HVAC unit for off-road vehicles
Field of Invention:
The present invention relates, to compact roof mounting unit for a vehicle. More particularly relates to roof mounting HVAC unit for directing heating, cooling or ventilating air to the off road vehicles.
Background and Prior Art:
In off road vehicles, no cooling & heating arrangement along with fresh air exist. Today, agricultural vehicles with roof-mounted heating ventilation and air conditioning systems (HVAC) are faced with a number of conflicting constraints. A roof support structure is required to protect the operator, seal the cabin environment from outside weather, and provide ample overhead clearance for the operator within the cabin. The roof structure must also house various components of the HVAC system, including the electrical/electronics, blower, heater and evaporator cores, as well as any other cab accessories the designer may desire to position overhead. The roof and support structure must also be compact in nature so that adequate overhead clearance for the vehicle operator is maintained without substantially increasing overall vehicle height.
Furthermore, an airflow system is required to supply air to the ventilation system blower and then distribute air using specifically positioned ducts and vent openings from the HVAC blower into the operator environment. Airflow must be directed to specific locations throughout the cab interior in order to defrost or defog windows and to maintain operator comfort. The roof structure must be aesthetically pleasing offering a colored appearance on the top of the vehicle. The roof structure must also be capable of protecting the cab from outside weather conditions. Today's vehicles typically provide a separate protective roof cap, HVAC unit support structure and air distribution system above the operator cabin. There are additional constraints in today', vehicle, such as operator visibility to the ground, attached implements, and ground environment, the overall height of the vehicle, and styling.
The multitude of functional requirements for an agricultural vehicle roof generally requires a complex roof structure with a significant plurality of individual component parts. Such assemblies are difficult and time consuming to assemble and can be problematic when subjected to the harsh environment typical of an off-road vehicle, In today's competitive market, functional performance using designs that are simple in construction is paramount.
The following patents relates to air ducts in a tractor cab roof for directing heating, cooling or ventilating air within the cab:
US Patent No. 7,334,834 relates to air ducts in a tractor cab roof for directing heating, cooling or ventilating air within the cab. Conditioned air ducts are between the upper roof member and the left and right side panels, with conditioned air outlet apertures in the sloping side walls. In this invention, no fresh air is included in the cooling & heating. In the present invention, fresh air supply is available which is included in the cooling and heating.
US Patent No. 6,780,097 relates to the roof portion of the cab structure having means for the treatment of cab atmosphere, such as heating, cooling or ventilating the air within the cab. There is no constant control of fresh air with filter. In the present invention, there is provided the constant control of fresh air with filter
Publication No EP0169040 relates to an air conditioning system for an enclosed compartment of a vehicle particularly for a cab of a tractor or a truck. System includes an intake duct disposed in the cab roof and containing a filter in series with one blower comprising an electric motor which may be of multi-speed type interposed between and driving two axial-inlet radial-flow fans for pressurizing the cab with dust-free ambient air when the windows are closed.
US Publication No. 20070205633 relates to a high-visibility roof system with integrated ventilation ducting for an agricultural vehicle such as, but not limited to, a tractor. An off-road vehicle, a tractor, having an enclosed cab covered by roof structure and equipped with an air handling system. An access panel is provided to allow access to the HVAC system for installation, maintenance, or replacement. The present invention provides easy rooftop service in HVAC unit.
The following patents have roof mounted cooling arrangement.
Publication No. EP1614558 relates to a roof-mounted air-conditioning system having a condenser chamber accommodating a condenser and at least one fan, and an evaporator chamber accommodating an evaporator and at least one fan.
Publication No DE4100266 relates to venting heating and/or cooling arrangement set on a base plate for incorporation within the roof of the cabin of a tractor where a blower, a substantially forward facing air outlet and downstream of the blower has a reversed trough-shaped pressure chamber is provided
Publication No. DEI9641642 relates to an air conditioner that is suitable for mounting on the roof of a vehicle, such as a bus. The invention comprises a mounting on the roof of a vehicle air conditioning unit suitable one from a single molded plastic material base; the base for direct mounting on the roof of the vehicle is suitable. Are integrally formed with the basic elements that certain components of an air conditioning system, including the evaporator coil, the condenser coil, the evaporator blower and condenser fan, can be stored.
US Patent No. 4,144,719 relates to air conditioning units adapted to be mounted to the roof of a vehicle cab, such as the cab of an agricultural tractor, combine or other vehicle.
Patents having ceiling mounted within the cabin are following
Publication No. JP6087317 relates to air conditioning unit arranged in the ceiling in the cabin of a vehicle.
Publication No CA1279680 relates to a tractor cabin having struts, a top framework, an air conditioner mounted on the top framework, and a ceiling assembly covering an entire ceiling area of the cabin.
