BACKGROUND

FIELD OF THE INVENTION

The present invention relates to an Electric Start System for a vehicle with Internal Combustion Engine.

DISCUSSION OF PRIOR ART

Internal Combustion Engines cannot self start unlike steam engines. The crankshaft assembly of the internal combustion engine has to be accelerated to a predetermined speed in order to sustain the combustion process. In vehicles with internal combustion engine either the crankshaft has to be rotated manually (kick starting or hand starting) or an Electric Start is used. Electric Start is an easier way of starting the Internal Combustion Engine (IC Engine) wherein a Starter Motor is energized to drive the crankshaft assembly to the required angular speed.

In an Electric Start System, a battery provides electrical energy required for Starter Motor operation. A Starter Relay connects the battery to the Starter Motor when a predetermined set of conditions are satisfied. For example, in a two-wheeler Electric Start system, the Starter Relay will connect Starter Motor to battery when the ignition switch is ON and engine transmission is in neutral condition. The battery is also responsible for supplying electrical energy to other DC loads. Conventionally, the battery Starter Relay and Starter Motor are mounted in different locations in the vehicle. Although the mounting locations are different, they are located as close as possible in order to reduce the voltage drop in connecting wires. The Starter Motor is mounted in the engine in order to interface with gear train assembly for driving the crankshaft assembly. The Starter Relay and Battery are located in the vehicle chassis close to the engine. The Starter Motor could be either pre-engaged with the gear train assembly or could have Bendix drive connecting the motor to the gear train upon energizing the Starter Motor. With a Bendix drive, the pinion comprising weights move axially along the motor shaft to engage with a mating gear coupled to the crankshaft assembly when motor speed exceeds a predetermined value. The Bendix drive permits one way transmission of power as the pinion would retract back along the motor shaft if the mating gear speed is greater than motor shaft speed. With pre-engaged Starter Motor systems, a one-way clutch ensures one way transmission of power from motor to crankshaft assembly. Some Starter Motors have a solenoid moving the pinion to mesh with the mating gear when Starter Motor is energized.

JP2009030450A titled "Starter Starting Circuit" discloses a Starter Starting circuit in which a Starter Relay is mounted on the Starter Motor and it also performs the solenoid function for axially moving the pinion. But the battery is externally connected in the circuit.

US8035259 titled "Electric motor starting device" describes a method of starting an electric motor having a rotor. The device incorporates air, gas, liquid or electrically actuated engine starter to initiate rotation of an electric motor and its associated driven components. Therefore it provides a method for starting an electric motor whether or not being used to drive any type of mechanical or electrical device.

US7594491 titled "Internal combustion engine start controller" describes an IC engine start controller in a vehicle provided with an internal combustion engine that is started by using the electric power supplied from a power source. It has a first motor and an electric power converter constructed to perform electric power conversion between the power source and the first motor by switching control of power semiconductor elements. The start controller has a start detecting device for detecting whether the engine is in a starting operation and a first frequency setting device. When the engine is in a starting operation, the first frequency setting device sets a switching frequency of the first electric power converter to a frequency lower than that used when the engine is not in a starting operation.

The Electric Start System disclosed according to the present invention comprises a Starter Motor, Starter Relay and Battery housed within a single assembly. Electrical connections between the Battery, Starter Motor and Starter Relay are provided within the housing and only actuating signals from switches or sensors are obtained from outside the Electric Start System housing. The Electric Start System is mounted on the engine.

SUMMARY OF THE INVENTION

The present invention describes an improved electric start system which comprises of a Starter motor, Starter relay and battery within a single housing and as these are close to each other, voltage drop in the high current path is minimized, thereby improving the efficiency of the Electric Start System and reducing the cost of high current wire. The high current connections between the Starter motor, Starter relay and battery are provided within the housing only. The embodiment comprises of a starter motor fitted with a battery pack and starter relay and the actuation signals for the system is provided to the starter relay through the connecting wires. This starter relay connects battery's positive terminal with starter motor positive terminal when a signal is received through a starter relay. Also the housing cover is made of a plastic material like PBT (Poly Butylene Terephthalate) or an alloy which protects the battery and starter relay from being exposed to rain and dust. The battery in the system is a second power source which provides signal to starter relay. It is capable of withstanding engine vibrations and the associated high temperatures.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 illustrates the conventional Electric Start System showing the side view of a two wheeler chassis;

Figure 2 illustrates an improved Electric Start system, according to the present invention;

Figure 3 illustrates the first embodiment of the Electric Start System;

Figure 4 illustrates the first embodiment with a cover;

Figure 5 illustrates the second embodiment of the electric circuit in the vehicle wherein a second battery is used to provide signal to Starter Relay according to the present invention; and

Figure 6 illustrates the second embodiment of electric circuit in the vehicle wherein the battery within the Electric Start System housing provides signal to Starter Relay.

