Claims:We Claim;
1. A thermal management system (300) for a motor vehicle (100), said thermal management system (300) comprising:
a controller (302), a temperature sensor (303) and an ignition system (303);
said controller (302) receives at least one or more input signal from said temperature sensor (303 ) as well as a power unit (125) of said motor vehicle (100) said controller (302) determines one or more output ignition timing of said ignition system (301 ) based on at least one or more input signals; and
said one or more ignition timing includes a standard ignition timing and a modified ignition timing, said ignition timings are cyclically activated based on inputs received from said at least one or more input signals .
2. The thermal management system (300) as claimed in claim 1, wherein said power unit (125) provides power unit load and power speed as said input to said controller (302).
3. The thermal management system (300) as claimed in claim 1, wherein said temperature sensor (303) senses temperature of said power unit (125) of said motor vehicle (100) and provide as said input to said controller (302).
4. A method for thermal management of a power unit of a motor vehicle with a thermal management system, said method for said vehicle comprising;
starting of a vehicle;
sending temperature of said power unit sensed by a temperature sensor to a controller;
sending power unit speed and power unit load of said power unit to said controller;
analyzing received input signals by said controller;
determining whether said temperature of said power unit is less than threshold temperature of said power unit stored in said controller;
activating standard ignition timing of ignition system;
activating modified ignition timing when said temperature of said power unit more than said threshold temperature of said power unit stored in said controller;
sending said temperature of said power unit sense by a temperature sensor to said controller;
5. A thermal management system (300) for a motor vehicle (100), said thermal management system (300) comprising:
a controller (302), an ignition system ( 301);
said controller (302) receives at least one or more input signal from a power unit (125) of said motor vehicle (100) and an instrument cluster (401) of said motor vehicle and determines one or more output ignition timing of said ignition system (301 ) based on at least one or more input signals; and
said one or more ignition timing includes a standard ignition timing and a modified ignition timing, said ignition timings are cyclically activated based on inputs received from said at least one or more input signals .
6. The thermal management system (300) as claimed in claim 5, wherein said instrument cluster (401) provide input as a duration of operation of said vehicle to said controller (302).
7. The thermal management system (300) as claimed in claim 5, wherein said power unit (125) provides power unit load and power speed as said input to said controller (302).
8. A method for thermal management of a power unit of a motor vehicle with a thermal management system, said method for said vehicle comprising;
starting of a vehicle;
sending duration of operation of said vehicle detected by instrument cluster to a controller;
sending power unit speed and power unit load of said power unit to said controller;
analyzing received input signals by said controller;
determining whether said duration of operation of said vehicle less than threshold duration of operation of said vehicle stored in said controller;
activating standard ignition timing of ignition system;
activating modified ignition timing when said duration of operation of said vehicle more than threshold duration of operation of said vehicle stored in said controller;
sending said duration of operation of said vehicle to said controller. , Description:TECHNICAL FIELD
[0001] The present subject matter relates to a motor vehicle. More particularly, the present subject matter relates to thermal management of a power unit of the motor vehicle.
BACKGROUND
[0002] In a saddle ride type vehicle, a power unit either is mounted or is low slung to a frame assembly of the vehicle. Moreover, in a scooter type vehicle with a step through type portion, the power unit is swingably mounted to the frame assembly through damping members, which are typically suspensions. Generally, the power unit of the vehicle is operated in a high temperature state. The high temperature state is caused due to generation of heat. The generation of heat happens or takes place because of friction of each moving part and combustion inside the power unit. In this regard, lubricating oil is used for lubricating the moving parts in the power unit. This results in low friction characteristics at high temperature, which enables higher fuel efficiency . However, when the power unit is heated up above a predetermined temperature because of overheating of the components of the power unit, it increases risk of damaging of moving parts due to mechanical contact, surface wear and tear. Hence, there is a constant drive from manufacturers to avoid overheating of the power unit.
BRIEF DESCRIPTION OF THE DRAWINGS

[0003] The detailed description is described with reference to an embodiment in a type step thru type two wheeled vehicle along with the accompanying figures. The same numbers are used throughout the drawings to reference like features and components.
[0004] Fig.1 is a side view of a straddle type vehicle as per one embodiment of the present invention.
[0005] Fig.2 is a perspective view of a power unit as per one embodiment of the present invention.
