GB2259549A - Two stroke engine with pressurised air direct fuel injection - Google Patents

Two stroke engine with pressurised air direct fuel injection Download PDF

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Publication number
GB2259549A
GB2259549A GB9119450A GB9119450A GB2259549A GB 2259549 A GB2259549 A GB 2259549A GB 9119450 A GB9119450 A GB 9119450A GB 9119450 A GB9119450 A GB 9119450A GB 2259549 A GB2259549 A GB 2259549A
Authority
GB
United Kingdom
Prior art keywords
piston
engine
fuel injection
annular chamber
chamber
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Withdrawn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
GB9119450A
Other versions
GB9119450D0 (en
Inventor
Brian Stanley Cumming
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.)
Ford Motor Co
Original Assignee
Ford Motor Co
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 Ford Motor Co filed Critical Ford Motor Co
Priority to GB9119450A priority Critical patent/GB2259549A/en
Publication of GB9119450D0 publication Critical patent/GB9119450D0/en
Publication of GB2259549A publication Critical patent/GB2259549A/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Withdrawn legal-status Critical Current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
    • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
    • F02B33/00—Engines characterised by provision of pumps for charging or scavenging
    • F02B33/02—Engines with reciprocating-piston pumps; Engines with crankcase pumps
    • F02B33/06—Engines with reciprocating-piston pumps; Engines with crankcase pumps with reciprocating-piston pumps other than simple crankcase pumps
    • F02B33/10—Engines with reciprocating-piston pumps; Engines with crankcase pumps with reciprocating-piston pumps other than simple crankcase pumps with the pumping cylinder situated between working cylinder and crankcase, or with the pumping cylinder surrounding working cylinder
    • F02B33/14—Engines with reciprocating-piston pumps; Engines with crankcase pumps with reciprocating-piston pumps other than simple crankcase pumps with the pumping cylinder situated between working cylinder and crankcase, or with the pumping cylinder surrounding working cylinder working and pumping pistons forming stepped piston
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01B—MACHINES OR ENGINES, IN GENERAL OR OF POSITIVE-DISPLACEMENT TYPE, e.g. STEAM ENGINES
    • F01B7/00—Machines or engines with two or more pistons reciprocating within same cylinder or within essentially coaxial cylinders
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
    • F02B1/00—Engines characterised by fuel-air mixture compression
    • F02B1/02—Engines characterised by fuel-air mixture compression with positive ignition
    • F02B1/08—Engines characterised by fuel-air mixture compression with positive ignition with separate admission of air and fuel into cylinder
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
    • F02B3/00—Engines characterised by air compression and subsequent fuel addition
    • F02B3/02—Engines characterised by air compression and subsequent fuel addition with positive ignition
    • 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
    • F02M67/00—Apparatus in which fuel-injection is effected by means of high-pressure gas, the gas carrying the fuel into working cylinders of the engine, e.g. air-injection type
    • F02M67/02—Apparatus in which fuel-injection is effected by means of high-pressure gas, the gas carrying the fuel into working cylinders of the engine, e.g. air-injection type the gas being compressed air, e.g. compressed in pumps
    • 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
    • F02M67/00—Apparatus in which fuel-injection is effected by means of high-pressure gas, the gas carrying the fuel into working cylinders of the engine, e.g. air-injection type
    • F02M67/02—Apparatus in which fuel-injection is effected by means of high-pressure gas, the gas carrying the fuel into working cylinders of the engine, e.g. air-injection type the gas being compressed air, e.g. compressed in pumps
    • F02M67/04—Apparatus in which fuel-injection is effected by means of high-pressure gas, the gas carrying the fuel into working cylinders of the engine, e.g. air-injection type the gas being compressed air, e.g. compressed in pumps the air being extracted from working cylinders of the engine
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
    • F02B75/00—Other engines
    • F02B75/02—Engines characterised by their cycles, e.g. six-stroke
    • F02B2075/022—Engines characterised by their cycles, e.g. six-stroke having less than six strokes per cycle
    • F02B2075/025—Engines characterised by their cycles, e.g. six-stroke having less than six strokes per cycle two

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Fuel-Injection Apparatus (AREA)

