The present disclosure relates generally to powertrains and, for example, to control of a hybrid powertrain system.
Internal combustion engines may be used to power different devices and/or machines. Internal combustion engines provide reliable power. However, internal combustion engines are associated with several drawbacks. For example, emissions from internal combustion engines may impact the environment and/or human health. Furthermore, internal combustion engines may be associated with high fuel costs, as fuel is consumed continuously while an internal combustion engine is operating, even during idling or waiting times. As another example, internal combustion engines produce a high level of noise. The noise produced by an internal combustion engine can be a nuisance, and in particular, may obstruct communication among a work crew for a machine that uses the internal combustion engine. Moreover, internal combustion engines produce significant amounts of heat. Accordingly, a machine that uses an internal combustion engine may utilize a large cooling package to dissipate heat.
China Patent Publication No. 112195730 (the '730 publication) discloses an electrically driven paver. The '730 publication states that the paver includes a power unit with a diesel engine, a generator driver, and a motor. The '730 publication states that the power unit may adopt a hybrid mode to improve fuel economy and reduce noise, or adopt a pure electric mode associated with low noise and zero emissions.
However, the '730 publication does not disclose controlling switching between the electric mode and the hybrid mode, or controlling the flow of power in the hybrid mode. One of the main challenges with a hybrid powertrain system is controlling when the hybrid powertrain system is to operate in a hybrid mode and/or controlling the distribution of power between an internal combustion engine and an electric motor. For example, it may be difficult to determine how much power should be provided by the internal combustion engine, how much power should be provided by the electric motor, and/or how much power should be provided to charge a battery.
The hybrid powertrain system of the present disclosure solves one or more of the problems set forth above and/or other problems in the art.
A hybrid powertrain system of a paver may include an electric machine that is configured to operate as both an electric motor and a generator, the electric machine being mechanically coupled to a pump. The hybrid powertrain system may include one or more batteries configured to provide power to, or receive power from, the electric machine. The hybrid powertrain system may include an engine mechanically coupleable to the electric machine and the pump via a clutch. The hybrid powertrain system may include a controller configured to cause, based on a state of charge (SOC) of the one or more batteries at least meeting an SOC threshold, the pump to be powered using the electric machine by disengagement of the engine from the electric machine and the pump via the clutch, and cause, based on the SOC of the one or more batteries being below the SOC threshold, the pump to be powered using at least the engine by engagement of the engine with the electric machine and the pump via the clutch.
A controller for a hybrid powertrain system including an engine and an electric machine may include one or more memories and one or more processors. The one or more processors may be configured to cause a load to be powered using the electric machine based on an SOC of one or more batteries connected to the electric machine at least meeting an SOC threshold and based on a power output of the electric machine at least meeting a level of demand of the load. The one or more processors may be configured to cause, based on the SOC of the one or more batteries and based on the level of demand of the load, power to be provided to the load via a first power output of the engine and a second power output of the electric machine in accordance with a ratio between the first power output and the second power output, the ratio being based on the level of demand of the load.
A method may include causing, by a controller for a hybrid powertrain system including an engine and an electric machine, disengagement of the engine from the electric machine via a clutch based on an SOC of one or more batteries connected to the electric machine at least meeting an SOC threshold, where disengagement of the engine causes the hybrid powertrain system to operate in an electric-only mode for powering a load. The method may include detecting, by the controller, a power event that includes at least one of a level of demand of the load exceeding a demand threshold based on a peak power output of the electric machine, or the SOC of the one or more batteries being below the SOC threshold. The method may include causing, by the controller and based on detection of the power event, engagement of the engine with the electric machine via the clutch, where engagement of the engine enables the hybrid powertrain system to operate in a hybrid mode for powering the load.
This disclosure relates to a controller, which is applicable to any machine that includes a hybrid powertrain system (e.g., a powertrain driven by one or more engines and one or more electric motors). For example, the machine may be a vehicle, a compactor machine, a paving machine, a cold planer, a grading machine, a backhoe loader, a wheel loader, a harvester, an excavator, a motor grader, a skid steer loader, a tractor, a dozer, a hydraulic fracturing system, a boat, a pump, a pump system, a generator system, and/or another machine that uses power generated via a hybrid powertrain system.
