GB1582047A - Otto cycle engines with charge stratification - Google Patents
Otto cycle engines with charge stratification Download PDFInfo
- Publication number
- GB1582047A GB1582047A GB33955/77A GB3395577A GB1582047A GB 1582047 A GB1582047 A GB 1582047A GB 33955/77 A GB33955/77 A GB 33955/77A GB 3395577 A GB3395577 A GB 3395577A GB 1582047 A GB1582047 A GB 1582047A
- Authority
- GB
- United Kingdom
- Prior art keywords
- chamber
- cylinder
- precombustion chamber
- combustion
- internal combustion
- 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.)
- Expired
Links
- 238000013517 stratification Methods 0.000 title description 2
- 238000002485 combustion reaction Methods 0.000 claims description 57
- 239000000446 fuel Substances 0.000 claims description 15
- MWUXSHHQAYIFBG-UHFFFAOYSA-N nitrogen oxide Inorganic materials O=[N] MWUXSHHQAYIFBG-UHFFFAOYSA-N 0.000 claims description 15
- 239000000203 mixture Substances 0.000 claims description 10
- 239000007789 gas Substances 0.000 claims description 9
- 238000004891 communication Methods 0.000 claims description 8
- 238000002347 injection Methods 0.000 claims description 6
- 239000007924 injection Substances 0.000 claims description 6
- 230000000694 effects Effects 0.000 claims description 5
- 239000003344 environmental pollutant Substances 0.000 claims description 4
- 231100000719 pollutant Toxicity 0.000 claims description 4
- 239000007921 spray Substances 0.000 claims description 4
- 238000000034 method Methods 0.000 claims description 3
- 230000015572 biosynthetic process Effects 0.000 claims description 2
- 238000011144 upstream manufacturing Methods 0.000 claims description 2
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 description 3
- 229910002091 carbon monoxide Inorganic materials 0.000 description 3
- 239000004020 conductor Substances 0.000 description 2
- 229930195733 hydrocarbon Natural products 0.000 description 2
- 150000002430 hydrocarbons Chemical class 0.000 description 2
- 238000000889 atomisation Methods 0.000 description 1
- 230000006835 compression Effects 0.000 description 1
- 238000007906 compression Methods 0.000 description 1
- 238000004512 die casting Methods 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
- 230000006698 induction Effects 0.000 description 1
- 238000003754 machining Methods 0.000 description 1
- 230000001473 noxious effect Effects 0.000 description 1
- 230000009291 secondary effect Effects 0.000 description 1
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
- F02B19/00—Engines characterised by precombustion chambers
- F02B19/12—Engines characterised by precombustion chambers with positive ignition
-
- 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
- F02B19/00—Engines characterised by precombustion chambers
- F02B19/10—Engines characterised by precombustion chambers with fuel introduced partly into pre-combustion chamber, and partly into cylinder
- F02B19/1004—Engines characterised by precombustion chambers with fuel introduced partly into pre-combustion chamber, and partly into cylinder details of combustion chamber, e.g. mounting arrangements
- F02B19/1014—Engines characterised by precombustion chambers with fuel introduced partly into pre-combustion chamber, and partly into cylinder details of combustion chamber, e.g. mounting arrangements design parameters, e.g. volume, torch passage cross sectional area, length, orientation, or the like
-
- 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
- F02B19/00—Engines characterised by precombustion chambers
- F02B19/10—Engines characterised by precombustion chambers with fuel introduced partly into pre-combustion chamber, and partly into cylinder
- F02B19/1019—Engines characterised by precombustion chambers with fuel introduced partly into pre-combustion chamber, and partly into cylinder with only one pre-combustion chamber
- F02B19/108—Engines characterised by precombustion chambers with fuel introduced partly into pre-combustion chamber, and partly into cylinder with only one pre-combustion chamber with fuel injection at least into pre-combustion chamber, i.e. injector mounted directly in the pre-combustion chamber
-
- 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
- F02B2075/027—Engines characterised by their cycles, e.g. six-stroke having less than six strokes per cycle four
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y02T10/00—Road transport of goods or passengers
- Y02T10/10—Internal combustion engine [ICE] based vehicles
- Y02T10/12—Improving ICE efficiencies
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Combustion Methods Of Internal-Combustion Engines (AREA)
- Ignition Installations For Internal Combustion Engines (AREA)
Description
(54) IMPROVEMENTS IN OTTO CYCLE ENGINES WITH CHARGE
STRATIFICATION
(71) We, FIAT SOCIETA PER AZIONI, an
Italian joint stock company, of Corso
Marconi No. 10, Turin, Italy, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- The present invention relates to an Otto cycle internal combustion engine having spark ignition, fuel injection and a precombustion chamber separate from each associated cylinder.
