TECHNICAL FIELD

[0001] The present subject matter relates to a vehicle. More particularly, to a hybrid vehicle.

BACKGROUND

[0002] Over last few years, with induction of new powertrain technologies concomitantly very substantial attention has been paid to reduction of pollutants emitted by the vehicles. To this end, much attention has also been paid to development of hybrid electric vehicles (HEV’s) for their optimal performance and durability as compare to electric vehicles (EV’s) since electric vehicles have had very limited range. Moreover, the performance and durability are essential vehicles attribute which attract customers to purchase the vehicle.

[0003] The above information disclosed in this background section is only for enhancement of understanding of the background of the disclosure and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.

BRIEF DESCRIPTION OF THE DRAWINGS

[0004] The present invention is described with reference to an exemplary embodiment of a hybrid vehicle with the accompanying figures. The same numbers are used throughout the drawings to reference like features and components. Further, the inventive features of the invention are set forth in the appended claims. The invention itself however, as well as a preferred mode of use, further objects and advantages thereof, will best be understood by reference to the following detailed description of an illustrative embodiment when read in conjunction with the accompanying drawings, wherein:

[0005] Figure 1 illustrates a schematic diagram of a drive mode engagement control system (100) for a hybrid vehicle (not shown) as per embodiment, in accordance with one example of the present subject matter. [0006] Figure 2 illustrates a schematic diagram of the drive mode engagement control system (100) for the hybrid vehicle (not shown) as per alternative embodiment, in accordance with one example of the present subject matter.

[0007] Figure 3 illustrates a flow chart of a method of eliminating jerk while mode transition of power sources in the hybrid vehicle as per embodiment, in accordance with one example of the present subject matter.

DETAILED DESCRIPTION

[0008] Various features and embodiments of the present subject matter here will be discernible from the following further description thereof, set out hereunder.

[0009] Generally, a hybrid vehicle combines the advantages of conventional vehicle and an electric vehicle into one vehicle. It comprises of dual powertrain in the form of an internal combustion (IC) engine and a traction motor which are engaged either jointly or separately, depending upon the user requirements i.e. need for more power or more fuel efficiency. The traction motor is powered by a rechargeable electric power unit.

[00010] Typically, the hybrid vehicle comprises of one or more driving modes. The driving modes comprise of a pure electric mode, a power hybrid mode, an economy mode, and a pure engine mode. The pure electric mode is a mode in which motion occurs only out of driving force of the traction motor. The power hybrid mode is a mode in which motion occurs out of drive force from both the IC engine and the traction motor. In other words, the power hybrid mode is the traction motor assist travelling mode. Further, the pure engine is a mode in which motion occurs only via driving force provided the IC engine. The economy mode is a mode in which the traction motor provides driving force till predetermined vehicle speed, and thereafter above the predetermined speed the driving force is provided by the IC engine. The economy mode prioritizes fuel efficiency by prioritizing traction motor as drive source.

[00011] In the above described hybrid vehicle, the transition of power sources occurs based on driving requirements or in the form of actuation by a controller based on user’s input through mode transition switch or the like. However, during mode transition of power sources, a sudden jerk is experienced by the user, which significantly affects the user’s comfort. This is caused due to different capacities of power sources i.e. IC engine and the traction motor. The unexpected sudden jerk can become a safety issue for a user possessing low driving skill to balance and control especially for a two wheeled vehicle. More specifically, during automatic switching of driving mode wherein the modes may be changed by a controller, the chance of undesirable jerk and loss of control can lead to a potential unsafe situation.

[00012] In order to address above said problem various control strategies are adopted to reduce the jerk during mode transition of power sources. Specifically, in four wheeled vehicles it is achieved by precisely controlling the clutch engagement and disengagement. However, it becomes a challenge in two wheeled saddle type vehicles configured to have a centrifugal clutch or automatic clutch. The centrifugal clutch automatically engages and disengages based on engine rev. per minute (rpm) and employing a control system for a compact saddle type vehicle is undesirable owing to its adverse impact on layout packaging, weight of vehicle, mass distribution as well as cost.

[00013] Therefore, there is a need for an effective and compact drive mode engagement control system and associated method for a hybrid vehicle comprising of dual power sources which overcomes all above problem and other problems of known art.

[00014] To this end, it is an object of the present invention is to provide a drive mode engagement control system and associated method to achieve seamless mode transition without compromising vehicle performance.

