EP0060802A1 - Air-charging control system for two-cycle diesel engine - Google Patents

Air-charging control system for two-cycle diesel engine Download PDF

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Publication number
EP0060802A1
EP0060802A1 EP82730026A EP82730026A EP0060802A1 EP 0060802 A1 EP0060802 A1 EP 0060802A1 EP 82730026 A EP82730026 A EP 82730026A EP 82730026 A EP82730026 A EP 82730026A EP 0060802 A1 EP0060802 A1 EP 0060802A1
Authority
EP
European Patent Office
Prior art keywords
scavenging
air
exhaust
chamber
cylinder
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.)
Ceased
Application number
EP82730026A
Other languages
German (de)
English (en)
French (fr)
Inventor
Yozo c/o. Nagasaki Technical Institute Tosa
Mataji C/O Nagasaki Technical Institute Tateishi
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.)
Mitsubishi Heavy Industries Ltd
Original Assignee
Mitsubishi Heavy Industries 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 Mitsubishi Heavy Industries Ltd filed Critical Mitsubishi Heavy Industries Ltd
Publication of EP0060802A1 publication Critical patent/EP0060802A1/en
Ceased 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
    • F02B33/44—Passages conducting the charge from the pump to the engine inlet, e.g. reservoirs
    • 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
    • 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
    • F02B3/06—Engines characterised by air compression and subsequent fuel addition with compression ignition

