U.S. patent application number 14/649779 was filed with the patent office on 2015-10-29 for apparatus and method of disabling a waste heat recovery apparatus working fluid flow.
The applicant listed for this patent is MACK TRUCKS, INC.. Invention is credited to John GIBBLE.
Application Number | 20150308318 14/649779 |
Document ID | / |
Family ID | 50978931 |
Filed Date | 2015-10-29 |
United States Patent
Application |
20150308318 |
Kind Code |
A1 |
GIBBLE; John |
October 29, 2015 |
APPARATUS AND METHOD OF DISABLING A WASTE HEAT RECOVERY APPARATUS
WORKING FLUID FLOW
Abstract
An apparatus and method for operating Waste Heat Recovery system
based on a Rankine cycle and including a vaporizer/boiler heated by
an internal combustion engine exhaust waste heat, an expander, a
condenser, and a pump for circulating a working fluid through the
circuit, includes a shutoff valve placed at the inlet side of the
pump and controlled in the event an emergency shutdown is needed to
stop working fluid circulation by closing and causing the pump to
cavitate.
Inventors: |
GIBBLE; John; (Chambersburg,
PA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
MACK TRUCKS, INC. |
Greensnboro |
NC |
US |
|
|
Family ID: |
50978931 |
Appl. No.: |
14/649779 |
Filed: |
December 19, 2012 |
PCT Filed: |
December 19, 2012 |
PCT NO: |
PCT/US12/70606 |
371 Date: |
June 4, 2015 |
Current U.S.
Class: |
60/615 ;
60/646 |
Current CPC
Class: |
F01K 27/02 20130101;
Y02T 10/16 20130101; Y02T 10/166 20130101; F01N 5/02 20130101; F02G
5/00 20130101; Y02T 10/12 20130101; F01K 13/02 20130101; F01K
23/065 20130101 |
International
Class: |
F01N 5/02 20060101
F01N005/02; F01K 13/02 20060101 F01K013/02 |
Claims
1. A method of operating a waste heat recovery apparatus associated
with an internal combustion engine of a vehicle, the apparatus
including a boiler, an expander, a condenser, and a pump connected
on a circuit circulating a working fluid, comprising the steps of:
monitoring a status of selected components of a vehicle having an
engine and a waste heat recovery apparatus; detecting a trigger
condition of at least one of the engine and the waste heat recovery
apparatus for shutting off a working fluid flow; and, closing a
valve ups of a pump inlet to stop working fluid flow to the
pump.
2. The method of claim 1, comprising monitoring the status of at
least one of a waste heat boiler, an expander, a condenser, an
accumulator, and a working fluid circuit.
3. The method of claim 1, wherein the trigger condition is a signal
indicating a pressure of the working fluid below a low pressure
threshold.
4. The method of claim 1, wherein the trigger condition is fault
code for a valve actuator of the working fluid circuit.
5. The method of claim 1, wherein the trigger condition is a signal
indicating a collision involving the vehicle.
6. The method of claim 1, wherein the trigger condition is a signal
indicating is a malfunction of the internal combustion engine.
7. A waste heat recovery apparatus for a vehicle having an internal
combustion engine, comprising: a waste heat boiler an expander, a
condenser, and a fluid pump arranged on the fluid circuit; a
shutoff valve disposed on the fluid circuit between the condenser
and fluid pump; and, a controller connected to the shutoff valve
and configured to shutoff fluid flow in the fluid circuit upon
receipt of a signal indicating an abnormal condition in a component
arranged on the fluid circuit.
8. The waste heat recovery apparatus of claim 7, wherein the
controller is connected to receive signals from vehicle systems,
and wherein the controller is configured to shut off fluid flow in
the fluid circuit upon receipt of a signal indicating a malfunction
of the internal combustion engine.
9. A vehicle having a waste heat recovery apparatus, comprising: an
internal combustion engine; a waste heat recovery apparatus
including a waste heat boiler, an expander, a condenser, and a
fluid pump arranged on a fluid circuit, the waste heat boiler being
connected to receive waste heat from the engine to heat a working
fluid; a shutoff valve disposed on the fluid circuit between the
condenser and the fluid pump; and, a controller connected to the
shutoff valve and connected to receive signals indicating a
condition of the internal combustion engine and waste heat recovery
apparatus, the controller including a memory storing trigger
conditions for closing the shutoff valve and configured to compare
a signal received to the trigger conditions and to close the
shutoff valve upon receipt of a signal indicating a trigger
condition.
Description
FIELD OF THE INVENTION
[0001] The invention is directed to a Waste Heat Recovery system
based on a Rankine cycle, including a working fluid circuit having
a vaporizer/boiler heated by waste heat of an internal combustion
engine, an expander, a condenser, and a pump for circulating a
working fluid through the circuit. More particularly, the invention
is directed to a shutoff valve placed at the inlet side of the pump
and controlled in the event a shutdown of working fluid circulation
is needed.