Abstract

Two or more stepped pistons 14 are reciprocable in respective stepped bores 12, each piston and cylinder unit defining a variable volume combustion chamber 16 and a variable volume annular chamber 18. The engine also has a fuel injection system with a pressurised air rail 40 for injecting fuel directly into the engine combustion chambers. Each annular chamber has two outlet ports. A first port 22 leads to the combustion chamber 16 of another piston and is closed by the piston before the piston reaches its top dead centre position. A second port leads from the top of each annular chamber to the pressurised air rail 40 of the fuel injection system to avoid the need for an external compressor. <IMAGE>

Description

Two Stroke Engine Field of the invention The present invention relates to a two stroke engine of the type having stepped pistons.
Background of the invention Two stroke engines with stepped pistons are known, for example from GB 2,113,800 and other publications in the name of B. Hooper. The stepped piston reciprocable in a stepped bore define two variable volume working chambers. The central chamber acts as a working chamber and the annular surrounding chamber acts as a compressor to compress the charge delivered to the working chamber of another cylinder.
This avoids the need for crankcase compression and the resulting problems in the design and lubrication of the crankshaft bearings.
Important advances in the fuelling of two stroke engines have also been made recently by the Orbital Company of Australia which have resulted in cleaner and more efficient engines. A form of fuel injection is used which uses a fuel rail containing pressurised air. When the injector valve is opened, air and fuel enter the combustion chamber in the form of a finely atomised mist which burns very efficiently.
A separate compressor is used in the Orbital engine to pressurise the fuel rail and this adds to cost and complexity.
Object of the invention The present invention seeks to provide a two stroke engine which benefits from the advantages of the Hooper and Orbital engines while avoiding the need for a separate compressor to pressurise the fuel rail.
Summarv of the invention According to the present invention, there is provided a two stroke internal combustion engine having at least one stepped piston reciprocable in a cylinder with a stepped bore to define a variable volume combustion chamber and a variable volume annular chamber, and a fuel injection system having a pressurised air rail for injecting fuel directly into each combustion chamber, wherein a first port leads from the annular chamber of each stepped piston to a combustion chamber of the engine, which first port is closed by the piston before the piston approaches its top dead centre position, and a second port leads from the top of each annular chamber to the pressurised air rail of the fuel injection system.
The annular variable volume chambers of the stepped pistons in the present invention serve two purposes. In the first part of the compression stroke, a pressurised charge is delivered to the combustion chamber of another piston in the same way as in a Hooper engine. Towards the end of the stroke, however, the annular chamber is isolated by the piston from the other cylinder and the remaining volume of the annular chamber acts as a compressor to pressurise the compressed air rail of the fuel injection system as present in an Orbital engine.
The invention will now be described further, by way of example, with reference to the accompanying drawing which is a schematic section through an engine of the invention.
The drawing shows a two cylinder engine having an engine block 10 with two stepped cylinder bores 12, 12' and two stepped pistons 14, 14'. In the drawings the same reference numerals will be used to designate similar components in the two cylinders, the numerals referring to the cylinder on the right in the drawing being primed.
Each piston-cylinder unit defines two variable volume working chambers 16 and 18 of which the chamber 16 is the main combustion chambers. As in a Hooper engine, the annular chambers 18, 18' act as compressors for the charge of another cylinder so that the charge for combustion chamber 16 is compressed in chamber 18' and the charge for combustion chamber 16' is compressed in annular chamber 18.
Each annular chamber has an air intake port 20. A second port 22 near, but not at, the top of the annular chamber 18 leads by way of a conduit 24 formed in the block 10 to an intake port 26' of the combustion chamber 16' of the other cylinder. As the piston 14 moves up from its illustrated position, air compressed in the annular chamber 18 is forced along the conduit 24 into the combustion chamber 16' which at that time will be expanding as a result of the downward movement of its piston 14'. Thus in the combustion c-le, the intake charge for the cylinder 12' is drawn in frc port 20, compressed by annular chamber 18 and transferred to the combustion chamber 16 through the conduit 24. After combustion, the exhaust gases are discharged through an exhaust port 28'.The air flow directions are therefore as represented by the arrows in the drawing.
As so far briefly described, the engine operates in the same manner as a Hooper engine and any developments applicable to a Hooper engine are equally applicable to the engine of the invention. For example, reed valves may be incorporated in the various conduits to control the air flow along them.
It should be mentioned at this juncture that though described by reference to a two cylinder engine, the invention can be applied to engines with three or more cylinders in which case the conduits 24 will not necessary connect adjacent cylinders. The invention may also be applied to a single cylinder engine having a so-called surge tank or reservoir.
The engine also has a compressed air rail 40 which is connected to the fuel injection system of the individual cylinders. The injection system has injectors and Valves which are not shown in the drawing but are known per se from the Orbital engine referred to above. For the purposes of the present invention, it suffices to know that the pressurised air rail is required for blowing air and fuel into the combustion chambers when the valves at the injection ports are open.
In known engines, the rail 40 is pressure by means of an engine driven compressor but in the present invention the need for an external compressor is avoided by using annular chambers 18. Because the port 22 is not at the top of the annular chamber, it is closed off by the piston 14 before the latter completes its stroke. The air in the annular chamber 18' above the piston 14' in the position illustrated is further compressed as the piston completes its stroke and is supplied by a channel 44' containing a suitable one-way valve (not shown) to the air rail 40.
Thus the first part of the compression stroke in each annular chamber 18 acts as a charge compressor for another cylinder and the last part of the stroke acts as a compressor for pressurising the air rail of the fuel injection system.

