GB2115486A - I.C. engine inlet valve form - Google Patents

I.C. engine inlet valve form Download PDF

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Publication number
GB2115486A
GB2115486A GB08304786A GB8304786A GB2115486A GB 2115486 A GB2115486 A GB 2115486A GB 08304786 A GB08304786 A GB 08304786A GB 8304786 A GB8304786 A GB 8304786A GB 2115486 A GB2115486 A GB 2115486A
Authority
GB
United Kingdom
Prior art keywords
valve
inlet
seating surface
inlet valve
stem
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Withdrawn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
GB08304786A
Other versions
GB8304786D0 (en
Inventor
Roger Harvey Slee
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.)
AE PLC
Original Assignee
AE PLC
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 AE PLC filed Critical AE PLC
Priority to GB08304786A priority Critical patent/GB2115486A/en
Publication of GB8304786D0 publication Critical patent/GB8304786D0/en
Publication of GB2115486A publication Critical patent/GB2115486A/en
Withdrawn legal-status Critical Current

Links

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
    • F01L3/00—Lift-valve, i.e. cut-off apparatus with closure members having at least a component of their opening and closing motion perpendicular to the closing faces; Parts or accessories thereof
    • F01L3/06—Valve members or valve-seats with means for guiding or deflecting the medium controlled thereby, e.g. producing a rotary motion of the drawn-in cylinder charge
    • 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
    • F02B29/00—Engines characterised by provision for charging or scavenging not provided for in groups F02B25/00, F02B27/00 or F02B33/00 - F02B39/00; Details thereof
    • F02B29/02—Other fluid-dynamic features of induction systems for improving quantity of charge
    • 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

Abstract

The valve head includes a transitional portion 19 between the seating surface 16 and the constant diameter valve stem 131 which flares outwardly from the end of the stem to the seating surface. The axial length of the transitional portion is more than 80% up to 100% of the diameter of the seating surface to provide a smooth flow passage for a charge when the inlet valve is open. <IMAGE>

