Patent Application
20130144514
This application claims priority to and the benefit of Korean Patent Application No. 10-2011-0129699 filed in the Korean Intellectual Property Office on Dec. 6, 2011, the entire contents of which are incorporated herein by reference.
(a) Field of the Invention
The present invention relates to a system and method for controlling the engine of a hybrid vehicle, and more particularly, to a method for controlling the engine of a hybrid vehicle, which is capable of improving output efficiency and fuel efficiency of the vehicle by controlling the ignition point of the engine.
(b) Description of the Related Art
A hybrid vehicle is propelled by two power sources, i.e., typically a motor and an engine, and is generally driven by the motor in a range where the power required by a driver (i.e., determined based on the depth of the accelerator pedal) is low such as at slow speeds. On the other hand, at high speeds, during acceleration, while climbing, etc., when the large amount of power is required by the driver, the engine is operated so as to output power simultaneously from the engine and the motor to drive the vehicle.
The vehicle's energy efficiency is changed according to the points at which the engine is switched on and off during driving. Accordingly, by effectively determining the engine on point, the fuel efficiency of the vehicle can be improved.
In some hybrid vehicles, as illustrated in
During stop-and-go driving such as city driving in which the driver frequently presses the accelerator pedal, as illustrated in
Further, once the engine is started, even if the driver were to immediately take his or her foot off the accelerator, the ignition is still left on with the engine idling for several seconds in preparation for re-acceleration and for the sake of drivability, whereupon fuel is consumed necessarily in most cases, resulting in diminished fuel efficiency.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention 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.
The present invention has been made in an effort to provide a system and method for controlling the engine of a hybrid vehicle, which can improve the fuel efficiency of the vehicle by preventing the consumption of fuel and the waste of electrical energy from needlessly turning the engine on/off, which can reduce the amount of generated toxic fumes, and which can improve the output efficiency of the vehicle.
An exemplary embodiment of the present invention provides a system and method for controlling the engine of a hybrid vehicle. In exemplary embodiments the method for controlling the engine of a hybrid vehicle includes: (a) continuously detecting an output required power when the engine of the vehicle in an Off state, and determining whether the required power exceeds a preset engine delayed ignition power; (b) determining whether the required power exceeds a preset engine non-delayed ignition power; and (c) starting the engine when the required power exceeds the engine non-delayed ignition power within a first set time, after the required power exceeds the engine delayed ignition power.
In some embodiments of the present invention, when the required power is greater than the engine delayed ignition power and less than the engine non-delayed ignition power, the engine may be started after the first set time elapses.
The system and method for controlling an engine of a hybrid vehicle may further include the step of (d) calculating a required power change amount (slope) over a period of time at a point when the first set time has elapsed, and using the calculated required power change amount to determine whether to start the engine. When the required power change amount is greater than 0, the engine may be started. When the required power change amount is 0, the engine may be started after a second set time elapses. When the required power change amount is less than 0, ignition of the engine may be kept Off.
After the first set time, when the required power increases and exceeds the engine non-delayed ignition power before the second set time elapses, the engine may be started. After the first set time elapses and before the second set time elapses, when the required power change amount becomes less than 0, the second set time may be reset to 0. After the second set time is reset to 0, when the required power becomes less than the engine delayed ignition power, the first set time and the second set time may be reset to 0. After the second set time is reset to 0, when the required power exceeds the engine delayed ignition power, the step (d) may be repeated.
The method for controlling an engine of a hybrid vehicle may further include (e) when the required power exceeds a preset engine Off power after the engine is started, the engine is kept on, and when the required power is less than the preset engine Off power after the engine is started, the engine is turned Off.
According to the method for controlling the engine of a hybrid vehicle of the present invention, by flexibly controlling the engine ignition time according to the amount of required power, consumption of fuel and electrical energy waste due to needless on/off of the engine may be prevented, and the fuel efficiency of the vehicle may be improved. Further, according to the present invention, needless on/off of the engine may be prevented to reduce the amount of generated toxic gas and to also improve the output efficiency of the vehicle.
Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the drawings.
It is understood that the term “vehicle” or “vehicular” or other similar term as used herein is inclusive of motor vehicles in general such as passenger automobiles including sports utility vehicles (SUV), buses, trucks, various commercial vehicles, watercraft including a variety of boats and ships, aircraft, and the like, and includes hybrid vehicles, electric vehicles, plug-in hybrid electric vehicles, hydrogen-powered vehicles and other alternative fuel vehicles (e.g. fuels derived from resources other than petroleum). As referred to herein, a hybrid vehicle is a vehicle that has two or more sources of power, for example both gasoline-powered and electric-powered vehicles.
