METHOD AND SYSTEM FOR CONTROLLING WATER INJECTION

Abstract

Method for a hybrid vehicle (102), comprising: Propelling the hybrid vehicle (102) via an internal combustion engine (10) operating with a water injection state selected based on driver demand and water availability on board the hybrid vehicle (102); and in response to a change in driver demand, adjusting the water injection state based on each of the changes in driver demand, a state of charge of an energy storage system (54) and water availability, wherein The setting includes the selection between maintaining a current water injection state and switching to an alternative water injection state based on fuel saving in each of the current and alternative water injection states with a stored power offset based on the state of charge, wherein the current water injection state has one of an activated water injection state and one of a deactivated water injection state, and wherein the alternative water injection state has the other of the activated water injection state and the deactivated water injection state.

Description

Area

[0001] The present description generally concerns methods and systems for controlling water usage of a machine coupled in a vehicle that has a hybrid transaxle transmission and an energy storage system. State of the art / Summary

[0002] Internal combustion engines can incorporate water injection systems that inject water into a variety of locations, such as the intake manifold, upstream of engine cylinders, or directly into the cylinders. Engine water injection offers several advantages, including increased fuel economy and engine power, as well as reduced engine emissions. Specifically, when water is injected into the engine intake or cylinders, heat is transferred from the intake air and / or engine components to evaporate the water, resulting in charge cooling. Injecting water into the intake air (for example, into the intake manifold) lowers both the intake air temperature and the combustion temperature at the engine cylinders. By cooling the intake charge, a tendency to knock can be reduced without enriching the air-fuel ratio.This can also allow for a higher compression ratio, earlier ignition timing, improved full-throttle performance, and reduced exhaust gas temperature. Fuel efficiency is therefore increased. Additionally, a higher volumetric efficiency can lead to increased torque. Furthermore, lower combustion temperature with water injection can reduce NOx emissions, while a more efficient fuel mixture (less enrichment) can reduce carbon monoxide and hydrocarbon emissions.

[0003] Machine control systems can select when to use water injection based on machine operating conditions, such as knock limits. One exemplary approach is shown in US 8,096,283 B2, where water use is based on water availability, knock limits, dilution requirements, and ignition requirements. Another exemplary approach is shown in US 5,148,776 A, where water use is set based on the amount of cooling required to manage premature ignition of an air-fuel mixture in machine cylinders.

[0004] DE 10 2008 028 787 A1 describes a hybrid drive system for a vehicle and a method for operating it. For example, the system comprises an internal combustion engine with at least one combustion chamber, a motor designed for selectively driving the vehicle by means of the drive wheel, a fuel system designed to supply a first substance and a second substance to the combustion chamber in changing relative quantities, wherein the first substance comprises a fuel and the second substance comprises a higher concentration of a knock-suppressing substance than the first substance; and a control system designed to operate the fuel system to change the relative quantities of the first substance and the second substance supplied to the combustion chamber in response to an operating condition, while operating the motor to drive the vehicle.

[0005] However, the inventors have recognized potential problems with approaches of the type described above. For example, in a machine with a step-ratio transmission, the optimal fuel-saving gain associated with water use may not be realized due to the transmission's fixed gear ratio. Specifically, for a given driver demand based on whether or not water is injected, there may be a fixed associated engine speed and load range that meet the driver demand. An engine control device can utilize water injection based on water availability on board the vehicle. However, during transitions between operation with and without water injection, engine limitations in the associated engine speed-load may be encountered, potentially reducing the fuel-saving benefit of the transition.For example, if water injection is not used, the engine may become more knock-limited at higher loads. Consequently, the optimal engine speed / load for operator demand may differ from that achieved when water injection is used. Another issue is that frequent changes in operator pedal input can cause the engine load to fluctuate, resulting in frequent switching between water injection on and off. Excessive switching can worsen fuel economy due to losses incurred during transits and can reduce component life. Additionally, frequent switching can lead to engine speed / load and air / fuel ratio disturbances.The problem can be exacerbated in a hybrid vehicle where the engine encounters multiple acceleration and deceleration cycles (such as during frequent start / stop events), with the engine being restarted or shut down while the vehicle is being driven.

[0006] The inventors have recognized that the operating efficiency of a hybrid powertrain can be improved (for example, maximized) by implementing the methods and vehicle systems according to claims 1, 11, and 13. Advantageous embodiments of the invention are described in the dependent claims.

[0007] Accordingly, the most efficient water injection state is determined by the power demanded by the operator, while battery power is used to compensate and, additionally, to smooth torque transients that utilize engine torque. Specifically, battery power can be used to reduce the frequency of water injection state switching while also improving operational efficiency, without being hampered by associated constraints and trade-offs. Furthermore, the fuel-saving benefits of a machine configured with water injection can be better exploited by integrating it with a hybrid transaxle transmission (such as a modular hybrid transmission or MHT), which can allow the machine speed and load to be adjusted based on water usage (and availability) while maintaining the machine's power output.In one example, fuel savings can be improved by a procedure for a hybrid vehicle that has an engine configured with water injection and a modular hybrid transaxle (MHT) transmission.The procedure may include: for a given performance level, comparing an initial fuel saving without water injection and an initial quantity of stored power offsets from an energy storage system to a second fuel saving with water injection at an initial set machine speed load and a second quantity of stored power offsets; in response to the second fuel saving exceeding the first fuel saving and to a higher water availability than threshold water availability, injecting a quantity of water into the machine and changing the initial set machine speed load; and in response to the first fuel saving exceeding the second fuel saving or to a water availability lower than threshold water availability, operating the machine without water injection and changing the machine speed load to a second set machine speed load.

[0008] As an example, a hybrid vehicle system could be configured with a battery-powered electric motor to drive the vehicle wheels via engine torque, an engine configured with water injection, and a hybrid transaxle transmission (such as an MHT). Water can be injected from a water reservoir into an engine intake manifold via one or more central and intake port injection systems and / or directly into an engine cylinder. For any given driver demand, the control unit can be configured to compare fuel efficiency versus power output with and without water injection.The control device can further calculate the efficiency of each water injection state with a range of battery offsets, combining the energy efficiency of the electrical system for generating, storing, discharging, and driving with the energy efficiency of the machine to determine an overall efficiency for each possible battery offset. The battery offsets can be determined based on the state of charge of the system battery and can have a positive offset (where battery power is used via battery discharge to increase machine output) as well as a negative offset (where battery power is used via battery charging to adjust machine output). The control device can then select whether to continue in the current water injection state (with or without battery offset) or to transition to the water injection state (with or without battery offset) by comparing the corresponding fuel efficiencies.In particular, if an efficiency improvement exceeding a threshold efficiency is achieved by switching to the other water injection state, the switchover can be performed; otherwise, the current water injection state can be maintained. Additionally, the battery offset corresponding to the more efficient state can be applied. Any transients occurring during the switchover can be smoothed using engine torque. Also following the selection of the more efficient water injection state, the control unit can use engine torque settings as well as hybrid transaxle transmission settings to operate the machine in a narrower speed-load operating range, optimizing the efficiency of the selected water injection state while maintaining a given vehicle power level.To counteract knocking, which is expected during operation without water injection, a machine control device can select a gear ratio of the MHT to increase the machine speed while reducing the machine load, thus maintaining the requested machine power output. Similarly, when operating with active water injection, a gear ratio of the MHT can be selected to decrease the machine speed (relative to the previous machine speed when water injection was inactive) while increasing the load (compared to the previous load when water injection was inactive).Since the amount of water in the reservoir is limited, a vehicle control device can aim to use the water only when a predetermined improvement in fuel efficiency occurs, so that it only injects the water and adjusts the engine speed load when the "water" efficiency improvement exceeds a threshold compared to the non-water engine speed load efficiency.

