Power plants – Fluid motor means driven by waste heat or by exhaust energy... – With supercharging means for engine
Reexamination Certificate
1998-05-07
2001-02-06
Koczo, Michael (Department: 3748)
Power plants
Fluid motor means driven by waste heat or by exhaust energy...
With supercharging means for engine
C060S608000, C123S0650BA, C123S0650VC, C123S703000
Reexamination Certificate
active
06182449
ABSTRACT:
TECHNICAL FIELD
This invention is directed to apparatus and methods of supplying charge air for two-cycle internal combustion engines, including a motor-assisted turbocharger, a motor-driven compressor, or a motor-driven compressor connected in series with a turbocharger compressor.
BACKGROUND ART
The most common internal combustion engine in use today is the four-cycle type, either spark ignited or diesel, wherein there is one power stroke for every two revolutions of the crankshaft. This type of engine has a suction stroke by which it can aspirate its own air, and thus it is able to start and run without the aid of an external or auxiliary air supply. In contrast, the two-cycle internal combustion engine does not have a separate suction stroke since there is a power stroke for every revolution of the crankshaft. Consequently, the two-cycle engine must employ other means of exhausting and charging the cylinder with fresh air after each power stroke has been completed.
Typically, two-cycle engines use either an engine-driven compressor or crankcase air compression to force air into the intake ports of the cylinders. Crankcase compression is undesirable due to the tendency to mix lubricant oil present in the crankcase with the air which can cause excessive lubricant oil consumption and increase the amount of pollutants in the exhaust gases. Thus, it is more desirable to use an air compressor driven separately than from the engine to provide the necessary air supply for starting and running the engine.
When engine-driven compressors are used, the fuel consumption of the engine is increased by virtue of the horsepower absorbed by the compressor. Adding an exhaust gas-driven turbocharger in series with the engine-driven compressor is a substantial improvement. However, there is still a residual power drain on the engine caused by the engine-driven compressor and its gear train. Clutches between the engine-driven compressor and the engine have been used to disconnect the compressor from the engine when the turbocharger is capable of scavenging and charging the cylinders by itself. However, the addition of a clutch in the compressor drive train adds a very significant amount of cost and complication to the mechanical configuration of the engine.
DISCLOSURE OF THE INVENTION
One very important objective of this invention is to eliminate the need for an engine-driven compressor on a two-cycle engine by employing a turbocharger with an internal, integral motor that can be energized from an external power supply, such as a battery system. The motor can be supplied with power during cranking of the engine thereby rotating the turbocharger compressor to a speed necessary to force air into the engine intake system to start the engine and permit it to run at idle. The motor remains active as long as the energy level in the exhaust gas in insufficient to allow the turbocharger to scavenge and charge the engine on its own. When the turbocharger is capable of providing an intake manifold pressure higher than the exhaust back pressure on the cylinder, the motor is de-energized and the power drain on the electrical system is eliminated. By suitable control means, the motor can be energized at any time the exhaust gas energy is insufficient to drive the turbocharger at a high enough speed to sustain proper engine operation.
One method of control of the motor power supply is to sense the pressure in the engine intake manifold and turn the power on to the motor when the level falls below a predetermined level and vice versa. Other means of control can also be employed where the motor remains energized at a lower power level at all times to maintain the turbocharger rotor speed at a predetermined minimum level. In this manner, the inertia of the turbocharger rotor is counteracted by the motor torque and the time to accelerate the turbocharger rotor where the engine throttle is opened is shortened significantly. By substantially reducing this so-called “turbocharger lag,” the engine accelerates faster, the vehicle driven becomes more responsive, and undesirable pollutants in the exhaust gases are markedly reduced.
In order to aid in the understanding of this invention, it can be stated in essentially summary form that it is directed to a motor-assisted turbocharger and/or a motor-driven compressor for use on two-cycle internal combustion engines. The motor drive, which is separate from the operation of the two-cycle internal combustion engine, permits the starting of the two-cycle internal combustion engine by supplying scavenging and charging air.
Thus, it is a purpose and advantage of this invention to provide a motor-assisted turbocharger where the compressor of the turbocharger is driven mainly by the motor at low speeds and by exhaust gas energy at high speeds.
It is a further purpose and advantage of this invention to supply a motor-assisted turbocharger which aids in the acceleration of the engine from low to high speed in a manner which produces less undesirable products of combustion.
REFERENCES:
patent: 2620621 (1952-12-01), Nettel
patent: 2710521 (1955-06-01), Nettel
patent: 3676999 (1972-07-01), Oldfield
patent: 4901530 (1990-02-01), Kawamura
patent: 4958497 (1990-09-01), Kawamura
patent: 684902 (1930-03-01), None
patent: 267149 (1927-08-01), None
patent: 1181488 (1970-02-01), None
patent: 44-22569 (1969-09-01), None
patent: 57-212331 (1982-12-01), None
Halimi Edward M.
Maloof Ralph P.
Woollenweber William E.
Brinks Hofer Gilson & Lione
Koczo Michael
Turbodyne Systems Inc.
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