A spark ignition internal combustion engine is known, for example from the
Italian Patent No. 920,436, having fuel injection and comprising at least one cylinder, a piston movable reciprocatingly in the said cylinder, means for the admission of air into the said cylinder, at least one precombustion chamber situated externally of the said cylinder, passage means which place the said precombustion chamber in communication with the said cylinder and through which air compressed by the piston passes completely into the said combustion chamber, and spark ignition means for igniting a stratified charge of fuel-air mixture in the precombustion chamber.
This arrangement is such that at the instant of sparking the said passage means are practically closed by the piston so that the combustion of the stratified charge takes place entirely outside the cylinder, in the precombustion chamber, which is of substantially spherical shape. Within the said precombustion chamber there is fixed, in a diametral position, a rod of suitable electrically conductive material which serves as a first electrode. A second electrode extends to the centre of the precombustion chamber and defines with the said first electrode a gap across which the spark jumps so as to effect ignition of a first fuel-rich portion of the stratified charge in the central zone of the precombustion chamber.
Practical tests carried out on such known engines have shown that, while the exhaust contains a minimum percentage of unburnt gases which are noxious as regards their atmospheric pollution effects, such as, for example, carbon monoxide (CO), nitrogen oxides (NO) and hydrocarbons, the specific power of such engines is not improved.
The present invention seeks to avoid this disadvantage and is based on the observation that in order to improve the specific power of such an engine while at the same time reducing the amount of the three aforementioned pollutant gases in the exhaust it is necessary to prolong the combustion of the said stratified fuel-air mixture, for example, in a second combustion chamber preferably situated in the crown of the piston.
With this object in view the present invention provides an internal combustion engine comprising at least one cylinder, a precombustion chamber external to the cylinder, said precombustion chamber and the cylinder communicating with one another, means for the injection of fuel into the precombustion chamber, a spark gap located centrally in the precombustion chamber, characterised in that, for the purpose of improving the specific power of the engine while reducing the quantity of unburnt gases in the engine exhaust, there is provided a second combustion chamber with a volume of between substantially 10 and 40 per cent of the total volume in which combustion takes place.
The provision of the second combustion chamber prolongs the combustion of the hot combustion products from the precombustion chamber and therefore reduces the amount of pollutant gases in the engine exhaust.
The invention will be further described, by way of non-limiting example, with reference to the accompanying drawings, in which:
Figure 1 is a fragmentary cross section of an internal combustion engine according to a preferred embodiment of the invention, and
Figure 2 is a fragmentary cross section of an internal combustion engine according to a further embodiment of the invention.
With particular reference to Figure 1, the illustrated engine comprises a block la formed with a number of cylinders 1, one only of which is shown, each cylinder 1 housing a piston 2 which is movable with reciprocating movement in the cylinder.
A substantially spherical precombustion chamber 3, one for each cylinder 1, is located externally of the cylinder 1 in a cylinder head 4 cooperating with the cylinder block, a gasket 4a being interposed in the plane Y-Y between the upper part of the cylinder block la and the cylinder head 4 to seal in the gases produced during the combustion stage within the cylinder 1.
A communication duct 5 in the cylinder head 4 places the precombustion chamber 3 in communication with the upper part of the associated cylinder 1. The duct 5 extends tangentially to the precombustion chamber 3 on one side of the longitudinal axis X-X of the cylinder 1. The axis of the duct 5 is inclined at an angle between 25 and 45" to the axis X-X of the cylinder 1, this angle being preferably 35". The duct 5, which is preferably of circular cross section, has a volume which is between 6 and 30% approximately of the volume of the precombustion chamber 3. Both the precombustion chamber 3 and the duct 5 are provided in the cylinder head 4 of the engine.
A second combustion chamber 6 is provided in the cylinder 1 itself, in a known way, by machining or by die-casting a shallow recess in the crown of the piston 2. The volume of the said second chamber 6, including that arising from the thickness of the gasket 4a between the cylinder head 4 and the cylinder block la, is between 10% and 40% approximately of the total volume in which combustion takes place, that is, the combined volume of the said precombustion chamber 3, the duct 5 and the second combustion chamber 6.