[0009] In this way, fuel-saving benefits can be improved. The technical impact of integrating water injection technology into a vehicle with an MHT transmission is that, for a given power demand from the driver, the benefits of water injection can be better utilized. Specifically, the engine speed and torque can be adjusted for a given driver-demanded power to reduce knock limits at higher loads, thereby increasing the maximum load, and to reduce friction losses at lower loads, while taking into account changes in knock limits due to water injection characteristics. One of the technical effects of using battery power to extend the engine's operation with a given water injection state is the reduction of losses associated with frequent switching of the water injection state.In particular, battery power can be used to maintain machine operation at a current water injection state with more efficient power output. While the machine is operating at the more efficient water injection state, battery power can be depleted up to a threshold to compensate for any difference in output. While the machine is operating at the more efficient and cost-effective water injection state, MHT settings can be used to extend machine operation with water injection despite changes in operator or wheel torque demand. Conversely, in conditions where the benefit of water injection is minimal, MHT settings can be used to extend machine operation without water injection despite changes in operator or wheel torque demand.By optimizing water usage, the benefits of water injection can be extended over a longer portion of a driving cycle, even when water availability is limited. In this way, a water-injected machine can be operated while providing improved fuel economy for a given driver demand by increasing the maximum load achievable without knocking, or, in other words, by raising the knock limit.

[0010] It must be understood that the summary above is provided to present, in simplified form, a selection of concepts that are described in more detail in the full description. It is not intended to identify any key or essential features of the claimed subject matter, the scope of which is clearly defined by the claims that follow the full description. Furthermore, the claimed subject matter is not limited to implementations that address the disadvantages noted above or in any part of this disclosure. Brief description of the drawings Fig. Figure 1 illustrates an example drive system for a hybrid electric vehicle. Fig. Figure 2 shows a schematic representation of a machine system that includes a water injection system. Fig. Figure 3 shows a high-level flowchart for selecting a water injection state for use in the machine system of the Fig. 1 based on simultaneous settings on a machine speed-load profile via hybrid transaxle transmission settings. Fig. Figures 4A-4B show maps that illustrate problems with vehicle performance during operation with a fixed-ratio gearbox. The Fig. Figures 5-6 show exemplary characteristic maps for selecting water usage and battery offsets to meet driver demand. Fig. Figure 7 shows exemplary water usage and hybrid transaxle transmission settings during hybrid vehicle operation. Detailed description

[0011] The following description concerns systems and methods for improving fuel economy in a hybrid vehicle system that has a hybrid transaxle transmission, such as the vehicle system of the Fig. 1. The vehicle system may include a machine configured with water injection capabilities, as described in the machine system of the Fig. 2 described. A control device can be configured to execute a control routine, such as the exemplary routine of the Fig. 3. To select a water injection state (active or inactive) based on water availability, while a machine speed-load profile is set via adjustments to a hybrid transaxle transmission speed ratio and battery power offset to better utilize the fuel-saving benefits of water injection. An example map that can be used by the control device to select whether to maintain or transition between water injection states is given with reference to the Fig. 5-6 shown. Battery power offset (including positive and negative power offset) can be applied to overcome problems associated with operating a fixed-ratio gearbox, as in the Fig. Figures 4A-4B illustrate an exemplary machine operation with water usage, battery power offsets, and hybrid transaxle transmission settings. Fig. Figure 7 shows that water injection technology can be integrated and synergized with hybrid vehicle technology to achieve significant fuel saving improvements.

[0012] Fig. Figure 1 depicts a hybrid drive system 100 for a vehicle. In the illustrated embodiment, the vehicle is a hybrid electric vehicle (HEV), but alternative embodiments could include hybrid vehicles that use hydraulic, pneumatic, flywheel, or other energy storage systems and motors. The hybrid drive system 100 includes an internal combustion engine 10. Fuel can be supplied to each cylinder of the internal combustion engine 10 by a fuel system (not shown) comprising one or more fuel tanks, one or more fuel pumps, and injectors. A detailed embodiment of the engine is described in reference to Fig. 2 provided.

[0013] The hybrid power transmission 18 has a first power source in the form of an internal combustion engine 10 and a second power source in the form of an electric motor 26, which can draw power from the battery 54 or an alternative energy storage device. The internal combustion engine 10 can be operatively connected to a starter 70, which can be used to start the internal combustion engine 10 when additional torque is required. An electric machine, shown here as a traction motor, can be operatively connected to the hybrid power transmission 18 and positioned between the internal combustion engine 10 and the gearbox 44 or the transmission. The internal combustion engine 10 can be selectively coupled to the electric motor 26 and the gearbox 44 by means of a disengagement clutch 62.Torque transmitted by the internal combustion engine 10 and the electric motor 26 can be provided through the hybrid power transmission 18 to the gearbox 44, which provides torque to drive the drive wheels 52.

[0014] A torque converter 60 can be provided between the transmission 44 and the internal combustion engine 10 and / or the electric motor 26 to provide torque through the transmission 44 to the drive wheels 52. Alternatively, a starting clutch can be provided instead of the torque converter.

[0015] The vehicle may include a control device 68, such as a vehicle system controller (VSC), to control various vehicle systems and subsystems. The control device 68 may include various types of computer-readable storage media to implement volatile and / or persistent memory. The control device 68 communicates with one or more sensors and actuators (not shown). The sensor or sensors may, for example, include a torque sensor 64 positioned to measure an input torque of the transmission 44.

[0016] In one embodiment, the control device 68 is a VSC comprising an engine control unit (ECU) 12 and a transmission control unit (TCU) 66. The ECU 12 is electrically connected to the internal combustion engine 10 to control the operation of the engine. The TCU 66 is electrically connected to and controls the electric motor 26 and the transmission 44. The ECU 12 communicates with the TCU 66 and other control devices (not shown) via a vehicle network using a common bus protocol (for example, CAN) in accordance with one or more embodiments of the present disclosure.Although the illustrated embodiment shows functionality of the VSC for controlling the MHT powertrain as contained in two control devices (ECU 12 and TCU 66), other embodiments of the hybrid vehicle may have a single VSC control device and / or a different combination of control devices for controlling the MHT powertrain.

[0017] Shifting an automatic transmission involves the engagement and / or disengagement of multiple friction elements (such as disc clutches, band brakes, etc.) that alter the speed and torque ratios by changing gear configurations. These friction elements can be hydraulic, mechanical, or driven by other strategies, utilizing one or more associated actuators. These actuators may communicate with a microprocessor-based control unit, which executes a specific control strategy based on signals received from one or more sensors. A possible combination of gear configurations determines the total number of ratio steps.

[0018] During a typical synchronous upshift event from a lower gear configuration to a higher gear configuration, both the gear ratio (defined as input shaft speed / output shaft speed of the automatic transmission) and the torque ratio (defined as output shaft torque / input shaft torque of the automatic transmission) decrease. During the upshift event, a friction element (called an off-going clutch - OGC) associated with the lower gear configuration disengages, while a different friction element (called an on-coming clutch - OCC) associated with a higher gear configuration engages.

[0019] In the illustrated example, the transmission 44 is a modular hybrid transmission (MHT), also referred to here as a hybrid transaxle transmission, which incorporates mechanical and hydraulic control devices for a system of multiple fixed-ratio gears for several forward gears, reverse, and a neutral position. The MHT can be an automatic transmission with fixed speed ratios, similar to other mechanical transmissions that offer a finite number of fixed gear ratios (speed ratios). For example, a machine speed can be reduced while a machine load is correspondingly increased to maintain power output by setting the MHT to a lower speed ratio. As another example, a machine speed can be increased while a machine load is correspondingly reduced to maintain power output by setting the MHT to a higher speed ratio.

