WO2022208524A1

WO2022208524A1 - A start stop system

Info

Publication number: WO2022208524A1
Application number: PCT/IN2022/050234
Authority: WO
Inventors: Karuppusamy Sakthivel; Ranganathan VINOTH BALARAM; Abirami M; Nagarjun Reddy M
Original assignee: Tvs Motor Company Limited
Priority date: 2021-03-31
Filing date: 2022-03-13
Publication date: 2022-10-06

Abstract

An engine start-stop system comprising an integrated starter generator machine (102), a starter switch (105), an ignition control unit (110), an ignition switch (106), and a kill relay (109). The starter switch is configured to operate the integrated starter motor generator. The ignition control unit controls spark provided to an engine (101). The ignition switch operates the ignition control unit. The kill relay controls the power supply to the ignition control unit, wherein the kill relay is configured to be operated to bring the engine in an OFF state in idle condition. It ensures that provide a start stop system which economizes the fuel efficiency. It also ensures that the engine is switched off in idling condition or while in traffic but allows other essential loads to be operative without increasing the part count, weight, and cost of the vehicle, making it more reliable and safer to operate.

Description

A START STOP SYSTEM

TECHNICAL FIELD

[0001] The present subject matter relates generally to a start stop system. More particularly but not exclusively the present subject matter relates to an engine start stop system of a vehicle. BACKGROUND

[0002] Traditionally, an internal combustion (IC) engine runs on fossil fuels to drive a vehicle. The ever-increasing crisis and the increasing cost of the fossil fuels has led to the demand of the vehicles with better fuel economy. Also, burning more fuel adds more undesirable gases in the environment. In order to meet the ever- increasing expectation on better fuel economy in IC engines-based vehicles, it is necessary to optimize one or more loads and engine operating duration in the vehicle. Also, fuel economy largely depends on the driving conditions, a lot of fuel is used in engine idling condition, when a user is waiting in traffic conditions. To ensure that the fuel is used judiciously without wasting, a suitable engine shut-off mechanism during the idling condition is required for improving the fuel efficiency of the vehicle.

BRIEF DESCRIPTION OF THE DRAWINGS [0003] The details are described with reference to an embodiment of a three wheeled vehicle along with the accompanying block diagrams. The same numbers are used throughout the drawings to reference similar features and components. [0004] Figure 1 exemplarily illustrates a block diagram for a conventional start stop system of the vehicle. [0005] Figure 2 exemplarily illustrates a mounting arrangement of different elements of the start stop system in the three-wheeled vehicle with frame layout and all panels omitted. [0006] Figure 3 exemplarily illustrates a mounting arrangement of a sub-assembly of the start stop system at a rear portion of the three-wheeled vehicle with frame layout and all panels omitted.

[0007] Figure 4 exemplarily illustrates a block diagram of the start stop system of the vehicle.

[0008] Figure 5 exemplarily illustrates a a flow diagram of a start stop system of the vehicle.

DETAILED DESCRIPTION

[0001] Generally, vehicle fuel economy is a very important aspect to be considered, while buying a vehicle by a user. Most importantly, fuel economy becomes more crucial parameter for those users whose livelihood depends on the vehicle wherein the vehicle is used for commercial transportation. Further, the increasing cost of fossil fuels has created an urgent need to look for ways to economize the fuel used in the vehicles. There are many mechanisms available to switch off the vehicle, when not in use or when the vehicle is in idling condition to save fuels. Many conventional designs comprise of a mechanical starter motor system to switch OFF the vehicle. But in the above-mentioned system, it is difficult to achieve sufficient frequency for ON-OFF cycles required to crank the engine. Therefore, the user has to make a lot of attempts in order to start or crank the engine. Apart from this, the existing mechanical starter motor system includes a number of mechanical parts which makes it slower, bulky and costly.

