Patent Description:
Hybrid power vehicles have developed rapidly in the past few years, and the main advantage lies in the reduction of carbon dioxide and exhaust pollutant emissions. This is made possible by the more efficient use of energy in the hybrid power system, such as the improved charging and discharging capacity of the storage battery, the increased power storage, and the smoother control method for switching between the motor and the internal combustion engine.

The conventional optimizing method for the hybrid power system is used to achieve energy efficiency and improve the overall system power. Most conventional optimizing methods adopt rule-based control (RBC), and the characteristics of this optimization method are easy implementation, high computing efficiency, and fast experimental verification. That is, actuating conditions for three operation modes, such as low load, medium load, and high load, are set and the hybrid power system is allowed to switch automatically to the appropriate operation mode according to the required torque value and speed value. However, the conventional rule-based control optimization method is limited by overly simplified actuating conditions, which fail to achieve the purpose of energy efficiency optimization.

<CIT> relates to a system, apparatus, and method for controlling the power output distribution of a hybrid power train. <CIT> relates to a hybrid transmission device which includes first and second transmission input shafts, a superposition gear unit arranged axially parallel to the first and second transmission input shafts for connecting an electric machine. <CIT> relates to a control apparatus and method for controlling a torque of an engine.

The following disclosure serves a better understanding of the present invention. The disclosure provides a hybrid power system that adopts equivalent consumption minimization strategies to achieve the best power distribution between an internal combustion engine and an electric motor, thereby improving the operating endurance of the hybrid power system.

The hybrid power system of the disclosure includes a control core, a driving mechanism, an internal combustion engine, an electric motor, and a storage battery. The driving mechanism is controlled by the control core. The internal combustion engine is connected to the driving mechanism and controlled by the control core. The electric motor is connected to the driving mechanism and controlled by the control core. The storage battery is coupled to the electric motor and the control core. In response to a required torque being input to the control core, the control core executes an equivalent consumption minimization strategy and actuates the internal combustion engine and/or the electric motor to transmit power to the driving mechanism.

The optimizing method of the hybrid power system of the disclosure includes a control core, a driving mechanism, an internal combustion engine, an electric motor, and a storage battery. The driving mechanism is controlled by the control core. The internal combustion engine is connected to the driving mechanism and controlled by the control core. The electric motor is connected to the driving mechanism and controlled by the control core. The storage battery is coupled to the electric motor and the control core. The optimizing method for the hybrid power system is described below. The hybrid power system is switched to a standby mode in response to a required torque detected by the control core being zero. A required torque is input to the control core to actuate the hybrid power system. It is determined whether the required torque is an arbitrary value greater than zero. The hybrid power system is switched to the standby mode in response to a negative result. An equivalent consumption minimization strategy is executed by the control core of the hybrid power system in response to a positive result. The internal combustion engine and/or the electric motor is actuated by the control core simultaneously to transmit power to the driving mechanism. The hybrid power system is switched off and showing a battery capacity of zero. The hybrid power system is switched to the standby mode.

According to the invention, the equivalent consumption minimization strategy establishes a four-loop formula, conducts a global search for the required torque, a rotating speed of the electric motor, and a remaining storage battery capacity of the storage battery, and uses a global grid search to calculate the minimum equivalent consumption of all conditions and output a multi-dimensional table.

In an embodiment of the disclosure, a function of the minimum equivalent consumption is J=min[me + f(SOC)*mm ]+γ.

In an embodiment of the disclosure, a corresponding array of values of the minimum equivalent consumption is obtained through the multi-dimensional table and through inputting parameters of a specific required torque, the rotating speed of the electric motor, and the remaining storage battery capacity, so as to find a corresponding output torque of the internal combustion engine in the array of values.