[0020] However, due to the fixed speed ratios, the range of possible machine speed settings is limited. The characteristic curve 400 of the Fig. Figure 4A illustrates this problem graphically. The characteristic map 400 depicts the change in machine speed during operation in a higher gear of the MHT at line 402, and a corresponding change in machine speed during operation in a lower gear of the MHT at line 404. Operation in the higher gear results in operation with a higher speed ratio, while operation in the lower gear results in operation with a lower speed ratio. For a given vehicle speed (Vs), shown here at 405, the machine can be operated at a first operating point 406 in the higher gear with an initial, lower machine speed (Spd1) and a correspondingly increased machine load.Alternatively, for the same vehicle speed 405, the machine can be operated at a second operating point 408 in the lower gear with a second, higher engine speed (Spd2) and a correspondingly reduced engine load. However, due to the fixed gear ratio, the machine cannot be operated at any engine speed between Spd1 and Spd2. Therefore, for a given driver demand, there is an operating point with a specific engine speed-load combination that provides the highest power efficiency (that is, delivers the greatest amount of power for a given amount of fuel). This operating point can change based on whether or not water is injected into the machine. However, there may be situations where neither operating point 406 nor operating point 408 is most efficient for the given driver demand and water injection condition.

[0021] The 450 characteristic map of the Fig. Figure 4B graphically illustrates this problem. Specifically, map 450 compares fuel efficiencies associated with different water injection states for a given driver-requested power output and compares fuel efficiencies associated with different engine speed-load profiles for a given water injection state. Map 450 depicts a first line of best efficiency versus power with water injection deactivated (water_inactive), also referred to here as a first fuel optimum efficiency load limit 454 (shown as a solid line). Map 450 also depicts a second line of best efficiency versus power with water injection activated (water_active), also referred to here as a second optimum efficiency load limit 456 (shown as a dashed line). The plots are shown with engine speed along the x-axis and engine load or torque along the y-axis.Engine speed-load combinations corresponding to a given operator demand are shown along power line 458. Power line 458 represents a constant power output for an initial power demand. Operating points 462 and 460 on power line 458 represent two such combinations whose product provides the same (initial) engine power output. Additional such lines, corresponding to higher and lower power outputs, can be represented similarly (not shown here). The interface between power line 458 and the first fuel optimum efficiency load limit 454 therefore represents an engine speed-load combination that has maximum efficiency when the engine is operated with water injection deactivated.Similarly, the interface between the power line 458 and the second fuel optimum efficiency load limit 456 represents a machine speed-load combination that has maximum efficiency when the machine is operated with water injection activated.

[0022] In the example shown, the power requested by the driver can be achieved by operating a transmission with a fixed gear ratio, such as the MHT. Fig. 1. The power demand can be met either in a lower or a higher gear. When operating in the lower gear, the power requested by the driver can be provided by the machine operating at a first, lower speed Spd_1 and a higher machine load at operating point 462. In contrast, when operating in the higher gear, the same power demanded by the driver can be provided by the machine operating at a second, higher speed Spd_2 and a lower machine load at operating point 460. However, neither operating point 460 nor 462 coincides with lines 456 or 454 of maximum efficiency. In other words, the operating points in both water injection conditions do not represent the most efficient operating point. Due to the fixed speed ratio of the MHT, an operating point between 460 and 462 that coincides with either line 456 or 454 of maximum efficiency is also not possible.This results in the machine output being lower than what is possible for a given driver demand.

[0023] As mentioned here with reference to the Fig. As outlined in Figures 3-6, a machine control device can use one or more such efficiency maps to determine the most efficient operating point at which a machine can be operated with or without water injection by adjusting a gear ratio of the MHT. Furthermore, if the machine cannot be operated at the most efficient operating point with or without water injection due to the fixed gear ratios, the battery power of the MHT can be used to compensate for the machine's power output. This allows for better utilization of the fuel-saving benefits of operating a machine with water injection. Exemplary speed ratio and water injection state selections are given with reference to the Fig. 5-6 described. In some examples, a generator can be driven by the electric motor 26 such that both the electric generator and the electric motor 26 can be operated using electrical energy from a power storage device, shown here as a battery 54. In some embodiments, a power conversion device, such as an inverter, can be coupled between the battery and the motor to convert the DC output of the battery into an AC output for use by the electric motor. In alternative embodiments, however, the inverter can be configured within the electric motor.

[0024] The electric motor 26 can be operated in a regeneration mode, that is, as a generator, to absorb energy from vehicle motion and / or the engine and convert the absorbed kinetic energy into a form of energy suitable for storage in the battery 54. Furthermore, the electric motor 26 can be operated as a motor or generator, as needed, to increase or absorb torque provided by the engine, such as during transitions of the internal combustion engine 10 between different combustion modes (for example, during transitions between a spark ignition mode and a compression ignition mode). For example, during conditions when the engine torque output is higher than the driver demand, the torque difference can be absorbed by the engine and used to charge the battery, thus smoothing out torque transients.

[0025] The Hybrid Drive System 100 can operate in various configurations, including a full hybrid system, where the vehicle is powered solely by the combined action of the engine and generator, or solely by the electric motor, or a combination thereof. Alternatively, assist or mild hybrid configurations can also be employed, where the engine is the primary source of torque, and the electric motor selectively adds torque during specific conditions, such as a tip-in event. The Hybrid Drive System 100 can operate in various operating modes.

[0026] The vehicle can, for example, be operated in a first machine-on mode, referred to here as a "machine" mode, in which the internal combustion engine 10 is operated as the main torque source to supply power to the drive wheels 52. During the "machine" mode, fuel can be supplied to the internal combustion engine 10 from a fuel tank via a fuel injector in such a way that the engine can rotate on fuel to provide the torque for propelling the vehicle. Specifically, the engine power is delivered to the transmission, which in turn delivers the power to the drive wheels 52. Optionally, the engine can be operated to output more torque than is required for propulsion, and in this case, the additional power is absorbed by the engine (in generation mode) to charge the battery 54 or to provide electrical power for other vehicle loads.In this mode, only machine power is used to drive the vehicle wheels.

[0027] In another example, the vehicle can be driven in a second machine-on mode, also referred to here as an "assist" mode. During the assist mode, the internal combustion engine 10 is operated and used as the main torque source to supply power to the drive wheels 52, and the electric motor is used as an additional torque source to work in conjunction with and supplement the torque provided by the internal combustion engine 10. During the "assist" mode, as in the machine-only mode, fuel is supplied to the internal combustion engine 10 to rotate the fuel-powered engine and provide torque to the vehicle wheels. In this mode, only engine power is used to drive the vehicle wheels.

[0028] In yet another example, the vehicle can be operated in an engine-off mode, also referred to here as an electric mode, in which the battery-powered electric motor 26 is operated and used as the sole torque source to drive the drive wheels 52. During the engine-off mode, therefore, no fuel can be injected into the internal combustion engine 10, regardless of whether the engine is rotating or not. The "engine-off" mode can be used, for example, when driving at a constant vehicle speed, during braking, gentle acceleration at low engine speeds, while stopping at traffic lights, etc. In particular, engine power is supplied to the drive wheels 52. In this mode, only engine torque is used to drive the vehicle wheels.

[0029] Control units 12, TCU 66 and 68 can receive input data from various sensors, process the input data, and trigger the actuators in response to the processed input data based on instructions or code programmed into them, according to one or more routines. Examples of control routines are given below. Fig. 3 described.

[0030] It will be appreciated that, although the examples revealed here are discussed in connection with a hybrid-electric vehicle that has an electrically driven motor, this is not intended to be limiting, and that the same approach can be applied to other hybrid vehicle systems, such as those that have a flywheel, a hydraulic and / or pneumatic motor. Likewise, any energy storage system can be used to provide motor torque, including, but not limited to, a system battery.