[0006] Fig.3 is a block diagram of a thermal management system having sensor as per one embodiment of the present invention.
[0007] Fig. 3a is a flow chart as per one embodiment of the present invention.
[0008] Fig. 4 is a block diagram of a thermal management system with an instrument cluster as per one embodiment of the present invention.
[0009] Fig. 4a is a flow chart as per one embodiment of the present invention.
[00010] Fig. 5 is a graphical representation of the ignition timing as per one embodiment of the resent invention.
DETAILED DESCRIPTION
[00011] Generally, temperature of the power unit increases with time and with operation of various components inside the power unit. In this regard, maintaining of temperature within a safe operating region or the predetermined temperature range is important as it increases the durability and efficiency of the components of the power unit. The overheating of the power unit happens because of factors like, thermostat failure, issues with belts and hoses etc., which impacts efficiency of the components of the power unit and thus ultimately decreases the efficiency of the power unit. Hence, there is a need to regulate the heat of the power unit and to provide constant cooling to the components of the power unit.
[00012] In different vehicles like saddle type vehicle, straddle type vehicle, HEV, Step thru type vehicle, location of the power unit in the vehicle also plays an important role in heat dissipation from the respective vehicle to the atmosphere. For example, in a saddle type vehicle, the power unit is mounted in a space formed between a down frame and centre frame of a frame assembly of the vehicle. The power unit is attached with various attachment means to the frame assembly of the vehicle. In the saddle type vehicle, the location of the mounting of the power unit has access to atmospheric air which results in cooling of the power unit of the vehicle. In some cases, fins are provided on components like cylinder block for channelizing atmospheric air on the power unit. This requires addition of material on the power unit which results in undesirable increase of weight. In straddle type vehicle or in step thru type vehicle, the power unit is low slung and also covered with component like side panels in the vehicle. The side panels as disposed, cover the power unit from all sides. This leads to overheating of the power unit as no or insufficient atmospheric air is channelized near the power unit to cool it down. In vehicle like HEV, or vehicle with auxiliary driving source like an Integrated Starter Generator (ISG) etc. the vehicle consists of the power unit and an electric motor or ISG. In this type of vehicle, low speed acceleration may be achieved by a simple single speed transmission. The single speed transmission reduces complexity of gear box and CVT. Although the low speed acceleration can be achieved by this configuration, however, maximum speed of the vehicle is dependent only on maximum power. Hence, in order to achieve higher vehicle speed there is a need for the power unit to operate at higher speed proportionately. Higher operating speed of power unit leads to higher operating temperature of engine. Additionally, for HEV type vehicles or ISG based vehicles or auxiliary energy storage type vehicles, the packaging of surrounding components like energy storage device, wiring harness for the vehicle also restricts natural cooling air circulation in the vehicle. In this regard, higher operating speed along with lower circulation of natural cooling air leads to overheating of the power unit which leads to increased lubricating oil temperature and faster wears out of parts and also makes customer uncomfortable while going for a long drive.
[00013] Also, excessive heat generated in operation of the power unit may cause the lubricating oil to degrade and breakdown losing its lubricating ability. When the lubricating oil breaks down, they oxidize, thermally degrade and lose viscosity due to shear force resulting in terminal failure and / or undesirable repair expenditures. Hence, there is a constant need of thermal management of the power unit to eliminate the overheating of the power unit in the vehicle.
[00014] To overcome this problem, typically, in known art, the vehicle may include a cooling system to reduce overheating of the power unit because of multiple factors like faulty carburetor, coolant leaking etc. Conventionally, a refrigerant is circulated through power unit block to remove heat from the overheated power unit. The cooling system may include various components like valves, thermostats etc. This system has its own disadvantages like if even one of the valve is subjected to performance degradation, then root cause of the overheating of the power unit cannot be easily traced, that is whether the overheating of the power unit happened because of the faulty valves or due to unexpected overheating of the lubricating oil or another factors. Advanced system like diagnostics and fault detection sensor may be additionally required which add to compact packaging of the vehicle, complexity of design as well as cost.
[00015] In another known art, a radiator is detachably in vicinity of the power unit which transfers the heat to ambient air. The radiator often uses forced convection provided by a fan. This has disadvantages like additional device is required to cooling of the power unit. This also leads to challenging task to package the additional component in the conventional compact layout of the vehicle.
