Internal-combustion engines – Poppet valve operating mechanism – With means for varying timing
Reexamination Certificate
2000-09-11
2001-10-30
Lo, Weilun (Department: 3748)
Internal-combustion engines
Poppet valve operating mechanism
With means for varying timing
C123S399000, C123S478000
Reexamination Certificate
active
06308671
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates, in general, to an internal combustion engine of the type equipped with an electronic throttle control system and a variable valve timing mechanism(s), and of the type controlled by a torque based management system. More particularly, the invention pertains to a method of increasing engine torque and/or of reducing engine emissions by varying the phasing of either the intake valves or the exhaust valves or both.
BACKGROUND OF THE INVENTION
The following background information is provided to assist the reader to understand one of the many environments in which the invention will typically be used. Upon reading this document, the reader will appreciate that the invention may also be applied or adapted to environments other than that described below.
FIG. 1
illustrates one cylinder of an electronically controlled multi-cylinder engine that is equipped with a mechanism capable of varying the timing of the opening and closing of the intake and exhaust valves. While the engine
1
is operating, air at atmospheric pressure is drawn into an inlet
2
through a filter
3
and into an intake duct
4
. The incoming air then flows into a throttle body
5
in which is disposed a throttle valve
6
. The throttle valve
6
typically takes the form of a rotatable plate.
Controlled by an electronic throttle control (ETC) system, the throttle plate
6
has its position adjusted regularly to allow an amount of air appropriate to present conditions to pass through the throttle body
5
and thereafter into an intake manifold
7
. The throttle control system typically features a pedal sensor
8
, a throttle position sensor (TPS)
9
, a motor
10
and an electronic control module (ECM)
11
. The pedal sensor
8
enables the ECM
11
to monitor the position of the accelerator pedal, and thus to determine whether the driver wants the vehicle to maintain, increase or decrease torque. The TPS sensor
9
enables the ECM
11
to monitor the angular position that the throttle plate
6
occupies in the throttle body
5
. Pursuant to prior art algorithms, the ECM
11
uses the input from these sensors, as well as other sensors, such as those shown in
FIG. 2
, to control the engine
1
so that it delivers the desired torque according to the conditions under which the vehicle is operating. In doing so, the ECM
11
controls via motor
10
the position of the throttle plate
6
, and thus the quantity of air that is drawn into the intake manifold
7
.
From the intake manifold
7
the incoming air then passes to an intake duct
12
that leads to the cylinder
13
. Meanwhile, fuel from a fuel tank
14
is pumped via a pump
15
through a pipe
16
to a fuel injector
17
. According to known practice, the ECM
11
uses data from several sensors to calculate the injector pulse width, i.e., the electrical signal that the ECM
11
uses to activate the fuel injector
17
for a time appropriate to current conditions. Activated via a drive circuit, the fuel injector
17
injects the precise amount of fuel into the intake duct
12
. There, the fuel mixes with the inlet air coming from the intake manifold
7
.
As noted in greater detail infra, a cam timing mechanism drives the intake valve
18
to the open position in timed relationship with the intake cycle of cylinder
13
. During the intake cycle, a low pressure condition develops within the combustion chamber
19
due to the downward movement of a piston
20
within the cylinder
13
. The low pressure draws the fuel-air mixture from the intake duct
12
past the intake valve
18
and into the combustion chamber
19
. For the subsequent compression cycle, the action of the cam timing mechanism(s), as noted infra, closes the intake and exhaust valves
18
and
21
at the top of the cylinder
13
. During the compression cycle itself, as is well known, the upward movement of the piston
20
compresses the air-fuel mixture in the combustion chamber
19
of the cylinder
13
.