Publication No. JP61205505 relates to air-conditioning box body as being unitized with a ceiling board, in case of an air conditioner does a farm tractor or the like.
Following patents/publications also provide HVAC systems for off-road vehicles such as tractors but not mounting of the roof/ceiling-
Publication No. JP63101121 relates to cabin ventilation for tractor by providing hollow bulge sections bulged outward on both right and left sides of a roof and forming inlets to guide the outside air on these bulge sections.
US Patent No. 4,072,487 relates to air conditioning apparatus for a tractor cab in which filter and air inlets are disposed in a portion of the roof projecting rearwardly beyond the cab, the air inlet being downwardly disposed so that foreign matter accumulating in the exterior of the filter is free to fall off of the filter and out through the air inlet.
Publication No. GB2106634 relates to cabs for vehicles such as tractors which include a heating and/or ventilating system in which air is drawn into the cab from the atmosphere using a fan.
US Publication No. 20070131408 relates to over-the-road and off-road vehicle air conditioning systems utilizing variable speed motor driven compressors and controls therefore.
US Publication No. 20090277202 relates to a vehicle that includes an insulated cabin and a HVAC system that conditions the cabin.
The article entitled "Performance study of spot cooling of tractor cabinet by A.E. Kabeela, G.I. Sultanb, Z.A. Zyadaa and M.I. El-Hadarya, Energy, 2 February 2010" talks about the cabinet is cooled from the roof by one port while the lower and side walls temperature is kept constant. The effect of inlet and outlet air ports positions in the cabinet is considered.
Disadvantage of Prior Art
None of the above listed prior arts talk about ease of the service. With the growing demand of overall business in construction industry as well in agriculture industry the need is felt to provide productivity improvement as well as comfort conditions for operator's environment. Therefore there is need of a system which is serviceable without removing the entire cabin. Also there needed a system which can maintain the positive pressure in the cabin to avoid dust and dirt entry.
In order to overcome the above listed prior art, the present invention provides a HVAC unit which is efficiently mounted on roof top with external serviceability. The roof mounting unit provides the unique advantage of flowing the cold/hot air from top of cabin to bottom side. Positive pressure is maintained in cabin even against constant fresh air entry, which avoids dust and dirt entry into the cabin.
Objective of present Invention:
The principal object of the present invention is to provide a compact roof mounted HVAC unit for the off road vehicles.
Another object of the present invention is to provide the comfortable environment conditions in the operator's cabin of the vehicle by means of HVAC unit efficiently mounted on roof top.
Yet another object of the present invention is to provide a compact roof mounted HVAC unit, whose servicing and maintenance can be done from outside the cabin of the vehicle.
Still another object of the present invention is to provide the roof mounted unit that leads to space saving & components reduction.
Another object of the present invention is to provide increase the productivity of the operator & business by providing comfortable conditions in the vehicle cabin.
Yet another object of the present invention is to provide a roof mounting HVAC unit which prevents the dust and dirt entry into the cabin.
Still another object of the present invention is to provide a roof mounting HVAC unit which controls the working environment against hazardous pesticide.
Another object of the present invention is to provide a light weight roof mounting HVAC unit.
Yet another object of the present invention is to prevent the bacteria/ fungus formation on the evaporator which in turn controls the quality of the air supplied into the cabin.
Summary of Invention:
Accordingly the present invention provides a compact roof mounted HVAC unit for off road vehicle. The roof mounting unit in the off road vehicles provides the unique advantage of flowing the cold/hot air from top of cabin to bottom side like shower along with the principle with flow of cold air from top to bottom and flow of hot air from bottom to top. The unit uses the roof of the tractor as mounting for its cooling & heating arrangement to save the space & reduce the components. The present invention has unique advantage of serviceability from outside which requires minimal parts opening & closing.
In the preferred embodiment of the present invention a HVAC unit is provided comprising a housing adapted to be fixed on the roof surface of a vehicle cabin; an opening at upright front in the said housing for providing ease for service/maintenance of the HVAC unit; an opening at upright back in the said housing for throwing the air from within the housing to the vehicle cabin from top of cabin to bottom side; atleast one fresh air duct to provide fresh air inside the housing; evaporator 1 and heater section comprising aluminum tube plate fin (CTPF) heat exchangers to reduce the temperature of a hot air; atleast one cold/ hot air outlet grills 4 within said housing for cooling/ heating the cabin uniformly; atleast one recirculation duct 5 located between the evaporator 1 and fresh air duct for increasing the cooling effect and uniform cooling; first and second blower to move the conditioned air through conditioned air ducts along the left and right sides of the vehicle's roof between the upper and lower roof members, and out
through conditioned air outlet apertures 4 into the vehicle ; a radiator to transfer the heat to the air; a condenser placed before radiator within said housing wherein its fan uniquely draws the air over condenser to cool the condenser first and then radiator.
