Motor vehicles – Power – Electric
Reexamination Certificate
2000-10-06
2003-10-28
Johnson, Brian L. (Department: 3618)
Motor vehicles
Power
Electric
C180S065310, C180S065510
Reexamination Certificate
active
06637530
ABSTRACT:
The present invention relates to a hybrid automotive vehicle, and more particularly to techniques for charging a battery by operating an electric generator while the vehicle is driven by an engine operated as a drive power source.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a hybrid automotive vehicle, and more particularly to techniques for charting a battery by operating an electric generator while the vehicle is driven by an engine operated as a drive power source.
2. Discussion of Related Art
There is known a control apparatus for a hybrid automotive vehicle which includes, as drive power sources, an engine operable by combustion of a fuel and an electric motor. The control apparatus is adapted to charge a battery by operating an electric generator while the vehicle is driven by the engine operated as a drive power source. JP-A-9-98516 discloses an example of such a hybrid vehicle control apparatus, which is arranged to control an output of the engine so as to maximize the efficiency of charging of the battery in terms of the fuel economy, while taking into account of the energy conversion efficiency of the electric generator and the battery.
However, the above-indicated control apparatus arranged to control the output of the engine so as to maximize the efficiency of charging of the battery in terms of the fuel economy does not necessarily permit sufficiently high degrees of energy conversion efficiency and fuel economy, depending upon the vehicle drive force as desired by the vehicle operator and the amount by which the battery is charged. For instance, the amount of charging of the battery is determined by the amount of electric energy presently stored in the battery, and the electric generator is operated to generate the amount of electric energy corresponding to the determined amount of charging of the battery. In this case, the operating speed and drive torque of the electric generator decrease with a decrease in the amount of charging of the battery, so that the energy conversion efficiency decreases with a decrease in the amount of charging of the battery. On the other hand, the output of the engine is controlled so as to maximize the fuel economy. This arrangement may have a risk that the vehicle cannot be driven with a drive force which is as large as desired by the vehicle operator where the operator's desired vehicle drive force is relatively large. The term “amount of charging of the battery” is interpreted to mean an amount of electric energy with which the battery is charged per unit time, namely, electric power W and the term “amount of electric energy presently stored in the battery” is interpreted to mean an amount of electric power Wh or Ah.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a hybrid vehicle control apparatus which provides a further improvement in the fuel economy of an engine and which permits a hybrid vehicle to be driven with a drive force as desired by the vehicle operator even when the operator's desired drive force is relatively large.
The above object may be achieved according to a first aspect of the present invention, which provides a control apparatus for controlling a hybrid automotive vehicle including an engine operable by combustion of a fuel and an electric motor as drive power sources for driving the vehicle, and an electric generator operable by the engine to generate an electric energy for charging a battery while the vehicle is driven by the engine, the control apparatus comprising a charging opportunity selecting device operable to determine whether the battery should be charged by the electric generator, on the basis of at least one of a required charging amount of electric energy with which the battery is charged and an energy conversion efficiency of the electric generator.
In the hybrid vehicle control apparatus constructed according to the first aspect of this invention, the charging opportunity selecting device is arranged to make a determination as to whether the battery should be charged by operation of the electric generator, on the basis of at least one of the required charging amount of the battery and the energy conversion efficiency of the electric generator. According to this arrangement, the battery is charged only when the energy conversion efficiency of the electric generator is relatively high, so that the fuel economy of the engine is accordingly improved. Further, the battery is charged when the speed of the engine is comparatively high, so that the charging does not take place when the accelerator pedal is released. If the battery charging took place upon releasing of the accelerator pedal, the engine speed Ne would be undesirably raised. Thus, the present arrangement prevents a rise of the engine speed due to the battery charging. Such rise and change of the engine speed upon charging of the battery is unexpected by the vehicle operator.
The required charging amount of the battery indicated above corresponds to an electric power generated by the electric generator, that is, the operating speed of the electric generator multiplied by the regenerative torque of the electric generator. Therefore, the energy conversion efficiency of the electric generator can be improved by permitting the charging of the battery only when the required charging amount of the battery is larger than a predetermined lower limit.
The control apparatus according to the first aspect of the invention is applicable to various hybrid automotive vehicles having a synthesizing/distributing device of a gear type such as a parallel or series type or a planetary gear type. The electric motor and the electric generator may be mutually separate units, or a single motor/generator unit which selectively functions as the electric motor or the electric generator. The present control apparatus is also applicable to a hybrid vehicle having a plurality of motor/generator units.
In one preferred form of the first aspect of the invention, the control apparatus further comprises means for determining the required charging amount of electric energy of the battery on the basis of an amount of electric energy presently stored in the battery. In this case, the electric generator is operated to charge the battery with the required charging amount. However, the electric generator may be operated to generate an electric energy so as to satisfy any other requirement relating to the charging of the battery. The electric generator may be mechanically connected to and driven by the engine. Alternatively, the electric generator may be driven by a rotary motion of the vehicle wheels transmitted thereto.
In a further preferred form of the control apparatus according to the first aspect of the invention, the charging opportunity selecting device determines whether the battery should be charged, on the basis of the energy conversion efficiency of the electric motor. In this case, the energy conversion efficiency of the electric motor need not be directly obtained. For instance, a permissible operating range (e.g., permissible operating speed and torque) of the electric generator within which the battery can be charged with a high energy conversion efficiency is determined, and the determination as to whether the battery should be charged is effected by determining whether the operating state of the electric generator is held within the permissible operating range.
In an alternative preferred form of the control apparatus, the charging opportunity selecting device determines whether the battery should be charged, on the basis of the required charging amount of the battery. Namely, the operating state of the electric generator is almost determined by the required charging amount of the battery as well as the vehicle-operator's desired vehicle drive power. In this respect, the determination may be effected by determining whether a sum of the required charging amount of the battery and the operator's desired vehicle drive power, which is the required total vehicle
Endo Hiroatsu
Hoshiya Kazumi
Oba Hidehiro
Umeyama Mitsuhiro
Johnson Brian L.
Kenyon & Kenyon
Shriver J. Allen
LandOfFree
Hybrid vehicle control apparatus wherein battery is charged... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Hybrid vehicle control apparatus wherein battery is charged..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Hybrid vehicle control apparatus wherein battery is charged... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3167075