Internal-combustion engines – Starting device – Condition responsive control of starting device
Reexamination Certificate
2001-02-20
2002-09-24
Mancene, Gene (Department: 3747)
Internal-combustion engines
Starting device
Condition responsive control of starting device
C307S010600, C180S065510
Reexamination Certificate
active
06453865
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a technique that controls idling stop of an internal combustion engine, which is carried out according to the driving state of a vehicle.
2. Description of the Related Art
Some proposed vehicles have an idling stop control function that stops driving an internal combustion engine at a temporary stop of the vehicle, for example, at a traffic light during a drive of the vehicle, and restarts driving the internal combustion engine in response to a driver's requirement for a start. In such vehicles having the function of automatically stopping and restarting the operation of the internal combustion engine, an auxiliary machinery driving electric electric motor is linked with the internal combustion engine and auxiliary machinery via fan belts to allow mutual connection thereof. While the internal combustion engine is at a stop, the auxiliary machinery like a water pump is driven by means of the auxiliary machinery driving electric electric motor. In the active state of the internal combustion engine, on the other hand, the auxiliary machinery is driven by means of the internal combustion engine. In order to disconnect the internal combustion engine from the driving system and reduce the loading of the auxiliary machinery driving electric electric motor while the auxiliary machinery is driven by means of the auxiliary machinery driving electric electric motor, a clutch (coupling mechanism) is interposed between the internal combustion engine and the auxiliary machinery driving electric electric motor to couple and release the internal combustion engine with and from the auxiliary machinery driving electric motor.
The auxiliary machinery driving electric motor also functions as the electric motor that restarts driving the internal combustion engine. At a start of driving the internal combustion engine, the clutch couples the internal combustion engine with the auxiliary machinery driving electric motor, which is currently driving the auxiliary machinery. This raises the velocity of the internal combustion engine to a starting speed of revolutions. One proposed technique couples the clutch after reduction of the velocity of the auxiliary machinery driving electric motor at a restart of driving the internal combustion engine, in order to reduce the occurrence of potential shocks and vibrations due to the velocity difference between the internal combustion engine and the auxiliary machinery driving electric motor, which is currently driving the auxiliary machinery.
In some driving states of the vehicle, the shocks and vibrations (energy) arising due to the coupling action of the clutch are not sufficiently absorbed by the fan belt. For example, in the cold time, partly because of the low temperature of the fan belt, the shocks and vibrations occurring due to the coupling action of the clutch are not sufficiently absorbed in the course of restarting the internal combustion engine under the idling stop control. Enhancing the rate of decrease in number of revolutions of the auxiliary machinery driving electric motor or in electric motor velocity to ensure the sufficient absorption, on the other hand, does not fulfil the requirement of quick restart of the internal combustion engine.
SUMMARY OF THE INVENTION
The object of the present invention is thus to reduce or even omit potential shocks and vibrations arising due to the coupling action of a coupling mechanism at the. time of starting an internal combustion engine, and to ensure a quick restart of the internal combustion engine.
At least part of the above and the other related objects is attained by an idling stop control apparatus mounted on a vehicle, wherein auxiliary machinery is driven by means of either one of an internal combustion engine and an electric motor, and an output shaft of the internal combustion engine and an output shaft of the electric motor are linked with each other via a coupling mechanism that is coupled to connect the internal combustion engine with the electric motor and is released to disconnect the internal combustion engine from the electric motor. The coupling mechanism is released and the auxiliary machinery is driven by means of the electric motor via a transmission belt while the internal combustion engine is at a stop. The idling stop control apparatus includes: a decision unit that determines whether a driving stop condition or a driving restart condition of the internal combustion engine is fulfilled; a braking load specification unit that, when the driving restart condition of the internal combustion engine is fulfilled, specifies a braking load to be applied to the electric motor, in order to reduce electric motor velocity or number of revolutions of the electric motor according to a kinetic energy absorbing state of the transmission belt; a drive stand-by unit that, when the driving restart condition of the internal combustion engine is fulfilled and the coupling mechanism is released, causes the output shaft of the internal combustion engine to be coupled with the output shaft of the electric motor via the coupling mechanism after application of the specified braking load to the electric motor; and an internal combustion engine operation control unit that executes a series of processing to restart operation of the internal combustion engine after the internal combustion engine is coupled with the electric motor via the coupling mechanism.
In the idling stop control apparatus of the present invention, the braking load to be applied to the electric motor is specified, in order to reduce the number of revolutions of the electric motor or the electric motor velocity according to the kinetic energy absorbing state of the transmission belt. This arrangement effectively reduces or even omits potential shocks and vibrations arising due to the coupling action of the coupling mechanism at the time of starting the internal combustion engine, and ensures a quick restart of the internal combustion engine.
In accordance with one aspect of the idling stop control apparatus of the present invention, the vehicle has a transmission belt elasticity measurement unit that measures elasticity of the transmission belt, and the braking load specification unit determines the kinetic energy absorbing state of the transmission belt based on the observed elasticity of the transmission belt and increases the braking load with a decrease in observed elasticity of the transmission belt. In accordance with another aspect, the vehicle has a transmission belt temperature measurement unit that measures temperature of the transmission belt, and the braking load specification unit determines the kinetic energy absorbing state of the transmission belt based on the observed temperature of the transmission belt and increases the braking load with a decrease in observed temperature of the transmission belt.
The kinetic energy absorbing state of the transmission belt represents the state that is capable or incapable of sufficiently absorbing energy like shocks and vibrations, and correlates with the properties, such as the elasticity and the hardness, of the transmission belt. Namely measurement of the elasticity of the transmission belt results in specifying the kinetic energy absorbing state of the transmission belt. The properties like the elasticity and the hardness of the transmission belt correlate with the temperature of the transmission belt. These properties can thus be specified according to the temperature of the transmission belt. Under the condition of low temperatures, the transmission belt tends to be cured and lose its elasticity and thus hardly absorbs the potential shocks and vibrations (energy) arising due to the coupling action of the coupling mechanism. Under the condition of high temperatures, on the contrary, the transmission belt readily absorbs the potential shocks and vibrations arising due to the coupling action of the coupling mechanism. The arrangement of varying the braking load by taking into account such conditions
Hirose Kiyoo
Ito Yukikazu
Kato Senji
Kitamura Tooru
Takahashi Jun
Castro Arnold
Mancene Gene
Toyota Jidosha & Kabushiki Kaisha
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