Internal-combustion engines – Charge forming device – Including exhaust gas condition responsive means
Reexamination Certificate
2002-06-28
2003-11-25
Solis, Erick (Department: 3747)
Internal-combustion engines
Charge forming device
Including exhaust gas condition responsive means
C060S277000, C060S311000
Reexamination Certificate
active
06651638
ABSTRACT:
TECHNICAL FIELD OF THE INVENTION
The present invention generally relates to internal combustion engines and, more particularly, to a system and method for derating an engine to encourage servicing of a vehicle.
BACKGROUND OF THE INVENTION
It is well established that vehicles having internal combustion engines require both periodic routine maintenance and non-routine maintenance, particularly with respect to the internal combustion engine. Many elements of an internal combustion engine are designed to receive preventative maintenance at preestablished times or to require servicing as the performance of various components is compromised through use. For example, and not by way of limitation, many vehicles include internal combustion engines which have a particulate filter disposed in-line with the exhaust system. One such prior art internal combustion engine is illustrated schematically in FIG.
1
.
As is known in the art, an internal combustion engine
10
includes an intake manifold
12
for the induction of air to be mixed with the fuel supply (not shown). The engine
10
also includes an exhaust manifold
14
for carrying away exhaust gases produced by the combustion process. Some engines, such as the one illustrated in
FIG. 1
, include a turbocharger
16
, which utilizes a finned wheel
18
driven by exhaust gases to rotate a coupled compressor wheel
20
that is operative to compress fresh intake air at the inlet
22
in order to provide a denser air supply to the intake manifold
12
. The incorporation of a turbocharger
16
is not necessary for practice of the present invention.
The engine
10
may have a particulate filter
24
positioned in-line with the exhaust system, particularly if the engine
10
is a diesel engine. The function of the particulate filter is to trap the majority of solid particulate matter produced by the combustion process within the engine
10
before the exhaust gases reach other sensitive exhaust aftertreatment components (such as a catalytic converter) downstream
26
from the particulate filter
24
or before the exhaust gases are simply exhausted to the environment.
It is well known in the art that a particulate filter
24
will eventually become partially clogged by the particulate matter that it is extracting from the exhaust gas. Such partial clogging creates a restriction to the flow of exhaust gases through the particulate filter
24
, thereby increasing the pressure of the exhaust gases upstream from the particulate filter
24
. This increase in exhaust gas pressure is known as backpressure. Increases in backpressure actually produce work in opposition to the productive work being performed by the engine
10
, thereby lowering its performance. Because of this, it is desirable to clean or replace the particulate filter
24
after it has achieved some level of particulate blockage. In the prior art system shown in
FIG. 1
, the backpressure is measured by a pressure sensor
28
and the signal is applied as an input to an electronic control module (ECM)
30
, which functions as a control system managing performance of the engine
10
. The software within ECM
30
is designed to evaluate the backpressure sensed by pressure sensor
28
in comparison to two thresholds. When the backpressure exceeds a first threshold, the ECM
30
activates a first output in order to illuminate a yellow warning light
32
that is visible to the driver. When the backpressure sensed by sensor
28
exceeds a second, higher level, ECM
30
activates a second output in order to illuminate a red warning light
34
, also visible to the driver. It will be understood that sensor
28
can be a transducer or simply a threshold switch.
Ideally, upon observation of the yellow warning light
32
, the driver of the vehicle will arrange for service of the particulate filter
24
at the next available opportunity. Certainly by the time the red warning light
34
is illuminated, service of the particulate filter
24
should be a high priority for the driver of the vehicle. Unfortunately, many engines
10
, particularly heavy duty diesel engines, are installed in vehicles which are being driven by persons other than those who own the vehicles. Such persons often do not have maintenance of the vehicle as their highest priority, particularly when the operator of the vehicle receives compensation in proportion to the amount of time that the vehicle is being operated.
The above-illustrated problem in inducing a vehicle operator to perform service of the particulate filter
24
is merely illustrative of a more widespread problem in encouraging vehicle operators to perform any necessary service that is not severely impacting the operability of the vehicle. In many cases, delaying such service can cause further damage to the vehicle, greatly increasing the cost of service. There is therefore a need in the prior art for a system which will provide an increased incentive to the operator of the vehicle to perform necessary service to the vehicle. The present invention is directed toward meeting this need.
SUMMARY OF THE INVENTION
In one embodiment of the present invention, a system is disclosed for monitoring the backpressure produced by a particulate filter of an internal combustion engine. When the backpressure of the engine exceeds a predetermined threshold, indicating that the particulate filter should be serviced soon, an input to the electronic control module (ECM) indicating the intake manifold boost pressure is shunted to ground, thereby giving the ECM a false indication that no boost is being applied to the intake manifold. This will cause the ECM, according to its normal engine management software, to derate the engine performance to a “no air torque setting”, thereby limiting the amount of torque that the vehicle operator can extract from the engine. This decreased performance of the engine provides a very high incentive to the vehicle operator to bring the vehicle in for servicing, at which point the particulate filter can be serviced. Upon servicing of the particulate filter, the backpressure threshold condition is no longer met, the input line to the ECM from the boost pressure sensor is no longer shunted to ground, and engine operation is returned to normal. Other embodiments of the present invention contemplate the use of engine performance derating in order to provide the vehicle operator with an incentive to have any sensed engine or vehicle condition serviced.
In one form of the present invention, a method for derating an engine to encourage servicing of a particulate filter in an exhaust system of the engine is disclosed, comprising the steps of a) sensing an exhaust backpressure upstream of the particulate filter; b) comparing the backpressure to a first threshold value; c) illuminating a first warning light visible to an operator of the engine if the backpressure exceeds the first threshold value; d) comparing the backpressure to a second threshold value; e) illuminating a second warning light visible to the operator if the backpressure exceeds the second threshold value; f) comparing the backpressure to a third threshold value; and g) derating a performance characteristic of the engine if the backpressure exceeds the third threshold value.
In another form of the embodiment, a method for derating an engine to encourage servicing of a particulate filter in an exhaust system of the engine is disclosed, comprising the steps of a) sensing an exhaust backpressure upstream of the particulate filter; b) comparing the backpressure to a threshold value; and c) derating a performance characteristic of the engine if the backpressure exceeds the threshold value.
In yet another form of the embodiment, a method for derating an engine to encourage servicing of a vehicle into which the engine is installed is disclosed, comprising the steps of a) sensing a condition of the vehicle; b) comparing the condition to a threshold value, wherein servicing of the vehicle is warranted if the condition exceeds the threshold value; and c) derating a performance characteristic of the engine if
Cummins Engine Company, Inc.
Solis Erick
LandOfFree
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