In another embodiment of the present invention an externally serviceable HVAC unit is provided for throwing air from top of the cabin to the bottom in off-road vehicles.
In another embodiment of the present invention shortest duct in the HVAC unit from evaporator section to the grill outlets increases the cooling effect & effectiveness of cooling by providing uniform cooling.
In yet another embodiment of the present invention, the filter & fresh air door duct of the HVAC unit allows constant & uniform mixing of fresh air and re-circulates the flow of the air inside the cabin.
In still another embodiment of the present invention, the positive pressure (above normal atmospheric pressure) is maintained in cabin to prevent dust and dirt entry into the cabin.
In another embodiment of the present invention, the roof mounted HVAC unit with cold/ hot air outlet grills can have multiple numbers of multi directional grills as per the requirement.
In yet another embodiment of the present invention, the off road vehicle can be such as but not limited to the tractor, earth mover, cranes etc.
In another embodiment of the present invention, the roof may be fitted with a number of fixtures such as lights, entertainment systems or instruments as per the requirement.
Brief Description of the Invention:
It is to be noted, however, that the appended drawings illustrate only typical
embodiments of this invention and are therefore not to be considered for
limiting of its scope, for the invention may admit to other equally effective
embodiments.
Fig la and lb shows a perspective view and line diagram of HVAC unit in
off road vehicle according to the present invention.
Fig 2 shows the cold/hot air outlet grills for HVAC unit in off road vehicle
Fig 3 shows the roof mounted HVAC unit with the filter & fresh air door.
Detailed Description of the Invention
Reference may be made to fig. 1 which shows a perspective view and line diagram of a HVAC unit for mounting on the roof of a vehicle according to the present invention. The HVAC unit is preferably mounted on the roof of the off road vehicles. The HVAC unit according to the present invention comprises a housing adapted to be fixed on the roof surface of a vehicle cabin; an opening at upright front in the said housing for providing ease for service/maintenance of the HVAC unit; an opening at upright back in the said housing for throwing the air from within the housing to the vehicle cabin from top of cabin to bottom side; atleast one fresh air duct to provide fresh air inside the housing; evaporator 1 and heater section comprising aluminum tube plate fin (CTPF) heat exchangers to reduce the temperature of a hot air; atleast one cold/ hot air outlet grills 4 within said housing for cooling/ heating the cabin uniformly; atleast one recirculation duct 5 located between the evaporator 1 and fresh air duct for increasing the cooling effect and uniform cooling 7; first and second blower to move the conditioned air through conditioned air ducts along the left and right sides of the vehicle's roof between the upper and lower roof members, and out through conditioned air outlet apertures 4 into the vehicle; a radiator to transfer the heat to the air; a condenser placed before radiator within said housing wherein its fan uniquely draws the air over condenser to cool the condenser first and then radiator.
The fresh air from outside enters in the roof mounted HVAC unit of the vehicle cabin through fresh air duct 6 and then the air is recirculated in the recirculation chamber. The recirculating air duct 5 is located between the evaporator 1 and fresh air duct 6. Recirculating air duct 5 intakes recirculating air from the cabin to be cooled or heated by evaporator 1/ heater 2 core. The evaporator 1/ heater2 core comprises aluminum tube plate fin (CTPF) heat exchangers. Recirculating air passages on the left and right sides of evaporator 1/heater 2 core allows flow of recirculating air from recirculating air duct to the air mixing chamber. Air mixing chamber provides a cavity for fresh air and recirculating air to mix before passing through evaporator 1/ heater 2. Conditioned air exiting the evaporator 1/ heater 2 enters air discharge cavities and then through blower 3 to conditioned air ducts 4. Then the conditioned air exits through conditioned air outlet apertures 4. The invention uses shortest duct from evaporator section to cold/ hot air outlet grills 4 which increases the cooling effect & effectiveness of cooling and provides uniform cooling. Air re-circulated from the vehicle cab is combined with fresh filtered air just upstream of the evaporator 1/ heater 2 core. Fresh air filter is mounted adjacent to the air mixing chamber, upstream of evaporatorl/ heater2 and is removable. Before entering recirculating air into the outlet ducts 4, air is filtered with filters located behind the operator's head. The conditioned air is blown through conditioned air outlets 4 into the cab.
The present invention is able to pressurize the enclosed cabin to restrict the dust entry inside the cabin with the help of blower.
Fig 2 shows cold/ hot air outlet grills in the roof mounted HVAC unit which throws the air from top of the cabin to the bottom like shower and cools/ heats the cabin faster & uniformly. There are preferably "8" cold/ hot air outlet grills placed below the blower in mirror position.
