GB2293412A - Control of turbocharged engine fuel injection - Google Patents

Control of turbocharged engine fuel injection Download PDF

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Publication number
GB2293412A
GB2293412A GB9418406A GB9418406A GB2293412A GB 2293412 A GB2293412 A GB 2293412A GB 9418406 A GB9418406 A GB 9418406A GB 9418406 A GB9418406 A GB 9418406A GB 2293412 A GB2293412 A GB 2293412A
Authority
GB
United Kingdom
Prior art keywords
fuel
engine
supply apparatus
air
conduit
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
GB9418406A
Other versions
GB9418406D0 (en
Inventor
S Sokell
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Cummins Ltd
Original Assignee
Cummins Engine Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Cummins Engine Co Ltd filed Critical Cummins Engine Co Ltd
Priority to GB9418406A priority Critical patent/GB2293412A/en
Publication of GB9418406D0 publication Critical patent/GB9418406D0/en
Publication of GB2293412A publication Critical patent/GB2293412A/en
Withdrawn legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M55/00—Fuel-injection apparatus characterised by their fuel conduits or their venting means; Arrangements of conduits between fuel tank and pump F02M37/00
    • F02M55/02—Conduits between injection pumps and injectors, e.g. conduits between pump and common-rail or conduits between common-rail and injectors
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D1/00—Controlling fuel-injection pumps, e.g. of high pressure injection type
    • F02D1/02—Controlling fuel-injection pumps, e.g. of high pressure injection type not restricted to adjustment of injection timing, e.g. varying amount of fuel delivered
    • F02D1/06—Controlling fuel-injection pumps, e.g. of high pressure injection type not restricted to adjustment of injection timing, e.g. varying amount of fuel delivered by means dependent on pressure of engine working fluid
    • F02D1/065—Controlling fuel-injection pumps, e.g. of high pressure injection type not restricted to adjustment of injection timing, e.g. varying amount of fuel delivered by means dependent on pressure of engine working fluid of intake of air
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M63/00—Other fuel-injection apparatus having pertinent characteristics not provided for in groups F02M39/00 - F02M57/00 or F02M67/00; Details, component parts, or accessories of fuel-injection apparatus, not provided for in, or of interest apart from, the apparatus of groups F02M39/00 - F02M61/00 or F02M67/00; Combination of fuel pump with other devices, e.g. lubricating oil pump
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M63/00—Other fuel-injection apparatus having pertinent characteristics not provided for in groups F02M39/00 - F02M57/00 or F02M67/00; Details, component parts, or accessories of fuel-injection apparatus, not provided for in, or of interest apart from, the apparatus of groups F02M39/00 - F02M61/00 or F02M67/00; Combination of fuel pump with other devices, e.g. lubricating oil pump
    • 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
    • F02M63/0225—Fuel-injection apparatus having a common rail feeding several injectors ; Means for varying pressure in common rails; Pumps feeding common rails
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M2200/00—Details of fuel-injection apparatus, not otherwise provided for
    • F02M2200/30—Fuel-injection apparatus having mechanical parts, the movement of which is damped

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Output Control And Ontrol Of Special Type Engine (AREA)
  • Electrical Control Of Air Or Fuel Supplied To Internal-Combustion Engine (AREA)

Abstract

To decrease the fuel delivery and black smoke emissions on rapid acceleration the rate of fuel pressure increase in the pump delivery conduit 4 is reduced by compression of air 13 in a blind conduit 11 branching from the delivery conduit. The fuel pump 2 provides a delivery pressure which increases as a direct function of engine speed and a quantity determined by the pressure in the intake manifold 2 and supplies injectors 5 with cam-operated plungers. <IMAGE>