[0002] In another existing starter motor system, a number of manually operating switches are utilized. This design mainly comprises of two or more switches, one of which is used to start the vehicle and the other is used to stop the vehicle. This is confusing to the user because the user has to operate multiple switches to turn on and turn off the engine while driving the vehicle, and it becomes even more difficult task when the user is stuck in traffic which requires quick and careful movements of the vehicle. In another type of starter motor system, the vehicle is provided with a manual or an automatic start stop system configured to switch off the vehicle entirely. In such systems, when the vehicle engine is turned off during idle condition or in traffic, other vehicle loads such as a head lamp, one or more tail lights, one or more indicators, and the like are also switched off. This causes the problem of complete vehicle shut down and it becomes extremely difficult for the user at night without any form of illumination and thus increases the chances of an accident. [0003] Figure 1 illustrates a block diagram for a conventional start stop system of the vehicle as per a known art. An engine (101) is integrally connected to an integrated starter generator unit (102). The integrated starter generator unit is electronically connected to a control unit (103). The control unit (103) is a microcontroller which generates signals to communicate electronically. The control unit (103) is mounted onto a cabin (not shown) for support and connectivity. The control unit (103) is further connected to a battery unit (104) which is mounted at a portion on a chassis (not shown) of the vehicle. The battery unit controls one or more DC loads (108). The one or more DC loads (108) includes one or more battery-controlled headlamps, one or more tail lights, one or more indicators and the like. The control unit (103) is further electronically configured to control and crank the engine (101) of the vehicle by communicating electronically with an electric start switch (105), an ignition switch (106) and an ignition control unit (107). The electric start switch (105) is configured to be turned ON by pressing or pushing to start the engine (101) of the vehicle. The ignition switch (106) is configured to be turned ON to start the ignition of the engine (101) of the vehicle. The ignition control unit (107) is configured to be electronically controlled by the control unit (103) to send signal to either supply fuel to start the engine (101) or otherwise. In this system, once the control unit (103) does not send any signal to the ignition control unit (107), the vehicle goes into an Off condition and the engine (101) of the vehicle along with the DC loads (108) are turned off. This causes inconvenience to the rider while riding at night time on the road.

[0004] Additionally, in vehicles having an integrated starter generator system, an ignition part of the vehicle is controlled by means of a controller like an Electronic Control Unit (ECU). So, in order to switch-off the engine, the control unit has to cut-off the fuel or ignition supply to the engine. This communication of cutting-off the fuel or ignition is achieved mainly by a CAN communication or by means of different similar logics. The CAN communication has many controllers, switches and costly buses making the overall system costly. But the CAN communication is very sensitive to improper wiring, noise, and incorrect termination. The CAN communication can send a false signal because of lots of noise in its vicinity as it will get confused with multiple frequencies being received on a same bus, leading to malfunction of the system. Also, now-a-days, it has become easy to corrupt the CAN system by an ill motive person, making the CAN data insecure and prone to theft. Additional electronic components must be added to the CAN Communication system to suppress the noise which makes the entire system bulky and costly. [0005] Also, a typically known start stop system comprises of a starter motor system which gives the ECU a very low current input of 4-5 A. However, a higher current input of approximately 20A is required to crank the engine for better starting ability. Hence, additional electronic equipment is required to provide the sufficient current to crank the engine which adds additional cost to the design. Although in this conventional design, the automatic start stop mechanism can efficiently work, but these automatic start stop mechanisms are extremely expensive. Thus, there is a need for a manual start stop system for an integrated starter generator machine which can economize the fuel efficiency of the vehicle, is simple as well as cost effective. The system should include lesser mechanical parts, be safe and not prone to be affected from external noises. Also, an alternate cost effective, reliable and efficient design of a start stop mechanism is desirable which is easy to use by the user.

[0006] An objective of the present subject matter is to provide an improved start stop system which can economize the fuel efficiency. The present invention also ensures that the engine is switched off in idling condition or while in traffic but allows other essential loads to be operative without increasing the part count, weight, and cost of the vehicle. It also ensures the safety of the user and the system. The present subject matter is described using an exemplary three-wheeled vehicle, whereas the claimed subject matter is applicable to any type vehicles, with required changes and without deviating from the scope of invention. [0007] As per an object of the present invention, the present subject matter discloses an improved start stop mechanism configured for an idling condition of the vehicle to economize fuel consumption.

[0008] It is another object of the present invention to provide a manual start stop mechanism with a single switch for better accessibility and comfort.