Claims (3)

1. A two stroke internal combustion engine having at least one stepped piston reciprocable in a cylinder with a stepped bore to define a variable volume combustion chamber and a variable volume annular chamber, and a fuel injection system having a pressurised air rail for injecting fuel directly into each combustion chamber, wherein a first port leads from the annular chamber of each stepped piston to a combustion chamber of the engine, which first port is closed by the piston before the piston approaches its top dead centre position, and a second port leads from the top of each annular chamber to the pressurised air rail of the fuel injection system.
2. A two stroke engine as claimed in claim 1, having a plurality of cylinders with stepped bores and in which the annular chamber of each piston serves to compress the charge supplied to the combustion chamber of another piston.
3. A two stroke internal combustion engine constructed, arranged and adapted to operate substantially as herein described with reference to and as illustrated in the accompanying drawing.
GB9119450A 1991-09-12 1991-09-12 Two stroke engine with pressurised air direct fuel injection Withdrawn GB2259549A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB9119450A GB2259549A (en) 1991-09-12 1991-09-12 Two stroke engine with pressurised air direct fuel injection

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB9119450A GB2259549A (en) 1991-09-12 1991-09-12 Two stroke engine with pressurised air direct fuel injection

Publications (2)

Publication Number Publication Date
GB9119450D0 GB9119450D0 (en) 1991-10-23
GB2259549A true GB2259549A (en) 1993-03-17

Family

ID=10701262

Family Applications (1)

Application Number Title Priority Date Filing Date
GB9119450A Withdrawn GB2259549A (en) 1991-09-12 1991-09-12 Two stroke engine with pressurised air direct fuel injection

Country Status (1)

Country Link
GB (1) GB2259549A (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6895909B2 (en) * 2002-04-12 2005-05-24 Kawasaki Jukogyo Kabushiki Kaisha Two-cycle combustion engine having two-staged piston
WO2013144723A3 (en) * 2012-03-26 2014-02-20 Ac Aeronautical Ltd. Cross charge transfer engine

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB133870A (en) *
GB1495556A (en) * 1973-11-10 1977-12-21 Norton Villiers Ltd Stepped-piston two-stroke engines

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB133870A (en) *
GB1495556A (en) * 1973-11-10 1977-12-21 Norton Villiers Ltd Stepped-piston two-stroke engines

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6895909B2 (en) * 2002-04-12 2005-05-24 Kawasaki Jukogyo Kabushiki Kaisha Two-cycle combustion engine having two-staged piston
WO2013144723A3 (en) * 2012-03-26 2014-02-20 Ac Aeronautical Ltd. Cross charge transfer engine
GB2509285A (en) * 2012-03-26 2014-06-25 Ac Aeronautical Ltd Cross charge transfer engine
GB2509285B (en) * 2012-03-26 2015-04-22 Ac Aeronautical Ltd Cross charge transfer engine

Also Published As

Publication number Publication date
GB9119450D0 (en) 1991-10-23

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Legal Events

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WAP Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1)