OA19030A - A hybrid vehicle - Google Patents

Abstract

The present invention relates to a control system for a hybrid vehicle and a method thereof. The control system (200) for a hybrid vehicle (100) includes a hybrid control unit (204), an integrated starter generator unit (203),a traction motor (202), and a power source (201). The control system is capable of providing power source to the hybrid control unit (204) and the integrated starter generator (203) through the single power source (201). Further, the control system (200) includes a traction motor (202) and said integrated starter generator unit (203) is controlled by the hybrid control unit (204). The single power source (201) saves resources and results in simpler circuitry that is easier to accommodate in the vehicle.

Description

A HYBRID VEHICLE

Technical Field

[000IJ The présent subject matter relates generally to hybrid vehicles and more particularly, but not exclusively, to a control system to control the hybrid vehicle and a method thereof.

Backgroljnd

[0002] Generally, a hybrid vehicle comprises of an internai combustion (IC) engine and a traction motor for powering the vehicle. The IC engine installed on such hybrid vehicle uses gasoline/fuel as any other conventional IC engine. The traction motor is powered by an on board auxiliary power source. The hybrid vehicle being operated using either the IC engine, or the traction motor, or the IC engine and the traction motor jointly. The user can operate the hybrid vehicle in any one of the three modes as required namely an engine mode, an eiectric mode, and a hybrid mode. The hybrid mode further comprises of a hybrid power mode and a hybrid economy mode. In the hybrid power mode, both the IC engine, and the traction motor set up are operated jointly. In the hybrid economy mode, the IC engine, and the traction motor are operated altematively. If the user wants more power, the vehicle can be operated in the hybrid power mode.

Brief Description of the Drawings

[0003] The detailed description of a hybrid control unit to control the hybrid vehicle of the present subject matter is described with reference to the accompanying figures. Same numbers are used throughout the drawings to reference like features and components.

[0004] Fig. 1 illustrâtes a left side perspective view of a step-through type vehicle in accordance with an embodiment of the present subject matter.

[0005] Fig. 2 illustrâtes a block diagram depicting the working of a hybrid control unit.

[0006] Fig. 3 illustrâtes a circuit diagram of a control system to control a hybrid vehicle in different working modes.

[0007] Fig. 4illustrates a method of operation of HCU powered by a single power source.

Detailed Description

[0008] The insufficiency of non-renewable energy resources has raised for the need to reduce fossil fuel consumption and émissions from vehicies powered by internai combustion engines is well known. One way to achieve the aforesaid goal is through an electrically driven vehicle. However, such a vehicle has greater body weight and shorter running distance per charge as compared to the conventional vehicies. Such drawbacks are overcome by hybrid vehicies, which utilize the advantages of an internai combustion engine and an electric traction motor into one vehicle. They provide great potential for reducing vehicle fuel consumption and émissions with no serious loss of vehicle performance or drivability.

[0009] Typically, an auxiliary power source and an internai combustion (IC) engine power a hybrid vehicle. A starter motor powered by a battery runs the magnéto to start the IC engine. Another battery powers the traction motor responsible for rotation of the rear wheel, i.e., to provide electric, A hybrid control unit controls both the IC engine and the traction motor. The traction motor also generates some power after a battery starts the traction motor. Further, the power generated by the magnéto and the traction motor could be used to power the battery to run the loads directiy. Both the magnéto and the traction motor generate power at higher voltages, at about 48-60V.

[00010] Hence, it is évident that operation of a hybrid vehicle requires two different motors including a traction motor and a starter motor.

[00011] The starter motor required to run the magnéto can be replaced by an integrated starter generator (ISG) that enables smooth starting of the IC engine. The ISG directiy rotâtes the crankshaft, resulting in smooth starting of the IC engine. Hence, ISG in a hybrid vehicle is more désirable.

[00012] The ISG and the traction motor operate at two different voltage levels. Hence, easier operation of the ISG and the traction motor in a hybrid vehicle is achieved by using two different power sources with two different voltage levels.