[0031] Fig. Figure 2 shows an exemplary embodiment of a machine system 104 configured with a water injection system 160. The machine system 104 is coupled in a motor vehicle 102, which is shown schematically. The machine system 104 has an internal combustion engine 10, which powers the internal combustion engine 10 of the Fig. 1. In the illustrated embodiment, the internal combustion engine 10 is a turbocharged engine coupled to a turbocharger 13, which has a compressor 14 driven by a turbine 116. In particular, fresh air is introduced into the internal combustion engine 10 along the inlet duct 142 via the air cleaner 31 and flows to the compressor 14. The compressor can be a suitable intake air compressor, such as a motor-driven compressor or a drive shaft-driven compressor of a mechanical supercharger. In the machine system 104, the compressor is shown as a turbocharger compressor mechanically coupled to the turbine 116 via a shaft 19, the turbine 116 being driven by the expanding engine exhaust gas. In one embodiment, the compressor and the turbine can be coupled within a twin-scroll turbocharger.In another embodiment, the turbocharger can be a variable geometry turbocharger (VGT), in which the turbine geometry is actively varied depending on machine speed and other operating conditions.

[0032] As in Fig. As shown in Figure 2, the compressor 14 is coupled to the throttle valve (for example, intake throttle) 20 via the charge air cooler (CAC) 118. The CAC can be, for example, an air-to-air or an air-to-coolant heat exchanger. The throttle valve 20 is coupled to the intake manifold 122. From the compressor 14, the hot, compressed air charge enters the inlet of the CRC 118, cools down as it passes through the CRC, and then exits to pass through the throttle valve 20 to the intake manifold 122. In the embodiment shown in Figure 2, the CAC 118 is coupled to the intake manifold 122 via the throttle valve 20. Fig. As shown in Figure 2, the air charge pressure within the intake manifold is detected by a manifold absolute pressure (MAP) sensor 224, and boost pressure is detected by the boost pressure sensor 124. A compressor bypass valve (not shown) can be connected in series between the inlet and outlet of the compressor 14. The compressor bypass valve can be a normally closed valve configured to open under selected operating conditions to release excess boost pressure. For example, the compressor bypass valve can open in response to compressor pumps.

[0033] The intake manifold 122 is coupled to a series of combustion chambers 180 or cylinders by a series of intake valves (not shown) and intake pipes (for example, intake ports) 185. As in Fig. As shown in Figure 2, the intake manifold 122 is located upstream of all combustion chambers 180 of the internal combustion engine 10. Additional sensors, such as an intake manifold temperature (MCT) sensor 33 and an intake air temperature (ACT) sensor 125, can be included to determine the intake air temperature at the respective locations in the intake manifold. The air temperature can also be used together with an engine coolant temperature to calculate, for example, the amount of fuel supplied to the engine. Each combustion chamber can also include a knock sensor 183 for identifying and distinguishing abnormal combustion events, such as knocking and pre-ignition. In alternative embodiments, one or more knock sensors 183 can be coupled at selected locations on the engine block.

[0034] The combustion chambers are further coupled to the exhaust manifold 136 via a series of exhaust valves (not shown). A cylinder head 182 sits on the combustion chambers 180, and they are coupled to fuel injectors 179 (although only one fuel injector is shown). Fig. As shown in Figure 2, each combustion chamber has a fuel injector coupled to it. Fuel can be supplied to the fuel injector 179 by a fuel system (not shown) comprising a fuel tank, fuel pump, and fuel distribution line. The fuel injector 179 can be configured as a direct injector for injecting fuel directly into the combustion chamber 180 or as a port injector for injecting fuel into an intake port upstream of an intake valve of the combustion chamber 180.

[0035] In the illustrated embodiment, a single exhaust manifold 136 is shown. In other embodiments, however, the exhaust manifold can have a plurality of exhaust manifold sections. Configurations with a plurality of exhaust manifold sections can allow exhaust gases from different combustion chambers to be directed to different locations in the engine system. A Universal Exhaust Gas Oxygen (UEGO) probe 126 is shown coupled to the exhaust manifold 136 upstream of the turbine 116. Alternatively, a dual-state exhaust oxygen sensor can replace the UEGO probe 126.

[0036] As in Fig. As shown in Figure 2, exhaust gas from one or more exhaust manifold sections is directed to the turbine 116 to drive the turbine. If reduced turbine torque is desired, some exhaust gas can be directed bypassing the turbine instead of through a wastegate (not shown). The combined flow from the turbine and the wastegate then flows through the emission control device 170. In general, one or more emission control devices 170 can include one or more exhaust aftertreatment catalysts configured to catalytically treat the exhaust flow, thereby reducing the amount of one or more substances in the exhaust flow.

[0037] All or part of the treated exhaust gases from the emission control device 170 can be released into the environment via the exhaust line 35. However, depending on the operating conditions, some exhaust gas can be diverted through the EGR cooler 50 and the EGR valve 152 to the compressor inlet 14 instead of to an exhaust gas recirculation (EGR) channel 151. In this way, the compressor is configured to draw in exhaust gas diverted from downstream of the turbine 116. The EGR valve 152 can be opened to allow a controlled amount of cooled exhaust gases to the compressor inlet for desired combustion and emission control performance. In this way, the machine system 104 is adapted to provide external low-pressure (LP) EGR. The rotation of the compressor, in addition to the relatively long LP EGR flow path in the machine system 104, provides excellent homogenization of the exhaust gas in the intake air charge.Furthermore, the arrangement of the EGR outlet and mixing points provides effective cooling of exhaust gas for increased available EGR mass and increased power. In other embodiments, the EGR system can be a high-pressure EGR system with EGR channel 151 connecting upstream of the turbine 116 to downstream of the compressor 14. In some embodiments, the MCT sensor 23 can be positioned to determine the manifold charge temperature and can include air and exhaust gas recirculated through the EGR channel 151.

[0038] The combustion chamber 180 also receives water and / or steam via the water injection system 160. Water from the water injection system 160 can be injected into the engine intake or directly into the combustion chambers 180 through one or more of the water injection nozzles 45-48. For example, water can be injected into the intake manifold 122 upstream of the throttle valve 20 via water injection nozzle 45, which is also referred to here as the central water injection. Alternatively, water can be injected into the intake manifold 122 downstream of the throttle valve via water injection nozzle 46. As another example, water can be injected into one or more intake pipes (for example, intake ports) 185 via the water injection nozzle 48 (also called intake port water injection here) and / or directly into the combustion chamber 180 via the water injection nozzle 47 (also called direct water injection here).In one embodiment, the water injection nozzle 48, which is installed in the intake manifolds, can be angled towards and relative to the intake valve of the cylinder to which the intake manifold is attached. The water injection nozzle 48 can therefore inject water directly onto the intake valve, resulting in faster evaporation of the injected water and the advantage of greater dilution of the water vapor. In another embodiment, the water injection nozzle 48 can be angled away from the intake valve and configured to inject water against the direction of intake airflow through the intake manifold. Therefore, more of the injected water can be carried into the airflow, thereby increasing the charge cooling advantage of water injection.

[0039] Although only one representative water injection nozzle 47 and water injection nozzle 48 in Fig. As shown in Figure 1, each combustion chamber 180 and each intake pipe 185 can have its own injection nozzle. In alternative embodiments, the water injection system 160 can have water injection nozzles positioned at one or more of these locations. In one embodiment, for example, the machine can have only the water injection nozzle 46. In another embodiment, the machine can have the water injection nozzle 46, water injection nozzles 48 (one on each intake pipe), and water injection nozzles 47 (one on each combustion chamber).

[0040] The water injection system 160 comprises a water tank 63, a water lifting pump 164, a collection system 72, and a water filling channel 69. The water stored in the water tank 63 is supplied to water injection nozzles 45-48 via the water channel 61 and the lines 161. In embodiments having multiple injection nozzles, the water channel 61 can contain a valve 162 (for example, a diverter valve, multi-way valve, metering valve, etc.) to direct water to the different water injection nozzles via the corresponding lines. Alternatively, each line 161 can have individual valves within the water injection nozzles 45-48 to adjust the water flow. In addition to the water lifting pump 164, one or more additional pumps can be provided in lines 161 to pressurize the water directed to the injection nozzles, as in the line coupled to the water injection nozzle 47.

