US4958516A
Expired / Lapsed
US
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Method and means for determining air mass in a crankcase scavenged two-stroke engine
Assignee: Motors Liquidation Co
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Filing: 1990-02-08
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Granted: 1990-09-25
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Expires: 2010-02-08
Abstract
Abstract A method and apparatus are described for determining the mass of air available for combustion within a cylinder of a crankcase scavenged two-cycle engine, without the use of a mass-air flow sensor. This is achieved by estimating the mass of air under compression within a crankcase chamber, prior to its transfer to a cylinder combustion chamber. The estimate for air mass is based upon the integration of crankcase pressure over the interval of decreasing crankcase volume, while air within the crankcase is under compression. The volume of the air within the crankcase chamber is derived as a function of engine cycle position, with crankcase air temperature being derived as a function of intake air temperature. Air pressure during compression is monitored with a crankcase pressure sensor. The estimate for air mass is corrected to account for air leakage and incomplete transfer of the air between the crankcase and combustion chambers.
Inventors
- 👤 Steven D. Stiles
- 👤 Paul E. Reinke
- 👤 Aparicio J. Gomez
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 10:52
CPC Classifications
G; G01; G01F; G01F1/00; G01F1/76; G01F1/86; F; F02; F02D; F02D41/00; F02D41/02; F02D41/18; F02B; F02B75/00; F02B75/02; F02B2075/022; F02B2075/025; F02D2400/00; F02D2400/04
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
172 words
In a crankcase scavenged two-stroke engine characterized by an operating cycle including portions during which air is inducted into a crankcase chamber of the engine, is thereafter compressed within the crankcase chamber while trapped in the crankcase chamber as the crankcase chamber undergoes shrinking volume, and is then transferred to the combustion chamber; a method for determining the mass of air transferred to the combustion chamber comprising the steps of: determining a portion of the operating cycle at which inducted air is trapped in the crankcase; determining the pressure P of the air mass M within the crankcase chamber during the determined portion of the operating cycle; determining the volume V of the crankcase chamber during the determined portion of the operating cycle; determining the temperature T of the air mass within the crankcase chamber during the determined portion of the operating cycle; and deriving an indication of the mass of air transferred to the combustion chamber in accordance with a predetermined function of derived pressure F, volume V and temperature T.
Claim 2
Dependent Claim
172 words
In a crankcase scavenged two-stroke engine characterized by an operating cycle including portions during which air is inducted into a crankcase chamber of the engine, is thereafter compressed within the crankcase chamber while trapped in the crankcase chamber as the crankcase chamber undergoes shrinking volume, and is then transferred to the combustion chamber; a method for determining the mass of air transferred to the combustion chamber comprising the steps of: determining a portion of the operating cycle at which inducted air is trapped in the crankcase; determining the pressure P of the air mass M within the crankcase chamber during the determined portion of the operating cycle; determining the volume V of the crankcase chamber during the determined portion of the operating cycle; determining the temperature T of the air mass within the crankcase chamber during the determined portion of the operating cycle; and deriving an indication of the mass of air transferred to the combustion chamber in accordance with a predetermined function of derived pressure F, volume V and temperature T.
Claim 3
Dependent Claim
247 words
In a crankcase scavenged two-stroke engine characterized by an operating cycle including portions during which air is inducted into a crankcase chamber of the engine, is thereafter compressed within the crankcase chamber while trapped in the crankcase chamber as the crankcase chamber undergoes shrinking volume, transferred to the combustion chamber and is then trapped in the combustion chamber; a method for determining the mass of air trapped in the combustion chamber comprising the steps of: determining a portion of the operating cycle at which inducted air is trapped in the crankcase; determining the pressure P of the air mass M within the crankcase chamber during the determined portion of the operating cycle; determining the volume V of the crankcase chamber during the determined portion of the operating cycle; determining the temperature T of the air mass within the crankcase chamber during the determined portion of the operating cycle; deriving an indication of the mass of air trapped in the crankcase chamber in accordance with a predetermined function of derived values of the pressure P, volume and temperature T; determining a trapping efficiency value representing the percentage of the derived indication of the mass of air trapped in the crankcase chamber that is transferred to and then trapped in the combustion chamber; and adjusting the derived indication of the mass of air trapped in the crankcase chamber in accord with the determined trapping efficiency value to provide a measure of the air mass trapped in the combustion chamber.