[00016] Hence, there exists a contradictory challenge of thermal management of the power unit in a compact layout of the vehicle, while achieving elimination of additional components for thermal management of the power unit in the vehicle and also retaining conventional layout design of the power unit and manufacturing set up of the vehicle.
[00017] Therefore, there is a need to have an improved thermal management system which overcomes all of the above problems and other problems of known art.
[00018] The present invention provides a solution to the above problems while eliminating need for additional components from the vehicle, thus ensuring low cost of the vehicle.
[00019] With the above objectives in view, the present invention is a thermal management system of the power unit to eliminate over heating of the power unit and more particularly an improved thermal management system having a closed loop method based on at least one or more inputs in the vehicle.
[00020] As per one aspect of the present invention, a vehicle includes a power unit, where the power unit is a low slung type power unit. The power unit is located below seat at a lower rear portion of the vehicle. The power unit is swingably supported by rear suspension system and attached to a frame of the vehicle. A CVT (continuous variable transmission) forms a part of the power unit and is disposed on rear portion of the power unit. The CVT is mounted so as to be disposed on right or left of the vehicle. The power unit includes a thermal management system, an ignition system for better combustion in the power unit. In another implementation, constant ratio chain drive also forms part of the power unit and is disposed on right or left of the vehicle
[00021] As per one aspect of the present invention, the thermal management system being a closed loop system includes a temperature sensor, an ignition system, and a controller. The mentioned paragraph elaborates on working of the thermal management system as per the present invention. As per one aspect of the present invention, the controller has predetermined threshold temperature stored in a look up table. When the power unit of the vehicle is in ON state, a magneto senses speed and load of the power unit through a pulsar coil and the temperature sensor senses the temperature of the power unit. The output generated from the magneto and temperature sensor is received by the controller. The controller then analyzes and determines that whether the temperature of the power unit is less than the threshold temperature stored in the look up table of the controller. If the temperature of the power unit exceeds the threshold temperature, the controller activates modified ignition timing, it means that the ignition timing for firing is modified and thus peak combustion temperature is reduced in the power unit. As the peak temperature of the combustion in the power unit is reduced with modified ignition timing, it leads to decrease in the temperature of the power unit and thus restrict the overheating of the components of the power unit. If the controller determines that temperature of the power unit is less than the threshold temperature stored in the look up table of the controller, then the controller activates standard ignition timing, it means that the ignition timing for firing is same as conventional timing, ensuring optimum combustion for efficient working of the power unit. Further, the temperature of the power unit is sensed by the temperature sensor and is sent to the controller as an input, forming a closed loop system. This also ensures that the components of the power unit are efficiently working and avoid over heating of the power unit. This is a closed loop configuration depending upon the factors like power unit speed, power unit load, lubricating oil temperature, where the temperature sensor constantly senses the temperature of the power unit. The output of the temperature sensor is sent to the controller along with other inputs like power unit load and power unit speed, which avoids overheating of the power unit.
[00022] As per another aspect of the present invention, the thermal management system being a closed loop system includes an instrument cluster, a controller, and an ignition system. The mentioned paragraph elaborates on working of the thermal management system as per the present invention to avoid overheating of the power unit. As per one aspect of the present invention, the controller has predetermined threshold time or duration of operation of the vehicle stored in a look up table. The time or duration of operation is derived from the relationship that speed is distance divided by time. As the distance and speed is known, hence from the speed, time and distance relationship, time or duration of operation of the vehicle is also known. When the power unit of the vehicle is in ON state, the magneto through sensor senses the load and speed of the power unit. Then the output generated from the magneto through the pulsar coil is fed into the controller as an input. The time or duration of operation of the vehicle is received by the controller. The controller analyzes the inputs received that are power unit load, speed and duration of operation of the vehicle. The controller determines that whether the duration of operation of the vehicle is less than the threshold duration of operation stored in the look up table of the controller. If the duration of operation of the vehicle exceeds the threshold duration of operation, the controller activates modified ignition timing, which means that the ignition timing for firing is modified and thus peak combustion temperature is reduced in the power unit. As the peak temperature of the combustion in the power unit is reduced with modified ignition timing, it leads to decrease in the temperature of the power unit and thereby restricting the overheating of the components of the power unit. If the controller determines that the duration of operation of the vehicle is less than the threshold duration stored in the look up table of the controller, then, the controller activates standard ignition timing; it means that the ignition timing for firing is same as conventional timing, ensuring optimum combustion for efficient working of the power unit. This also ensures that the components of the power unit are efficiently working and avoids over heating of the power unit. This is a closed loop method depending upon the factors like power unit speed, power unit load, distance travelled by the vehicle, which avoids overheating of the power unit.
