FORM 2
THE PATENTS ACT 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
(See Section 10; rule 13)
TITLE OF THE INVENTION An Improved Vehicle Heating System
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
Jayachandran D, Fernandes Valentina B
And Manoj P.N.
All are Indian Nationals
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 and the manner in which it is to be performed.

FIELD OF INVENTION
the present invention is related to heating ventilation and air conditioning (HVAC) system and more particularly it relates to an improved vehicle heating system in order to achieve user desired cabin temperature during cold ambient conditions using the alternator workload signal.
BACKGROUND OF INVENTION
In very cold ambient conditions like Russia, cabin of a vehicle is required to be heated to provide the comfort to the passenger. Typically in conventional system, the vehicle cabin is heated with the help of electric heaters provided in the HVAC modules. The wattage of said electric heaters depends on the cabin size of a vehicle. A typical crossover vehicle requires approximately 1000 Wattage heaters to heat up its cabin. This additional electrical load on the vehicle affects the other electrical loads such as head lamps and display. Such additional load on the vehicle causes head lamp dimming and display flickering etc and thereby resulting in customer dissatisfaction.
The conventional system does not monitor the electrical load of the vehicle and it deploys the electric heaters in stages based on pre-determined timing.
The present invention is developed which monitors such electrical loads on the vehicle and judiciously deploys the electric heater into different stages to cater the additional electrical load on the vehicle by compensating the engine idling torque as per the requirement of vehicle heating for comfort of passenger.
OBJECT OF INVENTION
The main object of the present invention is to provide an improved vehicle heating
system.

Another object of the present invention is to provide an improved vehicle heating system which monitors the electrical loads of vehicle to deploy PTC heater in different stages such that additional load requirement can be catered by adjusting the engine idling torque.
STATEMENT OF INVENTION
An improved vehicle heating system comprises; climate control module, engine management system, blower speed selection switch to monitor user requested blower speed, alternator regulator with workload sensing element to provide alternator workload signal to said climate control module and engine management system, plurality of fuse and relays interfaced with said climate control module, HVAC unit having plurality of PTC heaters, ambient temperature sensing element to monitor the outside ambient temperature, evaporator temperature sensing element to monitor the temperature of air entering to heater core, engine coolant temperature sensing element to sense coolant temperature, crank position sensing element to sense the engine rpm value, plurality of injectors interfaced with said engine management system, and vehicle CAN bus interfacing said climate control module and said engine management system, said alternator regulator provides workload signal to said climate control module and engine management system for deploying said PTC heaters into different stages such that engine idling torque is adjusted by engine management system to cater the electrical load variations on engine.
Vehicle heating system, in accordance with present invention, wherein input side of said climate control module are connected to said blower speed selection switch 03, ambient temperature sensing element, evaporator temperature sensing element and alternator workload signal from alternator regulator,
Vehicle heating system, in accordance with present invention, wherein output side of said climate control module is connected to plurality of said relays and PTC heaters.

Vehicle heating system, in accordance with present invention, wherein said plurality of PTC heaters are mounted on the HVAC unit and are interfaced with said PTC relays housed in the fuse and relay box.
Vehicle heating system, in accordance with present invention, wherein input side of engine management system are interfaced with said alternator workload signal from said alternator regulator, engine cooling sensing element, crank position sensing element and said climate control module via said CAN bus of vehicle.
Vehicle heating system, in accordance with present invention, wherein output side of engine management is interfaced with injector bank having plurality of injector cylinders for controlling fuel injection to adjust engine idling torque.
Vehicle heating system, in accordance with present invention, wherein said climate control module deploys said PTC heaters in three stages.
Vehicle heating system, in accordance with present invention, wherein numbers of stages to be activated are defined on the basis of the alternator workload signal received from said alternator regulator and battery voltage.
Vehicle heating system, in accordance with present invention, wherein activation of said PTC heaters are decided based on coolant temperature, temperature of air entering to heater core, air-flow availability or blower speed and desired set temperature.
Vehicle heating system, in accordance with present invention, wherein said climate control module defines the number of electrical heaters to be deployed based on environmental parameters.
Vehicle heating system, in accordance with present invention, wherein said environmental parameters are outside ambient temperature, coolant temperature, evaporator air out temperature, Air-flow availability or blower speed, desired set temperature and alternator duty frequency monitoring signal.