Claim 4
Dependent Claim
247 words
In a crankcase scavenged two-stroke engine characterized by an operating cycle including portions during which air is inducted into a crankcase chamber of the engine, is thereafter compressed within the crankcase chamber while trapped in the crankcase chamber as the crankcase chamber undergoes shrinking volume, transferred to the combustion chamber and is then trapped in the combustion chamber; a method for determining the mass of air trapped in the combustion chamber comprising the steps of: determining a portion of the operating cycle at which inducted air is trapped in the crankcase; determining the pressure P of the air mass M within the crankcase chamber during the determined portion of the operating cycle; determining the volume V of the crankcase chamber during the determined portion of the operating cycle; determining the temperature T of the air mass within the crankcase chamber during the determined portion of the operating cycle; deriving an indication of the mass of air trapped in the crankcase chamber in accordance with a predetermined function of derived values of the pressure P, volume and temperature T; determining a trapping efficiency value representing the percentage of the derived indication of the mass of air trapped in the crankcase chamber that is transferred to and then trapped in the combustion chamber; and adjusting the derived indication of the mass of air trapped in the crankcase chamber in accord with the determined trapping efficiency value to provide a measure of the air mass trapped in the combustion chamber.
Claim 5
Dependent Claim
157 words
In a crankcase scavenged two-stroke engine characterized by an operating cycle including portions during which air is inducted into the engine, is thereafter compressed within a crankcase chamber of shrinking volume, and is then transferred to the combustion chamber; a method for determining the mass of air transferred to the combustion chamber comprising the steps of: deriving an indication of the pressure P of the air mass within the crankcase chamber during compression; deriving an indication of the volume V of the crankcase chamber during compression; and deriving an indication of the mass of air transferred to the combustion chamber in accordance with the expression M=W/(u2-u1) where W is the work done in compressing the air in the crankcase chamber between an initial crankcase volume V1 and a final crankcase volume V2 and u2-u1 is the change in the specific internal energy in the air between the initial crankcase volume V1 and the final crankcase volume V2.
Claim 6
Dependent Claim
157 words
In a crankcase scavenged two-stroke engine characterized by an operating cycle including portions during which air is inducted into the engine, is thereafter compressed within a crankcase chamber of shrinking volume, and is then transferred to the combustion chamber; a method for determining the mass of air transferred to the combustion chamber comprising the steps of: deriving an indication of the pressure P of the air mass within the crankcase chamber during compression; deriving an indication of the volume V of the crankcase chamber during compression; and deriving an indication of the mass of air transferred to the combustion chamber in accordance with the expression M=W/(u2-u1) where W is the work done in compressing the air in the crankcase chamber between an initial crankcase volume V1 and a final crankcase volume V2 and u2-u1 is the change in the specific internal energy in the air between the initial crankcase volume V1 and the final crankcase volume V2.
Claim 7
Dependent Claim
198 words
In a crankcase scavenged two-stroke engine characterized by an operating cycle including portions during which air is inducted into the engine, is thereafter compressed within a crankcase chamber of shrinking volume, and is then transferred to the combustion chamber; a method for determining the mass of air transferred to the combustion chamber comprising the steps of: deriving an indication of the pressure P of the air mass M within the crankcase chamber during compression; deriving an indication of the volume V of the crankcase chamber during compression; deriving an indication of the temperature T of the air mass within the crankcase chamber during compression; and deriving an indication of the mass of air transferred to the combustion chamber in accordance with the expression M=W/{Cv(T2-T1)} where W is the work done in compressing the air in the crankcase chamber between an initial crankcase volume V1 and a final crankcase volume v2, Cv is the specific heat capacity of air at constant volume, T1 is the temperature of the air in the crankcase chamber when at the initial crankcase volume V1 and T2 is the temperature of the air in the crankcase chamber when at the final crankcase volume V2.
