CA1056241A - Adjustable cam system for internal combustion engine - Google Patents
Adjustable cam system for internal combustion engineInfo
- Publication number
- CA1056241A CA1056241A CA239,436A CA239436A CA1056241A CA 1056241 A CA1056241 A CA 1056241A CA 239436 A CA239436 A CA 239436A CA 1056241 A CA1056241 A CA 1056241A
- Authority
- CA
- Canada
- Prior art keywords
- valve
- engine
- timing
- lever arms
- valve actuating
- 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
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
- F01L31/00—Valve drive, valve adjustment during operation, or other valve control, not provided for in groups F01L15/00 - F01L29/00
-
- 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
- F01L1/00—Valve-gear or valve arrangements, e.g. lift-valve gear
- F01L1/12—Transmitting gear between valve drive and valve
- F01L1/18—Rocking arms or levers
-
- 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
- F01L13/00—Modifications of valve-gear to facilitate reversing, braking, starting, changing compression ratio, or other specific operations
- F01L13/0015—Modifications of valve-gear to facilitate reversing, braking, starting, changing compression ratio, or other specific operations for optimising engine performances by modifying valve lift according to various working parameters, e.g. rotational speed, load, torque
- F01L13/0063—Modifications of valve-gear to facilitate reversing, braking, starting, changing compression ratio, or other specific operations for optimising engine performances by modifying valve lift according to various working parameters, e.g. rotational speed, load, torque by modification of cam contact point by displacing an intermediate lever or wedge-shaped intermediate element, e.g. Tourtelot
-
- 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
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Valve Device For Special Equipments (AREA)
- Valve-Gear Or Valve Arrangements (AREA)
Abstract
ABSTRACT
The invention describes an internal combustion engine having a valve and a mechanism which will allow control of both valve overlap and duration of opening and also vary the rate of valve lift. This results in advantage including improvement in the thermal efficiency of the engine under a wide spectrum of operating conditions and in improvement in the emission of pollutants.
The invention describes an internal combustion engine having a valve and a mechanism which will allow control of both valve overlap and duration of opening and also vary the rate of valve lift. This results in advantage including improvement in the thermal efficiency of the engine under a wide spectrum of operating conditions and in improvement in the emission of pollutants.
Description
This invention relates to internal combustion engines ` having adjustable valve gear.
Conventional engines have fixed valve timing for normal R.P.M. and load conditions which are experienced during its lifetime.
This fixed valve timing is optimal for a small spectrum of normal operating conditions.
As a result when the engine is operating outside the optimal valve timing spectrum, the engine is inefficient and causes above average pollution. The thermal efficiency of ; the engine suffers and is diminished.
' Variable valve timing has been theoretic`ally known fora number of years. However, in order to implement such variable valve timing the previously proposed measures have been both complex and expensive to instal.
- Mechanisms are known where valve dwell, or period of opening, is controlled but valve overlap still remains fixed.
Conversely when valve overlap is controlled, the actual period the valve is open remains fixed. So far as is known the prior mechanisms do not control both the period of valve opening and valve overlap and also do not control the effective rate of valve lift.
; It is an object of the present invention to provide a mechanism in an internal combustion engine which will allow control of both valve overlap and duration of opening and also vary the rate of valve lift so as to improve the thermal efficiency of the engine under a wider spectrum of operating conditions and also to control the pollutant emission.
According to the~invention there is provided an internal combustion engine having a valve and a mechanism for controlling
Conventional engines have fixed valve timing for normal R.P.M. and load conditions which are experienced during its lifetime.
This fixed valve timing is optimal for a small spectrum of normal operating conditions.
As a result when the engine is operating outside the optimal valve timing spectrum, the engine is inefficient and causes above average pollution. The thermal efficiency of ; the engine suffers and is diminished.
' Variable valve timing has been theoretic`ally known fora number of years. However, in order to implement such variable valve timing the previously proposed measures have been both complex and expensive to instal.
- Mechanisms are known where valve dwell, or period of opening, is controlled but valve overlap still remains fixed.
Conversely when valve overlap is controlled, the actual period the valve is open remains fixed. So far as is known the prior mechanisms do not control both the period of valve opening and valve overlap and also do not control the effective rate of valve lift.
; It is an object of the present invention to provide a mechanism in an internal combustion engine which will allow control of both valve overlap and duration of opening and also vary the rate of valve lift so as to improve the thermal efficiency of the engine under a wider spectrum of operating conditions and also to control the pollutant emission.
According to the~invention there is provided an internal combustion engine having a valve and a mechanism for controlling
2 -:
.
r,. !
valve operation comprising means for actuating said valve, a non-interchangeable cam for controlling said valve actuating means, a pair of pivotable timing lever arms with inner ends interposed for contact engagemen-t by the cam for control of said valve actuating means, and two separate adjustment control means disposed for engagement with the outer end of each said timing lever arm for adjustment of the position of the respective arm during operation of the engine.