[0041] The water tank 63 can include a water level sensor 65 and a water temperature sensor 67, which transmit information related to water conditions to the control device 12. For example, under freezing conditions, the water temperature sensor 67 detects whether the water in the water tank 63 is frozen or available for injection. In some embodiments, an engine coolant channel (not shown) can be thermally coupled to the water tank 63 to thaw frozen water. The water level stored in the water tank 63, as identified by the water level sensor 65, can be communicated to the operator and / or used to stop engine operation. A water level indicator or a display on a vehicle instrument panel (not shown) can be used to report the water level.If the water level in water tank 63 is higher than a threshold level, it can be deduced that sufficient water is available for injection, and water injection can therefore be activated by the control device. Conversely, if the water level in water tank 63 is lower than the threshold level, it can be deduced that insufficient water is available for injection, and water injection can therefore be deactivated by the control device.

[0042] In the illustrated embodiment, the water tank 63 can be refilled manually via the water filling channel 69 and / or automatically by the collection system 72 via the water tank filling channel 76. The collection system 72 can be coupled to one or more vehicle components 74 such that the water tank on board the vehicle can be refilled with condensate collected from various machine or vehicle systems. In one example, the collection system 72 can be coupled to an EGR system to collect water condensed from exhaust gas passing through the EGR system. In another example, the collection system 72 can be coupled to an air conditioning system (not shown) for collected water condensed from refrigerant passing through a condenser.The manual water filling channel 69 can be fluidically coupled to a filter 168, which can remove small impurities that may be present in the water. A drain 92, which has a drain valve 91, can be used to drain water from the water tank 63 to a location outside the vehicle (for example, onto the road), such as when the water quality is below a threshold and it is considered unsuitable for injection into the machine (for example, due to lower conductivity, high particle content, etc.).

[0043] Fig. Figure 2 further shows a control system 28. The control system 28 can be coupled to various components of the machine system 104 to execute the control routines and actions described herein. The control system 28 can include an electronic digital control device 12. The control device 12 can be a microcomputer comprising a microprocessor unit, input / output ports, an electronic storage medium for executable programs and calibration values, direct access memory, keep-alive memory, and a data bus. The control device 12 can receive input from a variety of sensors 30, such as the various sensors of the Fig. 1-2, to receive input, which includes the transmission gear position, accelerator pedal position, brake demand, vehicle speed, engine speed, mass airflow through the engine, boost pressure, ambient conditions (temperature, pressure, humidity), etc. Other sensors include CAC 118 sensors, such as CAC intake air temperature, ACT sensor 125 and boost pressure sensor 124, CAC exhaust air temperature sensor and MCT sensor 23, knock sensor 183 for determining exhaust gas ignition and / or water distribution to the cylinders, etc. The control device 12 receives signals from the various sensors of the Fig. 1-2 and sets the different actuators of the Fig. 1-2 to adjust machine operation based on the received signals and the instructions stored in a memory of the control device. For example, injecting water into the machine may involve adjusting the pulse width of water injection nozzles 45-48 to vary the amount of water injected, while also setting the timing of the water injection and the number of injection pulses. In some examples, the storage medium may be programmed with computer-readable data representing instructions to be sent by the processor to execute the procedures described below (for example, in the case of Fig. 3) as well as other variants that are expected but not specifically listed.

[0044] In this way, the system enables Fig. 1-2 A vehicle system comprising: a machine; an engine powered by an energy storage system; a fuel injector for supplying fuel from a fuel tank to the machine; a water injector for supplying water from a water reservoir to the machine; a modular hybrid transaxle transmission (MHT) coupling the machine and engine to vehicle wheels, the MHT having a variety of speed ratios; and a control device with computer-readable instructions stored on non-volatile memory to: estimate a first efficiency associated with operating the machine with the water injector disabled and a first power offset from the energy storage system; estimate a second efficiency,which is associated with operating the machine with the water injection nozzle activated and a second different power offset; if the second efficiency is higher than the first efficiency and a water level in the water tank is higher than a threshold, to activate the water injection nozzle, to set an output of the motor to provide the second power offset, and to select one of the many speed ratios of the MHT to operate the machine with a first modified machine speed-load profile; and, if the second efficiency is lower than the first efficiency or the water level in the water tank is lower than the threshold, to deactivate the water injection nozzle, to set the output of the motor to provide the first power offset, and to select another of the many speed ratios of the MHT to provide a second modified machine speed-load profile.to provide a profile that differs from the first modified machine speed-load profile. In another example, the first modified machine speed-load profile is based on a machine knock limit and machine friction when operating with water injection, while the second modified machine speed-load profile is based on a machine knock limit and machine friction when operating without water injection. The first modified machine speed-load profile has a lower machine speed and a higher machine load than the second modified machine speed-load profile, and the machine output power with the water injection nozzle activated and the first modified machine speed-load profile is equal to the machine output power with the water injection nozzle deactivated and the second modified machine speed-load profile.

[0045] With reference to Fig. Section 3 describes an exemplary routine 300 for coordinating settings to select a water injection state with engine operation and settings for a speed ratio of a modular hybrid transmission (MHT) or hybrid transaxle transmission in a hybrid vehicle system. The procedure allows engine torque settings to be used to extend machine operation with a fuel-efficient water injection state despite changes in driver torque demand. Additionally, a machine powertrain profile (including machine speed and load) can be set while maintaining a required machine power output and while utilizing the charge-cooling properties (such as octane rating and knock-reduction capability) and fuel-saving benefits of water injection.Instructions for implementing procedure 300 and the other procedures contained herein may be issued by a control device based on instructions stored in a memory of the control device and in conjunction with signals received from sensors of the machine system, such as those mentioned above with reference to the . Fig. The sensors described in 1-2 can be used. The control device can utilize machine and motor actuators of the hybrid vehicle system to adjust vehicle operation according to the procedures described below. For example, the control device can adjust the activation and pulse width of a water injection nozzle that delivers water and select a gear ratio of the MHT to operate the machine at a selected engine speed.

[0046] At 302, the routine involves estimating and / or measuring machine operating conditions. These can include, for example, driver torque demand (such as based on the output of a pedal position sensor coupled to a driver pedal), ambient temperature, pressure, and humidity, machine temperature, battery charge level, fuel level in a fuel tank, water level in a water reservoir, octane rating of available fuel, etc. Additionally, machine operating conditions such as manifold pressure (MAP), manifold airflow (MAF), machine temperature, catalytic converter temperature, intake air temperature, knock limits, etc., can be estimated.

[0047] In 304, the procedure involves selecting a vehicle operating mode based on the estimated vehicle operating conditions. This involves switching between propelling the vehicle using engine torque and machine torque in response to operating conditions, including driver demand. For example, an electric operating mode might be selected when the torque demand is lower, when the fuel level in the fuel tank is lower, and / or when the battery charge level is higher. In electric mode, the vehicle wheels can be driven solely by engine torque from an electric motor powered by a battery system. As another example, a machine operating mode might be selected when the torque demand is higher, when the fuel level in the fuel tank is higher, and / or when the battery charge level is lower.In machine mode, the vehicle wheels can only be driven by machine torque from a machine. An assist mode can also be selected if the torque required is higher than what can be provided solely by machine torque. In this mode, the vehicle wheels can be driven by either the engine torque or the machine torque.

[0048] At 306, it can be confirmed whether the electric mode has been selected. If yes, the procedure at 310 involves driving the vehicle via engine torque. If the electric mode is not confirmed, it can be confirmed at 308 whether the machine mode has been selected. If yes, the procedure at 312 involves estimating the driver demand. In one example, the driver torque demand can be derived from a driver pedal position, such as an accelerator pedal position.The hybrid vehicle can be powered by the engine, which operates in a first water injection state (which may be either active or inactive) based on driver demand. In response to a change in driver demand, the control unit can select between maintaining the current water injection state or switching to a second, different water injection state based on both the change in driver demand and the battery charge level. This selection can further be based on fuel-saving benefits achieved by using a battery power offset.