Based on the above, the hybrid power system of the disclosure is adapted for vehicles, and the hybrid power system has an internal combustion engine, an electric motor, a storage battery, and a driving mechanism. Through the equivalent consumption minimization strategy, the minimum energy consumption under different parameter conditions, such as torque, rotating speed, and remaining battery, may be calculated, so as to achieve the purpose of efficient driving and power recycling. With the equivalent consumption minimization strategy, the hybrid power system may automatically adjust the output ratio of the dual power of the internal combustion engine and the electric motor, thereby improving the operating endurance of the hybrid power system and avoiding damage and security issues caused by excessive charge/discharge of the storage battery.

Furthermore, the optimizing method of the hybrid power system of the disclosure adopts the equivalent consumption minimization strategy to set a minimum equivalent consumption function. The minimum equivalent consumption function may calculate the minimum equivalent fuel consumption of the internal combustion engine and the electric motor under test conditions. In addition, a penalty value is also added to the minimum equivalent consumption function, and the global grid search is used to output the multi-dimensional table, so as to calculate the performance of the hybrid power system under different parameter conditions.

<FIG> is a structural schematic view of a hybrid power system according to an embodiment of the disclosure. <FIG> is a block schematic view of the hybrid power system in <FIG>.

Referring to <FIG> and <FIG>, a hybrid power system <NUM> of the disclosure is adapted for vehicles. Through an optimal strategy, the purpose of efficient driving and power recycling, as well as optimal deployment of hybrid power are achieved. <FIG> is a flowchart of the optimizing method of the hybrid power system in <FIG>.

Referring to <FIG> and <FIG>, the hybrid power system <NUM> includes a control core <NUM>, a driving mechanism <NUM>, an internal combustion engine <NUM>, an electric motor <NUM>, and a storage battery <NUM>.

The control core <NUM> is, for example, a central processing unit of a vehicle, which is configured to receive various signals to determine an operating status and output corresponding control commands according to the program logic, so as to achieve the purpose of automatic mode switching. The driving mechanism <NUM> is controlled by the control core <NUM>. The driving mechanism <NUM> is, for example, connected to tires of the vehicle. The internal combustion engine <NUM> is connected to the driving mechanism <NUM> and controlled by the control core <NUM>. The electric motor <NUM> is connected to the driving mechanism <NUM> and controlled by the control core <NUM>. The storage battery <NUM> is coupled to the electric motor <NUM> and the control core <NUM>. The storage battery <NUM> may be a rechargeable battery using lead-acid cells, nickel-metal hydride batteries, lithium-ion batteries, aluminum cells, or fuel cells.

With reference to <FIG>, in response to a required torque Td being input to the control core <NUM>, the control core <NUM> executes an equivalent consumption minimization strategy (as shown in <FIG>) and actuates the internal combustion engine <NUM> and/or the electric motor <NUM> to transmit power to the driving mechanism <NUM>. In short, the control core <NUM> calculates an optimal power output ratio of the internal combustion engine <NUM> and the electric motor <NUM> under the condition of the required torque Td according to the equivalent consumption minimization strategy.

Referring to <FIG> and <FIG>, the driving mechanism <NUM> has a first clutch <NUM>, a second clutch <NUM>, a first rotating wheel <NUM>, a second rotating wheel <NUM>, and a conveyor belt <NUM>. The first clutch <NUM> is disposed around a first rotation axis <NUM> of the internal combustion engine <NUM>. The second clutch <NUM> is disposed around a second rotation axis <NUM> of the electric motor <NUM>. The first rotating wheel <NUM> is connected to the first clutch <NUM>. The second rotating wheel <NUM> is connected to the second clutch <NUM>. The conveyor belt <NUM> is disposed around the first rotating wheel <NUM> and the second rotating wheel <NUM>.