Claim 8
Dependent Claim
198 words
In a crankcase scavenged two-stroke engine characterized by an operating cycle including portions during which air is inducted into the engine, is thereafter compressed within a crankcase chamber of shrinking volume, and is then transferred to the combustion chamber; a method for determining the mass of air transferred to the combustion chamber comprising the steps of: deriving an indication of the pressure P of the air mass M within the crankcase chamber during compression; deriving an indication of the volume V of the crankcase chamber during compression; deriving an indication of the temperature T of the air mass within the crankcase chamber during compression; and deriving an indication of the mass of air transferred to the combustion chamber in accordance with the expression M=W/{Cv(T2-T1)} where W is the work done in compressing the air in the crankcase chamber between an initial crankcase volume V1 and a final crankcase volume v2, Cv is the specific heat capacity of air at constant volume, T1 is the temperature of the air in the crankcase chamber when at the initial crankcase volume V1 and T2 is the temperature of the air in the crankcase chamber when at the final crankcase volume V2.
Claim 9
Dependent Claim
283 words
In a crankcase scavenged two-stroke engine characterized by an operating cycle including portions during which air is inducted into an intake manifold and then into a crankcase chamber of the engine, is thereafter compressed within the crankcase chamber during a portion of the operating cycle in which the inducted air is trapped in the crankcase chamber while the crankcase chamber undergoes shrinking volume, an is then transferred to the combustion chamber; a method for determining the mass of air transferred to the combustion chamber comprising the steps of: deriving an indication of the pressure P of the air mass M within the crankcase chamber during compression; deriving an indication of the volume v of the crankcase chamber during compression; measuring the temperature T of the air inducted into the intake manifolds; and deriving an indication of the mass of air transferred to the combustion chamber in accordance with the expression M=W/{Cv(T2-T1)} where W is the work done in compressing the air in the crankcase chamber between an initial crankcase volume V1 when the air is first trapped in the crankcase chamber and a final crankcase volume V2, Cv is the specific heat capacity of air at constant volume, T1 is the temperature of the air inducted into the intake manifold substantially at the time the air is first trapped in the crankcase chamber and T2 is a temperature of the air in the crankcase chamber when at the final crankcase volume V2 derived in accord with the expression T1(P2*V2)/(P1*V1) where P1 is the pressure of the air mass M when at the initial crankcase volume V1 and P2 is the pressure of the air mass M when at the final crankcase volume V2.
Claim 10
Dependent Claim
283 words
In a crankcase scavenged two-stroke engine characterized by an operating cycle including portions during which air is inducted into an intake manifold and then into a crankcase chamber of the engine, is thereafter compressed within the crankcase chamber during a portion of the operating cycle in which the inducted air is trapped in the crankcase chamber while the crankcase chamber undergoes shrinking volume, an is then transferred to the combustion chamber; a method for determining the mass of air transferred to the combustion chamber comprising the steps of: deriving an indication of the pressure P of the air mass M within the crankcase chamber during compression; deriving an indication of the volume v of the crankcase chamber during compression; measuring the temperature T of the air inducted into the intake manifolds; and deriving an indication of the mass of air transferred to the combustion chamber in accordance with the expression M=W/{Cv(T2-T1)} where W is the work done in compressing the air in the crankcase chamber between an initial crankcase volume V1 when the air is first trapped in the crankcase chamber and a final crankcase volume V2, Cv is the specific heat capacity of air at constant volume, T1 is the temperature of the air inducted into the intake manifold substantially at the time the air is first trapped in the crankcase chamber and T2 is a temperature of the air in the crankcase chamber when at the final crankcase volume V2 derived in accord with the expression T1(P2*V2)/(P1*V1) where P1 is the pressure of the air mass M when at the initial crankcase volume V1 and P2 is the pressure of the air mass M when at the final crankcase volume V2.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-09-24 | 1994-03-26 | 1994-09-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-09-24 | 1998-03-26 | 1998-09-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-09-24 | 2002-03-26 | 2002-09-25 | $7700.00 | Window Closed / Lapsed |