Description

FUEL SUPPLY APPARATUS FOR AN INTERNAL COMBUSTION ENGINE The present invention relates to fuel supply apparatus for an internal combustion engine, particularly a diesel engine.
There is prevailing concern over toxic emissions produced by vehicles and legislation throughout the world has reflected this concern by imposing limitations on engine exhaust emissions. In particular, there is strict control on the maximum amount of black smoke emitted by a diesel engine.
Black smoke or soot is produced from vehicle exhausts in certain circumstances by virtue of too much fuel being supplied to the combustion chamber of a diesel engine. Fuel which does not combust fully is emitted by the vehicle exhaust as soot or smoke. This problem is particularly prevalent in diesel engines which use a turbocharger to pressurise and increase the density of intake air. The amount of fuel supplied to fuel injectors of the engine is controlled by a fuel pump which delivers fuel at a rate dependent on the engine speed. During wide open throttle operation the engine can accelerate to its maximum rate in a very short period of time and so does the fuel rate. However, the turbocharger is driven by the exhaust gases and hence lags the acceleration of the engine by a significant amount and cannot deliver a sufficient level of air pressure to absorb the increased fuel vapour.The result is too much fuel being present during combustion and consequent generation of black smoke or soot emitted by the vehicle exhaust.
In an attempt to eliminate acceleration smoke, turbocharged engines are often fitted with an air/fuel control device which cooperates with the fuel pump to vary the fuel flow to the engine as a direct function of the intake manifold air pressure. Thus whenever the intake air pressure is below its maximum the control device acts to reduce the amount of fuel pumped to the engine.
The above described device is effective in minimising acceleration smoke.
However, the device cannot provide optimum performance throughout the engine range and overall engine performance may be affected. For example, the device may restrict the air/fuel mixture to a leaner ratio to avoid acceleration smoke but in the meantime this limits the engine power as the mix is not rich enough to produce maximum power over the full range of engine speeds.
US Patent No 4095572 describes a fuel system for a turbocharged diesel engine in which the fuel pressure is varied upon acceleration as a direct function of the engine's inlet air pressure. The air pressure signal used to control the amount of fuel is delayed by introducing a chamber of predetermined size. The air pressure signal must first fill the chamber before having an effect on the rate of fuel supply. The effect is to introduce a delay in the increase of the fuel rate to the engine thereby minimising acceleration smoke.
It is an object of the present invention to obviate or mitigate the aforesaid disadvantages.
According to the present invention there is provided fuel supply apparatus for an internal combustion engine, the apparatus comprising fuel delivery means for delivering fuel to the engine at a pressure level which increases as a direct function of increasing engine speed, and a fuel pressure damper acting between the fuel delivery means and the engine to damp the rate of increase of fuel pressure with time.
The damper is preferably pneumatic.
The fuel delivery means may supply fuel to the engine via a main fuel conduit and the damper is preferably in the form of an air-filled branch conduit connected to the main fuel conduit. The branch conduit may be a closed pipe filled at least partially with air and preferably mainly filled with air. Thus some of the fuel present in the main conduit will pass into the branch conduit and come into contact with the air. This will have the effect of damping any rapid changes in fuel pressure in the main conduit and allow the compressed air of a turbocharger to catch up with the increased fuel demand.
Preferably the branch pipe is in the form of a right-angled bend. The diameter to height ratio of the branch pipe is selected so that it cannot fill completely with fuel and is typically 30-40:1.
A specific embodiment of the present invention will now be described, by way of example only, with reference to the accompanying drawing which: Figure 1 is a schematic drawing of a diesel engine for use with the present invention; and Figure 2 is a schematic diagram of fuel supply apparatus according to the present invention.
Referring now to the drawings, Figure 1 shows an internal combustion diesel engine A with which the present invention may be used. Exhaust gases from the engine A pass across a turbine of a turbo charger B which drives a compressor C to pressurise air in inlet manifold D. Fuel for a turbocharged diesel engine (not shown) is drawn from a fuel tank 1 of a vehicle by fuel pump 2 in a conventional manner (see Figure 2).
The fuel is pumped via a solenoid valve 3 and fuel line 4 to fuel injectors 5 which are supplied by a common fuel line 6. The injectors 5 are of known direct injection design in which a cam actuated plunger (not shown) injects fuel at high pressure into engine cylinders (not shown) for combustion.
Any excess fuel not injected into the engine is returned to the tank 1 by return fuel line 7.
The fuel pump 2 has an air/fuel control device 8 which receives an air pressure signal 9 from an air intake manifold 10 of the engine and governs the amount of fuel to be pumped in response to the air pressure in the intake manifold. The greater the air pressure in the manifold the greater the amount of fuel air that is supplied by the fuel pump 2. The air/fuel control device 8 is of conventional bellows design and will not be described any further.
The exhaust gases from the engine pass over the turbine (not shown) of a turbocharger (not shown) which drives a corresponding compressor (not shown) to pressurise air in the intake manifold 10 in the conventional manner.
The fuel line 4 has an upstanding right-angled branch conduit 11 closed at an end 12 remote from the fuel line 4. The branch conduit 11 is filled mainly with air 13.
When fuel is delivered by the pump 2 to the injectors 5 via the common fuel line 6, a fraction of the fuel passes into the branch conduit 11 and communicates with the air 13 present therein.
When the vehicle operator requires the vehicle to accelerate, the increase of air pressure in the intake manifold 10 is detected by the air/fuel control device 8 and the pump 2 is operated to deliver a corresponding increase in fuel. The increase in fuel pressure in the common fuel line 6 will cause the fuel present in the branch conduit 11 to rise and compress the air 13 against the end 12. If the increase in the fuel pressure is gradual (i.e. a gradual acceleration is demanded by the vehicle operator) the compression of the air has no or negligible effect.
However, when full acceleration is demanded and the rate of increase of pressure in the fuel line 4 and branch conduit 11 is significant then the fuel in the branch conduit 11 rises and compresses the air. Compression of the air has a damping effect and restricts the rate of increase of the fuel pressure. This allows the turbocharger to catch up and supply air at increased pressure to absorb the fuel vapour. The damping effect prevents too much fuel being supplied to the engine and minimises the resultant black smoke from the non-combusted fuel without affecting the steady state operation of the engine.
The branch conduit is designed to prevent fuel completely filling the interior. A height to diameter ratio of 30-40:1 is suitable for most applications. It is also important that the upstanding part of the branch conduit remains vertical throughout a journey of a vehicle.
By acting directly on the fuel line as opposed to the air inlet (as in the system described in US 4095572) the reaction of the apparatus to the increased fuel demand is quicker and thus a faster response is achieved.
The present invention may be suitable for any form of fuel injection system where there is a lag between the air pressure and the fuel supply.