[00023] In the ensuing exemplary aspects, the vehicle is a straddle type vehicle. However, it is contemplated that the concepts of the present invention may be applied to any of the two wheeled vehicles without defeating the spirit of the invention.
[00024] Various other features of the invention are described in detail below with reference to the accompanying drawings. In the drawings, like reference numbers generally indicate identical, functionally similar, and/or structurally similar elements. The drawing in which an element first appears is indicated by the leftmost digit(s) in the corresponding reference number. With reference to the accompanying drawings, wherein the same reference numerals will be used to identify the same or similar elements throughout the several views.
[00025] Further “front” and “rear”, and “left” and “right” referred to in the ensuring description of the illustrated embodiment refer to front and rear, and left and right directions as seen in a state of being seated on a seat of the vehicle. Furthermore, a longitudinal axis refers to a front to rear axis relative to the vehicle, while a lateral axis refers to a side to side, or left to right axis relative to the vehicle. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. Further, the present subject matter can also be used in any two-wheeler, but for reference, the present subject matter is explained with respect to the straddle type two wheeled vehicle.
[00026] Fig. 1 a left side view of a straddle type vehicle (“the vehicle”) 100, in accordance with an embodiment of the present subject matter. The vehicle (100) illustrated, has a frame assembly (105) shown schematically by dotted lines. The frame assembly (105) includes a head tube (105A). One or more suspensions (110) connect a front wheel (115) to a handlebar assembly (120), which forms the steering assembly of the vehicle (100). The steering assembly is rotatably disposed through the head tube (105A). The main frame assembly extends rearwardly downward from the head tube (105A) and includes a bent portion thereafter extending substantially in a longitudinal direction. Further, the frame assembly (105) includes one or more rear frame member (105C) extending inclinedly rearward from a rear portion of the main frame assembly towards a rear portion of the vehicle (100).
[00027] The vehicle (100) includes a power unit (125) comprising at least one of an internal combustion (IC) engine (125) and a traction motor (135). For example, the traction motor (135) is a brush less direct current (BLDC) motor. The power unit is coupled to the rear wheel (145). In one embodiment, the IC engine (125) is swingably connected to the frame assembly (105). In the present embodiment, the IC engine (125) is mounted to the swing arm (140) and the swing arm (140) is swingably connected to the frame assembly (105). The traction motor (135), in one embodiment, is disposed adjacent to the IC engine (125). In the present embodiment, the traction motor 135 is hub mounted to the rear wheel (145). Further, the vehicle (100) includes a transmission means (130) coupling the rear wheel (145) to the power unit. The transmission means (130) includes a continuously variable transmission, an automatic transmission, or a fixed ratio transmission. A seat assembly (150) is disposed above the power unit and is supported by the rear frame member (105C) of the frame assembly (105). In the present embodiment, the seat assembly (150) is hingedly openable. The frame assembly (105) defines a step-through portion ahead of the seat assembly (150). A floorboard (155) is disposed at the step-through portion, wherein a rider can operate the vehicle 100 in a seated position by resting feet on the floorboard (155). Further, the floorboard (155) is capable of carrying loads.
[00028] The vehicle includes an on-board battery (not shown) that drives the traction motor (135). Further, the frame assembly (105) is covered by plurality of body panels including a front panel (160A), a leg shield (160B), an under-seat cover (160C), and a left and a right side panel (160D), mounted on the frame assembly (105) and covering the frame assembly (105) and parts mounted thereof.