[0049] Specifically, the procedure at 314 involves comparing the efficiency of the given fuel of the machine in each water injection state for the given driver demand. The different water injection states include an active water injection state, in which water injection is activated and water is injected into the machine (such as into the cylinder, intake port, or intake manifold), and a deactivated water injection state, in which water injection is deactivated. The active water injection state can therefore only be activated if there is sufficient water in the water tank. As an example, the fuel efficiency of the machine with activated water injection can be compared with the fuel efficiency of the machine with deactivated water injection.

[0050] In designs with multiple water injection options, fuel efficiency can be compared with each of the various water injection options (such as direct injection, port injection, and central water injection). The fuel efficiency of engine operation without water injection can be compared, for example, with the efficiency of injecting water directly into an engine cylinder via a direct water injection nozzle, with injecting water into an intake port upstream of an intake valve via a port injection nozzle, and also with injecting water into an intake manifold upstream or downstream of an intake throttle via a central water injection nozzle.

[0051] As used here, the fuel efficiency of the machine can be defined as the amount of work produced for a given amount of fuel in each water injection state, where a commonly used measurement technique in the field is brake specific fuel consumption (BSFC). In one example, the control device can compare the fuel efficiency of two water injection states by comparing the machine's brake specific fuel consumption (BSFC) for each state. The machine's BSFC for each water injection state can be stored in tables, maps, and / or equations as a function of operating conditions such as RPM, load, torque, temperature, humidity, derived fuel octane rating, etc.In particular, the driver demand control device can determine the machine's BSFC with water injection disabled and then determine the efficiency as the inverse of the BSFC. The control device can then determine the amount of water to be injected and the fuel efficiency with water injection enabled (including the fuel efficiency with the specified amount of water supplied via direct injection, port injection, and / or central injection), and determine the efficiency as the inverse of the BSFC.

[0052] In case 316, the procedure for the given driver demand involves determining fuel efficiency versus power for each water injection condition with a battery power offset. Various battery power offsets can therefore be evaluated, with the battery power offset range being selected based on a current battery state of charge (which indicates the amount of battery power that can be provided as well as the amount of charge that can be accepted by the battery). The battery power offsets can involve increasing the battery state of charge by charging the battery using machine power or decreasing the battery state of charge by discharging the battery to supplement machine power. The control device can, for example, repeat the efficiency calculation (e.g., BSFC calculation) assuming battery offsets of 5, 10, -5, and -10 kW to the machine.Here, 5 and 10 kW (positive) offsets mean that battery power is used to increase machine power, discharging the battery to operate the machine in a more efficient operating range. Conversely, -5 and -10 kW (negative) offsets mean that battery power is drawn from machine power, charging the battery above the machine power to operate the machine in a more efficient operating range. In one example, the battery power offset applied with the use of the first water injection state (for example, active water injection) may differ from the battery power offset applied with the use of the second water injection state (for example, inactive water injection). In other examples, the offsets may be the same. Exemplary characteristic maps can be used to determine the battery power offset, as described in the [reference to the relevant section]. Fig. 5-6 described, to determine.

[0053] In 318, the procedure involves determining whether the efficiency of the machine improves by more than a threshold quantity by changing the water injection state from the current state in which the machine is located to the other state, while taking into account the efficiency improvements achieved in each state with the battery power offset.

[0054] In one example, the control device can determine the amount of fuel required to meet operator demand with and without water injection. In machine speed-load ranges where water injection provides a knock-reducing benefit, spark delay usage is reduced, which decreases the net amount of fuel required to meet a given operator demand. The control device can retrieve fuel costs and use them to calculate the machine's operating costs with the determined amount of fuel needed to meet operator demand with and without water injection. The control device can divide the efficiency by the fuel costs to obtain a performance-per-dollar rating for each water injection condition.The control device can then retrieve estimated battery power costs (in conjunction with the battery offset) by assuming an average cycle efficiency for battery power generated by the machine. The control device can divide the efficiency of delivering power from the battery by the fuel costs, plus the power costs of charging the battery, to obtain a battery power-per-dollar rating. A comparison of these values ​​can be used to determine whether the efficiency has improved sufficiently to ensure a transition between water injection states.

[0055] For example, the machine may currently be operating with water injection disabled, and, in response to a change in driver demand, it can be determined whether the machine's fuel efficiency improves by more than a threshold by switching to operation with water injection enabled (in both cases without a battery offset). In another example, the machine may currently be operating with water injection enabled, and, in response to a change in driver demand, it can be determined whether the machine's fuel efficiency improves by more than a threshold by switching to operation with water injection disabled (in both cases without a battery offset). The control device can therefore select the water injection state, which provides the lower BFSC (Battery Fuel Consumption), as the more efficient state.

[0056] In yet another example, the control device can compare the power-per-dollar values ​​of the current water injection state with different battery power offsets to the other water injection state with different battery power offsets and select the water injection state / battery power offset combination with the highest power-per-dollar value. This involves determining whether the operating costs of the machine with the current water injection state, with (or without) a battery offset, are higher than the operating costs of the machine with the other water injection state, with (or without) a battery offset. Furthermore, it can determine whether the cost difference exceeds a threshold.

[0057] If the machine's efficiency does not improve by more than the threshold amount, the procedure then maintains the current water injection state of the machine at 324. This means that if the net result with the water injection transfer and the battery power offset is a fuel loss, the current water injection state is maintained in the machine. If water injection was already activated, the water injection nozzle is kept activated.

[0058] At 326, while maintaining the current water injection state, the control device can compensate for any operator demand deficit (if present) via engine torque from an electric motor coupled to the battery. Additionally, at 328, the control device can adjust the MHT to provide the machine speed-load profile optimal for the selected water injection state. This can involve maintaining a standard machine speed-load profile while maintaining the current water injection state. Alternatively, it can involve adjusting the machine speed-load profile for the current water injection state by modifying the MHT speed ratio while maintaining the current water injection state.In embodiments where the hybrid vehicle system does not have an MHT, engine torque settings can be used to keep the machine in a speed-load range that is optimal for the current water injection condition.

[0059] In this way, MHT and / or engine torque settings can be used to adjust the machine speed-load profile in the current water injection state to achieve additional fuel-saving benefits. For example, if the current state is with water injection enabled, an MHT gear ratio can be selected that allows the machine speed to be reduced while the machine load is increased via settings on a machine torque actuator. This reduces friction losses at low loads in the current water injection state while maintaining a requested machine power level. Alternatively, if the current state is with water injection disabled, the threshold could be negative, so that the water is switched off when the fuel benefit from water injection still exists but is very small.That would save water for future events offering higher fuel efficiency benefits.

[0060] If the machine's efficiency does not improve by more than the threshold amount—that is, if the net result with water state transition and / or battery power offset is a net benefit—the procedure proceeds to 320 to determine if there are any reasons why it should not be possible to switch to the alternative water injection state. For example, the current water injection state indicates that water injection is inactive, the alternative water injection state indicates that water injection is active, and it may not be possible to switch to the alternative water injection state because a water level in a water reservoir of the water injection system is lower than a threshold level, or because the available amount of water is less than the amount of water that is desired to be injected.As another example, the deterioration of a water injection system component (for example, a deteriorated water injection nozzle, deteriorated water pump, etc.) may prevent the transition to the alternative water injection state. Furthermore, the inadequacy of the water quality available for injection (such as low water conductivity) may also prevent the transition to the alternative water injection state.

