FORM 2
THE PATENT ACT, 1970
(39 OF 1970)
AND
THE PATENTS RULES, 2003
PROVISIONAL SPECIFICATION
(See Section 10; rule 13)
TITLE OF THE INVENTION
Engine Starter Motor Protection System For Vehicles
APPLICANT
TATA MOTORS LIMITED, an Indian Company
Having its registered office at Bombay House,
24 Homi Mody Street, Hutatma Chowk,
Mumbai 400001, Maharashtra, India
INVENTOR
Sayyed M.I.Y.
An Indian National
Of TATA MOTORS LIMITED an Indian company
Having its registered office at Bombay House,
24 Homi Mody Street, Hutatma Chowk,
Mumbai 400001, 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 relates to the engine protection system used in vehicles and more particularly it relates to the engine starter motor protection system.
BACKGROUND OF INVENTION
Generally all the automobiles are fitted with internal combustion engines to receive the power for the transmission of the vehicles. These engines burn the fuel and convert thermal energy into mechanical energy. These engines are switched on while the automobile is in use and switched off during the storage of the vehicle.
To switch on the internal combustion engines, it needs to be set running initially by external force till it takes off automatically. In case of smaller vehicles like motorbikes and scooters, the engine can be started by kicking the pedal provided on the engine hence inducing movement to crankshaft and piston inside the cylinder block of the engine. Once this initial movement is induced; engine starts burning the fuel and will remain in running condition as a long as fuel is supplied or not stopped by disconnecting the electrical circuit.
In some smaller engines, cord is wound on the crankshaft pulley and pulled to induce the required movement to start the engine. Other smaller engines can be started using the crank handle and manual force.
It is not possible to induce the required movement to start the big engines manually. These engines are started using the electrical starter motor. The motor is direct current motor and uses electrical supply from the battery. To start the engine, electrical supply is given to the starter motor and the gear on the starter motor engages with gear


mounted on the engine crankshaft. Once the engine starts, the starter motor is disconnected from the engine.
To switch on the engine having the electrical starter motor, starter motor is kept engaged with engine till engine starts. This engagement is controlled through electrical switching circuit. In case of the automobile, a key operates the ignition switch and switch is kept pressed till engine starts. Once engine starts the pressing of the switch is no more required, when the switch is released it retracts by spring action. During this process, the gear on the starter motors engages when switch is pressed and retracts when switch is released through electro-magnetic arrangement.
The electrical starter motors consists of three important parts:-1> Motor 2> Gear/ pinion 3> Solenoid -Electromagnet
While starting the engine solenoid is charged to make mechanical movement and the gear on starter motor gets engaged with gear mounted on crankshaft of the engine. Then starter motor powers the engine crankshaft movement. After engine starts running on its own; electrical supplies to starter motor are disconnected and the pinion also retracts from the engine gear. To start heavy/ big engines, starter motors are designed with heavy torque specifications and draw very high current during the starting process. Hence to operate the starter motor, electrical relay is used in the circuit, which is capable of handling the heavy electrical current.
If electrical starter is kept engaged with engine even after the engine has started running then it will damage the starter motor pinion and hence the starter motor. It is very important to disconnect the electrical starter motor from engine once engine is in running condition. The modern automobiles are equipped with quieter engines and there are chances of pressing ignition switch on already running engine, which can cause damage to starter motor.


The automobile internal combustion engines are also equipped with its own electrical power generation system. A part of the running engine power is used to run the electrical alternator, which creates electricity, and it is used to charge the battery pack as well as in operating electrical/ electronic gadgets on board. Alternator comes in operation once engine is running and supply power for all electrical functions of the vehicle. The battery during engine running remains as a buffer and storage unit. It also gets charged during this process.
OBJECTS OF INVENTION
• The main object of this invention is to provide an engine starter motor protection system
• Another object of this invention is to provide an engine starter motor protection system which is simple and cost effective.
STATEMENT OF INVENTION
Engine starter motor protection system for vehicles comprises ; starter motor for starting the engine mounted on engine case, starter relay for transmitting the current supply to said starter motor which is mounted on relay bracket of engine house, ignition switch for cranking engine provided on steering column below the steering wheel, alternator for generating direct current after engine has started which is mounted on engine casing , battery for supplying direct current to said starter motor which is mounted on battery tray in engine house , wherein said starter relay comprises solenoid coil and normally open contact terminal, one end of said solenoid coil is connected to the battery and other end to the said alternator which is earthed such that after said alternator has started, earthing cut off takes place which disables the said primary circuit which prevents the re-cranking of engine in already running


condition since negative terminal is not available to the solenoid coil of said starter relay for re- cranking.
Engine starter motor protection system for vehicles, in accordance with this invention, wherein said primary circuit is connected to the negative terminal of said battery through the said alternator for earthing.
Engine starter motor protection system for vehicles, in accordance with this invention, wherein said primary circuit comprises the ignition switch between the said battery and said starter relay for cranking.
Engine starter motor protection system for vehicles, in accordance with this invention, wherein said primary circuit comprises diode between said starter relay and said alternator for preventing return electrical supply form the said starter relay to said alternator.
Engine starter motor protection system for vehicles, in accordance with this invention, wherein said secondary circuit comprises normally open (NO) contact terminal between the said starter motor and said battery for starting the said motor.
Engine starter motor protection system for vehicles, in accordance with this invention, wherein said starter relay is configured to be disabled electrically when engine is running and alternator is functioning.
BRIEF DESCRIPTION OF INVENTION
In accordance with this invention , starter motor protection system for vehicles comprises ; starter motor (M) for starting the engine mounted on engine case, starter relay ( R) for transmitting the current supply to said starter motor which is mounted on relay bracket of engine house, ignition switch (K) for cranking engine provided on steering column below the steering wheel, alternator (A) for generating direct current