[00029] In addition, a front fender (165) is covering at least a portion of the front wheel (115). In the present embodiment, the front fender (165) is integrated with the front panel (160A). A utility box (not shown) is disposed below the seat assembly (150) and is supported by the frame assembly (105). A fuel tank (not shown) is disposed adjacently to the utility box (not shown). A rear fender (175) is covering at least a portion of the rear wheel (145) and is positioned below the fuel tank and upwardly of the rear wheel (145). One or more suspension(s) (180) having mono shock absorber or dual shock absorber, are provided in the rear portion of the vehicle (100) for connecting the swing arm (140) and the rear wheel (145) to the frame assembly (105) for damping the forces from the wheel (145) and the power unit from reaching the frame assembly (105).
[00030] Furthermore, the vehicle (100) comprises of plurality of electrical and electronic components including a headlight (185A), a tail light (185B), a transistor controlled ignition (TCI) unit (not shown), an alternator (not shown), a starter motor (not shown). Further, the vehicle 100 includes an anti-lock braking system (ABS), a synchronous braking system (SBS), or a vehicle control system (VCS)
[00031] Fig. 2 is a perspective view of a power unit as per one embodiment of the present invention The power unit 125 comprises a cylinder head cover 201, a cylinder head (not labelled), a cylinder block 203, and a casing 204. In one embodiment, the casing 204 is made of a first side casing 205 and a second side casing 206, which are capable of rotatably supporting various parts of the power unit 125 comprising a primary drive shaft. The primary drive shaft in an internal combustion engine acting as a power unit is a crankshaft. The power unit 125 supports at least one rotating member that requires lubrication and/ or cooling. A transmission system can be a multi-gear transmission which offers different gear ratios. Further, one or more covers of the power unit 200 are provided on lateral sides thereof for covering the components extending from the casing 204 and the components, which are disposed on outward lateral side of the casing 204. For example, a cover member is disposed to cover outer lateral side of the casing 204.
[00032] Fig. 3 is a block diagram of thermal management system (300) of the power unit as per one embodiment of the present invention. As per one embodiment of the present invention, a controller (302) receives input from the power unit (125) and a temperature sensor (303). The power unit (125) sends speed and load of the power unit, measured through magneto and pulsar coil, to the controller (302). Further, the temperature sensor senses the temperature of lubricating oil in the power unit and sends the output signal to the controller (302). Hence, on the basis of the received signal as an input from different sources, the controller (302) manages output ignition timing of ignition system (301). Thereby, protects the components and lubricating oil of the power unit from getting over heated.
[00033] Fig. 3a is a flowchart for methodology of thermal management system with sensor of the power unit as per one embodiment of the present invention. As per one aspect of the present invention, the controller has predetermined threshold temperature stored in a look up table. In step S304, when the power unit of the vehicle is in ON state, in step S305, the magneto senses the speed and load of the power unit through pulsar coil, and in a parallel step S306, the temperature sensor senses the temperature of the power unit. In step S307, the output generated from the magneto and temperature sensor is received by the controller and the controller analyzes the input received. In step S308, the controller then determines that whether the temperature of the power unit is less than the threshold temperature stored in the look up table of the controller. If the temperature of the power unit exceeds the threshold temperature then, in step S309, the controller activates modified ignition timing, it means that the ignition timing for firing is modified and thus peak combustion temperature is reduced in the power unit. As the peak temperature of the combustion in the power unit is reduced in modified ignition timing, it leads to decrease in the temperature of the power unit and thereby restricting the overheating of the components of the power unit. In step S308, if the controller determines that temperature of the power unit is less than the threshold temperature stored in the look up table of the controller, then in step S310, the controller activates standard ignition timing, it means that the ignition timing for firing is same as conventional timing, ensuring optimum combustion for efficient working of the power unit. Further, at step S311, the temperature of the power unit is sensed by the temperature sensor and is sent to the controller as an input, forming a closed loop system. This also ensures that the components of the power unit are efficiently working and avoids over heating of the power unit. The ignition timings are cyclically activated based on inputs received from the at least one or more input signals like power unit speed, power unit load, power unit temperature. This is a closed loop configuration depending upon the factors like power unit speed, power unit load, power unit temperature, where the temperature sensor constantly sense the temperature of the power unit. The output of the temperature sensor is sent to the controller along with other inputs like power unit load and power unit speed, which avoids overheating of the power unit
[00034] Fig. 4 is a block diagram of thermal management system with instrument cluster as per another embodiment of the present invention. As per another embodiment of the present invention, a controller (302) receives input from the power unit (125) and an instrument cluster (401). The power unit (125) sends speed and load of the power unit, measured through magneto and pulsar coil, to the controller (302). Further, the instrument cluster (401) sends the distance travelled by the vehicle to the controller (302). Hence, on the basis of the received signal as an input from different sources, the controller (302) controls the ignition timing of ignition system (301) either to be retained normal or adjusted to eliminate overheating of the power unit. This invention, thereby, protects the components and lubricating oil of the power unit from getting over heated.
