WO2010144071A1

WO2010144071A1 - Method and apparatus for truck heated body

Info

Publication number: WO2010144071A1
Application number: PCT/US2009/003497
Authority: WO
Inventors: Hugh Thomas Dickinson; John C. Higgins; David Keith Troupe
Original assignee: Volvo Group North America, Inc.
Priority date: 2009-06-10
Filing date: 2009-06-10
Publication date: 2010-12-16

Abstract

A control device for a truck dump body heating system includes a valve for controlling an exhaust gas flow to either an exhaust stack or an inlet to the dump body heating conduit. The valve may be manually controlled by the operator to select between the exhaust and heating functions. An override detects whether a diesel particulate filter regeneration is being performed, and responsive thereto, causes the valve to direct exhaust gas to the stack, preventing excessive heating of the dump body.

Description

METHOD AND APPARATUS FOR TRUCK HEATED BODY

[001] This application is a continuation-in-part of pending International Application No. PCT/US2007/25824, filed December 18, 2007, which is commonly owned with the instant application.

Field of the Invention

[002] The invention relates to trucks having conduits to convey exhaust gases to portions of the truck body or trailer the truck body or trailer, for example dump truck bodies and trailer beds. More particularly, the invention relates to a control method and system for a truck or trailer body heating system.

Background and Summary of the Invention

[003] Apparatuses for diverting a truck's exhaust gas to heat a truck body or trailer are known. Typically, an apparatus includes a valve for diverting exhaust gas from a stack pipe, through which the gas would escape to the environment, into a conduit path or circuit built into the body.

[004] Dump body heating is useful, for example, in cold weather when the load in the dump body may freeze to the dump body or become solidified and difficult to unload. The art shows devices for controlling the exhaust gas diverter when the dump body is raised, and there is art showing spring controlled devices for controlling the diverter based on the position of the dump body.

[005] U.S. Patent No. 5,797,656 (Caterpillar) discloses an exhaust diverter apparatus as part of a dump body heater that uses an electronically operated valve for directing exhaust gas to either the dump body or the stack exhaust. The controller monitors the position of the dump body, so that exhaust is directed into the stack when the body is in raised position.

[006] Recent changes in emissions regulations have resulted in the use of exhaust aftertreatment devices, such as diesel particulate filters to capture particulate matter in the exhaust flow. Diesel particulate filters require cleaning or removal of the collected particulate matter, which, otherwise over time can block the gas flow through the filter. An accepted manner of clearing the filter is a process called regeneration, involving raising the temperature of the exhaust stream entering the particulate filter sufficient high to cause the particulate matter, which is mostly carbon based, to burn. However, the high temperature of the exhaust gas during regeneration can cause damage to the truck body. [007] The patent art has not recognized the problem of excessive exhaust gas temperature (due to DPF regeneration or other causes) on an exhaust-heated truck body. What is needed is a control for a body heating apparatus to prevent exhaust gas at high temperatures from reaching the truck body or trailer bed. In the following description, the terms "truck body" or "body" are meant to include a trailer bed.

[008] A control apparatus in accordance with the invention includes a controllable valve having a first position directing exhaust gas to an exhaust outlet pipe and a second position directing exhaust gas to an inlet to a body-heating conduit, a switch functionally connected to the controllable valve for manually selecting between the first position and the second position, and, an override device being connected to receive a signal that an aftertreatment device regeneration is being performed and operationally connected to the controllable valve, the override device being configured to position the controllable valve in the first position responsive to receiving the signal.

[009] The valve may be operated by an air cylinder using the vehicle's on-board compressed air supply, or may be a solenoid or other controllable valve.

[010] The manual control switch may be conveniently located in the vehicle cab for operation by the driver.

[011] According to the invention, the override device is in communication with the vehicle system that controls regeneration of the diesel particulate filter to receive a signal that regeneration is being performed. The override device is configured to cause the valve to a position for exhaust through the exhaust stack regardless of whether the driver has selected body heating. For times no regeneration is being performed, the driver or operator has control of the position of the valve.

[012] The override device may also be configured to receive a signal indicative of a temperature of the exhaust gas exiting the diesel particulate filter, and causing the valve to move to the position for exhaust through the exhaust stack if the temperature is above a threshold determined to be harmful to the truck body.

Brief Description of the Drawings

[013] The invention will be better understood by reference to the following detailed description in conjunction with the appended drawings, in which: [014] Figure 1 is a schematic diagram of a controlled truck body heating apparatus in accordance with the invention; and,

[015] Figure 2 is a schematic of an embodiment of a control device in accordance with the invention.