Reference numeral 7 indicates a petrol injector with one or more jets which is supplied with fuel under pressure by an injection pump (not shown). The injector 7 is located in the cylinder head 4 in such a manner that the actual jet or jets of fuel from the injector 7 to provide a spray of fuel having an axis directed towards the centre of the precombustion chamber 3. Where there are multiple jets these should all be arranged to direct a spray of fuel comprised within a cone having a maximum aperture of 80 , this angle preferably being 40 , the axis of the cone being directed towards the centre of the precombustion chamber 3.
A single electrode rod 8 of electrically conductive material extends diametrically across the said precombustion chamber 3.
The electrode rod 8 serves as an earth electrode and cooperates with a singleelectrode sparking plug 9 which serves as a live electrode, defining a spark gap with the electrode rod 8 in the central zone of the chamber 3. The sparking plug 9 is so positioned on the cylinder head 4 that it is coaxial with the centre of the precombustion chamber 3, the axis of the plug 9 being inclined to the axis passing through the centre of the precombustion chamber 3 and parallel to the said cylinder axis X-X at an angle between 2" and 10 , this angle being preferably 5".
The position of the injector 7 relative to the single-electrode sparking plug 9 is of particular importance, the axis of the injector 7 being inclined to the axis of the sparking plug 9 at an angle between 45" and 1500, and preferably between 60 and 90 .
The operation of the engine illustrated in
Figure 1 will now be described.
During the induction stage, when the piston 2 is sliding in the cylinder 1 of the cylinder block la from the top dead centre (TDC) to the bottom dead centre (BDC) position, air is drawn into the cylinder 1 thrpugh an inlet duct 10 and an associated inlet valve 12 into the second combustion chamber 6 in the crown of the said piston 2.
Fuel is injected from the multiple-hole injector 7 onto the central electrode rod 8 in the precombustion chamber 3, and in the subsequent compression stage, when the piston 2 returns towards top dead centre 10--70% approximately of the volume of air admitted into the cylinder 1 is compressed and transferred to the precombustion chamber 3 through the duct 5 which, by virtue of its tangential position relative to the chamber, imparts to the compressed air a centrifugal vortex flow.As a result of this vortex flow a stratified charge is produced in the precombustion chamber 3 characterised by an instantaneous atomization of the combustible fluid sprayed against the said central electrode rod 8 with, as a secondary characteristic, an enrichment of the proportion of petrol in the central zone of the said first precombustion chamber 3 in the proximity of the said central electrode rod 8.
During the combustion and expansion stages part of the mixture is burnt, the rest of the unburnt mixture, rich in carbon monoxide and hydrocarbons, passing through the duct 5 into the underlying second cobustion chamber 6 in the crown of the piston 2.
In this manner there is obtained, as a first effect, a lengthened duration of the combustion of the aforesaid unburnt gases by virtue of the mass of air remaining in the said communication duct 5 and in the said second combustion chamber 6 and, as a secondary effect, the transmigration of the said unburnt gas and combustion products from high temperature precombustion chamber 3 into the second combustion chamber 6, at a lower temperature.
During this tranmigration, and by virtue of the lower combustion temperature in the chamber 6, the process of formation of nitrogen oxides (NO) is in effect halted.
Figure 2 represents another embodiment of the invention in which the communication duct 5 shown in Figure 1 between the precombustion chamber 3 and the second combustion chamber 6 is dispensed with.
In this embodiment it is necessary to provide, upstream of the inlet valve 12, an auxiliary fuel injector 11 located in the inlet duct 10.
The auxiliary injector 11 serves for the admission into the second combustion chamber 6 of a lean combustible mixture having a proportion of petrol considerably lower than normal, combustion of this mixture being initiated by the hot combustion products from the precombustion chamber 3. In this manner, any eventual residue of unburnt pollutant gas is progressively burnt by combustion of the mixture injected into the said second combustion chamber 6.
The single electrode sparking plug 9 and electrode rod 8 shown in Figure 1 is dispensed with in the embodiment of Figure 2 m favour of a twin electrode sparking plug 91 having suitably elongate electrodes.
It will be understood that practical embodiments and their constructional details, can be widely varied from what has been described and illustrated whilst adhering to the principle of this invention and without departing from the scope of the invention.
WHAT WE CLAIM IS:
1. An internal combustion engine comprising at least one cylinder, a precombustion chamber external to the cylinder, said precombustion chamber and the cylinder communicating with one another, means for the- injection of fuel into the precombustion chamber, a spark gap located centrally in the precombustion chamber, and a second combustion chamber in said cylinder with a volume of between substantially 10 and 40 per cent of the total volume in which combustion takes place.
2. An internal combustion engine according to Claim 1, in which the second combustion chamber is formed in the crown of the piston.