Definitions

  • the piston 01 then ascends again to cover the scavenging ports 08, followed by closing of the exhaust valve 03, too.
  • the air trapped inside the cylinder 02 is compressed by the rising piston 01 and is burned together with fuel injected, developing a high pressure to give an expansive work to the piston 01 in its expansion stroke. The work is taken out as power output.
  • FIG. 2 is shown schematically an existing turbocharged two-cycle diesel engine equipped with a piston-underside pump.
  • the numerals 01 to 08 are used to designate the members like those in FIG. 1.
  • a piston-underside chamber 09 communicates directly with the space underneath the piston.
  • a scavenging reservoir 010 is provided in communication with the blower 06 to receive compressed air. Between this scavenging reservoir 010 and the scavenging chamber 07 is installed a check valve 011 which permits a unidirectional flow of compressed air from the reservoir to the chamber.
  • Another check valve 012 is disposed between the scavenging reservoir 010 and the piston-underside chamber 09 to permit only the flow from the reservoir 010 to the latter.
  • This invention relates to improvements in the air-charging control system of a two-cycle engine.
  • FIGURE 1 is a schematic illustration of a conventional two-cycle diesel engine of the exhaust-turbo supercharged type.
  • a piston 01 a cylinder 02, an exhaust valve 03, and an exhaust manifold 04 which communicates with the cylinder 02 through the exhaust valve 03.
  • the reference numeral 05 indicates a turbine of the exhaust-turbo supercharger communicated with the exhaust manifold 04
  • the numeral 06 indicates a blower of the supercharger adapted to run on the same shaft as with the turbine 05.
  • a scavenging chamber 07 is formed around the cylinder 02 to receive compressed air from the blower 06.
  • scavenging ports 08 In the wall of the cylinder 02 are formed scavenging ports 08, which are closed and opened as the piston 01 moves up and down to control the communication between the scavenging chamber 07 and the cylinder 02.
  • the exhaust valve 03 opens to release exhaust gases from the cylinder 02 into the exhaust manifold 04.
  • the high- temperature, high-pressure exhaust energy drives the turbine 05 and therefore the blower 06 on the common shaft, with the consequence that air is compressed by the latter and led into the scavenging chamber 07.
  • FIG. 3 graphically represents changes in the pressure inside the cylinder (full line), scavenging pressure (broken line), and exhaust pressure (alternate long and short dashes line) during the upward or scavenging stroke of the piston 01 in the conventional engine of FIG. 1.
  • the exhaust valve 03 opens to release the exhaust gases under a high pressure.
  • the pressure inside the cylinder 02 decreases to a level below the scavenging pressure before the scavenging ports 08 are opened. This permits copious supply of scavenging air from the chamber 07 into the cylinder while the scavenging ports 08 are open, or over the period from SPO to SPC.
  • FIG. 4 is a pressure-stroke volume diagram of a cylinder cycle
  • delaying the timing for opening the exhaust valve 03, or EVO, from the point A to the point B increases the effective expansion stroke of the engine accordingly, enabling additional power corresponding to the hatched area in the figure to be taken out. This means more power output from a given amount of fuel and hence a lower fuel consumption by the engine.
  • Compressed air from the blower 06 is conducted into the scavenging reservoir 010 and thence, during the upward stroke of the piston 01, is drawn by suction into the piston-underside chamber 09 through the check valve 012 to relieve the partial vacuum formed by the rising piston.
  • the present invention has for its object the provision of an air-charging control system for a two-cycle diesel engine of the exhaust-turbo supercharged type capable of saving the fuel consumption in the light of the foregoing, scavenging ports 08 will open while.the pressure inside the cylinder 02 is still higher than that inside the scavenging chamber 07. Consequently, during the period hatched in FIG. 5, a phenomenon known as exhaust blowback will take place, in which the residual exhaust gases in the cylinder 02 flows back through the scavenging ports 08 into the scavenging chamber 07.
  • the blowback can choke the scavenging ports 08 with carbides in the residual exhaust gases during the scavenging period, thus seriously affecting the reliability of the engine.
  • the burned gases so blown back are again forced into the cylinder during the remainder of the scavenging period, largely decreasing the efficiency of scavenging the cylinder 02 and increasing the fuel consumption due to aggravation of combustion performance with insufficient air supply.
  • the attempt of extending the effective expansion stroke by delaying the timing for opening the exhaust valve gives a rather undesirable result of larger fuel consumption.
  • the other engine of the prior art shown in FIG. 2 is modified so that, as the piston 01 moves downward, the air in the piston-underside chamber 09 is compressed and forced into the scavenging chamber 07.
  • the scavenging pressure (broken line) in the scavenging chamber characterized in that:
  • the numeral 1 designates a piston, 2 a cylinder, 3 an exhaust valve, and 4 an exhaust manifold into which burned gases from the cylinder 2 is conducted through the exhaust valve 3.
  • the turbine 5 of an exhaust-turbo supercharger receives part of the gases from the exhaust manifold 4.
  • the blower 6 of the supercharger is driven in parallel with the turbine 5 on the same shaft.
  • a scavenging chamber 7 is formed around the cylinder 2 as one of separate compartments for the respective cylinders. Scavenging ports 8 are formed in the surrounding wall of each cylinder 2 to provide and shut off communication between the scavenging chamber 7 and the cylinder 2 as the piston 1 moves up and down.
  • An air-charging chamber 101 common to the cylinders 2 is adapted to receive compressed air from the blower 6.
  • One such charging chamber 101 may be provided for each blower 6 of the exhaust-turbo supercharger as well as for the total number of cylinders as in the embodiment being described.
  • Indicated at 102 are air-charging control valves for the individual cylinders, each installed between the air-charging chamber 101 and the scavenging chamber 7 of each cylinder.
  • Each air-charging control valve 102 is driven by an actuator 103 to close and thereby cut off the communication between the air-charging chamber 101 and the scavenging chamber 7 of the associated cylinder, for either the whole period in which the scavenging ports 8 of the associated cylinder are open or at least the part of the period including the point of time when the ports 8 close, and to open so as to charge air under a high pressure from the charging chamber 101 into the scavenging chamber 7 of the associated cylinder for the remainder of the period.
  • the actuator 103 is timed with the crank angle of the engine to open or close the air-charging control valve 102.
  • an oil hydraulic cylinder is shown in FIG. 7, the actuator may take the form of an electric or cam-type drive means.
  • the air-charging control valve 102 may be provided for each of the cylinders 2, or alternatively only certain cylinders may be equipped with such valves.
  • the air-charging chamber 101 is kept in communication with the scavenging chambers 7 of the remaining cylinders 2 not equipped with the valves.
  • Air under a high pressure is forced from the blower 6 into the air-charging chamber 101 and thence is charged into the scavenging chamber 7 through the air-charging control valve 102 as the valve is opened by the actuator 103 during the period in which the scavenging ports 8 remain covered by the piston 1 on its compression and expansion strokes.
  • the charging control valve 102 is closed by the actuator 103.
  • the pressure inside the scavenging chamber 7 drops as the air volume decreases due to the ingress of scavenging air into the cylinder 2.
  • the pressure inside the cylinder 2 declines, too, until it and the scavenging pressure are both reduced to levels substantially equal to the exhaust pressure immediately before the piston 1 that has passed its bottom dead center and rebounded covers the scavenging ports 8.
  • FIG. 9 are graphically shown changes in the pressure inside the cylinder (full line), scavenging pressure (broken line), exhaust pressure (alternate long and short dashes line), and pressure inside the air-charging chamber (dotted line) during the scavenging-exhaust stroke of the engine incorporating the present embodiment. Since the charging pressure can be set higher than the exhaust pressure as will be explained later, the scavenging pressure at the time the scavenging ports are opened, SPO, is kept high.
  • the pressure inside the cylinder after the opening of the scavenging ports 8 is lower than the pressure inside the scavenging chamber 7, and there is no possibility of the residual exhaust gases flowing back through the scavenging ports 8 into the chamber 7.
  • the quantity of scavenging air per cycle, G is, where the overall opening time and area of the scavenging ports 8 are adequate, approximately expressed as where P b is the pressure inside the air-charging chamber, P el is the exhaust pressure, and V is the volume of the scavenging chamber.
  • V s The greater the difference between the charging and exhaust pressures, or the larger the volume of the scavenging chamber, V s , the more is the quantity of air available for scavenging.
  • the energy balance between the turbine 5 and the blower 6 of the exhaust-turbo supercharger determines the level of the charging chamber pressure P b with respect to the exhaust pressure P el .
  • the pressure P b relative to the pressure P el can be raised as the supercharger efficiency increases, or as the scavenging air quantity decreases and the exhaust temperature increases.
  • this embodiment of the invention obtains a high scavenging pressure, at the time the scavenging ports are opened, by means of the turbine 5 and the blower 6 of the supercharger using the exhaust energy, not by the compression work of the piston in the piston-underside chamber as in FIG. 2.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Supercharger (AREA)
EP82730026A 1981-03-14 1982-03-09 Air-charging control system for two-cycle diesel engine Ceased EP0060802A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP56035983A JPS57151020A (en) 1981-03-14 1981-03-14 Supply air control device of 2-cycle diesel engine
JP35983/81 1981-03-14