The machine 100 includes a frame 102 with a set of ground-engaging elements 104 such as tracks or wheels coupled with the frame 102. The ground-engaging elements 104 may be driven by a hybrid powertrain system 200. Additionally, or alternatively, the hybrid powertrain system 200 may drive or power another component or system of the machine 100, such as one or more pumps (e.g., of a hydraulic power system of the machine 100) and/or other components described herein. A screed 106 can be positioned at the rear end of the machine 100 to spread and compact paving material into an asphalt mat 108 having a desired thickness, size, uniformity, crown profile, and cross slope. The machine 100 also includes an operator station 110 having a seat and a console, which includes various controls for directing operations of the machine 100 by inputting instructions at an input panel 112. A controller 114 is provided for electrically controlling various aspects of the machine 100. For example, the controller 114 can send and receive signals from various components of the machine 100 during the operation of the machine 100.
The machine 100 further includes a hopper 116 for storing a paving material, and a conveyor system including one or more conveyors 118 configured to move paving material from the hopper 116 to the screed 106 at the rear of the machine 100. One or more augers 120 are arranged near the forward end of the screed 106 to receive the paving material supplied by the conveyor 118 and spread the material evenly beneath the screed 106. The screed 106 can be pivotally coupled behind the machine 100 by one or more tow arms 122 that extend between the frame 102 of the paving machine and the screed 106. Alternatively, the screed 106 can be pivotally coupled behind the machine 100 by a pair of tow arms 122 that extend between a tow point on the frame 102 of the machine 100 and the screed 106.
The tow arms 122 can also have the tow point raised and lowered on the machine 100 using a positioning cylinder 124 which, when moved up and down, moves the tow point of the tow arms 122 and changes an angle of attack of the screed 106. Also, as part of a paving process, one or more cylinders 126 on the screed 106 can raise or lower portions of the screed 106. For example, to change a height or paving angle of a main screed plate 128, the machine 100 may use one or more extender screed plates 130. The screed 106 can include a screed frame 132 with the main screed plate 128 coupled to the screed frame 132. The screed plate 128 is configured to float on the paving material of the asphalt mat 108 laid upon a prepared paving bed and to “smooth” or level and compact the paving material on the base surface, such as for example a roadway or roadbed. The screed 106 can further include the one or more extender screed plates 130 that extend beyond the main screed plate 128 to extend the paving width of the screed 106.
The screed 106 can include a tamper bar assembly 134 positioned forward of the screed plate 128 and extending transversely to the direction of travel of the machine 100. The tamper bar assembly 134 may include a tamper bar 136. The tamper bar assembly 134 can be coupled to the screed frame 132 of screed 106 and configured such that the tamper bar 136 is reciprocated in an upward and downward direction substantially perpendicular to the asphalt mat 108 and substantially perpendicular to the direction of travel of the machine 100. The tamper bar assembly 134 pre-compacts the paving material as the machine 100 moves forward and the screed 106 smooths the paving material to remove air pockets and other voids to create a relatively flat, paved surface.
As indicated above,
The electric machine 202 may be a machine that is configured to operate as both an electric motor and a generator (e.g., based on a direction of flow of power to or from the electric machine 202). The electric machine 202 may be a switched reluctance machine, an induction motor machine, and/or a brushless permanent magnet motor machine, among other examples.
The engine 204 may be an internal combustion engine. For example, the engine 204 may be powered by fuel, such as gasoline, oil, and/or natural gas, among other examples. The engine 204 may include a cylinder block, cylinder head, pistons, connecting rods, crankshaft, valves, camshaft, spark plugs, fuel injectors, and/or an air intake system, among other examples.
The electric machine 202 may be mechanically coupled to the load 206. The engine 204 may be mechanically coupleable to the electric machine 202 and the load 206 via a clutch 218 (the term “mechanically coupled” encompasses both the direct and indirect connection of the engine 204 and/or the electric machine 202 to the load 206, for example, through one or more clutches (in addition to clutch 218) or gearsets). The clutch 218 may be configured for coupling of a parasitic load (e.g., the electric machine 202) to the engine 204. For example, the clutch 218 may be a type of disconnect clutch. Engagement of the clutch 218 engages the engine 204 with the electric machine 202 and the load 206 (e.g., via a driveshaft 216). Disengagement of the clutch 218 disengages the engine 204 from the electric machine 202 and the load 206. In some examples, the engine 204 may produce mechanical power that causes the driveshaft 216 to rotate (e.g., when the clutch 218 is engaged). The electric machine 202 may be mechanically coupled to the driveshaft 216. For example, the engine 204 may be configured to rotate a shaft of the electric machine 202 (e.g., when the clutch 218 is engaged). The electric machine 202 may be configured to receive power from the driveshaft 216 (e.g., when the electric machine 202 is operating in a generator mode) and provide power to the driveshaft 216 (e.g., when the electric machine 202 is operating in a motor mode).