Vehicle heating system, in accordance with present invention, wherein said climate control module and engine management system monitors alternator duty frequency monitoring signal from said alternator regulator to switch on said electric PTC heaters to required stages based on said environmental parameters inputs and alternator workload after a pre-determined calibratible delay time to minimize surges in switching current to meet varied additional electrical load demand on electrical system.
Vehicle heating system, in accordance with present invention, wherein said climate control module switches off said PTC heater after vehicle cabin being heated to users comfort and engine management system adjusts engine idling torque.
BRIEF DESCRIPTION OF INVENTION
In accordance with the present invention, an improved vehicle heating system comprises; climate control module 01, engine management system 02, blower speed selection switch 03, alternator regulator with workload sensing 04, plurality of fuse and relays 05, plurality of heaters 06, ambient temperature sensing element 07, evaporator temperature sensing element 08, engine coolant temperature sensing element 09, crank position sensing element 10 and plurality of injectors 11 interfaced with said engine management system 02, said alternator regulator with workload sensing 04 provides workload signal to climate control module 01 for deploying said PTC heaters 06 into different stages such that idling torque is adjusted by engine management system 02 to cater the electrical load variations on the engine.
BRIEF DESCRIPTION OF DRAWINGS
Figure-01 which shows the input and output interfaces of the PTC heaters with climate control module and engine management system.

Figure-02 which shows the Duty Frequency Monitoring (DFM) signals waveform of alternator workload at three stages.
DETAILED DESCRIPTION OF INVENTION
Referring now to the drawings wherein the showings are for the purpose of illustrating a preferred embodiment of the invention only, and not for the purpose of limiting the same,
Now refering to figure-0l and 02, In accordance with the present invention, an improved vehicle heating system comprises; climate control module 01, engine management system 02, blower speed selection switch 03 to monitor user requested blower speed, alternator regulator with workload sensing element 04 to provide alternator workload signal to said climate control module and engine management system, plurality of fuse and relays 05 interfaced with said climate control module, HVAC unit 06 having plurality of PTC heaters, ambient temperature sensing element 07, evaporator temperature sensing element 08, engine coolant temperature sensing element 09, crank position sensing element 10 and plurality of injectors 11 interfaced with said engine management system 02, vehicle CAN Bus 12 interfacing said climate control module and said engine management system, said alternator regulator with workload sensing 04 provides workload signal to climate control module 01 and engine management system 02 for deploying said PTC heaters into different stages such that idling torque is adjusted by engine management system 02 to cater the electrical load variations on the engine.
The Battery (V_Batt) and ground E0001 and E0002 are used for powering up the said engine management system 02 and climate control module 01 respectively. The ignition (V_Ign) are used as hardwired wake to the said climate control module 01 and engine management system 02.The blower motor M is provided in the HVAC unit 06.

The output side of the Climate Control Module (CCM) 01 is connected to said plurality of PTC heaters (PI, P2, P3). Said plurality of PTC heaters are mounted on the HVAC unit 06 and are interfaced with said PTC relays (Rl, R2, R3) 05 which are placed in the fuse and relay box. The input side of the said climate control module 01 are connected to the blower speed selection switch 03 to monitor the user requested blower speed, outside ambient temperature element 07 to monitor the outside ambient temperature and evaporator temperature sensing element 08 to monitor the temperature of air which is entering to the heater core or PTC core, and alternator workload signal from alternator regulator 04 to monitor the alternator workload.
The said alternator workload signal is also interfaced with input side of said engine management system 02 to adjust engine idling torque by controlling the plurality of injectors 11 from injector bank. The said engine management system 02 is also transmitting the engine coolant temperature value calculated from engine coolant temperature sensing element 09 and engine RPM value calculated from crank position sensing element 10 to said climate control module 01 via said CAN bus 12 of the vehicle.
At low workload waveform, the said PTC heaters, headlamps and fog lamps etc of vehicle are in OFF condition. This indicates that the electrical load on the vehicle is low.
At high workload waveform, the said PTC heaters with stage one is in ON condition and headlamps and fog lamps etc of vehicle are in OFF condition. This indicates that the electrical load on the vehicle is high.
At full workload waveform, the said PTC heaters with stages two and three are in ON condition and headlamps and fog lamps etc of vehicle are also in ON condition. This indicates that the electrical load on the vehicle is maximum.