[00015] According to the present subject matter, to attain the above-mentioned objectives, a first characteristic of the present invention is a drive mode engagement control system for a hybrid vehicle comprising of two or more driving sources, said system comprising a battery management system which activates said control system based on actuation of an ignition key and one or more vehicle mode processor units; The vehicle mode processor units are configured to process a mode change request information received from a user through a mode change interface or based on one or more vehicle operating condition. The vehicle mode processing units are configured to detect a real time operating state parameter values of the hybrid vehicle based on one or more inputs from plurality of sensors and compare with predetermined operating state parameter values of the hybrid vehicle to generate an output command.

[00016] In addition to the first characteristic, a second characteristic of the present invention is drive mode engagement control system which is based on said output command and the output command includes at least one command of: application of a predetermined brake torque on one or more electric machines; application of the predetermined brake torque on an integrated starter generator (ISG); and application of the predetermined brake torque on the integrated starter generator (ISG) and the one or more electric machines.

[00017] In addition to the first characteristic, a third characteristic of the present invention is the drive mode engagement control system, wherein plurality of sensor comprising of one or more speed sensors, said speed sensors are configured to provide vehicle speed; a throttle position sensor, said throttle position sensor is configured to provide an amount of opening of a throttle valve; one or more hall sensors, said hall sensors are configured to detect electric machine rpm; one or more coil temperature sensors, said coil temperature sensors are configured to detect thermal state of said electric machines; and one or more three axis acceleration sensors, said three axis acceleration sensors are configured to detect a gradient value. [00018] According to the present subject matter to attain the above-mentioned objectives, a fourth characteristic of the present invention is a method of eliminating jerk during mode transition in a hybrid vehicle comprising of two or more power sources, said method comprising of steps: receiving a mode transition input by one or more mode processing units; receiving a real time operating state parameter values from plurality of sensors; comparing said real time operating state parameter values of the hybrid vehicle with a predetermined operating state parameter values of the hybrid vehicle, by one or more said mode processing units; determining as a first event whether said real time operating state parameter values of the hybrid vehicle are lesser than said predetermined operating state parameter values of the hybrid vehicle, and based upon said first event, retaining the current driving mode; and further determining as a second event whether said real time operating state parameter values of the hybrid vehicle is more than said predetermined operating state parameter values of the hybrid vehicle, wherein based upon said second event, changing a drive mode from current mode to user requested mode which is different from said current drive mode.

[00019] In addition to the fourth characteristic, a fifth characteristic of the present invention is the method of eliminating jerk during mode transition in a hybrid vehicle, wherein said second event comprising of receiving inputs from one or more three axis acceleration sensor to detect a gradient value by one or more said vehicle mode processing units; comparing said detected gradient value with predetermined gradient value; if the detected gradient value is more than predetermined gradient value, then change mode to user requested mode.

[00020] In addition to the fourth characteristic, an sixth characteristic of the present invention is the method of eliminating jerk during mode transition in a hybrid vehicle, wherein if gradient value is less than predetermined value then second event further comprising of determining and outputting corresponding alternate signal by said vehicle mode processing units.

[00021] In addition to the fourth and sixth characteristic, a seventh characteristic of the present invention is the method of eliminating jerk during mode transition in a hybrid vehicle, wherein said determining and outputting corresponding alternate signal includes; detecting electric machines operating state parameter values and engine operating state parameter values; calculating the difference between said electric machine operating state parameter value and engine operating state parameter value; determining a corresponding brake torque required based on calculated difference between said electric machine operating state parameter value and engine operating state parameter value by said vehicle mode processing units; and generating corresponding output command electric signal to the determined brake torque.

[00022] In addition to the fourth and seventh characteristic, an eighth characteristic of the present invention is method of eliminating jerk during mode transition in a hybrid vehicle, wherein said corresponding output command comprising of applying corresponding brake torque required on one or more electric machine and/ or ISG to ensure smooth transition and simultaneously change mode to user requested mode.

[00023] In addition to the fourth characteristic and eighth characteristic, an ninth characteristic of the present invention is method of eliminating jerk during mode transition in a hybrid vehicle, wherein a recoverable electric energy due to brake torque application during mode transition is stored in a battery through a dedicated regenerative circuit.

[00024] In addition to the fourth characteristic, a tenth characteristic of the present invention is method of eliminating jerk during mode transition in a hybrid vehicle, wherein said vehicle operating state includes predetermined vehicle speed range and amount of opening of a throttle valve.