[0009] As per an aspect of the present subject matter, a method of manual start stop mechanism to start and stop an engine in an idle condition is disclosed. The method includes the steps of pressing an electric start switch by a user to send a first signal to an ISG control unit to activate a kill relay in a vehicle ON condition; and pressing the electric start switch by the user to send a second signal to the ISG control unit to deactivate the kill relay based on the vehicle being in an idle condition.

[00010] As per an aspect of the present subject matter, the method of manual start stop mechanism includes the steps of comparing, upon receiving the second signal by the ISG control unit, an engine RPM value to a predetermined RPM value; verifying a time duration for which the electric start switch is pressed to generate the second signal and comparing said time duration with a predetermined time duration; and switching OFF the kill relay by the ISG control unit, if the engine RPM being less than or equal to a predetermined engine RPM and the time duration of pressing the electric start switch is more than or equal to the pre-determined time duration, to shut down the engine.

[00011] As per an aspect of the present subject matter, the method of manual start stop mechanism includes keeping ON the kill relay by the ISG control unit, based on verification of the engine RPM is more than the predetermined engine RPM or the time duration of pressing the electric start switch is less than the pre-determined time duration, to continue running the engine.

[00012] As per an aspect of the present subject matter, the method of manual start stop mechanism includes pressing the electric start switch by the user to send a third signal to the ISG control unit to activate the kill relay to restart the engine, wherein the third signal is generated when the electric start switch is pressed during the idle condition when the engine is in OFF state. [00013] As per an aspect of the present subject matter, the method of manual start stop mechanism includes the vehicle starting condition defined as pressing the ignition switch by the user to start the vehicle and to activate the kill relay; pressing the electric start switch by the user for the first time, to generate the first signal; and pressing the electric start switch by the user for the second time or a plurality of times, to generate the second signal.

[00014] As per another aspect of the present subject matter, a start-stop system for an engine of a vehicle is disclosed. The start-stop system comprising an integrated starter generator machine, a starter switch, an ignition control unit, an ignition switch, and a kill relay. The starter switch is configured to operate the integrated starter motor generator. The ignition control unit configured to control ignition of said engine. The ignition switch is configured to operate the ignition control unit. A manual start stop mechanism being configured to bring the engine to an OFF state when in idle condition. [00015] As per an aspect of the present subject matter, the integrated starter generator machine is controlled by an integrated starter generator (ISG) control unit. The control unit is attached on a cabin, in the proximity of an engine of a vehicle.

[00016] As per an aspect of the present subject matter, the integrated starter generator machine is configured to be controlled by a manual start stop mechanism. [00017] As per an aspect of the present subject matter, the manual start stop mechanism comprises of an electric start switch and a kill relay. The kill relay is configured to start and stop the motion of the engine, based on the electric start switch operation. [00018] As per an aspect of the present subject matter, the manual start stop mechanism is configured to selectively shut off the engine by means of the kill relay and one or more remaining electrical loads to remain in working condition.

[00019] As per an aspect of the present subject matter, in the idle condition, the ISG control unit is configured to control the start or stop of the integrated starter generator machine, based on the inputs of the electric start switch and an engine RPM input. [00020] As per another aspect of the present subject matter, the integrated starter generator machine is switched ON from an OFF condition, when the kill relay switch is activated once.

[00021] As per another aspect of the present subject matter, the integrated starter generator machine is switched OFF from an ON condition, when the kill relay switch is activated when a user holds the kill relay for a predetermined duration of time.

[00022] As per another aspect of the present subject matter, the kill relay configured to be mounted on the engine to maintain a smaller distance between the engine and the kill relay.

[00023] As per another aspect of the present subject matter, the kill relay is configured to control an ignition coil or TCI (Transistor Controlled Ignition) system or a fuel pump to switch OFF the engine.

[00024] As per another aspect of the present subject matter, the kill relay is configured to switch OFF the engine by disabling one or more of an ignition coil input, a fuel injector input, an ECU or a TCU.

[00025] As per another aspect of the present subject matter, the manual start stop mechanism can be operated using one of a key, a switch, a touch signal or any other manual intervention mechanisms. The embodiments of the present invention will now be described in detail with reference to an embodiment in three wheeled vehicle along with the accompanying drawings. However, the present invention is not limited to the present embodiments. The present subject matter is further described with reference to accompanying figures. It should be noted that the description and figures merely illustrate principles of the present subject matter. Various arrangements may be devised that, although not explicitly described or shown herein, encompass the principles of the present subject matter. Moreover, all statements herein reciting principles, aspects, and examples of the present subject matter, as well as specific examples thereof, are intended to encompass equivalents thereof.