The electric machine 202 and/or the engine 204 are configured to drive or power the load 206. For example, the electric machine 202 and/or the engine 204 are mechanically coupled to the drive 208 (e.g., a drive box or a gear box) of the load 206. As shown, the electric machine 202 and the engine 204 may be arranged in series to drive or power the load 206. However, in some examples, the electric machine 202 and the engine 204 may be arranged in parallel to drive or power the load 206. In some examples, the electric machine 202 and/or the engine 204 are mechanically coupled directly to the load 206, such as via the driveshaft 216 (e.g., without a drive 208). As another example, the driveshaft 216 may be configured to provide mechanical power to the drive 208. The drive 208 is configured to transfer the mechanical power to the load 206. The load 206 may be the machine 100, a component or system of the machine 100, one or more pumps, a pump system, a vehicle (e.g., wheels of the vehicle and/or the ground-engaging elements 104), a generator, a tool, and/or another machine or component.
The electric machine 202 is electrically coupled to one or more batteries 212 via a converter 210 (e.g., an inverter). The one or more batteries 212 are configured to provide electric power to the electric machine 202 (e.g., to power the electric machine 202 when the electric machine 202 is operating in a motor mode). Additionally, the one or more batteries 212 are configured to receive electric power from the electric machine 202 (e.g., to charge the one or more batteries 212 when the electric machine 202 is operating in a generator mode). The converter 210 may be a device capable of converting direct current (DC) to alternating current (AC), and vice-versa. The converter 210 may be a variable frequency drive.
For example, the one or more batteries 212 may be a source of DC power, while the electric machine 202 is used as a load that requires AC power. The converter 210 serves as an interface between the two components by converting the DC power from the one or more batteries 212 to AC power that can be used to power the electric machine 202, and/or converting AC power provided by the electric machine 202 to DC power to be provided to charge the one or more batteries 212. The converter 210 is capable of bidirectional power flow. This means that the converter 210 can operate in both directions, converting DC power to AC power when the flow of power is in one direction, and converting AC power to DC power when the flow of power is in the opposite direction. By controlling the direction of the power flow through the converter 210, the direction of electrical power can be controlled. As another example, one or more components, such as a power diode or a power switch, may be used to control the direction of power flow. For example, a power diode can be used to allow current to flow in one direction only, while blocking current flow in the opposite direction. Similarly, a power switch, such as a transistor, can be used to selectively connect or disconnect a load from a power source, allowing the direction of power flow to be controlled. For example, the controller 214 may configure the direction of flow of power between the electric machine 202 and the one or more batteries 212.
The controller 214 may be the controller 114 or may be a separate controller. The controller 214 may include one or more processors and one or more memories. The processor may include a central processing unit, a graphics processing unit, a microprocessor, a controller, a microcontroller, a digital signal processor, a field-programmable gate array, an application-specific integrated circuit, and/or another type of processing component. The processor may be implemented in hardware, firmware, or a combination of hardware and software. The processor may include one or more processors capable of being programmed to perform one or more operations or processes described elsewhere herein. The memory may include volatile and/or nonvolatile memory. For example, the memory may include random access memory (RAM), read only memory (ROM), a hard disk drive, and/or another type of memory (e.g., a flash memory, a magnetic memory, and/or an optical memory). The memory may include internal memory (e.g., RAM, ROM, or a hard disk drive) and/or removable memory (e.g., removable via a universal serial bus connection). The memory may be a non-transitory computer-readable medium. The memory may store information, one or more instructions, and/or software (e.g., one or more software applications) related to the operation of the controller 214. The memory may include one or more memories that are coupled (e.g., communicatively coupled) to the one or more processors, such as via a bus. Communicative coupling between a processor and a memory may enable the processor to read and/or process information stored in the memory and/or to store information in the memory.
