Title of Invention

EFFICIENT WAY TO OPTIMIZE ENERGY CONSUMPTION IN HVAC SYSTEMS

Abstract The proposed energy efficient technique helps to improve the fuel economy and reduce the emission.
Full Text FORM 2
THE PATENTS ACT 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
PROVISIONAL SPECIFICATION
(See Section 10; rule 13)
TITLE OF THE INVENTION Efficient way to optimize energy consumption in HVAC systems"


APPLICANTS
TATA MOTORS LIMITED, an Indian company
having its registered office at Bombay House,
24 Homi Mody Street, Hutatma Chowk,
Mumbai 400 001 Maharashtra, India

INVENTORS
Ms.Valentina Fernandes, Mr.Jayachandran Duraisamy,
Mr.Maneesh Arora all Indian national
&, Mr. Neil Robson a United Kingdom national
of TATA MOTORS LIMITED an Indian company
having its registered office at Bombay House,
24 Homi Mody Street, Hutatma Chowk,
Mumbai 400 001 Maharashtra, India
PREAMBLE TO THE DESCRIPTION The following specification particularly describes the invention


FIELD OF INVENTION
The present invention relates to the Heating Ventilation and Air Conditioning (HVAC) system to provide occupants comfort from both physiological and safety view points and its impact on fuel economy and emissions.
BACKGROUND OF INVENTION
The invention of the energy efficient HVAC systems has been developed due to several reasons. Soaring gasoline prices. Global warming. Dwindling fossil fuel reserves. No matter what the reason is for the increasing day to day demands in acquiring more energy efficient systems in automobiles, thus a need has arisen to improve the energy efficiency across all the systems in the vehicle. Typically one of the major loads on the engine is HVAC systems since it contains large no of sub-systems viz. A/C compressor, clutch, blower motor, auxiliary heaters etc. Improving the method of providing conditioned air to the vehicle occupants is another effective way to reduce the amount of the fuel used for the climate control systems. Thus there is a scope to enhance the energy consumption by operating these sub-systems in more efficient manner.
The traditional HVAC systems switches ON the compressor the moment A/C request is enabled and it remains ON until evaporator temperature is dropped to a lower threshold value. The threshold value is selected in such a way that evaporator coil doesn't get iced up and temperature doesn't fall below 0°C. In this method the HVAC system simply switches ON or OFF the compressor and the evaporator sensor output just acts as a safety device to prevent icing. Subsequently the compressor loads the engine always whenever the A/C is made ON. The drawback of this system is consumes always full AC energy consumption from the engine even at low ambient conditions thereby has a significant impact on fuel efficiency and emissions.

The proposed technique minimizes the drawback of the above by cycling the compressor ON/OFF with appropriate additional inputs to the HVAC systems. By this method the time for which the compressor loads the engine is reduced. Thereby fuel efficiency is improved and emissions are reduced without affecting the occupants comfort.
OBJECT OF INVENTION
The object of the present invention is to operate the HVAC system in energy efficient manner to improve the fuel economy and reduce the emission.
To achieve the above object, a technique is provided to adaptively control the compressor on the basis of additional inputs from the vehicle and environmental conditions.
BRIEF DESCRIPTION OF INVENTION
In the proposed technique, the HVAC system's control panel has an additional push button to select ECONOMY mode (energy saving mode), additional inputs such as vehicle speed information, engine coolant information and outside air temperature. Based on these inputs the control panel controls the compressor ON/OFF.
Normally under the normal A/C operation (when ECONOMY mode is OFF) the control panel switches ON the compressor continuously until the evaporator temperature drops down to a threshold value which is selected in such a way that evaporator coil doesn't get iced up and temperature doesn't fall below 0°C. This temperature cutoff is maintained to avoid evaporator freezing. In this mode the compressor loading time over the engine is maximum.

When the user has requested energy saving mode by pressing the ECONOMY button the control panel monitors the vehicle speed information, coolant information, outside air temperature, user desired temperature setting, evaporator temperature. On the basis of this information control panel decided the optimum temperature to cutoff the compressor so that minimum energy is used from engine and still comfort inside the cabin is maintained. Thereby the amount of compressor loading time over the engine is reduced when the A/C operates in ECONOMY mode.
BRIEF DESCRIPTION OF DRAWINGS
Figure 1: shows the air flow system
Figure 2: shows the interface to the A/C ECONOMY Algorithm. The calibration no is
the software calibration no that is calculated on the basis of the inputs from INCAR
sensor, Outside Air temperature sensor and Solar sensor.
Figure 3: Flow diagram explaining compressor cycling
DETAILED DESCRIPTION OF INVENTION
The focus of proposed methodology is to operate the HVAC system in energy efficient manner to improve the fuel economy and reduce the emission.
The status of the Normal A/C and Economy A/C Request shall be arbitrated by the A/C and Economy pushbuttons on the control panels of either Manual HVAC or Fully Automatic Temperature Controller.
The fully automatic controller allows the user to configure the desired settings by adjusting the desired air delivery position, the set temperature, the blower speed, the air source and the desired A/C compressor status. With the Auto button, the user can select all the above settings to be controlled automatically by the climate control algorithm. The Climate control algorithm shall be designed to maintain the