[00026] Fig.2 exemplarily illustrates a mounting layout design of different elements of the start stop system in the vehicle as per the present subject matter. Fig.3 exemplarily illustrates a mounting configuration of a sub-assembly of the start stop system at a rear portion of the vehicle as per the present invention. Fig.2 and Fig. 3 shall be discussed together. In the present embodiment, the start-stop system includes an engine 101, an integrated starter generator machine 102, an ignition control unit 110, an ignition switch 106, an electric start switch (also referred as activator) 105, and a kill relay 109. The engine 101 is integrally connected to the integrated starter generator machine 102. The integrated starter generator (ISG) machine (hereinafter referred as ISG machine) 102 is electronically connected to an integrated starter generator (ISG) control unit 103 (hereinafter referred as ISG control unit) disposed at the rear compartment of the vehicle on at least one of the vehicle body portion. The ISG control unit 103 is a microcontroller which generates signals to communicate electronically with the ISG machine 102. The ISG machine 102 and the ISG control unit 103 are mounted onto a cabin of a three-wheeled vehicle for support and connectivity. The ISG control unit 103 is disposed in the rear cabin (not shown) and is supported by the back of a passenger seat assembly 111 of the three-wheeled vehicle (not shown). The ISG control unit 103 is further connected to one or more battery unit 104 (shown in fig.2) which is mounted on a portion of a chassis of the three-wheeled vehicle. The battery unit 104 supplies power to one or more DC loads 108 for their operation. The one or more DC loads 108 (shown in fig.2) which includes one or more battery-controlled headlamps, one or more tail lights, one or more indicators, and the like. The ISG control unit 103 is configured to be electronically connected to the kill relay 109. The integrated starter generator machine 102 is mounted on a crankshaft (not shown) and the integrated starter generator machine 102 consists of a permanent magnet rotor (not shown), a stator (not shown), one or more pulsar coil assembly (not shown), and the like. The ISG control unit 103 further consists of a microcontroller, one or more semiconductor components and one or more power electronic devices. The ignition switch 106 and the electric start switch 105 are mounted on a dashboard assembly (not shown) in the three-wheeled vehicle. The kill relay 109 and the ignition control unit 110 are mounted in the rear portion of the cabin, more specifically the kill relay and the ignition control unit 110 are disposed on the engine 101 to maintain a smaller distance between the engine 101 and the kill relay 109. In an embodiment, a relay main contactor 109 which is used to provide power connection from the battery unit 104 to the control unit 103 is located at rear end of the vehicle . Location of the relay main contactor 109 and a fuse assembly (not shown) is at rear end of the vehicle, inside the cabin (not shown) and in front of a rear tail door (not shown). [00027] Fig.4 exemplarily illustrates a block diagram of the start stop system of the vehicle. The ISG machine 102 can work both as a starter motor and as a starter generator. The integrated starter generator machine 102 is configured to work as a starter motor when power supply is given from the battery unit 104 through the ISG control unit 103. The ISG machine 102 work as a generator when power supply from the battery is disabled to the ISG machine 102 and the ISG machine 102 generates power which may be used to charge one or more of a battery 104 and run one or more of electrical loads 108 of the vehicle. The ISG control unit 103 is configured to make the decision that whether the ISG machine 102 has to function like a starter or a generator. In generator mode, the ISG control unit 103 is configured to regulate the generated voltage from the ISG machine 102 to a predetermined value and rectify the same from alternate current to direct current. The electric start switch 105 is configured to give a start signal and stop signal input to the ISG control unit 103. The ignition switch 106 is configured to switch ON/ OFF the power to the ISG control unit 103. The ignition control unit 103 is configured to control the spark to the engine 101. The kill relay 109 is configured to control the power supply to the ignition control unit 110. The ISG control unit 103 aids in switching from an operating mode to a generating mode during an idle condition of the vehicle. The ISG machine 102 is configured to send signal to the kill relay 109 and the kill relay 109 further sends this signal to the ignition control unit 110 to turn off the engine 101, during idling condition or when the user is standing still with the vehicle in traffic conditions, etc.