BACKGROUND AND SUMMARY
[0002] In waste heat recovery (WFIR) systems associated with
internal combustion engines, it is convenient to mechanically
connect the working fluid pump to a rotating component, such as the
expansion machine or the internal combustion engine, to be driven
by that component. In certain circumstances it is necessary to
quickly stop the working fluid flow, for example because of a WHR
component malfunction. Quickly stopping a mechanically driven pump
may be difficult or impossible because of difficulty stopping the
component driving the pump, which, as mentioned, may be the waste
heat apparatus expander or the internal combustion engine. A
malfunction may occur as a valve actuator failure or a line
transferring fluid failing to contain fluid. Other circumstances
may include a boiler (or evaporator) rupture, which could introduce
flammable fluid into the engine, causing engine runaway. External
failures, for example, a collision of the vehicle, could cause risk
to operator and environment.
[0003] Possible solutions include using a separately controlled
electronic pump or a shut off valve downstream of the pump;
however, neither of these solutions will mitigate risk in the event
of uncontrollable pump operation, actuator failure, or line failure
between pump and actuator.
[0004] According to the invention, an apparatus and method for
controlling working fluid flow in a waste heat recovery apparatus
includes a fluid shutoff valve positioned upstream of a working
fluid pump to stop fluid flow to the pump, causing the pump to
cavitate, when flow is not desired.
[0005] According to another aspect of the invention, the shutoff
valve is operationally connected to a controller, which may be an
electronic control unit as is known in vehicles, which is itself
connected to receive signals relating to the condition of
components of the waste heat recovery system, and responsive
thereto, control the fluid flow to the pump.
BRIEF DESCRIPTION OF THE DRAWING FIGURE
[0006] The invention will be better understood by reference to the
following detailed description in conjunction with the appended
drawing, in which:
[0007] The sole FIGURE is a schematic of a waste heat recovery
apparatus in accordance with the invention.
DETAILED DESCRIPTION
[0008] The FIGURE shows a schematic view of a waste heat recovery
apparatus 10 for a vehicle having an internal combustion engine in
accordance with the invention. The illustrated example of a waste
heat recovery apparatus is one based on the Rankine cycle, and
includes a working fluid circuit 12 to circulate working fluid to
the apparatus components, including a boiler 20, an expander
machine 22, a condenser 24, an accumulator or collection tank 26
and a pump 28.
[0009] The boiler 20 is arranged in heat transferring contact (heat
transfer being indicated by the arrow Q) with a source of engine
waste heat 14. The heat source 14 may be any heat generating or
handling system associated with a vehicle having an internal
combustion engine, including the engine exhaust, engine coolant
system, the exhaust gas recirculation (EGR) cooler charge air
cooler, engine oil cooler, or some combination of these. The boiler
20 heats the working fluid, which then flows to the expander 22
where work energy is extracted from the heated fluid. The work
energy may be used, for example, to drive a generator, may be added
to the engine drive shaft, or used to drive the pump 28.
[0010] The exemplary waste heat recovery apparatus 10 includes a
bypass line 30 to guide working fluid to avoid the expander machine
22. The bypass line 30 is controlled by a bypass valve 32 to direct
working fluid to the expander machine 22, to the bypass line 30, or
to divide the working fluid for proportional flow through both the
expander machine and bypass line as required by the system needs.
Other bypass Ines may be included, for example, a line bypassing
the boiler.
[0011] The waste heat recovery apparatus 10 may include other
valves and valve actuators to manage the flow rate, pressure and
distribution of working fluid to the various system components.
[0012] The condenser 24 receives the expanded working fluid, which
is cooled, condensed, and collected in the accumulator or tank 26.
The pump 28 pumps the working fluid from the accumulator 26 to the
boiler 20 where the cycle of heating and expanding repeats. As
mentioned, the pump 28 may be driven by the expander machine 22 by
connecting an input shaft 29 of the pump to an output shaft 23 of
the expander machine. Alternatively, the input shaft 29 of the pump
28 may be connected to the drive shaft of the engine (not
illustrated).
[0013] A shutoff valve 40 is disposed in the fluid flow circuit
between the accumulator 26 and the pump 28, that is, on the inlet
side of the pump. The shutoff valve 40 is operated to control flow
of the working fluid to the pump 28. Under certain circumstances it
is necessary to quickly shut off fluid flow in the fluid circuit
10. By closing the shutoff valve 40 at the pump inlet, no working
fluid flows to the pump 28, which causes the pump to cavitate and
effectively stops the fluid flow at the outlet side of the
pump.
[0014] A controller 44, which may be the electronic control unit
(ECU) for operating the waste heat recovery system or another
controller on the vehicle such as the engine ECU, is connected to
control the operation of the shutoff valve 40. The controller 44 is
also connected to receive signals from the various components of
the waste heat recovery system 10, the vehicle, and the internal
combustion engine. The controller 44 may be connected on a common
data bus with the other components, or may be directly connected to
the components, as is convenient. In addition or in the
alternative, the controller 44 may be connected to receive signals
from an on-board diagnostics system that monitors the function of
vehicle components, as is known in the art. The signals provided by
the components and/or the diagnostics system convey information to
indicate a condition of components of the waste heat recovery
apparatus, the engine, or other vehicle components. Signals
indicating certain conditions are identified by the controller as
trigger conditions for the shutdown of the waste heat recovery
system 10. The controller 44 may include a memory storing trigger
conditions and be configured to compare received signals to the
trigger conditions to identify signals indicating the valve is to
be shut off. The controller 44 is thus programmed to receive the
signals and generate a control signal for the valve 40 responsive
to the signals.