Furthermore, control logic executed by the control units of the present invention may be embodied as non-transitory computer readable media on a computer readable medium containing executable program instructions executed by a processor, controller or the like. Examples of the computer readable mediums include, but are not limited to, ROM, RAM, compact disc (CD)-ROMs, magnetic tapes, floppy disks, flash drives, smart cards and optical data storage devices. The computer readable recording medium can also be distributed in network coupled computer systems so that the computer readable media is stored and executed in a distributed fashion, e.g., by a telematics server or a Controller Area Network (CAN).
Although the below exemplary embodiments are described as using a plurality of units to perform the above process, it is understood that the below processes may also be performed by a single controller or unit.
The hybrid system to which the present invention is applied, as illustrated in
The driving requirement detection unit 10 may be configured to detect the vehicle's driving requirements (e.g., the vehicle's required power) received from a driver, and detect a start and an accelerator position sensor (APS) signal, a brake pedal signal, shift information (P/R/N/D/E/L) selected with a shift lever, etc., and output information corresponding thereto. Hereinafter, required power will be described mainly with respect to the APS.
The ECU 20 may be configured to control the overall operation of the engine 90 according to the driving requirement (required power) signal from the driving requirement detection unit 10, a coolant temperature, and engine torque and other engine state information.
The battery 40 supplies a voltage to the motor 80 in hybrid mode, and recovers and stores regenerative braking energy during stopping and while being charged. The BMS 50 integrally detects information related to the voltage, current, temperature, etc. of the battery 40 to manage and control the state of charge (SOC) state of the battery 40, and control an amount of current supplied according to the output torque from the motor 80.
The HCU 60 may be a priority controller that controls the overall operation of the hybrid vehicle, and connects a controller to a network for each device and provides and receives information therebetween, and performs collaborative control to control the output torque from the engine 90 and the motor 80 and control a target gear ratio while the vehicle is being operated. This hybrid system is widely known to persons of ordinary skill in the art, and thus, a detailed description on each element will not be provided.
In one or a plurality of embodiments, the required power of the engine may be determined through a sensing APS signal detected by the driving requirement detection unit 10 by based on the degree at which the accelerator pedal is pressed by the driver. Also, when the required power exceeds the engine delayed ignition power P2, a first time count is initiated in step S11 as illustrated in
Meanwhile, the vehicle ECU 20 or the HCU 60 may determine whether the required power exceeds a preset engine non-delayed ignition power P3 in step S20. As illustrated in
While the related art is based only on the engine non-delayed ignition power P3 and the engine off power P1, the present invention adds the engine delayed ignition power P2 thereto.
After exceeding the engine delayed ignition power P2, when the required power exceeds the engine non-delayed power P3 within a first set time, the vehicle ECU 20 or the HCU 60 may immediately turn on the engine in step S30. That is, point F2 on the required power line L of
In one or a plurality of embodiments, when the counted first time surpasses the first set time T1, the vehicle ECU 20 or the HCU 60 immediately starts the engine 90. Point F1 illustrated in
Further, in another or a plurality of other embodiments, after step S21 as illustrated in
When the required power change amount, that is, the slope of the required power is determined in step S41 to have a value greater than 0, the required power is in an increasing state, in which case the vehicle ECU 20 or the HCU 60 immediately starts the engine 90. This is Case 1 in
On the other hand, when the required power change amount, that is, the slope of the required power L in
When the required power change amount (slope) is 0, the required power amount is maintained the same, so that when the counted second time reaches a second set time T2 in step S44, the vehicle ECU 20 or the HCU 60 starts the engine 90. This is Case 2 from among the cases illustrated in
Further, when the required power change amount (slope) is less than 0, this indicates that the required power amount is being reduced, in which case the vehicle ECU 20 or the HCU 60 resets the counted second time to 0 in step S45.
This may be Case 3 illustrated in
As illustrated in
It is determined through step S46 that Case 3 in
According to the system and method for controlling an engine of a hybrid vehicle according to an exemplary embodiment of the present invention as described above, when the required power exceeds P3, the engine is immediately started in order to provide the desired output level without delay by operating the engine at high power.
Further, referring to
While this invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10-2011-0129699 | Dec 2011 | KR | national |