Detailed Description

[016] A truck body heating control apparatus in accordance with the invention is shown in schematic view in the figure. Particularly in colder weather, it is desirable to heat the body of a dump truck or a trailer bed to facilitate releasing the load from the body or bed. A load may become more solidified in colder weather, making it less able to flow, or may actually freeze to the body or bed. Dump trucks and trailers may include a circuit formed in the dump body or trailer bed for the passage of exhaust gas therethrough for heating the dump body or bed. The description that follows uses a dump truck in an exemplary embodiment of the invention; however, the invention may be applied to any truck body or trailer that uses an exhaust gas heating system.

[017] The apparatus is advantageously equipped on a vehicle having an engine 30 with an exhaust aftertreatment device, depicted here as a diesel particulate filter 32, connected to receive exhaust gas 34 from the engine 30 and capture and remove particulate matter from the exhaust. The treated exhaust 36 is delivered to either an exhaust stack 38 or a dump body heating circuit 40 by a controllable valve 10, as described in more detail below.

[018] The diesel particulate filter 32 becomes clogged with collected particulate matter over time, and requires a clearing or regeneration process. Regeneration involves raising the exhaust gas temperature sufficiently high to cause the particulate matter in the diesel particulate filter to burn, and may be performed in a number of ways known in the art. For example, methods include changing engine operating characteristics, or, as illustrated, using a heating device 42 such as an electric heater, burner, or a hydrocarbon injector. A hydrocarbon injector injects hydrocarbon into the exhaust flow and a catalyst oxidizes the hydrocarbon resulting in a raise in temperature. The particular choice of method or device for raising exhaust gas temperature for regeneration is not a part of the invention, and a heating device 42 is shown by way of illustration. [019] Exhaust gas heated for diesel particulate filter regeneration may be sufficiently hot to damage the dump body. The invention provides a controllable apparatus that prevents excessively heated exhaust gas from entering the dump body heating circuit.

[020] The apparatus includes a controllable valve 10 having an inlet 12 connectable to receive exhaust gas from an internal combustion engine 30, and having two outlets, a first outlet 14 connectable to an exhaust pipe 38 and a second outlet 16 connectable to an inlet 40 of a dump body heating circuit formed in a dump body, as is known in the art.

[021] The controllable valve 10 includes a flow directing device, depicted here as a flap 18, that is selectably positionable against the first outlet 14 to guide exhaust flow through the second outlet 16 for entry into the dump body heating circuit for heating the dump body, or against the second outlet 16 to guide flow through the first outlet 14 for exhaust through the stack pipe 38 to the environment. The control valve 10 is shown as a flap valve, however, those skilled in the art will understand that other valves may be employed.

[022] A motor 20 is operably connected to the flap 18 for moving the flap to the selected position. The motor 20 may be an air cylinder connected to receive compressed air from the vehicle's on-board compressed air system for actuation. Alternatively, the motor 20 may be a solenoid or other device capable of moving the flap 18 to the selected position. The flap 18 includes a biasing device 22 to bias the flap to the position closing the second outlet 16. The biasing device 22 acts to ensure that the default position of the flap 18 is to close the second outlet 16 and prevent exhaust from entering the dump body heating circuit 40.

[023] A manually operated switch 50 is connected to the motor 20 for selecting the position of the flap 18. The switch 50 may be mounted in a place convenient for operator use, for example, on the dashboard or control panel of the vehicle. The switch 50 may be a rocker switch, pushbutton switch, or other switch having two positions corresponding to the two positions of the valve 10. The vehicle operator may select stack exhaust or dump body heating mode using the switch 40.

[024] A control module 54 may be connected to the engine 30 to receive data from the engine and to control various engine functions. The control module 54 may also receive data regarding the particulate load status of the diesel particulate filter 32, and control the regeneration process. One known method for determining particulate load on the diesel particulate filter, for example, includes sensing a gas pressure drop across the diesel particulate filter. The control module 54 may be connected to the heating device (if provided) to initiate regeneration. Alternatively, on vehicles having systems that require an operator to initiate regeneration, the control module 54 will first receive an input from the operator before initiating the regeneration process.

[025] To prevent the excessively hot gases produced during regeneration from entering the dump body heating circuit, the control module 54 is also connected to the motor 20 to send an override signal that positions the flap 18 in the position against the second outlet 16, despite the position of the selector switch 50. When the regeneration process is completed, the control module 54 will cancel the override, allowing the switch 50 to control the position of the flap 18.