The controller 214 may perform one or more operations or processes described herein. For example, a non-transitory computer-readable medium (e.g., memory) may store a set of instructions (e.g., one or more instructions or code) for execution by the processor. The processor may execute the set of instructions to perform one or more operations or processes described herein. In some implementations, execution of the set of instructions, by one or more processors, causes the one or more processors and/or the controller 214 to perform one or more operations or processes described herein. Hardwired circuitry may be used instead of or in combination with the instructions to perform one or more operations or processes described herein.
For example, the controller 214 may control switching between an electric-only mode of the hybrid powertrain system 200 (e.g., in which the load 206 is powered by the electric machine 202 and the engine 204 is disengaged) and a hybrid mode of the hybrid powertrain system 200 (e.g., in which the engine 204 is engaged and the load 206 is powered using at least the engine 204). In particular, the hybrid powertrain system 200 may be in the electric-only mode when a state of charge (SOC) of the one or more batteries 212 at least meets an SOC threshold (e.g., 30% charge) and/or when a power output of the electric machine 202 can at least meet a level of demand of the load 206. Conversely, the hybrid powertrain system 200 may be in the hybrid mode when the SOC of the one or more batteries 212 is below the SOC threshold and/or when the level of demand of the load 206 exceeds the power output (e.g., a peak power output) of the electric machine 202. As described herein, in the hybrid mode, the electric machine 202 may operate in a generator mode or in a motor mode based on the level of demand of the load 206.
In the hybrid mode, the controller 214 may cause power to be proportionally provided to drive the load 206 via the engine 204 and the electric machine 202 in accordance with a ratio between a first power output provided via the engine 204 and a second power output provided via the electric machine 202. As an example, the controller 214 may cause power to be provided to the load 206 via the first power output of the engine 204 and the second power output of the electric machine 202 in accordance with the ratio. Moreover, the controller 214 may cause power to be provided to the load 206 via the first power output and the second power output based on the SOC of the one or more batteries 212 (e.g., when the SOC is below the SOC threshold) and based on the level of demand of the load 206 (e.g., the ratio may be optimized for a particular level of demand of the load 206). The controller 214 may configure the engine 204 to provide a first torque output and the electric machine 202 to provide a second torque output (e.g., to drive the driveshaft 216, the drive 208, and/or the load 206) based on a level of demand of the load 206. For example, the controller 214 may detect a level of demand associated with the load 206. The level of demand may be a torque level, a power level, and/or an energy level, among other examples. The controller 214 may determine a ratio between a power provided by the engine 204 and a power provided by the electric machine 202 to meet the level of demand or other operational parameters associated with the load 206 (e.g., in an efficient manner, in a low-noise manner, in a maximum-power manner, or the like).
The controller 214 may obtain one or more sensor measurements associated with the hybrid powertrain system 200. The sensor measurements may include a power output of the engine 204, a torque output of the engine 204, a power output of the electric machine 202, a torque output of the electric machine 202, a power input to the electric machine 202, a level of electric energy output by the electric machine 202 (e.g., a voltage and/or a current input to the electric machine 202), and/or a level of demand of the load 206 (e.g., a power level, a torque level, a pressure, a speed, and/or another level of demand), among other examples. Moreover, the sensor measurements may include an SOC of the one or more batteries 212. For example, the hybrid powertrain system 200 may include one or more sensors configured to communicate with the controller 214, such as one or more torque sensors, one or more dynamometers, one or more accelerators, one or more strain gauges, one or more pressure sensors, one or more voltage sensors, and/or one or more other sensors configured to measure the sensor measurements. The controller 214 may obtain (e.g., periodically) the sensor measurements from the one or more sensors.
The controller 214 may be configured to control the flow of mechanical and electrical energy associated with the hybrid powertrain system 200. For example, the controller 214 may be configured to control the flow of mechanical energy to the load 206 and the flow of electrical energy from the one or more batteries 212 or to the one or more batteries 212. For example, the controller 214 may be configured to control a charging rate of the one or more batteries 212 (e.g., that are charged via electrical energy or power output via the electric machine 202). The controller 214 may control the flow of mechanical and electrical energy associated with the hybrid powertrain system 200 based on the level of demand of the load 206, a control mode associated with the hybrid powertrain system 200, and/or an operating mode associated with the hybrid powertrain system 200, among other examples.
