Power plants – Fluid motor means driven by waste heat or by exhaust energy... – With supercharging means for engine
Reexamination Certificate
2000-09-06
2001-10-23
Kamen, Noah P. (Department: 3747)
Power plants
Fluid motor means driven by waste heat or by exhaust energy...
With supercharging means for engine
Reexamination Certificate
active
06305169
ABSTRACT:
BACKGROUND
This invention relates to improved operation of turbochargers as applied to internal combustion engines and the like. The general concept of turbo-charging is to employ the residual energy in engine exhaust to increase induction air pressure before final compression in the engine. It is internal combustion engines with which this invention is particularly concerned, of any combustion cycle, and preferably those state of the art engines into which fuel is fed according to regulatory environmental factors to which said engines are subjected; all of which includes the type of fuel, the mode of feeding said fuel, the angular velocity and torque change or constants, and the various temperature conditions, all as circumstances require. And in view of efficiency and environmental regulatory requirements, it is a general object of this invention to provide substantially instantaneous increases in induction air pressures into the engine according to variations in performance demand. To this end, the compressor rotor of the turbo-charger can be accelerated independently of the turbine rotor thereof, whereby the mass inertia of the turbine rotor does not retard acceleration of the compressor rotor.
Internal combustion engines are characterized by two basic requirements, controlled fuel feed, and the proper induction of air to establish a correct air-fuel ratio required for efficient combustion. These two basic requirements are interrelated and are subject to electronic computer control. State of the art electronics provides instantaneous operational calculations to which the engine must respond in order to achieve efficient operation with any internal combustion engine having multi-port, throttle-body or direct injection irrespective of fuel type. However, despite the instantaneous demand for increased combustion air due to sudden changes in load and torque demand, there is an inherent “turbo-lag” involved in the acceleration of state of the art turbochargers. In the internal combustion engine, carburetor fuel feed has been greatly replaced by electronically controlled fuel injection, the amount of fuel injected being determined by the time during which the injector remains in the “ON” position, calculated by an electronic computer geared to various parameters including; absolute pressure in the inlet manifold, Air flow rate, RPM, engine load, crankshaft position related to T.D.C., engine coolant temperature, engine inlet air temperature, exhaust oxygen content, and torque demand. Also, internal combustion engines are often supercharged with induction air and subject to wide ranges of operational requirements under varying conditions. And, heretofore the prevailing deficiency has been “turbo-lag” in the induction air pressure supplied, this time-lag resulting in deficient engine operation. It is therefore an object of this invention to provide a method and apparatus by which adequate combustion air is substantially instantaneously supplied to the induction manifold of an internal combustion engine.
The method and apparatus herein disclosed gives increased power and makes the engine more flexible and more responsive, for any given engine RPM and/or torque requirement. Cold starting becomes improved allowing immediate augmentation of engine compression heated air flow, and all adjustments become automatic. It moreover simplifies the fuel control process which enhances compliance with exhaust emission regulations, being a rational method and/or system which allows the engine to be fed adequate induction air as necessary together with adequate fuel for proper and efficient operation under all conditions of use.
State of the art turbochargers employ a “unitized” principle of construction, wherein the compressor rotor and turbine rotor are integrally coupled by a common shaft. Therefore, the mass of each is combined with the other so as to affect common acceleration and deceleration. It is the acceleration of the compressor rotor with which this invention is particularly concerned, because the turbine rotor is inherently coupled to respond to exhaust gas energy discharged from the engine combustion chambers. Furthermore, said exhaust gases are not increased (or decreased) in pressure and/or velocity until after a change in induction pressure and combustion temperature occurs. Accordingly, there is a measurable time period before an exhaust pressure change reaches the turbine rotor, and only then does the turbine rotor respond to gradually increase its momentum, while the engine waits for the required induction pressure increase to be reached. The result is “turbo-lag” during which the engine is starved of adequate induction air for proper acceleration.
The state of the art provides auxiliary prime movers for supplementing the turbine drive in order to accelerate the mass of the combined rotor components. However, there are at least two problems here. 1) The mass of the two rotors is approximately twice that of either, and rapid acceleration of the compressor rotor is essential in order to enhance air induction. Heretofore, the torque required of the auxiliary prime mover has been twice that which would be required to accelerate the compressor rotor alone, and therefore it is an object of the invention to disengage the compressor rotor from the turbine rotor and thereby maximize acceleration of the former independently of the latter. In practice, this separation occurs during the initial phase of acceleration, as will be apparent from the following: 2) The auxiliary prime mover is preferably an electric motor having high initial torque and acceleration. However, state of the art electric motors have RPM limitations which are exceeded by the ultimate RPM attained by state of the art turbochargers here under consideration, and therefore it is an object of this invention to isolate the RPM restricted electric motor drive from the ultimately higher RPM drive of the turbine rotor and compressor rotor when driven thereby. This arrangement thereby provides a substantially instantaneous supply of adequate induction air pressure to be followed by a “take-over” effect as and when the turbine rotor drive exceeds the “limit RPM” range of the motor drive.
From the foregoing it will be observed that there is a primary objective to protect the auxiliary electric motor drive from exceeding its structurally limited RPM which is lesser than turbocharger RPM. Heretofore, “single direction bearings” have been employed in the art in order to couple the prime mover auxiliary to the unitized compressor rotor and turbine rotors. It is therefore an object of this invention to provide a coupling means that transmits torque applied by said auxiliary electric motor drive to the compressor rotor. In practice, this is achieved by utilizing a hysteresis or eddy-current coupling that transmits torque to the compressor rotor during an “acceleration mode”, and which relinquishes its drive effect as and when the limit RPM of said motor is reached, whereupon the turbine rotor continues to accelerate the compressor rotor into a “running mode” beyond the auxiliary motor limit RPM.
It is also a primary object of this invention to separate the mass to be accelerated, and to reduce torque required of the auxiliary electric motor drive as well. To this end, the compressor rotor is disconnected from the turbine rotor during the acceleration mode, thereby permitting the compressor rotor to overrun the speed of the turbine rotor, which occurs during the acceleration mode when there is an increased induction air pressure demand. In practice, an overrunning clutch is ultilized for this function, whereby the compressor rotor mass is independently accelerated from the detached turbine rotor mass. As a result, the turbine rotor mass is free of the compressor rotor load and independently lags for its maximized acceleration comensurate with the delay in exhaust gas discharge which is reduced from the engine which is waiting for the induction air pressure increase demanded thereby. Accordingly, the compressor rotor mass is accelerated
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