[00028] Fig.5 illustrates a flow diagram of a start stop system of the vehicle. The present embodiment provides a method of switching mechanism to turn ON or OFF the engine 101 manually. The method of manual start stop mechanism to start and stop an engine in an idle condition is disclosed. The ISG control unit 103 is configured to control the start or stop of the integrated starter generator machine 102, based on the inputs of the ignition switch 106 and the engine 101 RPM input When the ignition switch 106 of the vehicle is turned ON at step 201 by a user, vehicle is switched ON at step 202, a first signal is sent to the ISG control unit 103 and the power from battery unit 104 is supplied to the ISG control unit 103. When the electric start switch 105 is pressed once by the user at step 202 of the vehicle the ISG control unit 103 is configured to supply power to ISG machine 102 to start the engine 101 at step 203. The method includes the 1^st step 201 to switch ON the ignition switch to generate the first signal, the 2^nd step includes of pressing the electric start switch 105 by the user to send the first signal to the ISG control unit 103 to activate the kill relay 109 in a vehicle starting condition, and to start the engine 101 at step 203. Upon pressing and holding the electric start switch 105 for a second time by the user, the ISG control unit 103 then verifies at step 204 a time duration for which the electric start switch 105 is pressed to generate the second signal and compares said time duration with a predetermined time duration. Then, a second signal is sent to the ISG control unit 103 at step 204 to deactivate the kill relay 109 if the vehicle is in an idle condition. The ISG control unit 103 compares at step 205, upon receiving the second signal, an engine RPM value to a predetermined RPM value. Further, the ISG control unit 103 switches OFF the kill relay 109 at step 206, if the engine RPM being less than or equal to a predetermined engine RPM and the time duration of pressing the electric start switch 105 is more than or equal to the pre-determined time duration, to shut down the engine 101. The ISG control unit 103 keeps ON the kill relay 109, if either the engine RPM being more than the predetermined engine RPM or the time duration of pressing the electric start switch 105 is less than the pre-determined time duration, to continue running the engine 101. The user has to press the electric start switch 105 again to send a third signal to the ISG control unit 103 at step 207 to activate the kill relay 103 to restart the engine 101, wherein the third signal is generated when the electric start switch 105 is pressed during the idle condition when the engine 101 is OFF. The vehicle starting condition is defined as pressing the ignition switch 106 by the user to start the vehicle and to activate the kill relay 109; pressing the electric start switch 105 by the user for the first time, to generate the first signal; and pressing the electric start switch 105 by the user for the second time or a plurality of times, to generate the second signal.

[00029] The manual start stop mechanism is configured to selectively shut off the engine 101 by means of the kill relay 109 and one or more remaining load supplies 108 like one or more headlights, one or more indicators, and the like to remain in working condition. The engine 101 is switched OFF by cutting the fuel supply or spark to the engine 101 by the ISG control unit 103, through the starter switch 105 input, however, the power from the one or more battery unit 104 is supplied to the one or more DC loads 108 by a different control unit (not shown). In an embodiment, the kill relay 109 is configured to control an ignition coil or TCI (Transistor Controlled Ignition) system or a fuel pump 107 to switch OFF the engine. In an embodiment, the kill relay 109 is configured to switch OFF the engine by disabling an ignition coil input (not shown). In another embodiment, the kill relay 109 is configured to switch OFF the engine 101 by disabling the fuel injector input 107. In yet another embodiment, the kill relay 109 is configured to switch OFF the engine 101 by sending a switching OFF signal to an ECU or a TCU 107. In an embodiment, the manual start stop mechanism can be operated using one of a key, a switch, a touch signal or any other manual intervention mechanisms. Many other improvements and modifications may be incorporated herein without deviating from the scope of the invention.

Claims

We claim:

1. A method of manual start stop mechanism to start and stop an engine (101), in an idle condition, the method comprising the steps: pressing an electric start switch (105) by a user to send a first signal to an ISG control unit (103) to activate a kill relay (109) in a vehicle ON condition; and pressing the electric start switch (105) by the user to send a second signal to the ISG control unit (103) to deactivate the kill relay (109) based on the vehicle being in an idle condition.