Publications (1)

Publication Number Publication Date
EP0060802A1 true EP0060802A1 (en) 1982-09-22

Family

ID=12457106

Family Applications (1)

Application Number Title Priority Date Filing Date
EP82730026A Ceased EP0060802A1 (en) 1981-03-14 1982-03-09 Air-charging control system for two-cycle diesel engine

Country Status (3)

Country Link
EP (1) EP0060802A1 (ja)
JP (1) JPS57151020A (ja)
DK (1) DK150316C (ja)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0469596A2 (en) * 1990-07-31 1992-02-05 Yamaha Hatsudoki Kabushiki Kaisha Multi-cylinder two cycle internal combustion engine
US5623895A (en) * 1994-02-07 1997-04-29 Yamaha Hatsudoki Kabushiki Kaisha V-type, multi-cylinder, two-cycle engine
WO1998000632A1 (en) * 1996-07-01 1998-01-08 Nilsson Nils Johan Engine
GB2473446A (en) * 2009-09-09 2011-03-16 Univ Brunel Two stroke internal combustion engine with a blower air reservoir

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH063141B2 (ja) * 1985-01-10 1994-01-12 三菱重工業株式会社 ユニフロ−機関の掃気ポンプ装置
EP0267905A1 (en) * 1986-05-29 1988-05-25 PIEN, Pao Chi A two-cycle internal combustion engine

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB737340A (en) * 1953-06-04 1955-09-21 Burmeister & Wains Mot Mask Improvements in and relating to turbo-charged two-stroke cycle internal combustion engines
GB765950A (en) * 1954-12-17 1957-01-16 Sulzer Ag Multi-cylinder two-stroke internal combustion engines having exhaust gas turbo chargers
FR1155449A (fr) * 1956-08-08 1958-04-28 S O B E M Soc De Brevets Et D Perfectionnements apportés aux moteurs à combustion interne suralimentés
CH342407A (de) * 1956-08-16 1959-11-15 Bbc Brown Boveri & Cie Mehrzylindriger Zweitaktbrennkraftmotor
GB1145945A (en) * 1966-10-11 1969-03-19 Sulzer Ag Supercharged two-stroke internal combustion engines

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB737340A (en) * 1953-06-04 1955-09-21 Burmeister & Wains Mot Mask Improvements in and relating to turbo-charged two-stroke cycle internal combustion engines
GB765950A (en) * 1954-12-17 1957-01-16 Sulzer Ag Multi-cylinder two-stroke internal combustion engines having exhaust gas turbo chargers
FR1155449A (fr) * 1956-08-08 1958-04-28 S O B E M Soc De Brevets Et D Perfectionnements apportés aux moteurs à combustion interne suralimentés
CH342407A (de) * 1956-08-16 1959-11-15 Bbc Brown Boveri & Cie Mehrzylindriger Zweitaktbrennkraftmotor
GB1145945A (en) * 1966-10-11 1969-03-19 Sulzer Ag Supercharged two-stroke internal combustion engines

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5251584A (en) * 1990-07-13 1993-10-12 Yamaha Hatsudoki Kabushiki Kaisha Two cycle engine
EP0469596A2 (en) * 1990-07-31 1992-02-05 Yamaha Hatsudoki Kabushiki Kaisha Multi-cylinder two cycle internal combustion engine
EP0469596A3 (en) * 1990-07-31 1993-03-03 Yamaha Hatsudoki Kabushiki Kaisha Multi-cylinder two cycle internal combustion engine
US5623895A (en) * 1994-02-07 1997-04-29 Yamaha Hatsudoki Kabushiki Kaisha V-type, multi-cylinder, two-cycle engine
WO1998000632A1 (en) * 1996-07-01 1998-01-08 Nilsson Nils Johan Engine
US6109248A (en) * 1996-07-01 2000-08-29 Nilsson; Nils-Johan Engine
GB2473446A (en) * 2009-09-09 2011-03-16 Univ Brunel Two stroke internal combustion engine with a blower air reservoir
GB2473446B (en) * 2009-09-09 2014-06-11 Univ Brunel Two stroke internal combustion engine with a blower air reservoir

Also Published As

Publication number Publication date
DK110082A (da) 1982-09-15
JPS57151020A (en) 1982-09-18
JPS6229612B2 (ja) 1987-06-26
DK150316C (da) 1987-11-23
DK150316B (da) 1987-02-02

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PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

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Effective date: 19821012

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Effective date: 19870624

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Inventor name: TATEISHI, MATAJIC/O NAGASAKI TECHNICAL INSTITUTE

Inventor name: TOSA, YOZOC/O. NAGASAKI TECHNICAL INSTITUTE