During the combustion cycle, the fuel-air mixture is ignited and exploded to produce power. Operating according to the spark sequence controlled by an electronic spark timing system, the ECM
11
causes the air-fuel mixture to be ignited in the combustion chamber
19
. More specifically, the combustion cycle is initiated, at the appropriate time, by a spark driven across the spaced electrodes of a spark plug
22
. The explosive force of the combustion drives the piston
20
downward within cylinder
13
. The downward thrust of the piston
20
is imparted via connecting rods
23
as a torque upon a crankshaft
24
of the engine
1
. Combined with the torque it receives from the other pistons in the engine
1
, the crankshaft
24
drives the wheels and the accessory loads, etc., of the motor vehicle, as is generally understood in the art.
For the exhaust cycle, a cam timing mechanism drives the exhaust valve
21
, at the appropriate time, to the open position. During the exhaust cycle, the upward movement of the piston
20
forces the exhaust gases produced by combustion past the exhaust valve
21
and into an exhaust manifold
25
. An exhaust pipe
26
then channels the exhaust gases to a catalytic converter
27
. A catalyst within the converter
27
aids the oxidization of unburned constituents, such as carbon monoxide (CO) and hydrocarbons (HC), and the reduction of nitrogen oxides (NO
X
). From the converter
27
, the purified exhaust gases are conveyed typically through a muffler and then through a tail pipe to atmosphere.
The ECM
11
monitors and controls the operation of the engine
1
through many data sensors, switches and control devices, some of: which are shown in
FIGS. 1 and 2
. In addition to the pedal and TPS sensors
8
and
9
, the data sensors include an intake air temperature (IAT) sensor
28
, a coolant temperature sensor (CTS)
29
, a manifold absolute pressure (MAP) sensor
30
, a vehicle speed sensor (VSS)
31
, an oxygen (O
2
2
) sensor
32
, and an engine speed (RPM) sensor
33
. On some vehicles, additional data sensors are used. These include a wide range air-fuel (WRAF) sensor
34
, a barometric pressure (BARO) sensor
35
, and a mass air flow (MAF) sensor
36
. The devices and subsystems that the ECM
11
controls, include the electronic throttle control system, the electronic spark timing system, the fuel injection system and the cam timing mechanisms.
The data sensors generate electrical signals, typically in analog form, indicative of the parameters they are intended to measure. The IAT sensor
28
typically measures the temperature of the air in the inlet
2
of the engine
1
. The CTS sensor
29
senses the temperature of the coolant that flows in channels
37
around the cylinders to keep the engine cool. The MAP sensor
30
measures the absolute air pressure in the intake manifold
7
. The VSS, sensor
31
generates a pulse representing the actual speed of the vehicle. The O
2
sensor
32
is typically mounted to the exhaust system downstream of the converter
27
so that its head lies exposed to the stream of exhaust gases produced by the engine
1
. It senses the free oxygen concentration in the exhaust gases, and conveys a corresponding signal to the ECM
11
. Typically exposed to the exhaust gases upstream of the converter
27
, the WRAF sensor
34
measures the air-fuel ratio. It is used on some vehicles to measure directly the ratio of air to fuel for purposes of controlling the delivery of fuel to the engine
1
. The ECM
11
uses the signals from the O
2
and WRAF sensors
32
and
34
to control more precisely the fuel-air mixture to achieve stoichiometry. This correction process is known as closed loop operation.
On vehicles equipped with BARO and MAF sensors, the BARO sensor
35
measures the pressure of the ambient air and provides data to the ECM
11
as to pressure changes due to altitude and weather. The MAF sensor
36
measures the rate at which the air mass flows into the intake manifold
7
. For vehicles not equipped with a BARO sensor
35
, the ECM
11
is programmed to estimate the barometric
Himes Edward George
Muller Martin
Reed Dennis C.
Schreurs Bart Hubert
Yoo Joon-Ho
Cichosz Vincent A.
Delphi Technologies Inc.
Lo Weilun
LandOfFree
Method of increasing torque and/or reducing emissions by... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method of increasing torque and/or reducing emissions by..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method of increasing torque and/or reducing emissions by... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2552222