[00025] In addition to the fourth characteristic and tenth characteristic, a eleventh characteristic of the present invention is method of eliminating jerk during mode transition in a hybrid vehicle, wherein said predetermined vehicle speed ranges from 15 to 60 km per hr and the opening amount of throttle valve is 30% or more.

[00026] In addition to the fourth characteristic and seventh characteristic, an twelfth characteristic of the present invention is method of eliminating jerk during mode transition in a hybrid vehicle, wherein said engine operating state parameter values include estimated engine torque wherein said estimated engine torque is calculated based on engine rpm, ignition timing, manifold inlet pressure, inlet air temperature, opening of the throttle valve and air fuel ratio etc.

[00027] In addition to the fourth characteristic and seventh characteristic, an thirteenth characteristic of the present invention is method of eliminating jerk during mode transition in a hybrid vehicle, wherein said electric machine state parameter values includes estimated electric machine torque wherein said estimated electric machine torque is calculated based on phase current, electric machine rpm, thermal state parameter of electric machine etc.

[00028] In addition to the first to thirteenth characteristic, an fourteenth characteristic of the present invention is method of eliminating jerk during mode transition in a hybrid vehicle, wherein said hybrid vehicle includes a two wheeled saddle type vehicle is configured to have a drive mode engagement control system and associated method of eliminating the jerk during mode transition.

[00029] 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.

[00030] The foregoing disclosure is not intended to limit the present disclosure to the precise forms or particular fields of use disclosed. As such, it is contemplated that various alternate embodiments and/or modifications to the present disclosure, whether explicitly described or implied herein, are possible in light of the disclosure. Having thus described embodiments of the present disclosure, a person of ordinary skill in the art will recognize that changes may be made in form and detail without departing from the scope of the present disclosure. Thus, the present disclosure is limited only by the claims.

[00031] In the foregoing specification, the disclosure has been described with reference to specific embodiments. However, as one skilled in the art will appreciate, various embodiments disclosed herein can be modified or otherwise implemented in various other ways without departing from the spirit and scope of the disclosure. Accordingly, this description is to be considered as illustrative and is for the purpose of teaching those skilled in the art the manner of making and using various embodiments of the disclosure. It is to be understood that the forms of disclosure herein shown and described are to be taken as representative embodiments. Equivalent elements, materials, processes or steps may be substituted for those representatively illustrated and described herein. Moreover, certain features of the disclosure may be utilized independently of the use of other features, all as would be apparent to one skilled in the art after having the benefit of this description of the disclosure. Expressions such as “including”, “comprising”, “incorporating”, “consisting of’, “have”, “is” used to describe and claim the present disclosure are intended to be construed in a non-exclusive manner, namely allowing for items, components or elements not explicitly described also to be present. Reference to the singular is also to be construed to relate to the plural.

[00032] Further, various embodiments disclosed herein are to be taken in the illustrative and explanatory sense, and should in no way be construed as limiting of the present disclosure. All joinder references (e.g., attached, affixed, coupled, connected, etc.) are only used to aid the reader's understanding of the present disclosure, and may not create limitations, particularly as to the position, orientation, or use of the systems and/or methods disclosed herein. Therefore, joinder references, if any, are to be construed broadly. Moreover, such joinder references do not necessarily infer that two elements are directly connected to each other.

[00033] Additionally, all numerical terms, such as, but not limited to, “first”, “second”, “third”, “primary”, “secondary”, “main” or any other ordinary and/or numerical terms, should also be taken only as identifiers, to assist the reader's understanding of the various elements, embodiments, variations and/or modifications of the present disclosure, and may not create any limitations, particularly as to the order, or preference, of any element, embodiment, variation and/or modification relative to, or over, another element, embodiment, variation and/or modification.

[00034] It will also be appreciated that one or more of the elements depicted in the drawings/figures can also be implemented in a more separated or integrated manner, or even removed or rendered as inoperable in certain cases, as is useful in accordance with a particular application. Additionally, any signal hatches in the drawings/figures should be considered only as exemplary, and not limiting, unless otherwise specifically specified.