2. The method of manual start stop mechanism as claimed in claim 1, wherein the method comprising the steps of: comparing, upon receiving the second signal by the ISG control unit (103), an engine (101) RPM value to a predetermined RPM value; verifying a time duration for which the electric start switch (105) being pressed to generate the second signal and comparing said time duration with a predetermined time duration; and switching OFF the kill relay (109) by the ISG control unit (103), if the engine RPM being less than or equal to a predetermined engine RPM and the time duration of pressing the electric start switch (105) being more than or equal to the pre-determined time duration, to shut down the engine

(101).

3. The method of manual start stop mechanism as claimed in claim 2, wherein the method comprises the step of: keeping ON the kill relay (109) by the ISG control unit (103), based on verification of the engine RPM being more than the predetermined engine RPM or the time duration of pressing the electric start switch (105) being less than the pre-determined time duration, to continue running the engine

(101).

4. The method of manual start stop mechanism as claimed in claim 1, wherein the method comprises the step of: pressing the electric start switch (105) by the user to send a third signal to the ISG control unit (103) to activate the kill relay (109) to restart the engine (101), wherein the third signal being generated when the electric start switch (105) being pressed during the idle condition when the engine (101) being in an OFF state.

5. The method of manual start stop mechanism as claimed in claim 1, wherein the vehicle starting condition defined as: pressing the ignition switch (106) by the user to start the vehicle and to activate the kill relay (109); pressing the electric start switch (105) by the user for the first time, to generate the first signal; and pressing the electric start switch (105) by the user for the second time or a plurality of times, to generate the second signal.

6. A start-stop system for an engine of a vehicle comprising: an integrated starter generator machine (102); a starter switch (105), the starter switch (105) configured to operate the integrated starter generator machine (102); an ignition control unit (110), the ignition control unit (110) configured to control ignition of said engine (101); an ignition switch (106), the ignition switch (106) configured to operate the ignition control unit (110); and a manual start stop mechanism configured to bring the engine (101) to an OFF state when in an idle condition.

7. The start-stop system as claimed in claim 6, wherein the integrated starter generator machine (102) being controlled by an integrated starter generator (ISG) control unit (103), the ISG control unit (103) being attached on a cabin (not shown), in the proximity of the engine (101) of a vehicle (not shown).

8. The start-stop system as claimed in claim 64, wherein the integrated starter generator machine (102) being configured to be controlled by a manual start stop mechanism.

9. The start-stop system as claimed in claim 6, wherein the manual start stop mechanism comprising an electric start switch (105) and a kill relay (109), the kill relay (109) being configured to start and stop the motion of the engine (101), based on the electric start switch (105) operation.

10. The start-stop system as claimed in claim 9, wherein the manual start stop mechanism being configured to selectively shut off the engine (101) by means of the kill relay (109) and one or more remaining electrical loads

(108) to remain in working condition.

11. The start-stop system as claimed in claim 6, wherein in the idle condition, the ISG control unit (103) being configured to control the start or stop of the integrated starter generator machine (102), based on the inputs of the electric start switch (105) and an engine (101) RPM input.

12. The start-stop system as claimed in claim 6, wherein the integrated starter generator machine (102) being switched ON from an OFF condition, when the kill relay (109) switch being activated once.

13. The start-stop system as claimed in claim 6, wherein the integrated starter generator machine (102) being switched OFF from an ON condition, when the kill relay (109) switch being activated when a user holds the kill relay

(109) for a predetermined duration of time.

14. The start-stop system as claimed in claim 6, wherein the kill relay (109) being configured to be mounted on the engine (101) to maintain a smaller distance between the engine (101) and the kill relay (109).

15. The start-stop system as claimed in claim 6, wherein the kill relay (109) being configured to control an ignition coil or TCI (Transistor Controlled Ignition) system or a fuel pump (107) to switch OFF the engine (101).

16. The start-stop system as claimed in claim 15, wherein the kill relay (109) being configured to switch OFF the engine (101) by disabling one or more of an ignition coil input (not shown), a fuel injector input (not shown), an ECU or a TCU (107). 17. The start-stop system as claimed in claim 6, wherein the manual start stop mechanism can be operated using one of a key, a switch, a touch signal or any other manual intervention mechanisms.