3. An internal combustion engine according to Claim 1 or Claim 2, in which the said injector means are arranged to direct a spray of fuel comprised within a cone having an aperture of 80" and an axis directed towards the centre of said precombustion chamber.
4. An internal combustion engine according to Claim 1, Claim 2 or Claim 3, in which the ignition means comprise a singleelectrode sparking plug arranged with its axis inclined at an angle between 2" and 10 to the axis passing through the centre of the precombustion chamber and parallel to the axis of the associated engine cylinder.
5. An internal combustion engine according to any one of Claims 1 to 4, wherein the precombustion chamber and the cylinder communicate through a communication duct.
6. An internal combustion engine substantially as herein described with reference to, and as shown in, Figure 1 or Figure 2 of the accompanying drawings.
**WARNING** end of DESC field may overlap start of CLMS **.
Claims (6)
1. An internal combustion engine comprising at least one cylinder, a precombustion chamber external to the cylinder, said precombustion chamber and the cylinder communicating with one another, means for the- injection of fuel into the precombustion chamber, a spark gap located centrally in the precombustion chamber, and a second combustion chamber in said cylinder with a volume of between substantially 10 and 40 per cent of the total volume in which combustion takes place.
2. An internal combustion engine according to Claim 1, in which the second combustion chamber is formed in the crown of the piston.
3. An internal combustion engine according to Claim 1 or Claim 2, in which the said injector means are arranged to direct a spray of fuel comprised within a cone having an aperture of 80" and an axis directed towards the centre of said precombustion chamber.
4. An internal combustion engine according to Claim 1, Claim 2 or Claim 3, in which the ignition means comprise a singleelectrode sparking plug arranged with its axis inclined at an angle between 2" and 10 to the axis passing through the centre of the precombustion chamber and parallel to the axis of the associated engine cylinder.
5. An internal combustion engine according to any one of Claims 1 to 4, wherein the precombustion chamber and the cylinder communicate through a communication duct.
6. An internal combustion engine substantially as herein described with reference to, and as shown in, Figure 1 or Figure 2 of the accompanying drawings.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| IT69274/76A IT1078645B (en) | 1976-09-22 | 1976-09-22 | IMPROVEMENT OF THE COMBUSTION CHAMBER, ESPECIALLY FOR STRATIFIED LOAD ENGINES |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| GB1582047A true GB1582047A (en) | 1980-12-31 |
Family
ID=11311727
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB33955/77A Expired GB1582047A (en) | 1976-09-22 | 1977-08-12 | Otto cycle engines with charge stratification |
Country Status (6)
| Country | Link |
|---|---|
| JP (1) | JPS5340109A (en) |
| DE (1) | DE2742500A1 (en) |
| FR (1) | FR2365696A1 (en) |
| GB (1) | GB1582047A (en) |
| IT (1) | IT1078645B (en) |
| SU (1) | SU886758A3 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2123482A (en) * | 1982-05-21 | 1984-02-01 | Dr Andrew Martin Storrar | I.C. Engine combustion chambers |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE2312201A1 (en) * | 1973-03-12 | 1974-09-19 | Volkswagenwerk Ag | COMBUSTION ENGINE OPERATED WITH CHARGE STRATIFICATION |
| US3921605A (en) * | 1974-02-04 | 1975-11-25 | Gen Motors Corp | Plasma jet ignition engine and method |
-
1976
- 1976-09-22 IT IT69274/76A patent/IT1078645B/en active
-
1977
- 1977-08-12 GB GB33955/77A patent/GB1582047A/en not_active Expired
- 1977-09-20 SU SU772522850A patent/SU886758A3/en active
- 1977-09-21 DE DE19772742500 patent/DE2742500A1/en active Pending
- 1977-09-21 JP JP11277877A patent/JPS5340109A/en active Pending
- 1977-09-21 FR FR7728481A patent/FR2365696A1/en active Granted
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2123482A (en) * | 1982-05-21 | 1984-02-01 | Dr Andrew Martin Storrar | I.C. Engine combustion chambers |
Also Published As
| Publication number | Publication date |
|---|---|
| FR2365696A1 (en) | 1978-04-21 |
| IT1078645B (en) | 1985-05-08 |
| SU886758A3 (en) | 1981-11-30 |
| JPS5340109A (en) | 1978-04-12 |
| DE2742500A1 (en) | 1978-03-30 |
| FR2365696B1 (en) | 1979-03-02 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PS | Patent sealed [section 19, patents act 1949] | ||
| PCNP | Patent ceased through non-payment of renewal fee |