, Generally this invention is most easily applied to four stroke engines, but it may also readily be used with a two stroke poppet valve engine.
The invention will be further described, by way of example, with reference to the accompanying drawings, in which:
Figures 1 to 3 illustrate preferred valve gear of engines embodying the invention.
Turning now to Figure 1, two timing levers 2 and 3 are - situated between a cam shaft 1 and a rocker arm 4.
These levers have a pivot point 5 connecting the rocker arm 4 and the timing levers 2 and 3.
, When a change in valve timing is required the timing levers 2 and 3 are angularly adjusted about the pivot 5 to a new position by movement of vertically movable control lever setting bars 6 and 7.
When the bar 6 is raised from the idling position shown in Figure 1 the flank of the cam 1 rotates through fewer degrees before coming into contact with lever 2. As the flank of the cam 1 exerts pressure upon the timing lever 2, the timing lever itself exerts pressure in turn upon the pivot 30 point 5 and the rocker arm 4.
.
r,. !
valve operation comprising means for actuating said valve, a non-interchangeable cam for controlling said valve actuating means, a pair of pivotable timing lever arms with inner ends interposed for contact engagemen-t by the cam for control of said valve actuating means, and two separate adjustment control means disposed for engagement with the outer end of each said timing lever arm for adjustment of the position of the respective arm during operation of the engine.
, Generally this invention is most easily applied to four stroke engines, but it may also readily be used with a two stroke poppet valve engine.
The invention will be further described, by way of example, with reference to the accompanying drawings, in which:
Figures 1 to 3 illustrate preferred valve gear of engines embodying the invention.
Turning now to Figure 1, two timing levers 2 and 3 are - situated between a cam shaft 1 and a rocker arm 4.
These levers have a pivot point 5 connecting the rocker arm 4 and the timing levers 2 and 3.
, When a change in valve timing is required the timing levers 2 and 3 are angularly adjusted about the pivot 5 to a new position by movement of vertically movable control lever setting bars 6 and 7.
When the bar 6 is raised from the idling position shown in Figure 1 the flank of the cam 1 rotates through fewer degrees before coming into contact with lever 2. As the flank of the cam 1 exerts pressure upon the timing lever 2, the timing lever itself exerts pressure in turn upon the pivot 30 point 5 and the rocker arm 4.
- 3 -, ~ ,._, . -; The rocker arm 4 then starts to depress valve 8. AS a result the valve 8 starts to open earlier in the four stroke cycle than at idling speed. How much earlier valve 8 starts to operate depends on how much the control lever setting bar ; 6 is lifted.
As~the lobe of cam 1 passes from timing lever 2 it begins to bear onto timing lever 3. This lever controls the closing of valve 8, aided by the valve spring 9.
; The point at which valve 8 actually closes depends on ; 10 the position of control lever setting bar 7.
. , .
10 is the rocker arm pivot post. 11 and 12 are timing lever springs which ensure that the timing levers 2 and 3 are always in contact with the timing lever setting bars 6 and 7. 13 is a rocker arm spring which biases the levers upwardly into engagement with the cam. 14 is the cylinder head of the internal combustion engine. As will be appreciated adjustment of the position of the timing lever arms 2 and 3 . .
is provided by movement of the setting bars 6 and 7.
Regarding Figure 2. The construction is the same as ~ 20 Figure 1 except the rocker arm 4 and rocker arm pivot post - 10 are replaced by a bucket tappet 4a.
Concerning Figure 3, this mechanism operates in a manner similar to the mechanisms of Figures 1 and 2 except that instead of having the pivot 5 connecting the levers 2 and 3 the levers 2 and 3 are pivoted at 5a and 5_ to the control lever setting bars 6a and 7a.-- Timing lever springs lla and 12a connect the control lever setting bars 6a and 7a with the timing levers 2 and 3 respectively to urge the overlapping ends of the timing levers 2 and 3 downwardly onto bucket tappet 4a for sliding engagement _ 4 _ ... _ .. . .. . . ..
,, ,, , ~ . . . . ~.
' ' ' . ' : - ' -1056;Z41 therewith. As the cam 1 rotates the lobe first comes into contact with timing lever 2 depressing it onto the bucket tappet 4a which then depresses valve 8. Timing levers 2 and 3 always maintain contact with bucket tappet 4a by reason of timing lever springs lla and 12a.
As the lobe of cam 1 rides off timing lever 2 it begins - to ride onto timing lever 3. Timing levers 2 and 3 are con-trolled by control lever setting bars 6a and 7a which are adjusted vertically to set the timing levers 2 and 3 for most desirable valve timing of the engine while the engine is in ~, operation.