[00013] But, the dîfficulty involved in two different power sources are, the usage of two different power sources to meet the requîrement of two different voltage levels along with the usage of two different motors calls for a complex circuitry. It becomes a tedious job to accommodate the complex circuitry in the space in the vehicle layout.

[00014] The aforementioned dîfficulty involved in usage of two different power sources operating at different voltages in a hybrid vehicle is overcome according to the proposed invention.

[00015] According to an embodiment of the présent invention, a single power source including an auxiliary power source is used to run both a traction motor and an ISG. In the présent embodiment, the auxiliary power source produces an output of 48V, which is suitable to run the traction motor and the ISG that is operating at I2V. According to an embodiment of the présent invention, the ISG used in the hybrid vehicle includes an inbuilt second controller. The second controller is in the présent embodiment, for example, an ISG controller and an inbuilt DC-DC converter. The second controller is configured to convert the output generated by the ISG. The output of the ISG is converted into desired voltage to enable one or more véhiculât loads. Therefore, accommodating a single power source including an auxiliary power source in the hybrid vehicle becomes comparatively easier. The complex circuitry is prevented leading to a simpler circuitry.

[00016] The présent invention proposes a control System for a hybrid vehicle. According to an embodiment of the présent invention, the control system includes an auxiliary power source capable of drîvîng both traction motor and the ISG. The traction motor and the ISG are controlled through a single controller, namely, a hybrid control unit (HCU). Various véhiculât loads including signaling devices and other similar devices are driven by the output generated by the ISG and are controlled by the HCU. The vehicular loads are provided with converted output voltage generated by the ISG. Hence, a comparatively simpler working of the control system and a simpler circuitry is achieved according to the proposed invention.

(00017] According to an embodiment of the present invention, the auxiliary power source operating at 48V is capable of providing input power to the ISG operating at 12V and to the traction motor operating at 48V. The high voltage is converted by a circuitry before feeding into the ISG. The circuitry includes two power modules comprising one hex bridge configuration for driving the traction motor and a second hex bridge to drive the ISG. The power modules couverts the DC input power from the auxiliary power source into controllable DC output power for driving the traction motor, which is, in the present case a BLDC motor. The DC input side of the first and the second power modules include individual DC link capacitors for flltering and a current sensing resistor for providing the information regarding input power to the traction motor and the ISG. Further, the power electronic switches include one or more internai body diodes for providing a current path during circulation of current when the switches are disabled, Particularly, the power electronic switches are driven through spécifie gâte driver integrated circuits. The gâte driver integrated circuits are further controlled by înputs supplied by a control module.

[00018] Further, the control module comprises of microcontrollers and corresponding power supply modules. Additionally, the inputs from the vehicle operating conditions such as throttie, vehicle speed, engine speed, ignition, brake are fed as analog and digital inputs to microcontroller ports.

[00019] Further, the operating of the traction motor and the ISG are controlled by a closed loop parameters dépendent upon vehicle operating conditions. The input to the traction motor and the ISG are the electrical power fed through controller from the single auxiliary battery. The output of the traction motor and the ISG is mechanical power which is measured in terms of vehicle speed, wheel force, and engine speed and cranking torque respectively.

[00020] Further, in order to control the ISG machine to achieve required carrent, the input voltage fed to the ISG is controlled through puise width modulation switching techniques.

[00021] Furthermore, the duty cycle of the operation of power electronic 5 switches is controlled by monitoring the output speed of the ISG.

[00022] The previously mentioned and other advantages of the present subject matter are described in detail in conjunction with the figures in the following description.

