US20220220886A1 - Casella hydraulic variable compression ratio piston - Google Patents
Casella hydraulic variable compression ratio piston Download PDFInfo
- Publication number
- US20220220886A1 US20220220886A1 US16/974,400 US202116974400A US2022220886A1 US 20220220886 A1 US20220220886 A1 US 20220220886A1 US 202116974400 A US202116974400 A US 202116974400A US 2022220886 A1 US2022220886 A1 US 2022220886A1
- Authority
- US
- United States
- Prior art keywords
- piston
- compression ratio
- eccentric
- variable compression
- lifter
- 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.)
- Granted
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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
- F02B75/00—Other engines
- F02B75/04—Engines with variable distances between pistons at top dead-centre positions and cylinder heads
- F02B75/044—Engines with variable distances between pistons at top dead-centre positions and cylinder heads by means of an adjustable piston length
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16J—PISTONS; CYLINDERS; SEALINGS
- F16J1/00—Pistons; Trunk pistons; Plungers
- F16J1/08—Constructional features providing for lubrication
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16J—PISTONS; CYLINDERS; SEALINGS
- F16J1/00—Pistons; Trunk pistons; Plungers
- F16J1/10—Connection to driving members
- F16J1/14—Connection to driving members with connecting-rods, i.e. pivotal connections
- F16J1/16—Connection to driving members with connecting-rods, i.e. pivotal connections with gudgeon-pin; Gudgeon-pins
- F16J1/18—Securing of gudgeon-pins
Definitions
- the present invention relates to a variable compression ratio piston which changes height relative to a common connecting rod to modify the compression ratio in a typical internal combustion engine.
- Compression ratio is thus defined as the largest cylindrical volume atop the piston, at bottom dead enter, divided by the smallest cylindrical volume atop the same piston at top dead center.
- a fixed compression ratio only allows combustion efficiency to occur at maximum engine torque and load with only partial combustion at lesser loads due to the partial filling of the cylinder. Partial filling occurs when only small injection of fuel and air are required for smaller engine loads or when the total mix of fuel and air does not completely fill the cylinder due to air friction and greater piston speeds.
- variable compression engine constantly changes the compression ratio to match the combination of air/fuel mix and engine load, thereby achieving full and efficient combustion at every engine speed.
- Variable compression does make for an overly complex and expensive engine design.
- the hydraulic variable compression ratio piston is a more reliable, simpler, and cheaper build, and still allows the flexibility of a variable compression engine.
- This invention changes compression by doing a partial movement of the piston relative to the connecting rod.
- the piston shrinks down relative to the connecting rod, much like a shock absorber, to avoid harmful pre-detonation in the case of excessive combustion pressure at the current compression ratio, for example, 12 to 1.
- This partial movement is achieved by the rotation of the eccentric piston pin.
- the relative position of the piston stays fixed at its current compression ratio.
- the compression ratio only changes when power levels and inertia of the piston and connecting rod at bottom dead center increases or decreases.
- This control of the compression ratio is achieved with a combination of return springs to the eccentric and an opposing contra-acting lifter to the eccentric.
- the function of the return springs, to return the eccentric to its original position, is opposed and controlled by the opposing lifter, installed within the piston.
- the lifter eventually loses oil and contracts, but very slowly at lower combustion and engine loads. At higher combustion and greater engine loads, the lifter expands as the return springs contract. The eccentric therefore only turns when there are changes in the combustion pressure. If power levels remain the same, the opposing lifter holds its position against the eccentric return springs, and the compression ratio stays the same.
- FIG. 1 depicts the variable compression piston at its highest, at top dead center, with the eccentric piston pin at its lowest position in the eccentric.
- the compression ratio is at its highest, for example 12 to 1.
- FIG. 2 depicts the variable compression piston at its lowest, at bottom dead center, with the eccentric piston pin at its highest position in the eccentric.
- the compression ratio is at its lowest, for example 8 to 1.
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- Engineering & Computer Science (AREA)
- General Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- Output Control And Ontrol Of Special Type Engine (AREA)
Abstract
The invention in question relates, in particular, to a hydraulic variable compression ratio piston comprising a full floating eccentric mounted in the body of said piston, wherein the eccentric accepts a piston pin, with the pin in turn, accepting the small end of the connecting rod. The eccentric moves in a circular manner against the force of preloaded springs installed at the bottom of the piston, thereby allowing the piston to move up or down relative to the connecting rod. An adjustment mechanism within the piston comprising of a combination of said preloaded springs and a lifter acting against the movement of the eccentric, holds the piston's current position relative to the connecting rod until an increase or decrease in combustion forces act upon the piston and changes the compression ratio.
