Internal-combustion engines – Cooling – With jacketed head and/or cylinder
Reexamination Certificate
2002-06-19
2004-04-06
Argenbright, Tony M. (Department: 3747)
Internal-combustion engines
Cooling
With jacketed head and/or cylinder
C123S0780AA, C123S090170, C123S0780AA, C123S1980DA
Reexamination Certificate
active
06715453
ABSTRACT:
INCORPORATION BY REFERENCE
The disclosure of Japanese Patent Application No. 2001-196920 filed on Jun. 28, 2001, including the specification, drawings and abstract, is incorporated herein by reference in its entirety.
BACKGROUND OF THE INVENTION
1. Field of Invention
This invention relates to techniques for changing the operating characteristics of an internal combustion engine. More particularly, this invention relates to a method and apparatus for preventing an engine-operating-characteristic changing device from being locked in a first operating state by locking unit, during an operation of the engine-operating-characteristic changing device which is operable between the first operating state and a second operating state, to change a compression ratio of an intake air of an internal combustion engine, for controlling the operating characteristic of the engine.
2. Description of Related Art
In the field of an internal combustion engine of an automobile, it is known to control the engine such that the engine is operated at a comparatively low compression ratio of an intake air so as to reduce the vibration and improve the fuel economy of the engine, during normal operation of the engine after a warm-up operation, while the engine is operated in a cold state at a comparatively high compression ratio of the intake air, so as to facilitate the starting of the engine, before the warm-up operation, particularly upon cranking of the engine in a cold state. The compression ratio of the intake air may be controlled depending upon a change in the load acting on the engine, even after the warm-up operation of the engine, in order to improve the fuel economy of the engine. In the case of an internal combustion engine of piston type, the compression ratio of the intake air can be changed in various methods by a valve timing regulating device, which is arranged, for instance: (a) to retard or advance the closing timing of each intake valve; (b) to temporarily open each exhaust valve at a suitably selected timing during a period of transition from the intake stroke to the compression stroke; (c) to suitably control the lift amounts of intake- and exhaust-valve drive cams in the form of three-dimensional cams; or (d) to provide an adjustable eccentric bearing at a point of connection between a piston rod and a crankshaft, or between the piston rod and a piston.
An example of an intake-valve timing control device arranged to retard or advance the closing timing of the intake valve for changing the compression ratio of the intake air is disclosed in U.S. Pat. No. 5,924,395 owned by the assignee of the present application. The intake-valve timing control device disclosed therein is arranged to change the opening and closing timings of the intake valve within respective predetermined ranges of the angular position or phase of the crankshaft, as indicated in
FIG. 1
, in particular, to retard or advance the closing timing relative to the reciprocating movement of the piston, so that the quantity of the intake air introduced in the corresponding cylinder at the moment of closure of the intake valve is increased or reduced to control the compression ratio of the intake valve. In a four-cycle engine, the closing timing of the intake valve generally corresponds to about 70° after the bottom dead center (abbreviated as “ABDC)” of the reciprocating movement of the piston. The intake-valve timing control device is arranged to increase this ABDC angle to about 110-120°, for retarding the closing timing, so that the quantity of the intake air existing in the cylinder upon closing of the intake valve is accordingly reduced. As a result, the compression ratio of the intake air is reduced. As shown in
FIG. 2
by way of example, the pressure within the cylinder at the end of the compression stroke considerably varies with a change in the closing timing of the intake valve by the intake-valve timing control device described above.
In the internal combustion engine wherein the compression ratio of the intake air is variable as described above, the compression ratio of the intake air is controlled to be comparatively low in a hot state of the engine after a warm-up operation, to permit a relatively higher cranking speed for starting the engine with reduced amounts of vibration and noise. When the engine is started in a cold state, the compression ratio of the intake air is controlled to be comparatively high, to assure a high degree of starting stability of the engine. In this respect, the internal combustion engine capable of changing the compression ratio of the intake air is suitable for automotive vehicles recently developed to meet increasing requirements for saving of fuel resources and environmental protection, such as economy-running system vehicles adapted to temporarily turn off the engine when the vehicle is stopped at a traffic signal, for instance, and hybrid vehicles which are driven by a suitably selected one of an internal combustion engine and an electric motor.
Referring to
FIGS. 3-5
, there is shown the intake-valve timing control device disclosed in the above-identified U.S. Patent, which is partly modified to meet the object of the present invention, and for adaptation to a hybrid vehicle.
FIGS. 4 and 5
are views taken along line A—A of
FIG. 3
, which show the intake-valve timing control device in two different operating states. In
FIG. 3
, reference sign “e” denotes an internal combustion engine having a crankshaft c, which is operatively connected through a torque distributing device p of planetary gear type to a first motor/generator mg
1
and a second motor/generator mg
2
, each of which is capable of functioning selectively as an electric motor and an electric generator. The internal combustion engine e, the first motor/generator mg
1
and the second motor/generator mg
2
cooperate to constitute a regenerative hybrid drive system which is operatively connected at a drive shaft of the motor/generator mg
1
to a pair of wheels w, through respective axles s, a differential gear d and a transmission t. The first motor/generator mg
1
and the second motor/generator mg
2
are electrically connected to a battery b through an inverter i, and are selectively operated as an electric motor or an electric generator, depending upon the specific operating or running state of the vehicle.
The above-indicated intake-valve timing control device, which is generally indicated at
10
in
FIGS. 3-5
, may be considered to function as an intake-air compression-ratio control unit for controlling the compression ratio of the intake air, as described below. This intake-valve timing control device
10
is constructed to operate as a rotary actuator operable between a gear
14
and an intake-valve camshaft
18
. The gear
14
is driven by the crankshaft c of the internal combustion engine e through an endless belt
12
, in synchronization with the crankshaft c. The intake-valve camshaft
18
holds an intake-valve operating cam
16
.
Described more specifically, an internally splined annular member
22
having four radial partition walls
26
, and an annular end plate
24
are fixedly assembled with the gear
14
through four bolts
20
, so as to define a working chamber. In this working chamber, there is accommodated a rotor
30
fixed to one end of the camshaft
18
by a bolt
28
. The rotor
30
includes a central hub portion, and four vanes
32
formed around the hub portion. A sectorial chamber
34
is formed between the adjacent two partition walls
26
located on the respective circumferentially opposite sides of each vane
32
, so that the vane
32
is movable in the corresponding sectorial chamber
34
, relative to a housing which is constituted by the gear
14
, annular member
22
and end plate
24
.
The housing is rotated in the clockwise direction indicated by arrows in
FIGS. 4 and 5
when the gear
14
is rotated through the endless belt
12
by forward rotation of the crankshaft c. In the state of the intake-valve timing control device
10
as shown in
FIG. 4
, the camshaft
18
is in a fu
Suzuki Naoto
Takaoka Toshifumi
Tomatsuri Mamoru
Ali Hyder
Argenbright Tony M.
Oliff & Berridg,e PLC
Toyota Jidosha & Kabushiki Kaisha
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