[0015] A trigger condition may be indicated when the vehicle is
stopped with the engine running for inspection or service to avoid
exposing an operator, inspector, service technician, or others to
high pressure fluids during engine service. The trigger condition
may be a signal that the engine is running along with a signal that
the parking brake is engaged
[0016] Another possible trigger condition is during engine braking,
the waste heat recovery system being disabled during power
absorption mode to avoid decreasing engine braking effectiveness.
The trigger condition may be a signal that engine braking is
activated.
[0017] A trigger condition may be indicated for a malfunction of a
vehicle system, the engine, or the waste heat recovery system. For
example, a leak or rupture in the boiler 20 could allow working
fluid (which may be a flammable fluid) to flow into contact with
the engine exhaust. A trigger condition here may be indicated by a
pressure loss in the boiler.
[0018] Another trigger condition may be indicated by an actuator
malfunction, for example, a malfunction of the bypass valve 32 or
another of the valve actuators managing working fluid flow.
[0019] Other conditions that could trigger shutoff relate to the
working fluid flow conditions. An abnormal or unexpected pressure
or temperature signal may be recognized as a trigger condition.
Pressure and temperature may be monitored in all fluid circuit
legs, that is, the conduits between each of the pump, boiler,
expander, condenser, and accumulator, by providing appropriate
pressure and temperature sensors. A sudden pressure drop in one or
more circuit legs (as compared to expected pressure), indicates a
possible internal or external fluid leak. in the event of a
pressure signal trigger, the shutoff valve 40 and other flow valves
are closed. An abnormal temperature signal could indicate a
malfunction of a system component, such as the boiler (abnormally
low temperature signal) or the condenser (abnormally high
temperature signal).
[0020] Another trigger condition is a malfunction of the internal
combustion engine, which is described here as an example of an
emergency shutdown situation. One type of engine malfunction that
can affect the waste heat recovery system is a so-called "runaway"
engine, indicated by an engine speed that exceeds an expected value
for the current operating conditions. A runaway engine event may
occur during downhill operation or may be caused by a fuel,
coolant, oil, or working fluid leak into the intake manifold or
power cylinder unit. To mitigate risk of component failure due to
continuing runaway conditions, a signal is sent to the Rankine
control system to stop all working fluid flow and enter a "safe"
mode. The first action is to close the shutoff valve 40 at the
accumulator 26 outlet/pump 28 inlet. This disables any further
working fluid from circulating in the system, and is done in case
the runaway event is caused by working fluid leaking into an engine
cylinder and combusting. Working fluid may leak into an engine
cylinder by failure of an EGR cooler connected to a heat exchanger
or boiler of the waste heat recovery apparatus. For example, a
crack, burst, external object damage or the EGR cooler in which
containment of working fluid is compromised may allow working fluid
to enter the EGR gas stream. Following closing of the shutoff valve
40, all other control parameters are sent to a pre-defined safe
condition. Fluid flow to the boiler 20 is stopped and sent to
bypass loops. Valves admitting fluid to the expansion machine are
closed and the valve 32 is controlled so that working fluid
bypasses the expansion machine and is directed to the condenser and
tank.
[0021] All conditions are monitored until it is determined the
engine and transmission are operating properly. Conditions in the
system may be monitored using diagnostic methods of system and
components, for example, the aforementioned on-board diagnostic
system that monitors the engine response during working fluid
shut-off. If it is determined to be possible to circulate the
working fluid again, for example, signals indicating the fluid
circuit under normal pressure, normal operation of the waste heat
recovery system will resume. lf, on the other hand, it is
determined the runaway engine condition was due to working fluid
entering the combustion chamber, a fault code is broadcast for the
operator to service and repair the system. For example, after the
valve shut-off, if engine function returns to normal, it can be
assumed the runaway engine condition and a working fluid circuit
abnormal condition are related. Also, a diagnostic system could
monitor on engine start-up the ability of the waste heat recovery
system to maintain and hold pressure, where, the ability to retain
positive pressure indicates no leak being present. Multiple
diagnostic methods could arrive at the same conclusion.
[0022] Other trigger conditions include Rankine system instability
(inability of the system to respond to control system pressures,
temperatures and flows), and inability of the system to control
working fluid flow/pressure/temperature due to failed actuators or
control algorithm error (the sensed temperature or pressure exceeds
the allowable target for working fluid, or sensor failure causing
faults, etc.).
[0023] The invention has been described in terms of an illustrative
embodiment and components, but the scope of the invention is
defined by the appended claims.
* * * * *