EP0320536A1 - Engine compression brake - Google Patents
Engine compression brake Download PDFInfo
- Publication number
- EP0320536A1 EP0320536A1 EP87202525A EP87202525A EP0320536A1 EP 0320536 A1 EP0320536 A1 EP 0320536A1 EP 87202525 A EP87202525 A EP 87202525A EP 87202525 A EP87202525 A EP 87202525A EP 0320536 A1 EP0320536 A1 EP 0320536A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- valve
- exhaust
- internal combustion
- exhaust valve
- combustion engine
- 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
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Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02D—CONTROLLING COMBUSTION ENGINES
- F02D9/00—Controlling engines by throttling air or fuel-and-air induction conduits or exhaust conduits
- F02D9/04—Controlling engines by throttling air or fuel-and-air induction conduits or exhaust conduits concerning exhaust conduits
- F02D9/06—Exhaust brakes
-
- 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
- F01L13/06—Modifications of valve-gear to facilitate reversing, braking, starting, changing compression ratio, or other specific operations for braking
Definitions
- the invention relates to an internal combustion engine, comprising cylinders with pistons and in- and exhaust valves, an exhaust system, an engine brake that is provided with means for destroying the compression energy at the end of the compression stroke.
- This type of internal combustion engine is generally known.
- Another method comprises closing a valve of the exhaust system, resulting in higher pressure than usual in the cylinder during the exhaust stroke (exhaust throttling).
- the braking action of an internal combustion engine is partly constituted as a result of loss due to friction and partly as a result of indicated energy.
- the above-stated pre-exhaust has the disadvantage that a complicated engine structure is required, since one must be able to interrupt the pre-exhaust during normal engine operation, for which purpose special profiles and/or operational mechanisms are required.
- the energy absorbed by the engine should be disposed of to the environment, preferably by a temperature increase of the exhaust gas.
- the fuel consumption of the normal operating engine should not increase.
- the invention aims to remove the above-indicated drawbacks and to increase the average effective brake action in internal combustion engines within the scope of the stated secondary terms, in particular in super-charged engines.
- the invention is characterized in that the engine brake comprises means for closing a brake valve in the exhaust system in order to create a pressure increase in the cylinder, means for opening the exhaust valve during the inlet stroke of the piston synchronously to the number of revolutions per minute of the engine to such an extent that exhaust gas flows back through said cylinder exhaust valve of the exhaust system to the cylinder.
- ABS anti-blocking system
- Said means for destroying the increased compression energy after the decompression stroke can e.g. consist of opening the outlet at the top dead centre.
- the partly shown cylinder 2 in which a piston 1 is mounted has a head 2 with inlet valve 3 and an exhaust valve 4, both provided with a valve spring 5, and a valve stem 6.
- the exhaust valve 4 is operated by a valve rocker 7 that is operable by a cam, a hydraulic or an electromagnetic system.
- the cylinder head furthermore comprises an inlet system 8 and an exhaust system 9 in which a brake valve 10 has been mounted.
- the exhaust valve 4 is opened via a valve rocker by a cam shaft (not shown). This can take place indirect through a bar system or direct from the cam system. The opening of the exhaust valve 4 can take place at any desired time.
- the rigidity of the exhaust valve spring is such that the valve opens spontaneously under the influence of a pressure build-up in the exhaust system 9 by means of the operable brake valve 10.
- the exhaust valve opens at the bottom dead centre of the piston under the influence of gas forces. This can to a limited extent be arranged by the choice of the closing force and the rigidity of the valve spring. The further course of the cycle in the internal combustion engine is equal to that of the embodiment of figure 1. Closing the brake valve can be performed manually, hydraulically, electrically or pneumatically (not shown).
- an exhaust valve 4 is applied that has in its closed position a permanent (small) opening (negative valve clearance).
- the clearance amounts to some tenths of millimeters. This construction provides the possibility of both an increased charge during the inlet stroke and a decompression during the compression stroke.
- the adjustment means is e.g. operable by an eccentric cam (not shown) mounted on the shaft of the valve rocker.
- this valve will be opened when nearing the end of the compression stroke by e.g. an hydraulic coupling between the exhaust valve and a cam suited for this purpose. If no cams with a suitable time adjustment are available, an extra cam per cylinder is required.
- the special valve operation (not shown) is interrupted during normal operation of the engine.