after engine has started which is mounted on engine casing , battery (B) for supplying direct current to said starter motor which is mounted on battery tray in engine house , wherein said starter relay comprises solenoid coil and normally open contact terminal, one end of said solenoid coil is connected to the battery and other end to the said alternator which is earthed such that after said alternator has started earthing cut off takes place which disables the said primary circuit which prevents the re-cranking of engine in already running condition since negative terminal is not available to the solenoid coil of said starter relay for re- cranking. When the engine is not running there is no voltage in the alternator. While starting the engine positive supply is given to the starter relay, which gets earthed through the alternator, hence the primary circuit is completed and starter motor is switched on through secondary relay circuit.
In case of re-starting attempt on the running engine, when engine starts running thereby induces the movement to alternator through belt. Since alternator is in operation and it is not possible to complete the primary circuit of the starter relay and hence secondary circuit on the starter relay will not operate. This stops the electrical supply to starter motor and it is protected against the possible damages in engine running condition. Once the engine is switched off, the alternator stops functioning and once again the circuit is normalized and can be re-started.
DETAILED DESCRIPTION OF INVENTION
Referring to the drawings wherein the showings are for the purpose of illustrating a preferred embodiment of the invention only, and for the purpose of limiting the same,
Figure-01:- Shows the Engine starter motor protection system for vehicles in accordance with this invention.
Engine starter motor protection system for vehicles ,in accordance with this invention basically comprises ; starter motor (M) for starting the engine mounted on engine


case, starter relay ( R) for transmitting the current supply to said starter motor which is mounted on relay bracket of engine house, ignition switch (K) for cranking engine provided on steering column below the steering wheel, alternator (A) for generating direct current after engine has started which is mounted on engine casing , battery (B) for supplying direct current to said starter motor which is mounted on battery tray in engine house , wherein said starter relay comprises solenoid coil and normally open contact terminal, one end of said starter relay (R) is connected to the battery and other end to the said alternator which is earthed such that after said alternator has started earthing cut off takes place which disables the said primary circuit which prevents the re-cranking of engine in already running condition since negative terminal is not available to the solenoid coil of said starter relay for re- cranking.
Wherein said primary circuit is connected to the negative terminal of said battery through the said alternator for earthing.
Wherein said primary circuit comprises the ignition switch between the said battery and said starter relay for cranking.
Wherein said primary circuit comprises diode (D) between said starter relay and said alternator for preventing return electrical supply form the said starter relay to said alternator.
Wherein said secondary circuit comprises normally open (NO) contact terminal between the said starter motor and said battery for starting the said motor.
Wherein said starter relay is configured to be disabled electrically when engine is running and alternator is functioning.
One end of the starter relay (R) is connected to the negative terminal of the said battery and other end of said starter relay is connected to the said alternator which is earthed, hence constituting the primary circuit.


One end of the normally open (NO) contact terminal (s) is connected to the positive terminal of the said battery (B) and other end of said normally open contact terminal (S) is connected to the starter motor (M) which constitute the secondary circuit.
The said primary circuit comprises ignition switch between the said battery and the said starter relay.
When the engine is not running there is no voltage in the said alternator. While starting the said engine, from the said battery, positive supply is given to the said starter relay (R) which gets earthed through the said alternator hence the said primary circuit is completed and said starter motor is switched on through said secondary circuit.
In case of re-starting attempt on the running engine, when engine starts running thereby induces the movement to alternator through belt. Since alternator is in operative mode that is running mode and it is not possible to complete the said primary circuit of the said starter relay and hence said secondary circuit on the starter relay will not operate. This stops the electrical supply to said starter motor and it is protected against the possible damages in engine running condition. Once the said engine is switched off, the said alternator stops functioning and once again the both primary and secondary circuit is normalized and can be re-started.
The battery (B) fixed on the automobile is used as a source of electrical power when engine is not running. To start the engine the ignition switch (K) is pressed, the electrical supply from the said battery is given to the said starter relay ( R). The said primary circuit is completed through the alternator (A) i.e. starter relay ( R) is earthed connected to negative terminal through the said alternator (A).


The solenoid coil inside the said starter relay gets charged and normally open (NO) contact (S) in the starter relay gets closed and gives power supply from said battery to the starter motor (R) which in turn starts the engine.
Once the engine starts, said alternator (A) starts creating the voltage in the electrical circuit. Thus it not possible to earth said alternator for establishing the negative terminal for the primary circuit on running engine even when ignition switch (K) is pressed since there is a positive terminal available from the said battery.
Thus this invention prevents the possible damage to the starter motor and gear teeth due to its engagement while engine is running.
The foregoing description is a specific embodiment of the present invention. It should be appreciated that this embodiment 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.