In a further mechanism not shown in a drawing, the variable valve timing mechanism, as described in Figure 3, is associated ' with the rocker arm of Figure 1. Here the timing levers 2a and 3a have their overlapping ends bearing down upon the rocker arm and the cam 1 operates as previously described.
As described in Figure 1, the timing lever arms 2 and 3 have a common pivot 5. In an alternative embodiment lever arms 2 and 3 may have separate pivots connectèd by a bridge fixed to the rocker arm or bucket tappet. This enables the cam to move of f timing lever arm 2 on to the bridge and then to pass on to timing lever arm 3.
Another application of this invention is to utilize a hydraulic system which is controlled generally as described above except that the action of the timing levers causes depression of a piston into a hydraulic system. The pressure within the hydraulic system then activates another piston situated above the valve which depresses the valve.
;~ .
, - 5 -r
As~the lobe of cam 1 passes from timing lever 2 it begins to bear onto timing lever 3. This lever controls the closing of valve 8, aided by the valve spring 9.
; The point at which valve 8 actually closes depends on ; 10 the position of control lever setting bar 7.
. , .
10 is the rocker arm pivot post. 11 and 12 are timing lever springs which ensure that the timing levers 2 and 3 are always in contact with the timing lever setting bars 6 and 7. 13 is a rocker arm spring which biases the levers upwardly into engagement with the cam. 14 is the cylinder head of the internal combustion engine. As will be appreciated adjustment of the position of the timing lever arms 2 and 3 . .
is provided by movement of the setting bars 6 and 7.
Regarding Figure 2. The construction is the same as ~ 20 Figure 1 except the rocker arm 4 and rocker arm pivot post - 10 are replaced by a bucket tappet 4a.
Concerning Figure 3, this mechanism operates in a manner similar to the mechanisms of Figures 1 and 2 except that instead of having the pivot 5 connecting the levers 2 and 3 the levers 2 and 3 are pivoted at 5a and 5_ to the control lever setting bars 6a and 7a.-- Timing lever springs lla and 12a connect the control lever setting bars 6a and 7a with the timing levers 2 and 3 respectively to urge the overlapping ends of the timing levers 2 and 3 downwardly onto bucket tappet 4a for sliding engagement _ 4 _ ... _ .. . .. . . ..
,, ,, , ~ . . . . ~.
' ' ' . ' : - ' -1056;Z41 therewith. As the cam 1 rotates the lobe first comes into contact with timing lever 2 depressing it onto the bucket tappet 4a which then depresses valve 8. Timing levers 2 and 3 always maintain contact with bucket tappet 4a by reason of timing lever springs lla and 12a.
As the lobe of cam 1 rides off timing lever 2 it begins - to ride onto timing lever 3. Timing levers 2 and 3 are con-trolled by control lever setting bars 6a and 7a which are adjusted vertically to set the timing levers 2 and 3 for most desirable valve timing of the engine while the engine is in ~, operation.
In a further mechanism not shown in a drawing, the variable valve timing mechanism, as described in Figure 3, is associated ' with the rocker arm of Figure 1. Here the timing levers 2a and 3a have their overlapping ends bearing down upon the rocker arm and the cam 1 operates as previously described.
As described in Figure 1, the timing lever arms 2 and 3 have a common pivot 5. In an alternative embodiment lever arms 2 and 3 may have separate pivots connectèd by a bridge fixed to the rocker arm or bucket tappet. This enables the cam to move of f timing lever arm 2 on to the bridge and then to pass on to timing lever arm 3.
Another application of this invention is to utilize a hydraulic system which is controlled generally as described above except that the action of the timing levers causes depression of a piston into a hydraulic system. The pressure within the hydraulic system then activates another piston situated above the valve which depresses the valve.
;~ .
, - 5 -r
Claims (8)
1. An internal combustion engine having a valve and a mechanism for controlling valve operation comprising means for actuating said valve; a non-interchangeable cam for controlling said valve actuating means, a pair of pivotable timing lever arms with inner ends interposed for contact engagement by the cam for control of said valve actuating means, and two separate adjustment control means disposed for engagement with the outer end of each said timing lever arm for adjustment of the position of the respective arm during operation of the engine.
2. An engine as claimed in claim 1, wherein said valve actuating means comprises a rocker arm disposed in sliding contact engagement with the timing lever arms.
3. An engine as claimed in claim 1, wherein said valve actuating means comprises a bucket tappet assembly disposed in sliding contact engagement with said timing lever arms.
4. An engine as claimed in claim 1, 2 or 3, wherein said lever arms are disposed for sliding engagement with said valve actuating means, the outer ends of said lever arms being pivotally connected with said respective adjustment controlling means.