The conditioned and recirculating air flows in mirrored HVAC air ducts 4 and vehicle cab. Conditioned air exit through conditioned air outlet apertures 4 into the cab, and then recirculated by entering recirculating air duct 5. Recirculating air then flows through recirculating air passages around the sides of evaporator 1/ heater 2 to the air mixing chambera Conditioned air exiting the evaporator 1/ heater 2 enters air discharge
cavities and then through blower 3 to conditioned air ducts 4. Then the conditioned air exits through conditioned air outlet apertures 4. The invention uses shortest duct from evaporator section to cold/ hot air outlet grills 4 which increases the cooling effect & effectiveness of cooling and provides uniform cooling.
Fig 3a and 3b shows the filter & fresh air door that allows constant & uniform mixing of fresh air & recirculation to flow inside the cabin. This restricts dust entry inside the cabin due to the pressurization of the cabin. This arrangement saves lot of energy. The multi flow condenser cores are highly efficient. The energy saving/ cabin temperature control is achieved by variable speed selection of the blower, which allows operator to maintain the air-conditioner desired air flow/cabin temperature. The high static blowers maintain the uniform airflow throughout the cabin. The armament pressurizes the enclosed cabin which restricts the dust entry inside the cab
As the HVAC unit is mounted over the roof top, the present invention is serviceable with out removing the entire cabin. The HVAC unit is provided with an access opening through which the major components of the HVAC module can be serviced, maintained and/or replaced. The HVAC module cover that is held in place by elastic straps protects the major components. The access opening is sized to permit removal and replacement of the major components of the HVAC module from outside the compartment. These major components includes such as but not limited to the blower, the evaporator core and the heater core. The present invention makes possible to control working environment against hazardous pesticides. The HVAC unit provides comfort conditions to the operator of the equipment. It enhances the working environment of the operator. Thus it increases the productivity of the operator & business. The unit is externally serviceable & environment friendly.
Numerous modifications and adaptations of the system of the present invention will be apparent to those skilled in the art, and thus it is intended by the appended claims to cover all such modifications and adaptations which fall within the true spirit and scope of this invention.

We Claims;
1. A roof-mounted HVAC unit for a cabin of a vehicle, comprising:
a housing adapted to be fixed on the roof surface of a vehicle cabin;
an opening at upright front in the said housing for providing ease for
service/maintenance of the HVAC unit;
an opening at upright back in the said housing for throwing the air from
within the housing to the vehicle cabin from top of cabin to bottom side;
atleast one fresh air duct comprising filter and fresh air door to provide
fresh air inside the housing;
evaporator and heater section comprising aluminum tube plate fin (CTPF)
heat exchangers to reduce the temperature of a hot air
atleast one cold/ hot air outlet grills within said housing for cooling/
heating the cabin uniformly;
atleast one recirculation duct located between the evaporator and fresh air
duct for increasing the cooling effect and uniform cooling;
first and second blower to move the conditioned air through conditioned air
ducts along the left and right sides of the vehicle's roof between the upper
and lower roof members, and out through conditioned air outlet apertures 4
into the vehicle
a radiator to transfer the heat to the air;
a condenser placed before radiator within said housing wherein its fan
uniquely draws the air over condenser to cool the condenser first and then
radiator..
2. The HVAC unit as claimed in any of the preceding claims, wherein
cold/ hot air outlet grills are ranging from 7-10 for increasing the cooling
effect and providing uniform cooling.
4. 3. The HVAC unit as claimed in any of the preceding claims, wherein the
filter & fresh air door allows constant & uniform mixing of fresh air &
recirculation to flow inside the cabin.
5. The HVAC unit as claimed in any of the preceding claims, wherein the condenser cores used is highly efficient type of condenser (Kindly explain how these are highly efficient) which automatically maintains a desired temperature in the cabin.
6. The HVAC unit as claimed in any of the preceding claims, wherein fan drawing the air over condenser to cool the condenser first and then radiator saves a lot of energy maximizing the cooling effect.
7. The roof-mounted HVAC unit in any of the preceding claims wherein the vehicle is an on/off road vehicle.
8. The roof-mounted HVAC unit in any of the preceding claims wherein the HVAC unit pressurizes the enclosed cabin to restrict the dust entry inside the cabin;
9. The HVAC unit as claimed in claim 1, wherein the HVAC unit provides comfort conditions to the operator of the equipment and enhances the working environment of the operator.
10. The HVAC unit as claimed in claim 1, wherein the serviceability of the HVAC system from outside requires minimal parts opening & closing.
10. A roof-mounted HVAC unit substantially as herein described with
reference to the drawings accompanying this specification.