Referring to <FIG> and <FIG>, the hybrid power system <NUM> is adapted for switching to an internal combustion engine <NUM> power mode, that is, switching off the electric motor <NUM> and using the internal combustion engine <NUM> as a single power source. In response to the control core <NUM> actuating the internal combustion engine <NUM>, the control core <NUM> locks the first clutch <NUM> and releases the second clutch <NUM>. The power of the internal combustion engine <NUM> is transmitted to the first clutch <NUM> through the first rotation axis <NUM>. Since the first clutch <NUM> is locked to the first rotation axis <NUM>, the first clutch <NUM> and the first rotating wheel <NUM> rotate along with the first rotation axis <NUM> and drive the second rotating wheel <NUM> to rotate relative to the second rotation axis <NUM> through the first rotating wheel <NUM> and the conveyor belt <NUM>.

Referring to <FIG> and <FIG>, the hybrid power system <NUM> is adapted for switching to an electric motor <NUM> power mode, that is, switching off the internal combustion engine <NUM> and using the electric motor <NUM> as a single power source. In response to the control core <NUM> actuating the electric motor <NUM>, the control core <NUM> locks the second clutch <NUM> and releases the first clutch <NUM>. The power of the electric motor <NUM> is transmitted to the second clutch <NUM> through the second rotation axis <NUM>. Since the second clutch <NUM> is locked to the second rotation axis <NUM>, the second clutch <NUM> and the second rotating wheel <NUM> rotate along with the second rotation axis <NUM> and drive the first rotating wheel <NUM> to rotate relative to the first rotation axis <NUM> through the second rotating wheel <NUM> and the conveyor belt <NUM>.

Referring to <FIG> and <FIG>, the hybrid power system <NUM> is adapted for switching to a maximum power mode, that is, simultaneously actuating the internal combustion engine <NUM> and the electric motor <NUM> as dual power outputs. In response to the control core <NUM> actuating the internal combustion engine <NUM> and the electric motor <NUM>, the control core <NUM> simultaneously locks the first clutch <NUM> and the second clutch <NUM>. The internal combustion engine <NUM> drives the first rotating wheel <NUM> through the first rotation axis <NUM> and the first clutch <NUM>, and the electric motor <NUM> drives the second rotating wheel <NUM> through the second rotation axis <NUM> and the second clutch <NUM>, thereby achieving the purpose of maximizing the power output.

Referring to <FIG> and <FIG>, the hybrid power system <NUM> is adapted for charging the storage battery <NUM> to achieve the purpose of power recycling. The trigger condition is that the remaining battery of the storage battery <NUM> is lower than a default value (e.g., lower than <NUM>%), and the control core <NUM> switches the electric motor <NUM> to a generator mode. In response to the electric motor <NUM> being switched to the generator mode, the control core <NUM> simultaneously locks the first clutch <NUM> and the second clutch <NUM>, and the electric motor <NUM> is switched off at this point to use the internal combustion engine <NUM> as a single power source. The power of the internal combustion engine <NUM> drives the first rotating wheel <NUM>, the conveyor belt <NUM>, the second rotating wheel <NUM> through the first rotation axis <NUM> in sequence to drive the second rotation axis <NUM> to rotate in the electric motor <NUM> for charging the storage battery <NUM>.

In this way, in response to the hybrid power system <NUM> using the internal combustion engine <NUM> as a single power source, it is suitable to recycle and use a portion of the power for charging. After the remaining battery of the storage battery <NUM> rises to a security level, the control core <NUM> automatically disable the generator mode of the electric motor <NUM> and return to a driving mode.

Referring to <FIG> and <FIG>, the hybrid power system <NUM> further includes a first torque sensor <NUM> and a second torque sensor <NUM>. The first torque sensor <NUM> is connected between the driving mechanism <NUM> and the internal combustion engine <NUM> and coupled to the control core <NUM>. The first torque sensor <NUM> is configured to detect a torque value when the internal combustion engine <NUM> is operating and return the torque value to the control core <NUM>. The second torque sensor <NUM> is connected between the driving mechanism <NUM> and the electric motor <NUM> and coupled to the control core <NUM>. The second torque sensor <NUM> is configured to detect a torque value when the electric motor <NUM> is operating and return the torque value to the control core <NUM>.