Claims (9)

1. Fuel supply apparatus for an internal combustion engine, the apparatus comprising fuel delivery means for delivering fuel to the engine at a pressure level which increases as a direct function of increasing engine speed, and a fuel pressure damper acting between the fuel delivery means and the engine to damp the rate of increase of fuel pressure with time.
2. Fuel supply apparatus according to claim 1, wherein the damper pneumatic.
3. Fuel supply apparatus according to any preceding claim, wherein the fuel delivery means supplies fuel to the engine via a main fuel conduit and the damper is a branch conduit connected to the main fuel conduit.
4. Fuel supply apparatus according to claim 3, wherein the branch conduit is closed at an end remote from the main conduit and filled at least partially with air.
5. Fuel supply apparatus according to claim 4, wherein the branch conduit is filled mainly with air.
6. Fuel supply apparatus according to claim 4 or 5, wherein the pipe has a right-angled bend.
7. Fuel supply apparatus substantially as hereinbefore described with reference to Figure 2 of the accompanying drawings.
8. An internal combustion engine having fuel supply apparatus according to any one of the preceding claims.
9. An internal combustion engine substantially as hereinbefore described with reference to the accompanying drawings.
GB9418406A 1994-09-13 1994-09-13 Control of turbocharged engine fuel injection Withdrawn GB2293412A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB9418406A GB2293412A (en) 1994-09-13 1994-09-13 Control of turbocharged engine fuel injection

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB9418406A GB2293412A (en) 1994-09-13 1994-09-13 Control of turbocharged engine fuel injection

Publications (2)

Publication Number Publication Date
GB9418406D0 GB9418406D0 (en) 1994-11-02
GB2293412A true GB2293412A (en) 1996-03-27

Family

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Family Applications (1)

Application Number Title Priority Date Filing Date
GB9418406A Withdrawn GB2293412A (en) 1994-09-13 1994-09-13 Control of turbocharged engine fuel injection

Country Status (1)

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GB (1) GB2293412A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2004076846A1 (en) * 2003-02-25 2004-09-10 Robert Bosch Gmbh High-pressure line for a fuel injection system

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB272450A (en) * 1926-06-11 1928-02-23 Sulzer Freres Societe Anonyme
GB2203803A (en) * 1987-04-15 1988-10-26 Perkins Engines Group Fuel injection

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB272450A (en) * 1926-06-11 1928-02-23 Sulzer Freres Societe Anonyme
GB2203803A (en) * 1987-04-15 1988-10-26 Perkins Engines Group Fuel injection

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2004076846A1 (en) * 2003-02-25 2004-09-10 Robert Bosch Gmbh High-pressure line for a fuel injection system

Also Published As

Publication number Publication date
GB9418406D0 (en) 1994-11-02

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