[00023] Fig. 1 illustrâtes a left side view of an exemplary vehicle 100, in accordance with an embodiment of the present subject matter. The vehicle 100 illustrated, has a step-through type frame assembly 105. The step-through type frame assembly 105 includes a head tube 105A, a main frame 105B. One or more rear tube(s) 105C extend inclinedly rearward from the main tube 105B. Further, one or more front suspensions 110A connect a front wheel 110B, and a handlebar assembly HOC fonning a steering assembly 110. The steering assembly 110 is rotatably connected through the head tube 105A. An engine 115 acts as a primary drive means for driving a rear wheel 120. Further, a traction motor 120, acts as a secondary drive means for driving the rear wheel 120. In a preferred embodiment, the traction motor 120 is hub mounted on the rear wheel 125. An on board battery 20 drives the traction motor 120. The engine 115 is mounted to a swing arm 130, which is swingably connected to the main frame 105B using a toggle link. The vehicle 100 is provided with plurality of body panels, mounted to the frame assembly 105, and the plurality of body panels includes a front panel 135A, a leg shîeld 135B, an under seat cover I35C and a pair of side panel 135C.

[00024] A front fender 140 is covering at least a portion of the front wheel 110A.

A floorboard 145 is provided at step-through space provided rearwardly of the handle bar assembly 110C. A seat assembly 150 is mounted to the main frame I05B. A utility box (not shown) is disposed below the seat assembly 150, A fuel tank (not shown) is posîtioned below the utility box. A rear fender 155 is covering at least a portion ofthe rear wheel 125 and is disposed below the fuel tank. One or more rear suspension(s) 160 are provided in the rear portion of the vehicle 100 for comfortable ride. The vehicle 100 comprises of a one or more electrical/electronic load(s) 165 (hereafter referred to as 'load(s)’) including components such as a headlight 165A, a tail light 165B, a transistor controlled ignition (TCI) unit (not shown), an alternator (not shown), and a starter motor (not shown).

[00025] Fig. 2 illustrâtes a block diagram depicting the working of a hybrid control unît. According to an embodiment of the present invention, a battery201 acting as a power source powers two 3-phase machines including a traction motor202 and an integrated starter generator (ISG)203. A hybrid control unit (HCU) 204 controls the working of the traction motor 202 and the ISG 2O3.The HCU 204 controls the traction motor 202 and the ISG 203 through various inputs 205 received by the HCU 204. The various inputs include a throttle position sensor, an ignition lock, a rotation per minute input, a mode switch, and brakes.

[00026] According to an embodiment of the present invention, the battery201 operating preferably at 48V is capable of operating the traction motor202 operating at 48V and the ISG 203 operating at 12V. The ISG 203 generates an output voltage of 12V. The output voltage 12V generated by the ISG 203 is enough to operate the loads 206operating at 12V.

[00027] According to another embodiment of the present invention, the hybrid control unit 204is configured to directly operate the loads 206operating at 12V.

[00028] Sînce, a single power source including the battery 201 is configured to power the traction motor 202 and the ISG 203 in a hybrid vehicle, a simple and cost effective system is obtained.

[00029] Fig. 3 illustrâtes a circuit diagram of a control system to control a hybrid vehicle in different working modes. The control System 200 includes a 48V auxiliary single power source 201, for example, a battery, a rechargeable energy storage system. Further, the control system 200 includes a hybrid control unit 204 comprising a integrated starter generator control module 204b, a traction motor control module 204a, and a DC-DC converter 204c. The integrated starter generator control module 204b is configured to control an integrated starter generator 203 opérable at 48V and capable of producing an output of 12V. The output of 12V so produced by the integrated starter generator 203 is used to power one or more DC loads opérable at l2V.The integrated starter generator 203 is switched ON by the integrated starter generator control 1er 204b whenever the mode switch is chose to be hybrid mode including a hybrid economy mode and a hybrid power mode depending upon the conditions chosen by the user. Further, the control System 200 includes a traction motor 202 controiled by the traction motor control 1er 204a. The traction motor 202, which is opérable at 48V, is powered by the single power source of 48V, particularly during electric mode of the hybrid vehicle and also during hybrid power mode, as and when the user chooses the desired modes through the mode switch. Furthermore, whenever the traction motor 202 is disabled during the hybrid economy mode, it is capable of generating power capable of powering the 48V power source in turn. Furthermore, the DC-DC converter 204c also helps to step down a very high output generated by the traction motor 202 into 12 V DC output that can power one or more DC vehicular loads 206, [00030] According to an embodiment of the present invention, the single power source 201 of 48V is capable of powering the one or more 12V DC vehicular loads 206.