Referring to <FIG> and <FIG>, the hybrid power system <NUM> further includes a dynamometer <NUM> and a third torque sensor <NUM>. The dynamometer <NUM> is connected to the second rotating wheel <NUM> of the driving mechanism <NUM> through a third rotation axis <NUM>, and the third rotation axis <NUM> and the second rotation axis <NUM> are disposed coaxially. The third torque sensor <NUM> is connected between the dynamometer <NUM> and the driving mechanism <NUM>. Specifically, the dynamometer <NUM> serves as a load simulator, that is, the weight of the vehicle itself and the resistance generated during driving, which is beneficial to improve the simulation accuracy of the equivalent consumption minimization strategy executed by the hybrid power system <NUM>.

Referring to <FIG>, the hybrid power system <NUM> further includes an encoder EC disposed around the first rotation axis <NUM> and configured to measure a rotating speed of the internal combustion engine <NUM> and feedback a signal to the control core <NUM>. The control core <NUM> is adapted for receiving signal values of the encoder EC, the first torque sensor <NUM>, and the second torque sensor <NUM> for dynamically switching the lock and release states of the first clutch <NUM> and the second clutch <NUM>. In this way, the control core <NUM> may optimize the power output ratio of the internal combustion engine <NUM> and the electric motor <NUM> to achieve the purpose of minimizing the energy consumption.

Referring to <FIG>, the optimizing method of the hybrid power system <NUM> of the disclosure is described below. Step S1: in response to a required torque Td detected by the control core <NUM> being zero, the hybrid power system <NUM> is not actuated. Step S2: the hybrid power system <NUM> is switched to a standby mode. Step <NUM>: a required torque Td is input by a user to the control core <NUM> to actuate the hybrid power system <NUM>. Step S4: the control core <NUM> determines whether the required torque Td is an arbitrary value greater than zero. Step S5: the hybrid power system <NUM> is switched to the standby mode in response to a negative result. Step S6: an equivalent consumption minimization strategy is executed by the control core <NUM> of the hybrid power system <NUM> in response to a positive result. At the same time, the control core <NUM> actuates the internal combustion engine <NUM> and/or the electric motor <NUM> to transmit power to the driving mechanism <NUM> according to the determination of the equivalent consumption minimization strategy. In this way, the control core <NUM> may optimize the power output ratio of the internal combustion engine <NUM> and the electric motor <NUM>. Step S7: the hybrid power system <NUM> is guided to step S1 and step S2 and switched to the standby mode in response to the hybrid power system <NUM> being switched off, that is, the vehicle being switched off and the power of the storage battery <NUM> is displayed as zero.

In addition, the equivalent consumption minimization strategy (ECMS) use the system simulation results to present a multi-dimensional look-up table, which is encoded by a program and directly downloaded to the control core <NUM>, so that the control core <NUM> may quickly search for the best solution according to various conditions, thereby adjusting the power output ratio of the internal combustion engine <NUM> and the electric motor <NUM>. Thus, the equivalent consumption minimization strategy is adapted for power management and an electric energy/power system. In addition, the equivalent consumption minimization strategy optimizes the power recycling of the hybrid power system <NUM> during braking and downhill coasting, such as front and rear wheel braking torque distribution and hydraulic and in-wheel motor braking power recycling. In short, the power recycling technology of the hybrid power system <NUM> may establish an optimal distribution strategy under different driving modes.

<FIG> is a schematic view of the loop calculation of the equivalent consumption minimization strategy of the hybrid power system in <FIG>.

Referring to <FIG>, in response to the control core <NUM> executing the equivalent consumption minimization strategy, a four-loop formula is established. A first loop F1 is the required torque Td. A second loop F2 is a rotating speed Nm of the electric motor <NUM>. A third loop F3 is a remaining storage battery capacity SOC. A fourth loop F4 is a function of the minimum equivalent consumption. The function of the minimum equivalent consumption is defined as J = min[me + f(SOC)*mm ]+γ.

