Power plants – Fluid motor means driven by waste heat or by exhaust energy... – With supercharging means for engine
Utility Patent
1999-03-25
2001-01-02
Kamen, Noah P. (Department: 3747)
Power plants
Fluid motor means driven by waste heat or by exhaust energy...
With supercharging means for engine
C060S602000, C060S605100
Utility Patent
active
06167703
ABSTRACT:
BACKGROUND OF THE INVENTION
Field of the Invention
This invention concerns a method for operation of an internal combustion engine with an exhaust gas turbocharger having a turbine portion with an adjustable turbine geometry controlled by a regulator mechanism to decrease the cross-sectional flow path leading to the turbine portion with increases of load on the internal combustion engine.
The power output of an internal combustion engine is proportionate to the volume of and density of air supplied for combustion with fuel. A turbocharger consists essentially of two turbine devices, specifically, an exhaust gas flow-driven turbine and an air compressor driven by the exhaust gas driven turbine. The turbine and the compressor are connected by a turbo-shaft and rotate synchronously. The mass flow of the supercharged charge air is a function of compressor speed. The air charge mass flow is delivered to the internal combustion engine intake through a charge air line.
The air pressure downstream of the compressor and the exhaust pressure upstream of the turbine reciprocally act on each other as a result of the momentary equilibrium communicated through the turbo-shaft. As a result of boost pressure acting on the compressor, exhaust gas is accumulated upstream of the turbine. Conversely, the dynamic pressure of the exhaust flow is translated into boost pressure in the charge air line in conformity with the pressure translation ratio of the exhaust gas turbocharger. The pressure translation ratio is determined by the respective cross-sections of the flows of exhaust to the turbine and of air from the compressor.
The amount of fuel required for a desirable mixture formulation of fuel/air for each combustion chamber of the internal combustion engine conforms with the momentary air thruput. With increasing output of the internal combustion engine, the demand or need for charge air increases, such that a correspondingly higher boost pressure of the turbocharger is needed. By means of an adjustable turbine geometry, e.g., adjustment of the angle of the turbine guide blades, the cross-section of flow to the turbine is changed. Resultantly, the dynamic energy imparted to the charge air by the compressor is varied. Under control of a charge regulator device, a turbine blade actuator acts to change the turbine geometry and bring the turbine geometry into a desirable operating position which produces a desired charge level. Resultantly, the cross-section of flow to the turbine is reduced with increasing engine output so that the turbocharger's rotative speed is increased which therefore increases compressor output and charge air mass flow through the charge air line to the internal combustion engine. This increase is proportioned to the increase in the operating condition of the engine.
In the operation of a supercharged internal combustion engine is that an ideal engine operating temperature, especially at low environmental temperatures, is difficult to achieve in a reasonable time and full functional capacity of the internal combustion engine is unavailable. As a result, the startup of accessory internal combustion engine units which utilize engine heat, for example, vehicle cab heating, is delayed.
SUMMARY OF THE INVENTION
The underlying objective of the invention is to enhance the heat generation capacity of the internal combustion engine and improve the ability to monitor the thermal balance of the quantity of heat required for various functions.
This objective is solved by this invention with methodology involving the use of a regulator mechanism to decrease the cross-sectional flow path to the turbine portion of a turbocharger in response to load increases imposed on the internal combustion engine.
In accordance with the invention, the aforementioned thermal balance is monitored by a thermoregulator, and the turbine geometry is adjusted by an actuator. When the thermoregulator determines that the engine's heat delivery should be increased, the cross-section of inlet flow to the turbine is reduced through adjustment of the turbine geometry. If additional heat delivery is needed, the actuator is energized to adjust the cross-section of inlet flow to the turbine from the position selected for the existing engine operating condition to a position which increases heat delivery. The reduction in the cross-section of the inlet flow increases turbocharger speed and causes the compressor consequently to deliver an increased air charge mass flow to the internal combustion engine intake. The increase in turbocharger speed and a corresponding increase in fuel mixed with the added air produces an excess combustion over and above what is called for by engine load. This increase in combustion produces a rapid heating of the internal combustion engine especially during the engine warm-up period.
The result of restricting the cross-section of flow to the turbine is increase in turbine intake pressure and temperature. Resultantly the output of the turbine is noticeably increased in the operating ranges of the internal combustion engine. Also, the compressor pressure ratio and compressor exhaust temperature also rise. In accordance with the invention, heat be extracted from the charge air mass flow to the engine by utilizing at least one heat exchanger to transfer heat from the charge air mass to a central working fluid which is fed to a separate thermal system. As the compressor draws in cold fresh air, the pressure and temperature are raised. The quantity of heat generated by the compressor is transferred by the heat exchanger great efficiency to the central working fluid in the heat exchanger and then fed to separate thermal system. By further adjustment of the turbine's geometry, towards a closed position characterized by minimal cross-section of the flow inlet to the turbine, the temperature of the charge air can be adjusted to an optimal level for the operation of the separate thermal system. The thermoregulator device is used to reduce the heat demand of the separate thermal system as needed and through adjustment of the turbine geometry modifies the charge air temperature.
The thermoregulator device establishes the thruput of the heat exchanger by a coordinated adjustment of a flow control valve located adjacent the intake of the heat exchanger and of a bypass valve positioned in a bypass line circumventing or bypassing the heat exchanger. By monitoring of the thermal balance and the additional heat generation produced by adjustment in the turbine geometry, several separate thermal systems each with a heat exchanger, can utilized. The thermal delivery of each separate thermal system is adjusted independently of each other by the thermoregulator. Useful applications of the quantity of heat which is extracted from the charge air are to warm up oil or fuel, to heat the oil pan and/or the fuel tank. For these purposes, the fuel tank or oil pan can be made of double-walled design and, therefore, provide a fluid flow space which allows cross-flow of the central working fluid of the heat exchanger. Heat transfer to the oil/fuel could also be produced by providing flow channels in the tank wall for conducting the central working fluid. The heat very quickly available downstream of the compressor can also be used for the heating a passenger cabin of a vehicle or for heating air used for vehicle windshield deicing. Finally, the hot charge air could also be used to more rapidly warm up the coolant of the internal combustion engine to the desired operating temperature.
REFERENCES:
patent: 5927075 (1999-07-01), Khair
patent: 5996347 (1999-12-01), Nagae et al.
patent: 40 25 901 C1 (1992-01-01), None
patent: 63-159619 (1988-07-01), None
patent: 4-47157 (1992-02-01), None
Rumez Werner
Schmidt Erwin
Sumser Siegfried
Daimler-Chrysler AG
Kamen Noah P.
MacLean Kenneth H.
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