Description

SPECIFICATION Improvements in or relating to inlet valves The invention relates to inlet valves for internal combustion engines and to internal combustion engines including such inlet valves.
An inlet valve of an internal combustion engine comprises a valve head including a seating surface for co-operation with a valve seat, and a valve stem which passes through an inlet passage to a valve operating mechanism. The velocity flow pattern of a charge as it passes through the inlet passage and around the inlet valve, before entering the associated cylinder, affects the performance of the engine.
In order to save weight, previously proposed inlet valves have a stem of constant or substantially constant diameter which is as long as possible with a very short transitional portion between the end of the stem and the seating surface. Such an inlet valve is shown in British Patent Specification No. 1 246522. In view of this weight saving requirement, improvements in the flow pattern of the charge have previously been sought by variations in the shape of the valve seat.
Such shapes are shown, for example, in the aforementioned British Patent Specification No.
1246522.
Although such modified inserts improve the flow pattern to a certain extent, their very short axial length makes their effect limited.
According to a first aspect of the invention, there is provided an inlet valve for an internal combustion engine and comprising a valve stem of constant or substantially constant diameter along the length thereof, and a valve head including a seating surface for engagement with an associated valve seat and having a transitional portion extending between the valve stem and the seating surface, the transitional portion having an axial length which is more than 80% of the diameter of the seating surface and flaring outwardly from the valve stem to the seating surface to provide a smooth flow surface for a charge when the inlet valve is open.
According to a second aspect of the invention, there is provided an inlet valve when included in an internal combustion engine comprising at least one cylinder, an inlet passage for conveying a charge of fuel to the cylinder, the inlet passage being controlled by the inlet valve, the inlet valve having a valve stem of constant or substantially constant diameter along the length thereof and a valve head having a seating surface co-operating with an associated valve seat, the valve head having a portion which is between the seating surface and the valve stem and within the inlet passage and which is so shaped as to form with the inlet passage a smoothly converging passage for the charge as the charge passes to the associated cylinder.
The following is a more detailed description of some embodiments of the invention, by way of example, reference being made to the accompanying drawings, in which: Figure 1 is a cross-section through an inlet valve and through an associated inlet passage formed in a cylinder head of an internal combustion engine; Figure 2 is a side elevation of a second form of valve head for the inlet valve of Figure 1; and Figure 3 is a perspective view of a third form of valve head for the inlet valve of Figure 1.
Referring first to Fig. 1 , the cylinder head 10 is formed with an inlet passage 11. An inlet valve 1 3 controls the passage of the charge to the cylinder and includes a valve head 14 and a valve stem 1 5.
The valve head 14 has an annular seating surface 1 6 for co-operating sealing engagement with a valve seat 17, which may be formed on a valve seat insert of the kind, for example, described in European Patent Publication No. 0049075A. The valve stem 1 5 is of constant or substantially constant diameter along its length and passes through a guide 18 to engage a valve opening and closing mechanism (not shown) such as a cam and tappet system.
The valve head 14 is axially elongate to define a transitional portion 1 9 extending from the end of the valve stem 1 5 to the seating surface 16. The axial length of this portion is greater than 80% of the diameter of the seating surface 1 6. Typically, this axial length may be generally the same as the diameter of the seating surface 1 6. This length is limited only by the need to prevent the end of the transitional portion 1 9 hitting the guide 18 when the valve is closed and the attainment of a progressive "charge" velocity profile in the inlet passage.The outer surface 20 of this transitional portion 19 flares outwardly from the end of the stem 1 5 to the seating surface 1 6 so that the surface 20 is concavely curved in planes including the axis of the valve.
In use, the inlet valve 1 3 is opened to admit charge into the interior 1 2 of the associated cylinder. The charge flows through an initial portion 1 a of the inlet passage 11 with a velocity V1, until it reaches a neck 1 b where the velocity increases slightly to V2. The charge then passes around the stem 1 5 with a velocity V3 before reaching the valve head 14. The mixture next passes between the valve head 1 4 and an end portion 1 C of the passage 11 which form together a smoothly converging passage.The surface 20 provides a low resistance surface over which the charge flows so that the charge gradually and smoothly accelerates before it passes the seating surface 1 6 at a velocity V4 and enters the interior 12 of the cylinder.
Also shown in Fig. 1 in broken line is the shape of the transitional portion 25 of a conventional inlet valve. It will be seen that the length of the stem 1 5 is increased and that the length of the transitional portion 25 is shortened so that it is less than 80% of the diameter of the seating surface 1 6. This produces a very sudden step between the stem 1 5 and the valve head 14 which causes the turbulence around the valve stem 1 5 as shown by the arrows 26 in Fig. 1.
Thus the charge undergoes an abrupt acceleration causing significant flow loss and reduced cylinder filling efficiency.
It has been found that, in comparison with the conventional inlet valve, the valve shown in full line in Fig. 1 produces a marked improvement in the volumetric efficiency of the associated engine with a consequent improvement in power efficiency and cost effectiveness. For example, one test has shown an improvement of 10-1 5% in volumetric efficiency and a 56% improvement in power efficiency with an improved fuel economy at full load of 3%. In a diesel engine, such a valve insert has shown a reduction in exhaust smoke and exhaust gas temperature.
It will be appreciated that the increased size of the valve head 14 will increase the weight of the valve. This weight may be reduced by forming the valve head 14 with a closed cavity as shown in Fig. 2. The cavity 30 may be filled with a metallic substance which cools the valve head 1 4 by the extraction of heat from the valve head and its transfer to the valve stem. Alternatively, the valve head 14 may be formed with a depression 31 as shown in Fig. 3. This latter valve head 14 is formed separately from the valve stem 1 5 and is connected thereto by friction welding or electron beam welding.
The inlet valves of any of the types described above with reference to the drawings may be formed from a sintered metal.
It will be appreciated that the inlet valves of any of the above described types are interchangeable with conventional inlet valves without any engine re-design and in particular, without any inlet passage re-design.

