Prime-mover dynamo plants – Electric control – Engine control
Reexamination Certificate
1998-02-12
2001-01-09
Enad, Elvin (Department: 2834)
Prime-mover dynamo plants
Electric control
Engine control
C290S00400D, C290S00400D, C290S00400D, C290S04000F, C290S04000F, C290S04000F
Reexamination Certificate
active
06172427
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to an electric energy supply system for a vehicle on which a driving source such as an internal combustion engine is mounted, and particularly to the electric energy supply system which makes it possible to effectively use exhaust gas energy or the like discharged from the internal combustion engine of an automotive vehicle and reduce the amount of fuel used for the engine thereby improving energy efficiency.
BACKGROUND OF THE INVENTION
An alternator is mounted on a vehicle to supply power to an electric load of the vehicle and to charge a storage battery in accordance with an electricity storage condition, using the power output shaft of the engine as a power source. The output of this alternator depends on the rotational speed of a rotor and an electric power demand. Accordingly, electric power is generated when the electric power demand increases even during acceleration of the vehicle, and therefore the driving force from the power output shaft of the engine is required. This further increases the load energy required for acceleration of the vehicle. During deceleration of the vehicle, little electric power is generated under some electric power using conditions, and the kinetic energy of the vehicle is dissipated as brake heating and the like and as pumping loss of the engine.
The electric power demands for a vehicle in recent years has increased due to the addition of electrical equipment such as an anti-braking system (ABS), a four-wheel drive system (4WS), a traction control system (TRC), a power steering system (PS) and the like. In order to supply sufficient electric power to satisfy this increased demand, the capacity of the alternator tends to increase; however, the efficiency of the alternator is around 50% at maximum.
In general, the energy which can be taken out from the power output shaft of the engine is around 30% of the energy contained in fuel in an automotive vehicle having a gasoline-fueled engine. The energy necessary for the normal running of the vehicle is similarly around 25%. In contrast, when the maximum electric power generation is made using the alternator having, an electric power generation capacity of 1 kW, for example, 2 to 3 kW of the energy to be used for running of the vehicle is consumed by the electric power generation of the alternator. This corresponds to about 6 to 9% of the energy contained in gasoline fuel. Accordingly, the fuel economy is degraded 19 to 26% at maximum electric power generation.
In order to improve the electric power supply in such a vehicle, an electric power supply source which is used in addition to the conventional alternator and does not use the power output shaft of the engine as an energy source, or a control manner for the electric power obtained by this are proposed in Japanese Patent Provisional Publication 61-254082, Japanese Patent Provisional Publication No. 63-262075 and Japanese Patent Provisional Publication No. 5-111101. Of these, both the electric power supply sources disclosed in Japanese Patent Provisional Publication No. 61-254082 and Japanese Patent Provisional Publication No. 63-262075 use an exhaust gas heat electric power generation device which converts the thermal energy of exhaust gas discharged from an internal combustion engine to electric energy. This exhaust gas heat electric power generation device includes a heat absorption section in contact with exhaust gas, a cooling section in contact with outside air or liquid, and a thermoelectric converter element interposed between the heat absorption section and the cooling section to convert to electric energy the thermal energy due to a temperature difference.
Additionally, the electric power supply source and the electric power control method disclosed in Japanese Patent Provisional Publication No. 5-111101 is provided with a solar electric power generating means for converting solar energy to electric energy, in addition to thermoelectric converting means for converting exhaust gas thermal energy from the engine to electric energy as mentioned above. During the running and idling of the vehicle, exhaust gas thermal energy from the engine is converted to electric energy to be stored in a storage battery by using the thermoelectric converting means. When the vehicle is located outside, solar energy is converted to electric energy to be stored in the storage battery by using the solar electric energy generating means. The stored energy is utilized as energy for driving auxiliary electrical equipment parts, accessories, and the like.
Applying the above-described exhaust gas heat electric power generation device theoretically contributes to fuel economy improvements. However, since the amount of electric power generation is around 100 W, it is impossible to satisfy the electric power requirements of the vehicle only with the exhaust gas heat electric power generation device.
Additionally, the reduction in fuel consumption is as small as around 5% merely by using, as an energy for driving accessories and the like, the electric power obtained by the electric power supply source other than the alternator, such as the thermoelectric converting means utilizing exhaust gas heat and the solar electric power generating means utilizing sunlight. Thus, the conventional techniques are relatively ineffective in improving fuel economy improvement and therefore are not practical.
In view of the above-described conventional techniques, there is a need for an electric energy supply system for a vehicle, which can reduce fuel consumption in all vehicle driving modes by controlling the amount of generated electric power obtained from a variety of electric power generating sources, in accordance with the driving condition of the vehicle and the electricity storage condition of a storage battery.
This and other needs are met by the present invention, which provides an electric energy supply system for a vehicle, comprising a plurality of electric power generators for generating electric power by utilizing different energies which can be taken out from a driving source for driving the vehicle. Electricity storing devices are provided for storing electric energy. Driving condition judging means judge a driving condition of the vehicle and electricity storage condition judging means judges an electricity storage condition within the electricity storing means. Electric power controlling means for control a supply amount of electric energy to be used in the vehicle. The controlling means is configured to control an amount of electric power generated by each of the plurality of the electric power generating sources in accordance with information obtained from the driving condition judging means and the electricity storage condition judging means.
In certain embodiments of the invention, the driving source includes an internal combustion engine, and the plurality of the electric power generators includes a power output shaft electric power generator for generating electric power by utilizing a power energy obtained from the internal combustion engine, and an exhaust gas electric power generator for generating electric power by utilizing exhaust gas energy of the internal combustion engine.
The exhaust gas electric power generator includes a thermoelectric generator for generating electric power by utilizing a heat energy of exhaust gas discharged from the internal combustion engine, in certain embodiments of the present invention. In further embodiments of the invention, the exhaust gas electric power generator includes a turbine generator for generating electric power by utilizing kinetic energy of exhaust gas discharged from the internal combustion engine.
Additionally, in an electric energy supply system for a vehicle according to certain embodiments of the present invention, the electric power controlling means is configured to operate the exhaust gas electric power generating means as a main generating source to generate electric power and to supply an electric energy obtained by this electric power generation
Furuya Kenji
Kobayashi Masakazu
Kushibiki Keiko
Shinohara Kazuhiko
Enad Elvin
McDermott & Will & Emery
Nissan Motor Co,. Ltd.
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