or substantially stoichiometric air/fuel ratio in the spark ignition engine in at least a part of the part of the drive cycle in which the at least one direct injector and the at least one port injector introduce the mixture of ethanol with gasoline into the spark ignition engine,
wherein the fuel management system is further configured such that the at least one direct injector is inoperable to provide direct injection of the mixture of ethanol with gasoline when torque decreases below a selected value,
wherein the fuel management system is further configured to determine the selected value of torque by employing at least one of open loop control or closed loop control, and
wherein the fuel management system is further configured to prevent undesired autoignition of end gas in at least one cylinder in the spark ignition engine.

8. The fuel management system of claim 7 ,
wherein the open loop control is employed to determine the selected value of torque, and
wherein the open loop control uses predetermined information that comprises information about a dependence of an occurrence of undesired autoignition of end gas in at least one cylinder of the spark ignition engine upon engine torque.

9. The fuel management system of claim 7 , wherein closed loop control is employed to determine the selected value of torque.

10. The fuel management system of claim 7 ,
wherein the selected value of torque depends on an engine speed of the spark ignition engine, and
wherein the highest torque value at which the engine is operable depend on engine speed.

11. The fuel management system of claim 7 wherein the fuel management system is further configured such that an octane enhancement from ethanol in the mixture of ethanol with gasoline that is introduced by the at least one direct injector increases at a rate of at least four octane numbers for every 20% energy fraction of the mixture of ethanol with gasoline that is provided by the ethanol, the octane enhancement relative to gasoline being due to both higher evaporative cooling than gasoline and a higher octane number than gasoline.

12. The fuel management system of claim 7 , wherein the fuel management system is further configured to provide a uniform fuel distribution during at least a part of the part of the drive cycle in which both direct injection and port injection are used to introduce the mixture of ethanol with gasoline into the spark ignition engine.

13. A fuel management system for a spark ignition engine, comprising:
at least one direct injector;
at least one port injector; and
an electronic control unit configured to control use of the at least one direct injector and the at least one port injector,
wherein the fuel management system is configured to use both the at least one direct injector and the at least one port injector to introduc

Assignees

• Massachusetts Inst Technology

Inventors

• Bromberg Leslie
• Cohn Daniel R
• Heywood John B

Classifications

• Y02T10/30

  Use of alternative fuels, e.g. biofuels · CPC title

• F02B17/005

  having direct injection in the combustion chamber · CPC title

• F02D19/12

  peculiar to engines working with non-fuel substances or with anti-knock agents, e.g. with anti-knock fuel · CPC title

• Y02T10/12

  Improving ICE efficiencies · CPC title

• F02M37/0088

  Multiple separate fuel tanks or tanks being at least partially partitioned · CPC title