[00035] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[00036] Figure 1 illustrates a schematic diagram of a drive mode engagement control system (100) for a hybrid vehicle (not shown) as per embodiment, in accordance with one example of the present subject matter. A drive system (not shown) of the hybrid vehicle (not shown) comprising of an internal combustion (IC) engine (HO), and one or more electric machines (104). The IC engine (110) is four stroke IC engine, and one of the drive sources of the hybrid vehicle (not shown). In the IC engine (110), engine start & stop control and the like are carried out based on output commands from one or more vehicle mode processing units (103). As per preferred embodiment, the vehicle mode processing unit (103) can be a Hybrid Control Unit (HCU). Further, the one or more electric machines (104) are controlled based on output commands from the vehicle mode processing unit (103). As per preferred embodiment, the one or more electric machines (104) include traction motor which is powered by high-watt batteries (not shown) through a Battery Management system (BMS) (101). More specifically, the vehicle mode processing unit (103), BMS (101), mode switching interface (102), plurality of sensors, one or more electric machines (104) and IC engine (110) are communicating with each other through a controller area network (CAN) bus of the hybrid vehicle (not shown). The plurality of sensors includes a throttle position sensor (106), one or more hall sensors (107), one or more coil temperature sensors (108) to detect thermal state of the electric machine, and one or more three axis acceleration sensors (109) for sensing the vehicle state parameter values. The amount of opening of a throttle valve (not shown) is detected by the throttle position sensor (106). The hall sensors (107) are configured to detect electric machine revs, per minute (r.p.m). As per embodiment of the present invention, the hall sensors are three in number. Further, the three axis acceleration sensors detect the gradient value.

[00037] During operation, when rider switches ON the ignition key (113), the BMS (101) energies the drive mode engagement control system (100). Immediately after switching on the ignition key (113), the hybrid vehicle (not shown) enters into idle mode for predetermined time. During idle mode, the hybrid vehicle (not shown) remains in immovable state. Further, based on ride mode inputs from the user, the vehicle mode processing unit (103) generates the output command to one or more power sources (110, 104). As per preferred embodiment of the present invention, when no input is received from the user the hybrid vehicle (not shown) automatically switches to default mode from idle mode. The default mode includes economy mode. In economy mode, the electric machine (104) provides driving force or traction torque, so as to enable the forward and backward motion of vehicle until predetermined operating state parameter values of the hybrid vehicle. Thereafter, above the predetermined operating state parameter values of the hybrid vehicle, the power source switches from electric machine (104) to the IC engine (110) to provide a driving force. During transition the engine cranking is performed by a starter motor (112) connected through a starter relay (111) to the IC engine (110). During this mode transition, the vehicle mode processing unit (103) processes the input received from the three axis acceleration sensor to compare the detected positive gradient value with a predetermined positive gradient value. Thereafter, if the detected positive gradient value is less than predetermined positive gradient value, the vehicle mode processing unit (103) gives output commands to the electric machine (104) to function as a generator. Thus, an estimated brake torque is applied on the electric machine (104) based on estimated torque difference between the electric machine (104) and the IC engine (110). This phenomenon generates a reverse torque to allow optimum torque transfer from IC engine (110) to the wheels (not shown) during mode transition to achieve smooth transition. However, if the detected positive gradient value is greater than predetermined positive gradient value then no brake torque is applied on the electric machine (104) as vehicle torque demand is higher on positive gradient as compare to flat road. Importantly, the positive gradient implies “uphill slope”. Thereby, the control system (100) improves the riding comfort as it eliminates the jerk felt during the mode transition without compromising the vehicle performance. Further, the recoverable electric energy produced by the electric machine (104) during mode transition is stored in the batteries (not shown) through a dedicated regenerative circuit (not shown).

[00038] Figure 2 illustrates a schematic diagram of a drive mode engagement control system (100) for a hybrid vehicle (not shown) as per alternative embodiment, in accordance with one example of the present subject matter. For sake of brevity reference is made only to differentiating aspects of alternative embodiment within single inventive concept. As per alternative embodiment, an Integrated Starter Generator (ISG) (201) is installed on a crankshaft (not shown) of the IC engine (HO). The ISG (201) performs motoring functioning by receiving a power supply from the batteries (not shown) to crank the IC engine (110). Further, it functions as io an electric generator and charges the batteries (not shown). During, the transition phase, the ISG (201) is used as a generator thereby an estimated brake torque is applied on the crankshaft (not shown) based on estimated torque difference between the electric machine (104) and the IC engine (110). In other words, this phenomenon generates a reverse torque to allow optimum torque transfer from IC engine (110) to the wheels (not shown) during mode transition to achieve smooth transition. Further, the recoverable electric energy produced by the ISG (201) during mode transition is stored in the batteries (not shown) through the dedicated regenerative circuit (not shown).