A global search is conducted for the required torque Td, the rotating speed Nm of the electric motor <NUM>, and the remaining storage battery capacity SOC of the storage battery <NUM>. For example, a search range of the required torque Td is <NUM> to <NUM>, a search range of the rotating speed Nm is <NUM> rpm to <NUM> rpm, and a search range of the remaining storage battery capacity SOC is <NUM>% to <NUM>%. A global grid search is used to calculate multiple minimum equivalent consumption of all conditions and output a multi-dimensional table. In detail, in response to a required torque Td of <NUM>, the rotating speed Nm is <NUM> rpm and the remaining battery SOC is <NUM>%. By substituting the three parameters above into J = min[me + f(SOC)*mm ]+γ for calculation, one of the values of minimum consumption may be obtained. As for the global grid search, a bunch of parameters of the required torque Td, the rotating speed Nm, and the remaining storage battery capacity SOC are substituted, in sequence, into J = min[me + f(SOC)*mm ]+γ to obtain values of all the minimum equivalent consumption J within the search range and sort out a multi-dimensional table.

A corresponding array of values of the minimum equivalent consumption J is obtained through the multi-dimensional table and through inputting parameters of a specific required torque Td, the rotating speed Nm of the electric motor <NUM>, and the remaining storage battery capacity SOC, so as to find a corresponding output torque Te of the internal combustion engine <NUM> in the array of values. In addition, the required torque Td is satisfied by output power of the internal combustion engine <NUM> and the electric motor <NUM>. Moreover, in the equivalent consumption minimization strategy, the ratio of the rotating speed Ne of the internal combustion engine to the rotating speed Nm of the electric motor is set to <NUM>:<NUM>. The output torque Te of the internal combustion engine <NUM> may be calculated by using the parameters such as the required torque Td, the rotating speed Nm of the electric motor, and the remaining storage battery capacity SOC.

Furthermore, the hybrid power system <NUM> of the disclosure is in pursuit of minimum energy consumption, so the minimum equivalent consumption function J = min[me + f(SOC)*mm ]+γ is defined for calculating a total dynamic energy consumption of the hybrid power system <NUM>. In the minimum equivalent consumption function, the electric energy consumption of the electric motor <NUM> is converted into the equivalent fuel consumption and summed up with the fuel consumption of the internal combustion engine <NUM> to obtain the equivalent total fuel consumption (minimum equivalent consumption J).

Specifically, in the above minimum equivalent consumption function, me is an actual fuel consumption of the internal combustion engine <NUM>, and mm is the equivalent fuel consumption of the electric motor <NUM>.

In the minimum equivalent consumption function, in order to enable the electric motor to be used with the storage battery <NUM> under a good working condition, a weight f(SOC) of the charging status of the battery is designed. The weighting value f(SOC) and a relation curve of the battery and the charging status may be obtained through the formula f(SOC)=<NUM>-(<NUM>-<NUM>. 7xsoc)* xsoc<NUM>.

The hybrid power system <NUM> gives a weighting value f(SOC) according to the charging status of the storage battery <NUM> at each sampling time. In response to high remaining battery of storage battery <NUM>, the weighting value f(SOC) is low; in response to low remaining battery of storage battery <NUM>, the weighting value f(SOC) is high. For example, in response to low remaining battery of the storage battery <NUM> and a high weighting value f(SOC), the equivalent fuel consumption mm of the electric motor <NUM> at a same rotating speed Nm increases. That is, the storage battery <NUM> consumes more energy when the battery is low, and saves more energy when the battery is high.

γ is a penalty value of the physical limit of the element. In response to the hybrid power system <NUM> executing the minimum equivalent consumption function to calculate the output torque of a dual power source, the minimum equivalent consumption function gives the penalty value γ in response to the substituted torque parameter exceeding an actual physical limit of the internal combustion engine <NUM> and the electric motor <NUM>. The minimum equivalent consumption J calculated by the minimum equivalent consumption function generates a maximum, and this best value result is not used by the control core <NUM>.