[00035] Fig. 4a is a flowchart for methodology of thermal management system with instrument cluster as per another embodiment of the present invention. The controller has predetermined threshold duration of operation of the vehicle stored in a look up table. The time or duration of operation is derived from the relationship that speed is distance divided by time. As the distance and speed is known, hence from the speed, time and distance relationship, duration of operation of the vehicle is also known. In step S403, when the power unit of the vehicle is in ON state, the magneto through a sensor senses the load and speed of the power unit. Then in step S404, the output generated from the magneto through the pulsar coil is fed into the controller as an input. In a parallel step S405, the duration of operation of the vehicle is received by the controller. In Step S406, the controller analyzes the inputs received that are power unit load, speed and duration of operation of the vehicle. In step S407, the controller determines that whether the duration of operation of the vehicle is less than the threshold duration of operation stored in the look up table of the controller. If the duration of operation of the vehicle exceeds the threshold duration of operation, then in step S408, the controller activates modified ignition timing, which means that the ignition timing for firing is modified and thus peak combustion temperature is reduced. As the peak temperature of the combustion in the power unit is reduced with modified ignition timing, it leads to decrease in the temperature of the power unit thereby restricting the overheating of the components of the power unit. If at step S407, the controller determines that the duration of operation of the vehicle is less than the threshold duration of operation stored in the look up table of the controller, then in step S409, the controller activates standard ignition timing, it means that the ignition timing for firing is same as conventional timing, ensuring optimum combustion for efficient working of the power unit. This also ensures that the components of the power unit are efficiently working and avoids over heating of the power unit. The ignition timings are cyclically activated based on inputs received from the at least one or more input signals like power unit speed, power unit load, duration of operation of the vehicle. This is a closed loop configuration depending upon the factors like power unit speed, power unit load, distance travelled by the vehicle, which avoids overheating of the power unit.
[00036] Fig. 5 is a graphical representation of the standard and modified ignition timing executed by present invention of an improved thermal management system of the power unit. For example, CC’ is a safe operating upper limit temperature of the power unit and DD’ is a minimum temperature for optimum efficiency of the power unit. Taking reference from the method described in above mentioned paragraph, when the vehicle is travelling within safe operating temperature, the controller activates standard ignition timing (DA). Further, when the vehicle reaches safe or peak operating temperature, then the controller activates modified ignition timing (AB), where the efficiency of the power unit decreases for gradually decreasing the speed of the vehicle. Now, when the vehicle reaches at minimum operating temperature for optimum efficiency of the power unit, the controller activates standard ignition timing. Hence, this system is a closed loop system ensuring thermal management of the power unit for better efficiency.
[00037] The invention helps in overcoming the problem of use of additional components, for thermal management of the power unit in the vehicle while maintaining the overall weight and width of the vehicle and ultimately makes it cost effective.
[00038] Advantageously, the embodiments of the present invention, describes the potential modifications in the thermal management system of the power unit, where thermal management system is a closed loop system.
[00039] Many other improvements and modifications may be incorporated herein without deviating from the scope of the invention.
List of reference symbol:
Fig. 1:
100: Vehicle
185A: headlight
160A: front panel
105: frame assembly
105A: Head Tube
165: Front Fender
110: Front Suspensions
115: Front Wheel
160B: Leg Shield
155: Floorboard
105B: main tube
160C: Under Seat Cover
125: Power Unit
130: Transmission Means
140: Swing Arm
145: Rear Wheel
135: Traction Motor
180: Rear Suspension
175: Rear Fender
185B: Tail Light
160D: right side panel
105c, 105d: Rear Tubes
150: Seat Assembly
Fig. 2:
201: Cylinder Head Cover
203: Cylinder Block
204: Casing
Fig. 3
301; Ignition System
302: Controller
303: Temperature Sensor
Fig. 4:
401: Instrument Cluster