Electricity: motive power systems – Battery-fed motor systems
Reexamination Certificate
2000-08-31
2001-11-27
Dang, Khanh (Department: 2837)
Electricity: motive power systems
Battery-fed motor systems
C320S140000
Reexamination Certificate
active
06323608
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention generally relates to a drive device for a vehicle having an engine and a motor and, more particularly, to such a drive device that is equipped with a single battery capable of supplying two types of power.
In conventional practice, additional batteries are provided to idle stop devices (drive devices) that require a main supply voltage (referred to as a 36-V battery hereinbelow) above that of a 12-V battery for common electrical equipment. A 14-V stator or a bi-directional DC/DC converter is preferably also provided to permit jump-starting of the equipment from the outside with a separate 12-V battery when the 36-V battery has deteriorated or expired.
The above-described conventional arrangement can be made to function by retaining the existing starter technology and mounting new batteries and idle stop starters. However, it is impossible to save space or reduce weight by retaining the existing 12-V system. Accordingly, manufacturing expense and product costs are increased because the system can only be installed on a limited number of car models.
SUMMARY OF THE INVENTION
The present invention is directed toward managing battery energy in an optimal manner by employing a novel battery operating procedure. The present invention is further directed toward a method for controlling a motor controller and a DC/DC converter in a coordinated manner to provide an idle stop function, and to achieve better fuel economy with a compact system.
In accordance with the one aspect of the present invention, a main battery is provided for driving a vehicle drive device equipped with an engine and with a motor linked to the engine drive shaft. The main battery includes a 12-V battery for common electrical equipment and a low-capacity or ancillary battery of a different type. The low-capacity battery may be an ultracapacitor, a lithium battery, a nickel battery, a high-output lead battery, or any other advanced battery.
In operation of the vehicle incorporating the present invention, the motor may function as a generator. However, the 12-V battery unit must still supply power to the common electrical equipment on a constant basis. Therefore, a DC/DC converter is connected between the motor (generator) and the 12-V battery via a separate charging route to avoid disrupting the charge-discharge balance. The capacity of the 12-V battery unit can be reduced by varying the rating of the DC/DC converter.
The present invention is further directed toward a method for more efficiently using energy. In accordance with the inventive method, a state of operation of the vehicle (idle stop, start, acceleration, cruising, and deceleration) is determined. As a result of the determined state of vehicle operation, the set voltage of the motor controller and the mode of the DC/DC converter is switched, making it possible to control the battery condition in an optimal manner.
An engine cannot be started if the car battery voltage has deteriorated or if the battery has been completely discharged as a result of neglect. The urgent measures undertaken in such cases include procuring a new battery or obtaining power from another vehicle. Existing vehicle batteries have a voltage of 12-V, and are therefore not useful to jump-start conventional automobiles incorporating a 36-V battery system. With the battery of the present invention, external starting from a 12-V power supply can be performed when an ultracapacitor with physically reversible poles is used as the ancillary battery. On the other hand, when the ancillary battery is one whose poles cannot be reversed, a single switch can be provided between the 12-V battery and the ancillary battery to control these batteries.
The present invention dispenses with the need for an existing separate 12-V system and provides a compact, lightweight system. The present invention also permits optimal battery management by cooperative control of the motor controller and DC/DC converter, thereby improving the idle stop function and fuel economy.
REFERENCES:
patent: 3667025 (1972-05-01), Campbell et al.
patent: 4723105 (1988-02-01), Matouka et al.
patent: 5166538 (1992-11-01), Norton
patent: 5350994 (1994-09-01), Kinoshita et al.
patent: 5710699 (1998-01-01), King et al.
patent: 5898282 (1999-04-01), Drozdz et al.
Dang Khanh
Honda Giken Kogyo Kabushiki Kaisha
Rankin, Hill Porter & Clark LLP
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