For example, the controller 214 may be associated with multiple control modes for controlling the hybrid powertrain system 200. A control mode may define how the controller 214 ramps up or down a charging rate of the one or more batteries, sets the ratio of power levels, and/or determines when to switch the electric machine 202 from operating in a generator mode to operating in a motor mode, among other examples. For example, the multiple control modes may include the electric-only mode (e.g., depicted and described in more detail in connection with
The controller 214 may be associated with multiple operational modes. An operational mode may be associated with a function or current use case of the machine 100. An operational mode may define how the controller 214 ramps up or down a charging rate of the one or more batteries and/or how the controller 214 ramps up or down a ratio of power outputs by the engine 204 and the electric machine 202 in connection with operation of the hybrid powertrain system 200 in the hybrid mode. As an example, the control mode may be represented with a graph depicting battery current versus machine power demand (e.g., the graphs depicted in
The controller 214 may determine a power ratio or a power distribution (e.g., between a power provided by the electric machine 202 and a power provided by the engine 204), to be used in the hybrid mode, based on an efficiency metric. The efficiency metric may be based on, or otherwise associated with, a fuel consumption by (e.g., a fuel efficiency of) the engine 204, and/or a noise level produced by the hybrid powertrain system 200, among other examples. For example, the controller 214 may determine a power ratio or a power distribution associated with a highest efficiency metric for a given level of demand of the load 206. In other words, different power ratios and/or different power distributions may result in different levels of efficiency of the hybrid powertrain system 200 and/or of the engine 204. The controller 214 may determine, for a given level of demand of the load 206, a power ratio or a power distribution associated with the highest efficiency metric. The controller 214 may cause the hybrid powertrain system 200 to operate using the power ratio or the power distribution associated with the highest efficiency metric. As the level of demand of the load 206 changes, the controller 214 may change and/or determine the optimal power ratio or power distribution (e.g., associated with the highest efficiency metric) for other levels of demand.
In some implementations, the controller 214 may use a machine learning model (e.g., an artificial intelligence model) to determine the optimal power ratios and/or optimal power distributions for different levels of demands and/or in different use cases of the hybrid powertrain system 200. Additionally, or alternatively, the controller 214 may use the machine learning model to determine an optimal timing for switching between an electric-only mode and a hybrid mode of the hybrid powertrain system 200 (e.g., an optimal timing for engaging or disengaging the clutch 218). An input to the machine learning model may indicate power inputs and power outputs of the hybrid powertrain system 200 over time. For example, an input to the machine learning model may indicate historical fuel consumption of the engine 204 (or similar engines) at different levels of demand, different power outputs of the engine 204 (or similar engines) over time, historical power consumption of the electric machine 202 (or similar electric machines) at different levels of demand, different power outputs of the electric machine 202 (or similar electric machines) over time, and/or different battery SOCs and/or load demand levels at mode switching times.
The machine learning model may be trained to output the optimal power ratios and/or optimal power distributions for different levels of demands. For example, an output of the machine learning model may be a value of the efficiency metric for different power ratios at different levels of demand. As another example, the output of the machine learning model may be a value of optimal power ratios at different levels of demand (e.g., that result in an optimized or highest efficiency metric). For example, the machine learning model may learn a most efficient combination of electric machine 202 power and engine 204 power based on charging and/or discharging rates of the one or more batteries 212, electric machine 202 torque or power output, and/or engine 204 torque or power output. The machine learning model may output an indication of a power distribution or power rate (e.g., information similar to the graphs depicted in
Additionally, or alternatively, the machine learning model may be trained to output an optimal timing for switching between an electric-only mode and a hybrid mode. For example, the output of the machine learning model may indicate a battery SOC and/or a load demand level for switching from an electric-only mode to a hybrid mode or for switching from a hybrid mode to an electric-only mode. As an example, the machine learning model may learn a most efficient switching time based on charging and/or discharging rates of the one or more batteries 212, electric machine 202 torque or power output, and/or engine 204 torque or power output. The machine learning model may output an indication of a switching timing (e.g., information similar to the graph depicted in
The controller 214 may control the hybrid powertrain system 200 in accordance with the output of the machine learning model. The machine learning model may be a linear regression model, a random forest model, a support vector regression model, a gradient boosting model, and/or a neural network model, among other examples.