5. An engine as claimed in claim 1, 2 or 3 comprising spring means connected between each said timing lever arm and said adjustment controlling means for urging the timing lever arms into contact with the valve actuating means.
6. An engine as claimed in claim 1, wherein said lever arms are pivotally connected with respect to said valve actuating means, the outer ends of said lever arms being disposed in sliding contact engagement with said adjustment controlling means.
7. An engine as claimed in claim 6, comprising spring means connected between each said timing lever arm and said adjustment controlling means.
8. An engine according to claim 6 or 7, wherein during operation thereof the cam contacts in turn one timing lever arm, the valve actuating means, and the other timing lever arm.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| AU958874 | 1974-11-12 | ||
| AU303575 | 1975-09-04 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1056241A true CA1056241A (en) | 1979-06-12 |
Family
ID=25609960
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA239,436A Expired CA1056241A (en) | 1974-11-12 | 1975-11-12 | Adjustable cam system for internal combustion engine |
Country Status (5)
| Country | Link |
|---|---|
| JP (1) | JPS5172817A (en) |
| CA (1) | CA1056241A (en) |
| DE (1) | DE2550848A1 (en) |
| FR (1) | FR2291352A1 (en) |
| GB (1) | GB1527743A (en) |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2058992B (en) * | 1979-07-06 | 1983-05-05 | Lucas Industries Ltd | Actuator mechanism |
| JPS6226562Y2 (en) * | 1981-03-10 | 1987-07-08 | ||
| US4438737A (en) * | 1981-10-13 | 1984-03-27 | Investment Rarities, Incorporated | Apparatus and method for controlling the valve operation of an internal combustion engine |
| US4414931A (en) * | 1981-10-13 | 1983-11-15 | Investment Rarities, Incorporated | Variable valve operating mechanism for internal combustion engines |
| FR2583105B1 (en) * | 1985-06-05 | 1989-06-23 | Peugeot | DEVICE FOR VARIABLE CONTROL OF A STEM VALVE OF AN INTERNAL COMBUSTION ENGINE |
| US6357406B1 (en) * | 2000-11-22 | 2002-03-19 | Borgwarner Inc. | Variable valve actuation system |
-
1975
- 1975-11-12 JP JP13676075A patent/JPS5172817A/en active Granted
- 1975-11-12 CA CA239,436A patent/CA1056241A/en not_active Expired
- 1975-11-12 GB GB4676775A patent/GB1527743A/en not_active Expired
- 1975-11-12 DE DE19752550848 patent/DE2550848A1/en not_active Withdrawn
- 1975-11-12 FR FR7534457A patent/FR2291352A1/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5172817A (en) | 1976-06-24 |
| GB1527743A (en) | 1978-10-11 |
| FR2291352B1 (en) | 1980-07-11 |
| FR2291352A1 (en) | 1976-06-11 |
| DE2550848A1 (en) | 1976-05-13 |
| JPS5523326B2 (en) | 1980-06-23 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| EP1611319B1 (en) | Variable valve lift control system for a combustion engine with underneath camshaft | |
| US4530318A (en) | Intake and exhaust valve system for internal combustion engine | |
| CA1074197A (en) | Valve timing mechanisms | |
| GB2047801A (en) | Valve operating mechanism for an internal combustion engin | |
| JP2814613B2 (en) | Engine Valve Actuator | |
| US7475659B2 (en) | Device combustion engine | |
| JPH05306607A (en) | Valve system of internal combustion engine | |
| US6659053B1 (en) | Fully variable valve train | |
| JP4897216B2 (en) | Internal combustion engine equipment | |
| US4249488A (en) | Valve lift adjusting device | |
| US4221199A (en) | Plural lash engine valve gear and device for selecting same | |
| GB2180597A (en) | Valve control | |
| WO1982001217A1 (en) | Cam apparatus with a rotatable,variable-profile cam means | |
| CA1056241A (en) | Adjustable cam system for internal combustion engine | |
| US4836155A (en) | Variable duration valve opening mechanism | |
| CN201874632U (en) | Fully variable valve timing gear containing variable-speed swing mechanism | |
| GB2068495A (en) | I.C. engine valve lift hydraulic adjusting device | |
| US4359019A (en) | Process for preventing the pumping of a hydraulic valve clearance compensating element in valve operating mechanisms of internal combustion engines | |
| US4495902A (en) | Mechanism for variably controlling an internal combustion engine valve | |
| US3112739A (en) | Valve tappets of internal combustion engines | |
| EP0966595A1 (en) | Operating mechanisms for valves | |
| GB2214570A (en) | Variable lift i.c. engine valves | |
| US3590796A (en) | Free valve compression relief for four cycle engines | |
| WO1994021897A1 (en) | Valve operating gear | |
| JPS606564Y2 (en) | Valve mechanism of internal combustion engine |