DETAILED DESCRIPTION OF THE ACCOMPANYING EMBODIMENTS

Figure 1 shows the conventional Electric Start System explained using a side view of a two-wheeler chassis 10. An Internal Combustion Engine 30 is mounted on frame 20. The internal combustion engine 30 comprises a Starter Motor 60 for accelerating the crankshaft assembly while starting. A Battery 40 is fitted on the vehicle frame 20 to provide electrical energy to DC loads including Starter Motor 60. A Starter Relay 50 connects the Batteiy 40 to the Starter Motor 60 when a set of predefined conditions are satisfied. A high current cable 70 connects the Starter Relay 50 to the Starter Motor 60. Figure 2 discloses according to the present invention, an Electric Start System 80 which comprises a Starter Motor 100, a Starter Relay 120 and a Battery 110 within a single housing 73. The high current connections 70 between the Starter Motor 100, the Starter Relay 120 and the Battery 110 are provided within the housing 73. The low current connection is indicated as 76. A switch and sensor output 72 required for energizing the Starter Relay 120 are obtained from outside the housing 73. Based on the sensor outputs 72, the Starter Relay 120 connects the Battery 110 to the Starter Motor 100 which in turn drives a crankshaft assembly 71. Figure 3 show a preferred first embodiment of the present invention wherein the Electric Start System 80 comprises a Starter Motor 100 fitted with a battery 110 and a Starter Relay 120. The actuation signal for the Electric Start System 80 is provided to the Starter Relay 120 through connecting wires 130. A Starter Motor pinion 90 will mesh with a mating gear for driving the crankshaft assembly 71. The Starter Relay 120 connects the Battery 110 positive terminal with the Starter Motor 100 positive terminal 140 when appropriate signal is received through the Starter Relay 120 connecting wires 130.

The battery 110, capable of providing sufficient electrical energy for cranking internal combustion engine is connected within the housing 73. The Starter Relay 120 is mounted on the Starter Motor 100 for connecting the positive terminal 140 of the battery 110 to the Starter Motor 100 positive terminal 140 when appropriate signal is provided through the connecting wires 130. Figure 4 shows the preferred embodiment of the present invention along with a cover 150 which protects the battery 110 and Starter Relay 120 from being exposed to rain and dust. For a vehicle with a geared transmission system, it should be possible to crank the engine by electric start when the rider presses the Electric Start (ES switch) button with ignition in ON condition and transmission is in neutral. For a vehicle with Continuously Variable Transmission (CVT) system, it should be possible to crank the engine by electric start when the rider presses the Electric Start button with ignition in ON condition and with either of the brakes applied. Based on these predetermined conditions, an electric circuit will provide signal to connecting wires 130 when Electric Start is required. The electric circuit can either use a second power source (Figure 5) other than the battery 110 or it could use the battery 110 itself (Figure 6).

Figure 5 and Figure 6 represent the electric circuit for vehicle with a geared transmission system. In case of a vehicle with Continuously Variable Transmission (CVT), brake switch will replace the neutral switch. The invention disclosed is for an Electric Start System 80 of a Vehicle with an Internal Combustion Engine. The Electric Start System 80 comprises a Starter Motor 100, Starter Relay 120 and Battery 110 within a single housing. Figure 5 shows an electric circuit in vehicle, wherein a second power source in the form of a battery Vb2 is used to provide signal to the Starter Relay 120 by means of a connector 160. The connector 160 is connected with the Electric Start System 80 by means of connecting wires 130. When the ignition switch (Ig S ) is in ON condition and when ES switch is pressed with transmission in neutral condition then the Ignition switch (Ig Sw), ES switch and Neutral switch are closed. The voltage across battery Vb2 terminals are then applied to the Starter Relay 120 along connector 160 and then wires 130. The Starter Relay 120 then connects the Battery 110 positive terminal 140 to Starter Motor 100 positive terminal 140. The Starter Motor 100 negative terminal is always connected to the Battery 110 negative terminal and hence Starter motor 100 activates to crank the engine.

Figure 6 shows an electric circuit in vehicle wherein the battery 110 within the Electric Start System 80 is used to provide signal to Starter Relay 120. When ignition switch, neutral switch and ES switch are all closed then the battery 110 voltage is applied to Starter Relay 120 which again connects the positive terminal 140 of Starter Motor 100 to positive terminal 140 of Battery 110. The Starter Motor 100 is activated to crank the engine. The Starter Relay 120 and Battery 110 are mounted on the Starter Motor 100 and a cover 150 prevents water and dust from entering into the assembly. The housing cover 150 could be made of a plastic material like PBT (Poly Butylene Terephthalate) or an alloy. The battery 110 is capable of withstanding engine vibrations and the associated high temperatures.

Since the Electric Start System 80 comprises of Starter Motor 100, battery 110 and Starter Relay 120 in a single assembly, vehicle assembly is more convenient. Also as the Starter Motor 100, battery 110 and Starter Relay 120 are close to each other, voltage drop in the high current path is minimized. Thereby Electric Start System 80 efficiency improves and high current wire cost is reduced.