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Valve Device For Special Equipments (AREA)
- Output Control And Ontrol Of Special Type Engine (AREA)
Abstract
The invention relates to an internal combustion engine, comprising cylinders with pistons and inlet and exhaust valves, an exhaust system, an engine brake that is provided with means for disposing of the compression energy at the end of the compression stroke, the engine brake comprising means for closing a brake valve (10) in the exhaust system in order to establish a pressure increase in the cylinder (2), means for opening the exhaust valve (4) during the inlet stroke of the piston (1) synchronously to the number of revolutions per minute of the engine to such an extent that exhaust gas flows back through said cylinder exhaust valve of the exhaust system to the cylinder.
Description
- The invention relates to an internal combustion engine, comprising cylinders with pistons and in- and exhaust valves, an exhaust system, an engine brake that is provided with means for destroying the compression energy at the end of the compression stroke.
- This type of internal combustion engine is generally known.
- As a result of opening the exhaust valuve at the end of the compression stroke, the work performed by the piston during the compression stroke cannot be recuperated during the expansion stroke (pre-exhaust).
- Another method comprises closing a valve of the exhaust system, resulting in higher pressure than usual in the cylinder during the exhaust stroke (exhaust throttling).
- The braking action of an internal combustion engine is partly constituted as a result of loss due to friction and partly as a result of indicated energy.
- Since the loss due to friction has only a slight impact on the engine brake action it has been tried to increase the indicated energy.
- The above-stated pre-exhaust has the disadvantage that a complicated engine structure is required, since one must be able to interrupt the pre-exhaust during normal engine operation, for which purpose special profiles and/or operational mechanisms are required.
- The above-indicated exhaust throttling is mostly applied. A drawback of exhaust throttling, however, is that the braking action is restricted by the occurring exhaust gas temperature and the possible occurrence of uncontrolled opening of the exhaust valves (valve bouncing).
- Moreover the brake power, obtained with said pre-exhaust and exhaust throttling with respect to the engine power is low during normal operation if they are applied to super-charged engines. Furthermore the braking action of those two systems is insufficiently controllable, which is a drawback with higher brake powers.
- When aiming at an increase of the indicated brake power, the following secondary terms should be taken into account.
- The energy absorbed by the engine should be disposed of to the environment, preferably by a temperature increase of the exhaust gas.
- Only minimal adjustments can be made to the cylinder head and the remaining engine parts, in view of the cost and the weight of the engine.
- The fuel consumption of the normal operating engine should not increase.
- The invention aims to remove the above-indicated drawbacks and to increase the average effective brake action in internal combustion engines within the scope of the stated secondary terms, in particular in super-charged engines.
- For that purpose, the invention is characterized in that the engine brake comprises means for closing a brake valve in the exhaust system in order to create a pressure increase in the cylinder, means for opening the exhaust valve during the inlet stroke of the piston synchronously to the number of revolutions per minute of the engine to such an extent that exhaust gas flows back through said cylinder exhaust valve of the exhaust system to the cylinder.
- By applying these measures an increased engine braking action is obtained that can be adjusted, e.g. by means of a variation of the passage of the brake valve. The thus obtained adjustment characteristic is less steep and subsequently leads to a more favourable dosability of the engine brake power. Moreover, since it is so easily controlled, the engine brake can be applied in combination with an anti-blocking system (ABS).
- Said means for destroying the increased compression energy after the decompression stroke can e.g. consist of opening the outlet at the top dead centre.
- There are tried mechanisms for transposing the standard exhaust cam profile so that for the benefit of the present engine braking system.
- The invention will be further elucidated on the basis of the drawing.
- Figure 1 schematically shows a cylinder head of an internal combustion engine, comprising an inlet and exhaust valve with brake valve according to the invention.
- Figure 2 shows a cylinder head of the same type with another exhaust valve construction that is operable by gas pressure.
- Figure 3 shows the same cylinder head of the same type with again another exhaust valve construction with operation mechanism.
- The partly shown
cylinder 2 in which a piston 1 is mounted, has ahead 2 withinlet valve 3 and anexhaust valve 4, both provided with avalve spring 5, and avalve stem 6. Theexhaust valve 4 is operated by avalve rocker 7 that is operable by a cam, a hydraulic or an electromagnetic system. - The cylinder head furthermore comprises an inlet system 8 and an
exhaust system 9 in which abrake valve 10 has been mounted. - For the passage of the brake valve, several constructive embodiments are possible.