As indicated above,
The operations associated with the control mode 300 may be depicted via the graph shown in
As shown in
To cause the load to be powered using only the electric machine 202, the controller 214 may cause disengagement of the engine 204 from the electric machine 202 via the clutch 218. For example, the controller 214 may cause disengagement of the engine 204 from the electric machine 202 via the clutch 218 based on the SOC of the one or more batteries 212 at least meeting the SOC threshold and/or based on the power output of the electric machine 202 at least meeting the level of demand of the load 206. The disengagement of the engine 204 causes the hybrid powertrain system 200 to operate in an electric-only mode for powering the load 206. As shown in
During operation of the hybrid powertrain system 200 in the control mode 300 (e.g., the electric-only mode), the controller 214 may detect a power event that is to cause switching of the hybrid powertrain system 200 to a hybrid mode. The power event may include a level of demand of the load 206 exceeding a demand threshold that is based on a peak power output of the electric machine 202 (the demand threshold is shown as a dashed vertical line in
The controller 214 may cause, based on detection of the power event (e.g., based on the level of demand of the load 206 exceeding the demand threshold and/or the SOC of the one or more batteries 212 being below the SOC threshold), the load 206 to be powered using at least the engine 204 (e.g., by engagement of the engine 204 with the electric machine 202 and the load 206 via the clutch 218) in a hybrid mode of the hybrid powertrain system 200. For example, the controller 214 may cause, based on detection of the power event, engagement of the engine 204 with the electric machine 202 via the clutch 218. The engagement of the engine 204 causes the hybrid powertrain system to operate in a hybrid mode for powering the load 206, as described in connection with
As indicated above,
The operations associated with the control mode 400 may be depicted via the graph shown in
The hybrid powertrain system 200 may operate in the control mode 400 (e.g., by engaging the engine 204 with the electric machine 202 via the clutch 218) based on the SOC of the one or more batteries 212 being below the SOC threshold and/or based on the level of demand of the load 206 exceeding the power output (e.g., the peak power output) of the electric machine 202, as described herein. As an example, in the control mode 400, the load 206 may be powered using at least the engine 204.
As shown in
For example, the controller 214 may cause the load 206 to be powered via the engine 204 based on a first value of a power level associated with the load (e.g., a first level of demand) not exceeding a power threshold. This corresponds to the downward-sloping line shown in the upper left quadrant of
The controller 214 may cause, based on the first value of the power level associated with the load 206 (e.g., the first level of demand) not exceeding the power threshold, power to be provided to charge the battery 212. In other words, by causing the load to be powered using only the engine 204, the controller 214 may cause the electric machine 202 to be driven by the engine 204 to generate power to charge the one or more batteries 212. As an example, the controller 214 may cause, in the control mode 400 (e.g., in the hybrid mode), the electric machine 202 to operate in a generator mode to charge the battery 212 based on the level of demand of the load 206 being below the power threshold. For example, as shown in
The controller 214 may control a charging rate of the battery 212 based on the power level associated with the load 206 (e.g., where the charging rate is represented by the slope of the solid line in the graph depicted in
For example, the controller 214 may detect that a second value of the power level associated with the load 206 at least meets the power threshold (e.g., is on the right side of the power threshold shown in
For example, the controller 214 may cause a flow of mechanical power to be provided from the engine 204 to the load 206 and from the electric machine 202 to the load 206 (e.g., via the electric machine 202 providing power or torque to the drive 208). The controller 214 may cause a flow of electrical power to be provided from the battery 212 to the electric machine 202 (e.g., to power the electric machine 202 operating in the motor mode). For example, when the level of demand of the load 206 is higher than the engine torque and/or power capability (e.g., the power threshold and/or the power rating of the engine 204), the controller 214 may activate the electric machine 202 and cause the electric machine 202 to operate in the motor mode (e.g., act as a motor), thereby adding torque and power to the driveshaft 216 and providing additional torque and power to the load 206.
The controller 214 may increase a power output of the electric machine 202 to the load 206 as the level of demand associated with the load 206 increases. For example, the controller 214 may cause an amount of current provided from the battery 212 to the electric machine 202 to increase as the level of demand increases. A rate at which the power output of the electric machine 202 is increased (e.g., corresponding to a slope of a dashed line on the right side of the graph depicted in
As an example,
As indicated above,
The operations associated with the control mode 500 may be depicted via the graph shown in
The hybrid powertrain system 200 may operate in the control mode 500 (e.g., by engaging the engine 204 with the electric machine 202 via the clutch 218) based on the SOC of the one or more batteries 212 being below the SOC threshold and/or based on the level of demand of the load 206 exceeding the power output (e.g., the peak power output) of the electric machine 202, as described herein. As an example, in the control mode 500, the load 206 may be powered using at least the engine 204.