Claims (12)

1. An inlet valve for an internal combustion engine and comprising a valve stem of constant or substantially constant diameter along the length thereof, and a valve head including a seating surface for engagement with an associated valve seat and having a transitional portion extending between the valve stem and the seating surface, the transitional portion having an axial length which is more than 80% of the diameter of the seating surface and flaring outwardly from the valve stem to the seating surface to provide a smooth flow surface for a charge when the inlet valve is open.
2. An inlet valve when included in an internal combustion engine comprising at least one cylinder, an inlet passage for conveying a charge of fuel to the cylinder, the inlet passage being controlled by the inlet valve, the inlet valve having a valve stem of constant or substantially constant diameter along the length thereof and a valve head having a seating surface co-operating with an associated valve seat, the valve head having a portion which is between the seating surface and the valve stem and within the inlet passage and which is so shaped as to form with the inlet passage a smoothly converging passage for the charge as the charge passes to the associated cylinder.
3. An inlet valve according to claim 1 or claim 2 wherein the axial length of the portion between the seating surface and the valve stem is equal to the diameter of the seating surface.
4. An inlet valve according to claim 1 or claim 2 wherein the valve stem is for receipt in or is received in a guide provided in the engine, the length of the portion between the seating surface and the valve stem being substantially equal to the distance from an end of said guide in the inlet passage and the seating surface, in an axial direction along the inlet valve and when the inlet valve is closed.
5. An inlet valve according to any one of claims I to 4 wherein the surface of the portion between the seating surface and the valve stem is concavely curved in planes including the axis of the valve stem.
6. An inlet valve according to any one of claims 1 to 5 wherein the valve head contains a closed cavity for reducing the weight of the valve.
7. An inlet valve according to claim 6 wherein the closed cavity is filled with a metallic substance for transferring heat from the valve head to the valve stem to cool the valve head.
8. An inlet valve according to any one of claims 1 to 5 wherein the valve head is formed with a depression on a surface thereof which, in use, faces into the associated cylinder of the internal combustion engine.
9. An inlet valve according to any one of claims 1 to 8 wherein the valve head and the valve stem are formed separately and are then connected together.
10. An inlet valve according to any one of claims 1 to 9 and formed by a sintering process.
11. An inlet valve substantially as hereinbefore described with reference to the accompanying drawings.
12. An inlet valve when included in an internal combustion engine and substantially as hereinbefore described with reference to the accompanying drawings.
GB08304786A 1982-02-20 1983-02-21 I.C. engine inlet valve form Withdrawn GB2115486A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB08304786A GB2115486A (en) 1982-02-20 1983-02-21 I.C. engine inlet valve form

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB8205068 1982-02-20
GB08304786A GB2115486A (en) 1982-02-20 1983-02-21 I.C. engine inlet valve form

Publications (2)

Publication Number Publication Date
GB8304786D0 GB8304786D0 (en) 1983-03-23
GB2115486A true GB2115486A (en) 1983-09-07

Family

ID=26282034

Family Applications (1)

Application Number Title Priority Date Filing Date
GB08304786A Withdrawn GB2115486A (en) 1982-02-20 1983-02-21 I.C. engine inlet valve form

Country Status (1)

Country Link
GB (1) GB2115486A (en)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4779584A (en) * 1987-02-24 1988-10-25 Warr Valves, Inc. Internal combustion engine intake valve
US5081965A (en) * 1990-08-15 1992-01-21 Warr Valves, Inc. Intake valve for internal combustion engine
US5335634A (en) * 1991-05-14 1994-08-09 Mazda Motor Corporation Combustion chamber structure for an engine
US5771852A (en) * 1997-03-04 1998-06-30 Trw Inc. Poppet valve with embossed neck structure

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4779584A (en) * 1987-02-24 1988-10-25 Warr Valves, Inc. Internal combustion engine intake valve
US5081965A (en) * 1990-08-15 1992-01-21 Warr Valves, Inc. Intake valve for internal combustion engine
WO1992003638A1 (en) * 1990-08-15 1992-03-05 Warr Valves, Inc. Improved intake valve for internal combustion engine
AU632710B2 (en) * 1990-08-15 1993-01-07 Warr Valves, Inc. Improved intake valve for internal combustion engine
US5335634A (en) * 1991-05-14 1994-08-09 Mazda Motor Corporation Combustion chamber structure for an engine
US5771852A (en) * 1997-03-04 1998-06-30 Trw Inc. Poppet valve with embossed neck structure

Also Published As

Publication number Publication date
GB8304786D0 (en) 1983-03-23

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