- In figure 1 the
exhaust valve 4 is opened via a valve rocker by a cam shaft (not shown). This can take place indirect through a bar system or direct from the cam system. The opening of theexhaust valve 4 can take place at any desired time. - In the construction of figure 2, the rigidity of the exhaust valve spring is such that the valve opens spontaneously under the influence of a pressure build-up in the
exhaust system 9 by means of theoperable brake valve 10. - The exhaust valve opens at the bottom dead centre of the piston under the influence of gas forces. This can to a limited extent be arranged by the choice of the closing force and the rigidity of the valve spring. The further course of the cycle in the internal combustion engine is equal to that of the embodiment of figure 1. Closing the brake valve can be performed manually, hydraulically, electrically or pneumatically (not shown).
- In figure 3 an
exhaust valve 4 is applied that has in its closed position a permanent (small) opening (negative valve clearance). The clearance amounts to some tenths of millimeters. This construction provides the possibility of both an increased charge during the inlet stroke and a decompression during the compression stroke. - The adjustment means is e.g. operable by an eccentric cam (not shown) mounted on the shaft of the valve rocker.
- If the exhaust valve with pre-exhaust is applied, this valve will be opened when nearing the end of the compression stroke by e.g. an hydraulic coupling between the exhaust valve and a cam suited for this purpose. If no cams with a suitable time adjustment are available, an extra cam per cylinder is required. The special valve operation (not shown) is interrupted during normal operation of the engine.
Claims (5)
1. Internal combustion engine, comprising cylinders with pistons and inlet and exhaust valves, an exhaust system, an engine brake that is provided with means for destroying the compression energy at the end of the compression stroke, characterized in that the engine brake comprises means for closing a brake valve (10) in the exhaust system in order to establish a pressure increase in the cylinder (2), means for opening the exhaust valve (4) during the inlet stroke of the piston (1) synchronously to the number of revolutions per minute of the engine to such an extent that exhaust gas flows back trough said cylinder exhaust valve of the exhaust system to the cylinder.
2. Internal combustion engine according to claim 1, characterized in that one of the means for opening the exhaust valve (4) comprises a valve rocker (7) that can be operated direct by the cam shaft or indirect through a rod system (figure 1).
3. Internal combustion engine according to claim 1, characterized in that opening the exhaust valve (4) is performed by means of a valve spring (5) being rigid to the extent that the valve opens spontaneously under the influence of the pressure build-up in the exhaust system (9) (figure 2).
4. Internal combustion engine according to claim 1, characterized in that one of the means for opening the exhaust valve (4) comprises an adjusting means for keeping the exhaust valve (4) permanently open, said adjusting means being operable by an eccentric cam mounted on the shaft of the valve rocker (7) (figure 3).
5. Internal combustion engine according to claim 4, characterized in that the exhaust valve (4) has negative valve clearance amounting to a few tenths of millimeters.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP87202525A EP0320536A1 (en) | 1987-12-15 | 1987-12-15 | Engine compression brake |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP87202525A EP0320536A1 (en) | 1987-12-15 | 1987-12-15 | Engine compression brake |
Publications (1)
Publication Number | Publication Date |
---|---|
EP0320536A1 true EP0320536A1 (en) | 1989-06-21 |
Family
ID=8197722
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP87202525A Ceased EP0320536A1 (en) | 1987-12-15 | 1987-12-15 | Engine compression brake |
Country Status (1)
Country | Link |
---|---|
EP (1) | EP0320536A1 (en) |
Cited By (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE3922884A1 (en) * | 1989-07-12 | 1991-01-24 | Man Nutzfahrzeuge Ag | ENGINE BRAKE FOR AIR COMPRESSING ENGINES |
WO1996005415A1 (en) * | 1994-08-08 | 1996-02-22 | Fev Motorentechnik Gmbh & Co. Kommanditgesellschaft | Engine brake device for a commercial vehicle |
EP0736672A2 (en) * | 1995-04-04 | 1996-10-09 | Steyr Nutzfahrzeuge Ag | Engine braking process for a four stroke internal combustion engine |
EP0822321A1 (en) * | 1996-04-16 | 1998-02-04 | Daimler-Benz Aktiengesellschaft | Method for slowing down a 4 stroke internal combustion engine, in particular, when used for vehicle propulsion |