As shown in
When the engine 204 is idling, the controller 214 may cause a flow of mechanical power to be provided from the engine 204 to the electric machine 202. The electric machine 202 may generate electrical power (e.g., may generate current). The controller 214 may cause the generated electrical power to be provided to the battery 212 (e.g., via the converter 210) to charge the battery 212. In other words, the controller 214 may cause the load 206 to be powered using only the engine 204 based on the engine 204 operating in the idling mode. For example, in the idling mode, the engine 204 may output enough power to overcome system parasitics (e.g., of the hybrid powertrain system 200) and to provide sufficient power to the electric machine 202 to enable the electric machine 202 to generate enough current to charge the battery 212 (e.g., to at least trickle charge the battery 212). By causing the load 206 to be powered using only the engine 204, the controller 214 may cause the electric machine 202 to be driven by the engine 204 to generate power to charge the one or more batteries 212. As an example, the controller 214 may cause, in the control mode 500 (e.g., in the hybrid mode), the electric machine 202 to operate in a generator mode to charge the battery 212 based on the engine 204 operating in the idling mode. This enables the hybrid powertrain system 200 to utilize the mechanical power generated by the engine 204 during idling and/or periods of very low levels of demand (e.g., mechanical power that would have otherwise been not used or consumed productively by the machine 100) to charge the battery 212. In some implementations, the controller 214 may cause the hybrid powertrain system 200 to operate in the electric-only mode (e.g., by causing disengagement of the engine 204 via the clutch 218) based on the SOC of the battery 212 at least meeting the SOC threshold (e.g., due to charging of the battery 212).
The controller 214 may cause the load 206 to be powered using the engine 204 and the electric machine 202 based on the engine operating in an operational mode. For example, the controller 214 may cause, in the control mode 500 (e.g., in the hybrid mode), the electric machine 202 to operate in a motor mode to power the load 206 based on the engine 204 operating in an operational mode. As used herein, “operational mode” may refer to a mode of operation where the engine 204 is operating to produce a power output for a level of demand that is greater than in the idling mode. For example, where the load 206 is a pump, the operational mode of the engine 204 may be associated with a power output greater than needed merely to spin the pump and overcome parasitics.
As an example, the controller 214 may cause, based on a level of demand of the load 206 and based on the engine 204 operating in an operational mode (e.g., based on the level of demand of the load 206 causing the engine 204 to operate in the operational mode), power to be provided to the load via a first power output of the engine 204 and a second power output of the electric machine 202 in accordance with a ratio between the first power output and the second power output. The ratio may be based on the level of demand of the load 206. For example, the controller 214 may detect that the level of demand of the load 206 is greater than or equal to the first power threshold. The controller 214 may cause the electric machine 202 to be configured to act as an electric motor (e.g., switching a direction of flow of electrical power to be from the battery 212 to the electric machine 202). The controller 214 may cause the load 206 to be powered via the engine 204 and the electric machine 202 based on the level of demand of the load 206 being greater than or equal to the first power threshold. The first power threshold may be a level of demand that causes the engine 204 to transition from the idling mode to an operational mode.
For example, when a working load is placed on the hybrid powertrain system 200, the controller 214 may cause the electric machine 202 to apply torque to the driveshaft 216 to help drive the load 206. This reduces a fuel consumption of the engine 204 by using battery energy instead (e.g., electrical power provided by the battery 212). For example, the controller 214 may increase the second power output of the electric machine 202 relative to the first power output of the engine 204 as the level of demand of the load 206 increases. A rate at which the second power output of the electric machine 202 is increased may be associated with an efficiency metric, as described in more detail elsewhere herein.
The controller 214 may increase the power output of the electric machine 202 at a first rate when the level of demand is greater than or equal to the first power threshold and less than or equal to a second power threshold. The second power threshold may be, or may be similar to, the power threshold described and depicted in connection with
In a similar manner as described elsewhere herein, a rate at which the power output of the electric machine 202 is increased (e.g., corresponding to a slope of the dashed line depicted in
As an example,
As indicated above,
As shown in
As further shown in
As further shown in
Process 600 may include causing, in the hybrid mode of the hybrid powertrain system, the electric machine to operate in a generator mode to charge the one or more batteries based on the engine operating in an idling mode or based on the level of demand of the load being below a threshold that is based on a power rating of the engine. Causing the electric machine to operate in the generator mode may include controlling a charging rate of the one or more batteries based on the level of demand associated with the load. Controlling the charging rate may include decreasing the charging rate as the level of demand associated with the load increases.