[0061] If it is possible to switch to the alternative state, such as when water availability is limited, the procedure at 322 for switching the machine to the more efficient water injection state is carried out by adjusting the corresponding water injection nozzles. For example, if the alternative state is that water injection is disabled, the control device can send a signal to disable the water injection nozzle(s). As another example, if the alternative state is that water injection is enabled, the control device can send a pulse width signal to the water injection nozzle(s) to enable the specified quantity of water to be delivered through the injection nozzle to the specified location(s) (for example, central, intake manifold, or direct injection points). Furthermore, the specified battery offset quantity is applied.This involves using engine torque settings to select a battery power setting that provides the specific positive or negative offset.

[0062] At 328, the control device can adjust the MHT and the engine to provide the engine speed-load profile that is optimal for the selected water injection condition (such as an engine speed-load profile that eliminates knock limitations). For example, the engine can be switched to the activated water injection condition while the MHT is set to a speed ratio that reduces the engine speed. Simultaneously, one or more engine actuators can be adjusted to increase the engine load while maintaining the same powertrain output. The one or more engine actuators can, for example, include an engine intake throttle, intake and / or exhaust cams, and ignition timing control.The control device can, for example, set an intake throttle opening degree, select a timing control or profile of the intake and / or exhaust cams, and vary an amount of ignition timing delay, applied to increase the engine load, whereby the engine load is increased by an amount based on reducing the engine speed in order to maintain the same powertrain output power.

[0063] At 324, during the transition from one water injection state to another, torque transients can also be smoothed by using engine torque. In this way, battery power is used to smooth torque transients by filling torque dips caused by switching water injection states. This results in additional fuel economy improvements by reducing the need for ignition retardation that would otherwise be required to smooth the torque transients. The engine torque can be derived from an energy storage system not limited to a battery. In another example, the engine torque could consist of one or more electric, hydraulic, flywheel, and pneumatic engine torque sources.

[0064] Upon returning to 320 if it is not possible to switch to the alternative state, the procedure continues at 324 to maintain the current water injection state in the machine. Although the other water injection state is more fuel-efficient for the given driver demand, the control device may therefore keep the machine in the current water injection state given the impossibility of providing the requested water injection due to water injection system limitations. Alternatively, the control device may keep the machine in the current water injection state to avoid excessive water consumption when water availability is limited. As discussed above, at 324 the control device may then compensate for a difference / deficit in torque demand using battery power.Battery power can be consumed up to a battery power threshold, which is based on the battery's state of charge. Additionally, the control device at 328 can adjust the MHT to provide the machine speed-load profile that is optimal for the current water injection condition. This can involve maintaining a standard machine speed-load profile while maintaining the current water injection condition, or adjusting the machine speed-load profile for the current water injection condition by modifying the MHT gear ratio.

[0065] In one example, as can be seen with reference to the Fig. As described in sections 5-6, the fuel efficiency data collected from the fuel island maps for each water injection state are reduced to two best efficiency lines that the control unit can interpolate more quickly in real time. Otherwise, the control unit would have to optimize each map and then attempt to further optimize a point between the two water injection states. With the present approach, the control unit can use fuel island maps to predetermine a line of optimal efficiency. Then, for the current power demand, the control unit can look up lines of optimal efficiency for a given operating power and evaluate the two curves to determine the optimal efficiency.The control device can linearly interpolate between the line of optimal efficiency for an activated water injection state and a deactivated water injection state, as well as for the different speed ratios available with the fixed-ratio MHT. Although the line may not be perfectly linear, the changes can be small enough that a linear approximation can be a reasonable real-time approximation.

[0066] In this way, a hybrid vehicle can be powered by a machine that operates with a water injection state selected based on driver demand and water availability on board the vehicle; and in response to a change in driver demand, the water injection state can be adjusted based on any of the changes in driver demand, state of charge of an energy storage system, and water availability.Here, the setting can include a choice between maintaining a current water injection state and switching to an alternative water injection state based on fuel savings. Both the current and alternative water injection states have a stored power offset based on the state of charge. The current water injection state has one set of activated and one set of deactivated water injection states, and the alternative water injection state has the other set of activated and deactivated water injection states. The stored power offset applied with the first water injection state can differ from the stored power offset applied with the alternative water injection state.The stored battery power offset can also include an increase in the state of charge by charging the energy storage system using machine torque and a decrease in the state of charge by discharging the stored power to supplement the machine torque.The selection can include switching to the alternative water injection state if the fuel saving associated with the alternative water injection state with the stored power offset is more than a threshold amount higher than the fuel saving associated with the current water injection state with the stored power offset, and a higher level of water than the threshold level is available in a water reservoir; and maintaining the current water injection state if the fuel saving associated with the alternative water injection state with the stored power offset is lower than the fuel saving associated with the current water injection state with the stored power offset, or is less than the threshold amount lower, or a lower water level than the threshold level is available in the water reservoir.Furthermore, while the current water injection state is maintained, the control device can compensate for a driver demand deficit by drawing torque from a motor coupled to the energy storage system. In response to maintaining the current water injection state, the machine can operate with a first preset speed-load profile while maintaining a certain vehicle performance level using engine torque. In response to transitioning to the alternative water injection state, the machine can operate with a second preset speed-load profile while maintaining the vehicle's performance level using engine torque.The first set machine speed-load profile can be based on a knock limit of machine operation with the current water injection state, while the second set machine speed-load profile can be based on a knock limit of machine operation with the alternative water injection state. For example, the current water injection state is the activated water injection state, and the first set machine speed-load profile has a lower machine speed than the standard machine speed and a higher machine load than the standard machine load. The alternative water injection state has the deactivated water injection state, and the second set machine speed-load profile has a higher machine speed than the standard machine speed and a lower machine load than the standard machine load.The hybrid vehicle can feature a modular hybrid transaxle (MHT) transmission, and operation with the first set speed-load profile can involve selecting a first MHT speed ratio corresponding to the first set speed-load profile, while operation with the second set speed-load profile can involve selecting a second, different MHT speed ratio corresponding to the second set speed-load profile. A machine power level can therefore be maintained during each machine operation in the current water injection state with the first set speed-load profile and in the alternative water injection state with the second set machine speed-load profile, where the power level is a drivetrain output of the machine determined as the product of the machine load and the machine speed.As used here, operating the machine in the activated water injection state can involve injecting a quantity of water into the machine via one or more direct injections into a machine cylinder via a direct water injection nozzle, suction port injection into an intake port upstream of an intake valve via a suction port water injection nozzle, or central injection into a suction pipe upstream or downstream of an intake throttle via a central water injection nozzle.

[0067] With reference to Fig. Figure 5 shows an exemplary map 500 for comparing fuel efficiencies associated with different water injection states for a given driver-requested power output, as well as for comparing fuel efficiencies associated with different engine speed-load profiles for different speed ratios of an MHT at a given water injection state. In an example, the map can be Fig. 5. The map is generated during machine calibration and stored in the memory of the machine control device. The control device can then refer to the map during machine operation to determine whether to maintain the current water injection state or switch to an alternative water injection state in response to a change in operator demand. Additionally, the control device can refer to the map to determine the fixed speed ratio at which an MHT should operate the machine and further determine a battery power offset that can be used to operate the machine with maximum fuel efficiency while delivering the requested power. In this way, machine power and battery power can be combined to deliver the requested power while operating the machine in the most fuel-efficient manner.

[0068] The 500 characteristic map of the Fig. Figure 5 shows a first line of maximum efficiency versus power with water injection disabled (water_inactive) in graph 504 (shown as a solid line), and a second line of maximum efficiency versus power with water injection enabled (water_active) in graph 506 (shown as a dashed line). The graphs are shown with machine speed along the x-axis and machine load or torque along the y-axis. Lines of constant power output are shown on power lines 530 and 540. Each constant power output line represents machine speed-load combinations whose product provides a given power output. In the example shown, power line 530 represents a constant power output of 15 kW, while power line 540 represents a constant power output of 20 kW.Additional such lines, corresponding to higher and lower power outputs, can be represented similarly (not shown here). For example, the interface between power line 530 and graphic 504 represents a machine speed-load combination that provides 15 kW of power at maximum efficiency when the machine is operated with water injection disabled. Likewise, the interface between power line 530 and graphic 506 represents a machine speed-load combination that provides 15 kW of power at maximum efficiency when the machine is operated with water injection enabled. Similarly, the interface between power line 540 and graphic 504 represents a machine speed-load combination that provides 20 kW of power at maximum efficiency when the machine is operated with water injection disabled.Similarly, the interface between the power line 540 and the graphical representation 506 provides a machine speed-load combination that delivers 20kW of power at maximum efficiency when the machine is operated with water injection activated.

