Internal-combustion engines – Starting device – Condition responsive control of starting device
Reexamination Certificate
2000-09-11
2002-10-08
Mancene, Gene (Department: 3747)
Internal-combustion engines
Starting device
Condition responsive control of starting device
C123S179310, C123S179400
Reexamination Certificate
active
06460500
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a start control system for an internal combustion engine of a type which starts the engine by utilizing oil pressure.
2. Description of the Related Art
Conventionally, in a start system for an internal combustion engine for an automotive vehicle, when the driver operates an ignition key to start the engine, electric power is supplied from a battery to an electric motor of a starter, whereby the electric motor forcibly causes rotation of a crankshaft of the engine, and at the same time an air-fuel mixture is supplied to cylinders of the engine. The air-fuel mixture thus supplied to cylinders is ignited to start the engine. Then, after the start of the engine, the driver releases the ignition key, whereby the electric motor is stopped.
Further, in recent years, a start control system for an internal combustion engine for an automotive vehicle has been employed which is capable of automatically stopping idling of the engine, e.g., when the driver is waiting for traffic lights to change or for a crossing gate to open, and then automatically restarting the engine when the vehicle is started. In the start control system, the restart of the engine after the automatic stoppage of idling is carried out by causing the above start system to operate in response to a vehicle start operation by the driver. The driver's vehicle start operation includes operating a clutch or a shift gear, releasing a brake, or stepping on an accelerator pedal. When the vehicle start operation is carried out, electric power is supplied from the battery to the electric motor of the starter, whereby the electric motor forcibly causes rotation of the crankshaft, and the mixture is supplied to the cylinders. The air-fuel mixture thus supplied to the cylinders is ignited to start the engine. According to this start control system, because idling is automatically stopped, as described above, e.g., when the driver is waiting for traffic lights to change, excellent fuel economy can be ensured.
However, the above start control system uses the battery as a power source for the electric motor of the starter, and the starting torque of the motor is small. Hence, the motor is generally combined with a reduction gear system. For this reason, during the start or restart of the engine, the crankshaft can only be rotated at a rotational speed which is considerably loser than an idling rotational speed, so that it takes much time for the engine to start actually. Further, during cranking of the engine there occurs torque variation due to compression and expansion of air within the cylinder of the engine, which causes variation in the rotational speed of the crankshaft. In this case, the rotational speed of the crankshaft driven by the electric motor is reduced due to increased viscous friction of lubricating oil in the engine and stabilized at a low level, so that the variation in the rotational speed of the crankshaft becomes large, which causes the reduction gear mechanism to produce untoward noises. As described above, because it takes much time before the engine is actually started to start the vehicle in response to the vehicle start operation by the driver, and vibrations of the engine and noises from the driving system, which are undesired by the driver, are caused during the start of the engine, the start control system degrades marketability of the vehicle.
To solve the problems, there was proposed a start control system for an internal combustion engine e.g. in Japanese Laid-Open Patent Publication (Kokai) No. 60-85249, in which compressed air is utilized to start the engine. The start control system includes a compressor driven by rotation of a crankshaft and a reserve tank for storing compressed air supplied from the compressor. According to the system, in response to an engine start operation by an ignition key, the crankshaft is driven for rotation by using the compressed air in the reserve tank as a driving force source, whereby the engine is started. Also, for the restart of the engine, similar control is carried out in response to the engine start operation by the ignition key. Thus, the use of the compressed air makes it possible to obtain larger torque than the torque from the electric motor of the starter, thereby shortening the time period required for starting the engine. Further, it is possible to increase the engine rotational speed to the idling rotational speed in a short time period, thereby reducing vibration of the engine and noises caused during the start of the engine.
Further, there has been proposed another type of the start control system for an internal combustion engine, which includes a large-sized electric motor and a large-capacity battery, and is applied to a vehicle configured to travel by driving force from the large-sized electric motor and the internal combustion engine installed thereon, i.e., a so-called hybrid vehicle. Some of the start control systems of this type are capable of not only starting the engine by the large-sized electric motor, but also automatically restarting the engine without the engine start operation by the ignition key. Through the use of the large-sized electric motor which generates considerably larger torque in comparison with the electric motor of the starter, this type of the start control system is capable of starting the engine in a shorter time period as well as reducing the vibrations of the engine. Further, because the engine can be automatically restarted without the engine start operation by the ignition key, high marketability of the system is ensured.
However, according to the above conventional start control system using compressed air, because the torque of the engine is employed as a driving force source for the compressor, it is impossible to drive the compressor during stoppage of the engine. For this reason, when compressed air within the reserve tank was consumed by an erroneous operation or the like before the stoppage of the engine, and no pressure has been stored within the tank, the engine cannot be started. Further, there is a limit to available high pressure of air, and it is required to provide a large-sized reserve tank so as to secure sufficient amount of compressed air for starting the engine, which results in an increase in the weight of the system and makes it difficult to provide space for accommodating the system. Moreover, when the temperature falls, saturation vapor pressure also decreases, which causes condensation within the reserve tank and piping. When the temperature becomes extremely low, the condensed water freezes, which can cause breakage or failure of the system. Another problem is that a large amount of energy remains in the compressed air discharged from the start control system during operation of the same, and noise produced by the discharge can become considerably large untoward noise. Still another problem is that it is required to carry out the engine start operation by the ignition key to restart the engine.
On the other hand, the conventional start control systems of the type which is applied to the hybrid vehicle are each required to be provided with a large-sized electric motor and a large-capacity battery which are very expensive and heavy, which results in considerable increases in the weight and manufacturing costs of the system.
SUMMARY OF THE INVENTION
It is an object of the invention to provide a start control system for an internal combustion engine, which is capable of automatically restarting the engine while ensuring excellent startability and fuel economy of the engine, and permits reduction of the size of the system, to reduce the weight and manufacturing costs of the system.
To attain the above object, the present invention provides a start control system for an internal combustion engine, comprising:
an electric motor;
an oil pump driven by the electric motor;
an accumulator for accumulating oil pressure delivered from the oil pump;
an oil passage through which the oil pressure is transmitted;
a hydraulic
Fushimi Koichi
Ooyama Kazuo
Armstrong Westerman & Hattori, LLP
Castro Arnold
Honda Giken Kogyo Kabushiki Kaisha
Mancene Gene
LandOfFree
Start control system for internal combustion engine does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Start control system for internal combustion engine, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Start control system for internal combustion engine will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2923244