[00039] As per another alternative embodiment, based on driving conditions. During, this transition phase electric machine (104) and ISG (201) are used as a generator thereby the estimated brake torque is applied on the crankshaft (not shown) and the electric machine (104) based on estimated torque difference between the electric machine (104) and IC engine (110) for achieving smooth transition. Further, the recoverable electric energy produced by the electric machine (104) and ISG (201) during mode transition is stored in the batteries (not shown) through the dedicated regenerative circuit (not shown).

[00040] Figure 3 illustrates a flow chart of a method of eliminating jerk while mode transition of power source in a hybrid vehicle as per an embodiment, in accordance with one example of the present subject matter. After switching on the ignition key, the battery management system activates or starts the drive mode engagement control system. Further, at step (S101) the mode processing unit receives a mode transition input from the user. Thereafter at step (S102) the mode processing unit receives a real time operating state parameter values from plurality of sensors. At step (S103), the vehicle mode processing unit compares the real time operating state parameter values of the hybrid vehicle with a predetermined operating state parameter values of the hybrid vehicle and determines as a first event whether said real time operating state parameter values of the hybrid vehicle are lesser than said predetermined operating state parameter values of the hybrid vehicle. Further based upon said first event, at step (S104) the vehicle mode processing unit retains the current driving mode. However, the vehicle mode processing unit determines as a n second event whether said real tune operating state parameter values of the hybrid vehicle is more than the predetermined operating state parameter values of the hybrid vehicle. Thereafter the second event further comprising of at step (S105A) detecting a positive gradient value. At step (S105B) comparing with predetermined positive gradient value by a vehicle mode processing unit. Further, upon determination if the detected positive gradient value is more than predetermined positive gradient value, then at step (S105) vehicle mode processing unit switches a drive mode from current mode to user requested mode which is different from said current drive mode. However, if upon determination, the positive gradient value is less than or equal to predetermined gradient value, then second event further comprises of determining and outputting corresponding alternate signal by said vehicle mode processing unit. As per an embodiment, the predetermined gradient value ranges from 3 degree to 7 degree. The determining and outputting corresponding alternate signal comprises of further steps as disclosed. At step (S105C), detecting electric machines operating state parameter values and engine operating state parameter values. As per one embodiment, the electric machine operating state parameter value includes estimated electric machine torque which is calculated based on phase current, electric machine rpm, thermal state parameter of electric machine etc. Further, the engine operating state includes estimated engine torque which is calculated based on engine rpm, ignition timing, manifold inlet pressure, inlet air temperature, opening of the throttle valve and air fuel ratio etc. Subsequent to that, at step (S105D), the vehicle mode processing unit calculates the difference between said current electric machine operating state parameter value and engine operating state parameter value and at step (S105E), determines a corresponding brake torque required. Thereafter, at step (S105F), the vehicle mode processing unit generates a corresponding output command electric signal. The corresponding output signal comprising of applying corresponding brake torque required on one or more said electric machine and/or ISG to ensure smooth transition and simultaneously switching a drive mode from current mode to user requested mode which is different from said current drive mode. [00041] According to above architecture, the primary efficacy of the present invention is that a smooth mode transition is achieved without comprising the vehicle performance. Specifically, the estimated brake torque is applied on the electric machine based on calculated estimated torque difference between engine and electric machine based on road inclination.

[00042] According to above architecture, one of the primary efficacies of the present invention is to recover energy and store it in batteries while applying brake torque. This extends the driving range of the hybrid vehicle in pure electric mode thereby improving energy conservation.

[00043] The above-described embodiments, and particularly any “preferred” embodiments, are possible examples of implementations and merely set forth for a clear understanding of the principles of the invention. For example, electric machine can be an integrated starter generator or traction motor. Further, the hybrid vehicle can include an in wheel hub motor or independent traction motor. It will be apparent to those skilled in the art that changes in form, connection, and detail may be made therein without departing from the spirit and scope of the invention.

List of References:

100 - Drive mode engagement control system

101 - Battery Management system

102 - Mode switching interface

103 - Vehicle Mode processing unit

104 - Electrical machines

105 - Speed sensors

106 - Throttle position sensors

107 - Hall sensor

108 - Coil Temperature sensors 109 - Three axis acceleration sensors

110 - Internal Combustion (IC) engine

111 - Starter relay

112 - Starter Motor 113 - Ignition Key 01 - Integrated Starter Generator (ISG)