[00031] According to another embodiment of the present invention, the DC-DC controller 204c is not a part of the hybrid control unit 200.

[00032] According to an embodiment of the present invention, the DC-DC controller 204c is an inbuilt part of the hybrid control unit 200,

[00033] Fig. 4 illustrâtes a method of operation of HCU powered by a single power source. According to an embodiment of the present invention, a single power source including a battery powers the traction motor and the integrated starter generator. Firstly, at step 301 the functioning of the hybrid control unit is started, the ignition lock is checked for ON/OFF at step 302. If the ignition switch is ON, then the HCU switches into any one of the three modes of a hybrid vehicle at mode switch 303, the three modes of the hybrid vehicle include an EV mode (electric vehicle mode), a hybrid mode, and an engine mode. The hybrid mode further includes a hybrid economy mode and an hybrid power mode, which may be selected by the user depending upon the conditions provided. Whenever the vehicle is working in an electric mode as indicated in step 304, the HCU checks for throttle position sensor (TPS) to be greater than a pre-determined number as indicated in step 305. Ifthe TPS reads as greater than 5%, then the traction motor is turned ON by the HCU, the traction motor is powered by a single power source as indicated in step 3O7.The output of the traction motor is used to run the loads operating at 12 volts as indicated in the step 308. Further, if the detected mode switch is not electric mode in step 304, then the vehicle opérâtes in either hybrid mode or engine mode. Ifthe mode switch selected is for hybrid mode as indicated in step 306, then the vehicle is operated under the hybrid economy mode as indicated in step306a, then the TPS is checked by the HCU. If the reading of the TPS is greater than 5% as indicated in step 309, then the traction motor is powered by a single power source through an HCU as indicated in step 310. Further, if the speed of the vehicle exceeds a predetermined value, for example 25kmph as indicated in step 311, then the engine is started through the single power source and the running traction motor is stopped as indicated in step 312. Once, the engine starts running, the power generated by the engine operation is used to power the 12V loads as indicated in step 313.

[00034] Further, after the mode switch is selected for hybrid mode as indicated in step 306 and not for hybrid economy mode, then the hybrid power mode is selected as indicated in step 314. Under the hybrid power mode, the TPS is checked, if the TPS is greater than 5%, then the HCU activâtes powering of the 1SG and also the traction motor simultaneously through the single power source as indicated in step

315. Further, after the génération of power begins through the ISG and the traction motor, the so generated power is used to power the 12V loads as indicated in step

316.

[00035] If the mode switch selected is not a hybrid mode, then engine mode is selected. Further, the TPS is constantly monîtored. If the TPS is greater than 5% as indicated in step 317, then the engine of the vehicle is started by powering the ISG from the single power source through HCU as indicated in the step 318. Further, 5 the power generated by the ISG is capable of running the I2V loads in the vehicle.

In this step, both the engine and the traction motorare started using a single power source. The power generated is used to operate the 12V loads as indicated in step 315.

[00036] According to another embodiment of the present invention, the hybrid 10 control unit 204 is configured to directly operate the loads 206 operating at 12V.

[00037] Since, a single power source including the battery 201 is configured to power the traction motor 202 and the ISG 203 in a hybrid vehicle, and a single hybrid control unit is configured to control the traction motor 202 and the ISG 203, a simple and cost effective System is obtained.

Although the subject matter has been described in considérable detail with reference to certain embodiments thereof, other embodiments are possible. It is to be understood that the aspects of the embodiments are not necessarily limited to the features described herein.