Description
- The present invention relates to a variable compression ratio piston which changes height relative to a common connecting rod to modify the compression ratio in a typical internal combustion engine.
- In modern internal combustion engines, a higher compression ratio yields more power and greater fuel efficiency. Compression ratio is thus defined as the largest cylindrical volume atop the piston, at bottom dead enter, divided by the smallest cylindrical volume atop the same piston at top dead center. By definition, a fixed compression ratio only allows combustion efficiency to occur at maximum engine torque and load with only partial combustion at lesser loads due to the partial filling of the cylinder. Partial filling occurs when only small injection of fuel and air are required for smaller engine loads or when the total mix of fuel and air does not completely fill the cylinder due to air friction and greater piston speeds.
- A variable compression engine, however, constantly changes the compression ratio to match the combination of air/fuel mix and engine load, thereby achieving full and efficient combustion at every engine speed. Variable compression does make for an overly complex and expensive engine design.
- The hydraulic variable compression ratio piston, however, is a more reliable, simpler, and cheaper build, and still allows the flexibility of a variable compression engine.
- This invention changes compression by doing a partial movement of the piston relative to the connecting rod. As the combustion wave front pushes against the piston, the piston shrinks down relative to the connecting rod, much like a shock absorber, to avoid harmful pre-detonation in the case of excessive combustion pressure at the current compression ratio, for example, 12 to 1. This partial movement is achieved by the rotation of the eccentric piston pin.
- The relative position of the piston stays fixed at its current compression ratio. The compression ratio only changes when power levels and inertia of the piston and connecting rod at bottom dead center increases or decreases.
- This control of the compression ratio is achieved with a combination of return springs to the eccentric and an opposing contra-acting lifter to the eccentric. The function of the return springs, to return the eccentric to its original position, is opposed and controlled by the opposing lifter, installed within the piston.
- The lifter eventually loses oil and contracts, but very slowly at lower combustion and engine loads. At higher combustion and greater engine loads, the lifter expands as the return springs contract. The eccentric therefore only turns when there are changes in the combustion pressure. If power levels remain the same, the opposing lifter holds its position against the eccentric return springs, and the compression ratio stays the same.
-
FIG. 1 depicts the variable compression piston at its highest, at top dead center, with the eccentric piston pin at its lowest position in the eccentric. In this depiction the compression ratio is at its highest, for example 12 to 1. -
FIG. 2 depicts the variable compression piston at its lowest, at bottom dead center, with the eccentric piston pin at its highest position in the eccentric. In this depiction the compression ratio is at its lowest, for example 8 to 1.
Claims (8)
1. (canceled)
2. (canceled)
3. A variable compression ratio piston for an internal combustion engine, the variable compression ratio piston comprising:
a spring-loaded hydraulic lifter with a retractable piston which changes the lifter's effective length, thereby turning an eccentric in the piston, both said eccentric and lifter locked in position until changes in engine power level occur.
4. (canceled)
5. (canceled)
6. (canceled)
7. The variable compression ratio piston of claim 3 , wherein said spring-loaded hydraulic lifter moves freely and fits firmly between said eccentric and rounded machined top corner of the piston.
8. The variable compression ratio piston of claim 7 , wherein oil intake channels built into said spring-loaded hydraulic lifter pulls in oil from the piston's bottom lubrication as said lifter retractable piston expands out and locks in position by means of a built-in check valve.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
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US16/974,400 US11384685B1 (en) | 2021-01-14 | 2021-01-14 | Casella hydraulic variable compression ratio piston |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
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US16/974,400 US11384685B1 (en) | 2021-01-14 | 2021-01-14 | Casella hydraulic variable compression ratio piston |
Publications (2)
Publication Number | Publication Date |
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US11384685B1 US11384685B1 (en) | 2022-07-12 |
US20220220886A1 true US20220220886A1 (en) | 2022-07-14 |
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US16/974,400 Active US11384685B1 (en) | 2021-01-14 | 2021-01-14 | Casella hydraulic variable compression ratio piston |
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US (1) | US11384685B1 (en) |
Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN205503273U (en) * | 2016-04-20 | 2016-08-24 | 吉林大学 | Two -stage vary voltage scaling piston link assembly |
-
2021
- 2021-01-14 US US16/974,400 patent/US11384685B1/en active Active
Patent Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN205503273U (en) * | 2016-04-20 | 2016-08-24 | 吉林大学 | Two -stage vary voltage scaling piston link assembly |
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US11384685B1 (en) | 2022-07-12 |
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