temperature selected by the user during the fully automatic operation. The user can also select to operate the compressor either in a normal or economy mode.
Both Normal A/C and Economy A/C shall allow the user to manually request the compressor to be turned on. The control head shall request the compressor to turn on or off by a discrete digital output to the Engine Management Electronic Control Unit. The state of the A/C LED in case of Manual HVAC control panels indicates the state of A/C request (Normal A/C, ECONOMY A/C and A/C OFF state). In case of Fully Automatic Temperature Controller control panels a dedicated ECONOMY pushbutton is used for ECONOMY ON / ECONOMY OFF modes.
When the user requests for Normal A/C mode the control panel switches ON the compressor continuously until the evaporator temperature drops down to a threshold value. This is elaborated with an example as follows; Refer figure 1. For a particular case when outside Air temperature is 38°C and the user request is 20 °C, assuming threshold for AC cutoff is programmed at 2 °C.
Under the above conditions the compressor remains ON continuously such that the evaporator core temperature cools down to 2 °C. This over-cooled air of 2 °C is then reheated by 18 °C. Thus the resultant air at the outlet of the evaporator core is 20 °C as per the desired temperature settings. This air then flows through the desired flaps as per the mode setting desired by the user or the program.
Thus when the outside air temperature is moderate, the traditional cooling systems over-cool, dehumidify, and then reheat the ambient air thereby making compressor run for longer time and hence decreasing the fuel efficiency of the system.

ECON A/C mode: Refer figure 1. ECONOMY mode is realized by reducing excessive cooling of HVAC airflow to just above 2°C and the subsequent reheating by engine coolant before discharging into the passenger compartment to meet the comfort requirements. Compressor power consumption is reduced by reducing the reheat. This is achieved by elevating the compressor control point such that the air coming out of the evaporator is cooled only as low as needed and directly discharged to the passenger compartment without getting reheated.
When the user requests for ECONOMY A/C mode the request cycles the compressor ON/OFF until the evaporator temperature drops down to a slightly elevated evaporator threshold value of 8°C. Refer figure 2. like when the outside Air temperature 38°C and the user request is 20 °C.
Under the above conditions the compressor cycles ON/OFF such that the evaporator core temperature cools to a slightly elevated temperature of about 8°C as compared to Normal A/C threshold 2 °C. The air coming out of the evaporator core is 8 °C. Thus air outside the evaporator core is heated by 12 °C. The resultant temperature being 20°C as per the user's request. The air flows through the respective flaps as requested by the user's mode settings.
The selection of the elevated evaporator temperature is determined on the basis of the ambient conditions such as temperature and humidity (refer figure 3)
This technique avoids the energy used for unnecessary cooling and reheating of incoming air to meet the customer demands.

This results in the time for which the compressor loads the engine is reduced. Thereby fuel efficiency is improved and emissions are reduced without affecting the occupants comfort.
The foregoing description is a specific embodiment of the present invention. It should be appreciated that this embodiment is described for purpose of illustration only, and that numerous alterations and modifications may be practiced by those skilled in the art without departing from the spirit and scope of the invention. It is intended that all such modifications and alterations be included insofar as they come within the scope of the invention as claimed or the equivalents thereof.

WE CLAIM

1. The proposed energy efficient technique helps to improve the fuel economy and reduce the emission.
2. The proposed energy efficient technique is easily achieved over the Controller Area Network. Since vehicle speed, outside temperature and coolant information are very much available over the CAN to perform several tasks.
3. This proposed methodology results in lowest development cost for software.
Dated this 26th day of March 2009
TATA MOTORS LIMITED By their Agent & Attorney

Karuna Goleria of DePENNING & DePENNING

Documents:

http://ipindiaonline.gov.in/patentsearch/GrantedSearch/viewdoc.aspx?id=ZPqE2YFK+jEfy79OLAhNvA==&loc=vsnutRQWHdTHa1EUofPtPQ==


Patent Number 279983
Indian Patent Application Number 754/MUM/2009
PG Journal Number 06/2017
Publication Date 10-Feb-2017
Grant Date 06-Feb-2017
Date of Filing 30-Mar-2009
Name of Patentee TATA MOTORS LIMITED
Applicant Address BOMBAY HOUSE, 24 HOMI MODY STREET, HUTATMA CHOWK, MUMBAI 400 001, MAHARASHTRA, INDIA.
Inventors:
# Inventor's Name Inventor's Address
1 VALENTINA FERNANDES BOMBAY HOUSE, 24HOMI MODY STREET, HUTATMA CHOWK, MUMBAI 400 001, MAHARASHTRA, INDIA.
2 JAYACHANDRAN DURAISAMY BOMBAY HOUSE, 24 HOMI MODY STREET, HUTATMA CHOWK, MUMBAI 400 001.
3 MANEESH ARORA BOMBAY HOUSE, 24 HOMI MODY STREET, HUTATMA CHOWK, MUMBAI 400 001.
4 NEIL ROBSON BOMBAY HOUSE, 24HOMI MODY STREET, HUTATMA CHOWK, MUMBAI 400 001.
PCT International Classification Number F24H9/20; G05D23/19; F24H9/20
PCT International Application Number N/A
PCT International Filing date
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 NA