Process 600 may include causing, based on the engine operating in an idling mode, power to be provided to the electric machine via the engine, and causing, based on power to be provided to the electric machine via the engine, power to be provided to the one or more batteries to charge the one or more batteries. Process 600 may include causing power to be provided to the load via a first power output of the engine and a second power output of the electric machine based on the level of demand of the load causing the engine to operate in an operational mode.
Process 600 may include causing, in the hybrid mode of the hybrid powertrain system, the electric machine to operate in a motor mode to power the load based on the engine operating in an operational mode or based on the level of demand of the load at least meeting a threshold that is based on a power rating of the engine. Causing the electric machine to operate in the motor mode may include causing the load to be powered using the engine and the electric machine by increasing a power output of the electric machine to the load as a level of demand of the load increases.
Although
The hybrid powertrain system described herein may be used to power a load of any machine. For example, the hybrid powertrain system may be used to power a pump, or a pump system, of a hydraulic power system of a paver machine. In general, one of the main challenges with hybrid operation of a machine is controlling when the machine is to operate in a hybrid mode and/or controlling the distribution of power between an internal combustion engine and an electric motor. For example, it may be difficult to determine how much power should be provided by the internal combustion engine, how much power should be provided by the electric motor, and/or how much power should be provided to charge a battery.
The hybrid powertrain system described herein includes at least an engine, an electric machine mechanically coupled to a load, a battery for the electric machine, and a clutch to engage or disengage the engine from the load. The hybrid powertrain system is useful for controlling switching between an electric-only mode (e.g., by disengaging the clutch) and a hybrid mode (e.g., by engaging the clutch) of the hybrid powertrain system and/or for controlling the distribution of power between the engine and the electric machine in the hybrid mode. In particular, the hybrid powertrain system may switch between the electric-only mode (e.g., where only the engine is powering the load) and the hybrid mode based on a state of charge of the battery and/or a level of demand of the load. For example, the hybrid powertrain system may use the electric-only mode, thereby improving efficiency, emissions, and fuel economy, until an SOC of the battery falls below a threshold and/or until the level of demand of the load exceeds a power output of the electric machine. Furthermore, if the SOC of the battery is below the threshold, the hybrid powertrain system, operating in the hybrid mode, may charge the battery while the level of demand of the load is relatively low (e.g., during engine idling or wait times). Moreover, in the hybrid mode, the hybrid powertrain system may control the distribution of power between the engine and the electric machine based on the level of demand of the load. For example, the electric machine may assist the engine in driving the load.
Accordingly, the hybrid powertrain system may employ a smaller engine and/or a smaller cooling package (e.g., due to the smaller engine generating less heat) relative to a traditional internal combustion engine powertrain. For example, the engine may be associated with a peak load (e.g., 55 kilowatts or less) that is less than a maximum level of demand by a load of the hybrid powertrain system, because the electric machine can contribute to the peak load. In this way, the hybrid powertrain system achieves improved fuel efficiency, reduced emissions, reduced noise, and reduced heat generation, among other examples.
The foregoing disclosure provides illustration and description, but is not intended to be exhaustive or to limit the implementations to the precise forms disclosed. Modifications and variations may be made in light of the above disclosure or may be acquired from practice of the implementations. Furthermore, any of the implementations described herein may be combined unless the foregoing disclosure expressly provides a reason that one or more implementations cannot be combined. Even though particular combinations of features are recited in the claims and/or disclosed in the specification, these combinations are not intended to limit the disclosure of various implementations. Although each dependent claim listed below may directly depend on only one claim, the disclosure of various implementations includes each dependent claim in combination with every other claim in the claim set.
As used herein, “a,” “an,” and a “set” are intended to include one or more items, and may be used interchangeably with “one or more.” Further, as used herein, the article “the” is intended to include one or more items referenced in connection with the article “the” and may be used interchangeably with “the one or more.” Further, the phrase “based on” is intended to mean “based, at least in part, on” unless explicitly stated otherwise. Also, as used herein, the term “or” is intended to be inclusive when used in a series and may be used interchangeably with “and/or,” unless explicitly stated otherwise (e.g., if used in combination with “cither” or “only one of”).