Fuel injector control incorporating fuel vaporization parameters

• US 5,408,972 A
• Filed: 06/28/1993
• Issued: 04/25/1995
• Est. Priority Date: 06/28/1993
• Status: Expired due to Fees

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Motor Company
• Inventors: Servati, Hamid B.
• Primary Examiner(s): Nelli, Raymond A.
• Application Number:
  US08/082,565
• Time in Patent Office: 666 Days
• Field of Search: 123/478, 123/684, 123/492, 123/493, 123/480, 123/682, 364/431.08
• US Class Current: 123/478
• CPC Class Codes: F02B 2275/14 Direct injection into combustion chamber
• CPC Class Codes: F02D 41/047 Taking into account fuel evaporation or wall wetting; special correction after fuel cut-off F02D41/126
• CPC Class Codes: Y02T 10/12 Improving ICE efficiencies

Abstract

A fuel injector control apparatus and system of controlling fuel injector operation is disclosed. The control utilizes signals representative of fuel vaporization parameters including conductive and convective fuel flow characteristics. In particular, the presence of liquid fuel on the walls of an intake port which fails to vaporize upon injection is compensated for by the fuel injector control. Algorithms are utilized for controlling fuel injection based upon the convective fuel vapor flow mass and the conductive fuel vaporization rate.

Claims

1. A method for controlling a fuel injection system of an internal combustion engine, said injection system including a microprocessor adapted to respond to engine speed, intake manifold pressure, mass air flow and charge temperature, the method comprising the steps of:

determining puddle fuel vapor pressure and generating a puddle fuel vapor pressure signal representative thereof;

determining air charge temperature and generating an air charge temperature signal representative thereof;

determining engine air mass flow and generating an engine air mass flow signal representative thereof;

determining fuel wetted area characteristic diameter signal representative thereof;

determining manifold pressure and generating a manifold pressure signal representative thereof;

determining engine speed and generating an engine speed signal representative thereof;

calculating, from the data represented by the puddle fuel vapor pressure signal, the air charge temperature signal, the engine air mass flow signal, the fuel wetted area characteristic diameter signal, the fuel wetted area characteristic length signal, the manifold pressure signal, and the engine speed signal, convective fuel vapor flow mass according to the following formula stored in a memory portion of said microprocessor;

##EQU4## where;

VAP=puddle fuel vapor pressure (in PSI)

ACT=air charge temperature (in °

R.)

AM=engine air mass flow (in pounds per second)

D=fuel wetted area characteristic diameter (in feet)

L=fuel wetted area characteristic length (in feet )

PMAN=manifold pressure (in inches of Hg)

N=engine speed (in RPM),

determining injected fuel flow mass rate and generating an injected fuel flow mass rate signal representative thereof;

determining puddle fuel temperature and generating a puddle fuel temperature signal representative thereof;

calculating conductive fuel vaporization rate according to the following formula;

space="preserve" listing-type="equation">M.sub.f *VAPFAC

where;

M_f =injected fuel flow mass rate

T_f =puddle fuel temperature (in °

F.)

VAPFAC=0.002 for Tf≦

0

VAPFAC=0.0021*T_f for 0<

T_f <

200

VAPFAC=0.003625*T_f -0.305 for 200<

T_f <

400; and

controlling the amount of fuel injected accordingly to compensate for fuel deposited on intake component surfaces and subsequently vaporized and mixed with air during injection cycles.

2. A method for controlling a fuel injection system of an internal combustion engine to regulate fuel delivery to a fuel/air mixture intake port in an intake manifold for said engine, said injection system including a microprocessor adapted to respond to engine speed, manifold pressure, mass air flow and charge temperature, an air charge temperature sensor in said intake manifold, an air mass flow sensor in said intake manifold, and a manifold pressure sensor in said intake manifold, the method comprising the steps of:

determining puddle fuel vapor pressure for liquid fuel delivered to said intake port and generating a puddle fuel vapor pressure signal representative thereof;

determining air charge temperature for combustion air delivered to said intake port and generating an air charge temperature signal representative thereof;

determining engine air mass flow of combustion air delivered to said intake port and generating an engine air mass flow signal representative thereof;

determining fuel wetted area of said intake port and generating a fuel wetted area characteristic diameter signal representative thereof;

determining intake manifold pressure and generating an intake manifold pressure signal representative thereof;

determining engine speed and generating an engine speed signal representative thereof;

calculating convective fuel vapor flow mass, using a control algorithm stored in a memory portion of said microprocessor, as a function of said signals represented by the puddle fuel vapor pressure, the air charge temperature, the engine air mass flow, the fuel wetted area characteristic, the manifold pressure, and the engine speed;

determining injected fuel flow mass rate and generating an injected fuel flow mass rate signal representative thereof;

determining fuel temperature of puddle fuel on said wetted area and generating a puddle fuel temperature signal representative thereof;

calculating conductive fuel vaporization rate as a function of said injected fuel mass flow rate signal and said puddle fuel temperature signal; and

controlling the amount of fuel injected accordingly to compensate for fuel deposited on intake manifold component surfaces and subsequently vaporized and mixed with air during injection cycles.