Claims (13)

1. I/We claim:

   1. A hybrid vehicle (100) comprising:

   a control system (200) for controlling said hybrid vehicle, said control System including a hybrid control unit (HCU) (204) to enable switching between different working modes of said hybrid vehicle (100), an integrated starter generator (ISG) (203) coupled to an internai combustion engine (115) of said hybrid vehicle (203), a traction motor (202) capable of driving said hybrid vehicle (100) independently and in combination with said internai combustion engine (115), and a power source (201), wherein, said traction motor (202) and said integrated starter generator unit (203) both receive power supply from said power source (201) and said traction motor (202) and said integrated starter generator (203) are controlled by said hybrid control unit(204).
2. 2. The hybrid vehicle (100) as claimed in claim 1, wherein said integrated starter generator (203) is configured to independently power the one or more vehicular loads (206).
3. 3. The hybrid vehicle (100) as claimed in claim 1, wherein said traction motor (202) is capable of powering said one or more vehicular loads (206) through said hybrid control unit (204).
4. 4. The hybrid vehicle (100) as claimed in claim 1, wherein said traction motor (202) is capable of powering the power source (201) during génération of said traction motor (202).
5. 5. The hybrid vehicle (100) as claimed in claim 1, wherein said hybrid control unit (204) includes an inbuilt DC-DC converter (204c).
6. 6. The hybrid vehicle (100) as claimed in claim 1, wherein said power source (201) produces an output of 48V, said output of 48V is fed to said ISG (203) operating at 12V through a circuitry including at least one hex bride capable of driving said traction motor (202) and a second hex bridge configured to drive said ISG (203).
7. 7. The control system (200) for a hybrid vehicle (100) as claimed in claim 1, wherein said power source (201) is an on-board battery.
8. 8. The control system (200) for a hybrid vehicle (100) as claimed in claim 2, wherein said one or more loads (206) includes a headlight (165a), a tail light (165B), a transistor controlled ignition unit, an altemator, and a starter motor.
9. 9. A method to control a hybrid vehicle (100), said method comprising steps of:

   monitoring (302) an ignition switch state and a throttle position sensor status by a hybrid control unit (204);

   switching (303) to any one of three modes of said hybrid vehicle (100) through said HCU (204), if status of ignition lock is ON through a mode switch (303);

   switching ON a traction motor (308) if EV mode is selected through said HCU (204) and if the TPS is greater than a predetermined value;

   switching to hybrid mode (306) through said HCU (204) and if TPS is greater than a predetermined value and if speed is greater than a predetermined value;

   switching to engine mode (320) through said HCU (204) if said EV mode (304) and said hybrid mode(306) are not detected; and enabling one or more vehicular loads thorough said power source (201) if any one of the three modes is selected through said HCU (204).
10. 10. The method to control a hybrid vehicle (100) as claimed in claim 9, wherein said hybrid control unit (204) checks for throttle position sensor to be greater than a pre-determined number as indicated in step (305), whenever the vehicle is working în an electric mode as indicated in step (304).
11. 11. The method to control a hybrid vehicle (100) as claimed in claim 9, wherein said hybrid control unit (204) checks for TPS to be greater than 5% as indicated in step (309) to power the traction motor (202) by a single power source (201) if the mode switch selected is for hybrid mode economy mode as indicated in step (306a).
12. 12. The method to control a hybrid vehicle (100) as claimed in claim 9, wherein said power source (201) is configured to power an engine (115) by powering said integrated starter generator (203) and also enable said traction motor (202) through said hybrid control unit (204) if speed of the vehicle exceeds a predetermined value of 25 Kmph as indicated in step (314) under hybrid power mode.
13. 13. The method to control a hybrid vehicle (100) as claimed in claim 9, wherein said mode switch (303)switches to an engine mode(320) if the modes selected are not electric mode (304) and not hybrid mode (306), said hybrid control unit (204) monitors TPS as indicated in step (317) and if TPS is greater than a predetermined

    value, then only said engine (115) is activated by powering said integrated starter generator (203) through said power source (201).