[026] Figure 2 illustrates, as an example, an embodiment of a control module 54 for the system of the invention. The control module 54 includes a Jl 939 serial reader and is connected to the truck's J 1939 CAN bus by a two wire pair, high 60 and low 62, to read communications on the bus to determine when a DPF regeneration process is being performed. The control module 54 is also connected to a circuit 66 having a coil 68 to energize a solenoid 20 for controlling the flow of exhaust gas, by, for example, changing the position of the valve 22 shown in Figure 1. The circuit is connected to a power supply, conveniently the vehicle's 12 volt power supply, to provide power to energize the coil 68. When the control module 54 reader detects a signal indicating that a regeneration is being performed, or has been commanded by another control unit, the control module energizes the coil 68 to control the solenoid 20 to move the valve to close the passage for heating the truck body and open the passage to the exhaust stack.

[027] Optionally, the apparatus may be installed on a truck configured without a driver selection switch for directing the exhaust gas, for example, a truck in which exhaust gas normally flows through the body or trailer bed. The invention then includes control module 54 that has full control of the valve position according to messages detected on the vehicle bus, and will normally have the valve positioned to direct exhaust gas through the truck body heating circuit, and will divert exhaust to the stack when a regeneration event occurs, as described above.

[028] Additionally, the apparatus may include a temperature sensor 60 to sense exhaust gas temperature on an outlet side of the diesel particulate filter 32. The temperature sensor 60 may advantageously be connected to deliver a signal indicative of the exhaust gas temperature to the control module 54. The control module 54 may use the temperature data as a further input for determining whether to apply the override on the motor 20. For example, at the end of the regeneration process it will take some time for the large heated mass of the diesel particulate filter to cool to a level at which exhaust gases will not damage the dump body. The control module 54 will delay canceling the override until the temperature of the exhaust gas has dropped to or below a threshold level.

[029] In addition, there may be operating conditions of the engine, heavy load, for example, where the exhaust gas temperatures are sufficiently high themselves to damage the dump body or sufficiently high to support regeneration without assistance, such that the exhaust gas may damage the dump body. The control module 54 may monitor the temperature of the exhaust gas exiting the diesel particulate filter 32, and control the motor 20 responsive to exhaust gas temperature, imposing or canceling the override as appropriate.

[030] The invention has been described in terms of preferred principles, embodiment, and components; however, those skilled in the art will understand that substitutions of equivalents may be made without departing from the scope of the invention as defined in the appended claims.

Claims

What is claimed is:

1. A control apparatus for heating a truck body, the truck body having at least one conduit for guiding exhaust gas through the truck body, the truck having an exhaust aftertreatment device requiring occasional regeneration, the control apparatus comprising: a controllable valve having a first position directing exhaust gas to an exhaust outlet pipe and a second position directing exhaust gas to an inlet to a truck body conduit; and, an override device being connected to receive a signal that an aftertreatment device regeneration is being performed and operationally connected to the controllable valve, the override device being configured to cause the controllable valve to move to the first position responsive to receiving the signal.

2. The control apparatus of claim 1, wherein the controllable valve includes a biasing device configured so that the first position is a default position.

3. The control apparatus of claim 1, wherein the controllable valve includes an air operated cylinder for moving the valve.

4. The control apparatus of claim 1, wherein the controllable valve includes a solenoid for changing the valve position.

5. The control apparatus of claim 1, further comprising a switch functionally connected to the controllable valve for manually selecting between the first position and the second position.

6. The control apparatus of claim 5, wherein the override device causes the valve to change to the first position despite the switch position.

7. The control apparatus of claim 5, wherein the switch is disposed in a cab of the vehicle.

8. The control apparatus of claim 1, wherein the controllable valve comprises a body having an inlet and two outlets, a pivotable valve flap mounted for movement between alternative positions closing one of the two outlets.

9. The control apparatus of claim 1, further comprising a temperature sensor disposed to sense an exhaust gas temperature at an outlet of an exhaust gas aftertreatment device and connected to deliver a temperature signal to the override device, and wherein the override device is configured to position the controllable valve responsive to the delivered signal.

10. The control apparatus of claim 1, wherein the override device includes a reader connected to a Jl 939 bus of the truck to detect communications on the bus relating to a regeneration event for an exhaust aftertreatment device.

11. A method for controlling a dump body heating apparatus in a vehicle having an exhaust aftertreatment device requiring occasional regeneration, and having a controllable valve having a first position directing exhaust gas to an exhaust outlet pipe and a second position directing exhaust gas to an inlet to a dump body conduit, the method comprising the steps of: monitoring whether regeneration of the aftertreatment device is in process; responsive to regeneration being in process, controlling the controllable valve to the first position directing exhaust gas to the exhaust outlet pipe; and, responsive to regeneration not being in process, allowing the controllable valve to be in a position selected by a vehicle operator.

12. The method of claim 11, further comprising the step of sensing an exhaust gas temperature at an outlet of the aftertreatment device, and responsive to the exhaust gas temperature being above a threshold level, controlling the controllable vale to the first position.