Said climate control module 01 deploys the said PTC heaters in three stages which are mounted on the said HVAC unit 06 through the said PTC relays 05 which are placed in the fuse and relay box. The numbers of stages to be activated are defined on the basis of the alternator workload signal received from said alternator regulator 04 and the battery voltage. The activation of the said PTC heaters are decided based on coolant temperature, evaporator air out temperature which is temperature of air entering the heater core or PTC core, Air-flow availability or blower speed and desired set temperature. The engine management system 02 adjusts the idling torque to cater the sudden increase in electrical load on the engine. The switching of the individual heater shall be accomplished with a calibratible delay so as to limit surges in switching current.
The said climate control module 01 defines the number of PTC heaters needs to be switched on based on the environmental parameters inputs such as Outside Ambient Temperature, Coolant temperature, Evaporator air out temperature which is temperature of air entering the heater core / PTC core, Air-flow availability/blower speed, desired set temperature and alternator duty frequency monitoring signal.
The said climate control module 01 and engine management system 02 monitors the alternator workload signal from said alternator regulator 04.
When the engine is in running state, the said climate control module 01 monitors the said environmental inputs and alternator duty frequency monitoring signal and switches on the said electric PTC heater to stage one. Due to sudden increase in additional electrical load on electrical system, the load on said alternator regulator 04 on engine is increased and the duty frequency monitoring cycle is varied. This change in duty cycle is monitored by engine management system 02 which adjusts the engine idling torque by increasing the fueling on the said injectors 11.

Similarly the said climate control module 01 switches on the said electric PTC heaters to stage two and three based on the said environmental inputs and the alternator workload after a pre-determined time which is calibratible.
Once the cabin is heated to the user desired temperature, the said climate control module 01 switches off the said PTC heater and engine management system 02 which adjusts the engine idling torque as per the current electrical load on the vehicle.
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. An improved vehicle heating system comprises; climate control module,
engine management system, blower speed selection switch to monitor user
requested blower speed, alternator regulator with workload sensing element to
provide alternator workload signal to said climate control module and engine
management system, plurality of fuse and relays interfaced with said climate
control module, HVAC unit having plurality of PTC heaters, ambient temperature
sensing element to monitor the outside ambient temperature, evaporator
temperature sensing element to monitor the temperature of air entering to heater
core, engine coolant temperature sensing element to sense coolant temperature,
crank position sensing element to sense the engine rpm value, plurality of injectors
interfaced with said engine management system, and vehicle CAN bus interfacing
said climate control module and said engine management system, said alternator
regulator provides workload signal to said climate control module and engine
management system for deploying said PTC heaters into different stages such that
engine idling torque is adjusted by engine management system to cater the
electrical load variations on engine.
2. Vehicle heating system as claimed in claim 1, wherein input side of said climate control module are connected to said blower speed selection switch 03, ambient temperature sensing element, evaporator temperature sensing element and alternator workload signal from alternator regulator.
3. Vehicle heating system as claimed in claim 1, wherein output side of said climate control module is connected to plurality of said relays and PTC heaters.
4. Vehicle heating system as claimed in claim 1, wherein said plurality of PTC heaters are mounted on the HVAC unit and are interfaced with said PTC relays housed in the fuse and relay box.

5. Vehicle heating system as claimed in claim 1, wherein input side of
engine management system are interfaced with said alternator workload signal from
said alternator regulator, engine cooling sensing element, crank position sensing
element and said climate control module via said CAN bus of vehicle.
6. Vehicle heating system as claimed in claim 1, wherein output side of
engine management is interfaced with injector bank having plurality of injector
cylinders for controlling fuel injection to adjust engine idling torque.
7. Vehicle heating system as claimed in claim 1, wherein said climate control module deploys said PTC heaters in three stages.
8. Vehicle heating system as claimed in claim 1 and 7, wherein numbers of stages to be activated are defined on the basis of the alternator workload signal received from said alternator regulator and battery voltage.
9. Vehicle heating system as claimed in claim 1, wherein activation of said PTC heaters are decided based on coolant temperature, temperature of air entering to heater core, air-flow availability or blower speed and desired set temperature.
10. Vehicle heating system as claimed in claim 1, wherein said climate control module defines the number of electrical heaters to be deployed based on environmental parameters.
11. Vehicle heating system as claimed in claim 1, wherein said
environmental parameters are outside ambient temperature, coolant temperature,
evaporator air out temperature, Air-flow availability or blower speed, desired set
temperature and alternator duty frequency monitoring signal.
12. Vehicle heating system as claimed in claim 1, wherein said climate
control module and engine management system monitors alternator duty frequency
monitoring signal from said alternator regulator to switch on said electric PTC
heaters to required stages based on said environmental parameters inputs and

alternator workload after a pre-determined calibratible delay time to minimize surges in switching current to meet varied additional electrical load demand on electrical system.
13. Vehicle heating system as claimed in claim 1, wherein said climate control module switches off said PTC heater after vehicle cabin being heated to users comfort and engine management system adjusts engine idling torque.
14. An improved vehicle heating system as herein described with reference to accompanying drawings.