DE19852552A1 (en) * | 1998-11-13 | 2000-05-25 | Daimler Chrysler Ag | Method for operating a four-stroke internal combustion engine |
DE10250771B4 (en) * | 2002-10-30 | 2014-09-11 | Iav Gmbh Ingenieurgesellschaft Auto Und Verkehr | Motor brake device and method for its control |
Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE335332C (en) * | 1916-04-18 | 1921-03-31 | Last Automobilfabrik A G Deuts | Exhaust and brake control for explosion engines |
CH118905A (en) * | 1926-02-11 | 1927-02-16 | Franz Brozincevic & Cie | Four-stroke engine for vehicles that can be used for braking. |
CH306146A (en) * | 1952-09-24 | 1955-03-31 | Saurer Ag Adolph | Method for engine braking of motor vehicles with four-stroke piston internal combustion engine and internal combustion engine for carrying out the method. |
US3234923A (en) * | 1962-06-18 | 1966-02-15 | Caterpillar Tractor Co | Method and braking system for internal combustion engines |
DE2832526A1 (en) * | 1978-07-25 | 1980-02-07 | Maschf Augsburg Nuernberg Ag | Four-stroke IC engine with exhaust gas braking - has stops preventing full exhaust valve closure when brake flap valve is operated |
GB2162580A (en) * | 1984-08-03 | 1986-02-05 | Daimler Benz Ag | Control of exhaust valves and exhaust brake of an internal combustion engine |
-
1987
- 1987-12-15 EP EP87202525A patent/EP0320536A1/en not_active Ceased
Patent Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE335332C (en) * | 1916-04-18 | 1921-03-31 | Last Automobilfabrik A G Deuts | Exhaust and brake control for explosion engines |
CH118905A (en) * | 1926-02-11 | 1927-02-16 | Franz Brozincevic & Cie | Four-stroke engine for vehicles that can be used for braking. |
CH306146A (en) * | 1952-09-24 | 1955-03-31 | Saurer Ag Adolph | Method for engine braking of motor vehicles with four-stroke piston internal combustion engine and internal combustion engine for carrying out the method. |
US3234923A (en) * | 1962-06-18 | 1966-02-15 | Caterpillar Tractor Co | Method and braking system for internal combustion engines |
DE2832526A1 (en) * | 1978-07-25 | 1980-02-07 | Maschf Augsburg Nuernberg Ag | Four-stroke IC engine with exhaust gas braking - has stops preventing full exhaust valve closure when brake flap valve is operated |
GB2162580A (en) * | 1984-08-03 | 1986-02-05 | Daimler Benz Ag | Control of exhaust valves and exhaust brake of an internal combustion engine |
Cited By (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE3922884A1 (en) * | 1989-07-12 | 1991-01-24 | Man Nutzfahrzeuge Ag | ENGINE BRAKE FOR AIR COMPRESSING ENGINES |
WO1996005415A1 (en) * | 1994-08-08 | 1996-02-22 | Fev Motorentechnik Gmbh & Co. Kommanditgesellschaft | Engine brake device for a commercial vehicle |
US5730102A (en) * | 1994-08-08 | 1998-03-24 | Fev Motorentechnik Gmbh & Co. Kommanditgesellschaft | Engine brake device for a commercial vehicle |
EP0736672A2 (en) * | 1995-04-04 | 1996-10-09 | Steyr Nutzfahrzeuge Ag | Engine braking process for a four stroke internal combustion engine |
EP0736672A3 (en) * | 1995-04-04 | 1997-03-19 | Steyr Nutzfahrzeuge | Engine braking process for a four stroke internal combustion engine |
EP0822321A1 (en) * | 1996-04-16 | 1998-02-04 | Daimler-Benz Aktiengesellschaft | Method for slowing down a 4 stroke internal combustion engine, in particular, when used for vehicle propulsion |
DE19852552A1 (en) * | 1998-11-13 | 2000-05-25 | Daimler Chrysler Ag | Method for operating a four-stroke internal combustion engine |
DE19852552C2 (en) * | 1998-11-13 | 2000-10-05 | Daimler Chrysler Ag | Method for operating a four-stroke internal combustion engine |
DE10250771B4 (en) * | 2002-10-30 | 2014-09-11 | Iav Gmbh Ingenieurgesellschaft Auto Und Verkehr | Motor brake device and method for its control |
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Legal Events
Date | Code | Title | Description |
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PUAI | Public reference made under article 153(3) epc to a published international application that has entered the european phase |
Free format text: ORIGINAL CODE: 0009012 |
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AK | Designated contracting states |
Kind code of ref document: A1 Designated state(s): DE FR GB IT NL SE |
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17P | Request for examination filed |
Effective date: 19891212 |
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17Q | First examination report despatched |
Effective date: 19900510 |
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STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: THE APPLICATION HAS BEEN REFUSED |
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18R | Application refused |
Effective date: 19910304 |