Specifically, in response to calculating the fuel consumption me of the internal combustion engine <NUM>, the hybrid power system <NUM> gets a current average brake-specific fuel consumption (BSFC) through two-dimensional lookup according to the torque and rotating speed sampled at each moment. Therefore, the formula for the fuel consumption me is me(t) =[BFSC(t) * Te*Ne/<NUM>]/<NUM>. Te is the output torque of the internal combustion engine, and Ne is the output rotating speed of the internal combustion engine.

In detail, the equivalent fuel consumption mm of the electric motor <NUM> is the sum of two modes of the electric motor <NUM>, that is, mm= mm,t + mm,g. The former (mm,t) is the motor driving mode, and the latter (mm,g) is the generator mode.

With reference to <FIG>, in the motor driving mode, the electric motor <NUM> converts the electric energy of the storage battery <NUM> into power and outputs to the driving mechanism <NUM>. The equivalent fuel consumption formula thereof is defined as mm,t =<NUM>*(Tm*Nm/<NUM>)/<NUM>*ηm. In the above formula, mm,t indicates the equivalent fuel consumption in the motor driving mode, Tm and Nm indicate, respectively, the output torque and the rotating speed in the motor driving mode, and ηm indicates the rotating efficiency of the electric motor <NUM> in the motor mode.

In response to the electric motor <NUM> switching to the generator mode, the power of the internal combustion engine <NUM> is transmitted to the second rotation axis <NUM> of the electric motor <NUM> to drive the second rotation axis <NUM> to rotate in the electric motor <NUM> and charge the storage battery <NUM>. The equivalent fuel consumption formula thereof is defined as mm,g =<NUM>* (Tm*Nm/<NUM>)/<NUM>*ηg. In the above formula, mm,g indicates the equivalent fuel consumption in the generator mode, Tm and Nm indicate, respectively, the torque (a negative torque value represents the generator mode) and the rotating speed (driving mode and generator mode have the same rotating speed) in the generator mode, and ηg is the rotating efficiency of the electric motor <NUM> in the generator mode.

To sum up, the hybrid power system of the disclosure is adapted for vehicles, and the hybrid power system has an internal combustion engine, an electric motor, a storage battery, and a driving mechanism. Through the equivalent consumption minimization strategy, the minimum energy consumption under different parameter conditions, such as required torque, motor rotating speed, and remaining battery, may be calculated, so as to achieve the purpose of efficient driving and power recycling. With the equivalent consumption minimization strategy, the hybrid power system may automatically adjust the output ratio of the dual power of the internal combustion engine and the electric motor, thereby improving the operating endurance of the hybrid power system and avoiding damage and security issues caused by excessive charge/discharge of the storage battery.

Claim 1:
A hybrid power system (<NUM>), comprising:
a control core (<NUM>);
a driving mechanism (<NUM>), controlled by the control core (<NUM>);
an internal combustion engine (<NUM>), connected to the driving mechanism (<NUM>) and controlled by the control core (<NUM>);
an electric motor (<NUM>), connected to the driving mechanism (<NUM>) and controlled by the control core (<NUM>); and
a storage battery (<NUM>), coupled to the electric motor (<NUM>) and the control core (<NUM>),
wherein in response to a required torque (Td) being input to the control core (<NUM>), the control core (<NUM>) executes an equivalent consumption minimization strategy and actuates the internal combustion engine (<NUM>) and/or the electric motor (<NUM>) to transmit power to the driving mechanism (<NUM>),
wherein the hybrid power system is characterized in that
the equivalent consumption minimization strategy establishes a four-loop formula, conducts a global search for the required torque (Td), a rotating speed of the electric motor (<NUM>), and a remaining storage battery (<NUM>) capacity of the storage battery (<NUM>), and uses a global grid search to calculate a plurality of minimum equivalent consumption (J) of all conditions and output a multi-dimensional table.