[0069] In the example shown, the power requested by the driver is 20 kW. This can be achieved by operating the machine at operating point 518, using a fixed-ratio gearbox, such as the MHT. Fig. 1, in a lower gear. As a result of selecting a lower gear ratio at operating point 518, the machine operates at a lower initial speed Spd _11 and a higher machine load. However, operating point 518 falls outside the range of graphs 506 and 504 and therefore does not represent the most efficient operating point.

[0070] As an alternative example, the driver's requested power of 20 kW can be achieved by operating the machine at operating point 520, with the fixed-ratio transmission in a higher gear. As a result of selecting a higher gear ratio at operating point 520, the machine operates at a second, higher speed (Spd _12) and a lower machine load. However, operating point 520 also falls outside the range of graphs 506 and 504 and therefore does not represent the most efficient operating point.

[0071] To improve fuel efficiency under the constraints of the limited speed-load combinations possible with the fixed-ratio transmission, the control device can instead operate the machine with battery power offset while selecting a speed ratio that optimizes a specific water injection state (which can be the current water injection state or the alternative state). In the illustrated example, fuel efficiency is increased by shifting the machine operating point from 518 to 522. The operating point represents a machine state where maximum efficiency is provided by operating the transmission in the lower gear, with the machine speed at Spd_11 and with water injection enabled (since it falls on graphical representation 506).The machine is therefore operated more efficiently at operating point 522 by activating water injection (if water injection was previously deactivated) or maintaining activated water injection (if it was already activated), and furthermore by switching to the lower gear ratio of the MHT (if it was in an alternative speed ratio) or maintaining the lower speed ratio of the MHT (if it was already in the lower speed ratio). However, operating point 522 lies along power line 530 and represents a lower machine power output than the power requested by the operator. The power difference between operating points 522 and 518, here a negative difference (i.e., a deficit), is therefore provided using a positive battery power offset 524.This means that the battery power corresponding to the difference between operating points 518 and 522 is sent to the vehicle wheels via a motor to meet the power demanded by the driver, resulting in a discharge of the battery charge. In this case, the machine power output is therefore 15 kW, the battery offset is +5 kW, and the combination results in the driver-demanded power of 20 kW being delivered to the vehicle wheels. In this way, driver demand can be met by operating the machine in the most fuel-efficient water injection condition and by selecting a fixed speed ratio optimized for that given water injection condition. Then, based on the fact that the machine power at this operating point is lower than the driver demand, a battery offset is provided to cover the driver demand deficit.

[0072] With reference to Fig. Figure 6 shows another exemplary map for comparing fuel efficiencies associated with different water injection states for a given driver-requested power output, as well as for comparing fuel efficiencies associated with different engine speed-load profiles for different speed ratios of an MHT in a given water injection state. In one example, the map of Fig. 6. The map is generated during machine calibration and stored in the memory of the machine control device. The control device can then refer to the map during machine operation to determine whether to maintain the current water injection state or switch to an alternative water injection state in response to a change in operator demand. Additionally, the control device can refer to the map to determine the fixed speed ratio of an MHT at which the machine should operate, and furthermore to determine a battery power offset that can be used to operate the machine with maximum fuel efficiency.

[0073] The 600 characteristic map of the Fig. Figure 6 shows a first line of maximum efficiency versus power with water injection disabled (water_inactive) in graph 504 (shown as a solid line), and a second line of maximum efficiency versus power with water injection enabled (water_active) in graph 506 (shown as a dashed line). The graphs are shown with machine speed along the x-axis and machine load or torque along the y-axis. Lines of constant power output are shown on power lines 540 and 550. Each constant power output line represents machine speed-load combinations whose product provides a given power output. In the example shown, power line 540 represents a constant power output of 20 kW, while power line 550 represents a constant power output of 25 kW.Additional lines corresponding to higher and lower power outputs can be represented similarly (not shown here). For example, the interface between power line 540 and graphic 504 represents a machine speed-load combination that provides 20 kW of power at maximum efficiency when the machine is operated with water injection disabled. Similarly, the interface between power line 540 and graphic 506 represents a machine speed-load combination that provides 20 kW of power at maximum efficiency when the machine is operated with water injection enabled. Likewise, the interface between power line 550 and graphic 504 represents a machine speed-load combination that provides 25 kW of power at maximum efficiency when the machine is operated with water injection disabled.Similarly, the interface between the power line 550 and the graphical representation 506 provides a machine speed-load combination that delivers 25kW of power at maximum efficiency when the machine is operated with water injection activated.

[0074] In the illustrated example, the power requested by the driver is 20 kW. This can be achieved by operating the machine at operating point 618, using a fixed-ratio gearbox, such as the MHT. Fig. 1, in a lower gear. As a result of selecting a low gear ratio at operating point 618, the machine operates at a lower initial speed Spd_21 and a higher machine load. However, operating point 618 falls outside the range of graphs 506 and 504 and therefore does not represent the most efficient operating point.

[0075] As an alternative example, the driver's requested power of 20 kW can be achieved by operating the machine at operating point 620, with the fixed-ratio transmission in a higher gear. As a result of selecting a higher gear ratio at operating point 620, the machine operates at a second, higher speed (Spd_22) and a lower machine load. However, operating point 620 also falls outside the range of graphs 506 and 504 and therefore does not represent the most efficient operating point.

[0076] To improve fuel efficiency under the constraints of the limited speed-load combinations possible with the fixed-ratio transmission, the control device can instead operate the machine with battery power offset while selecting a speed ratio that optimizes a specific water injection state (which can be the current water injection state or the alternative state). In the illustrated example, fuel efficiency is increased by shifting the machine operating point from 618 to 622. The operating point represents a machine state where maximum efficiency is provided by operating the transmission in a higher gear, with the machine speed at Spd_22 and water injection disabled (since it corresponds to graphical representation 504).The machine is therefore operated more efficiently at operating point 622 by deactivating water injection (if water injection was previously activated), or maintaining deactivated water injection (if it was already deactivated), and furthermore by switching to the higher gear ratio of the MHT (if it was in an alternative speed ratio) or maintaining the higher speed ratio of the MHT (if it was already in the higher speed ratio). However, operating point 622 lies along power line 550 and represents a higher machine power output than the power requested by the operator. The power difference between operating points 622 and 618, here a positive difference (i.e., a surplus), is therefore corrected by using a negative battery power offset 624.This means that power equal to the difference between operating points 618 and 622 is drawn into the engine by the vehicle wheels to meet the power demanded by the driver, resulting in a charge to the battery. In this case, the engine power output is therefore 25 kW, the battery offset is -5 kW, and the combination results in the driver's requested power of 20 kW being delivered to the vehicle wheels. In this way, driver demand can be met by operating the engine in the most fuel-efficient water injection condition and by selecting a fixed speed ratio optimized for that given water injection condition. Then, based on the fact that the engine power at this operating point is higher than the driver demand, a battery offset is provided to compensate for the excess of driver demand.

[0077] In this way, for a given operator demand, an engine control unit can estimate a first fuel saving associated with maintaining a first water injection state with water injection disabled, and a second fuel saving associated with transitioning to a second water injection state with water injection enabled while operating with a knock-adapted engine speed-load profile. If the second fuel saving is greater than the first, the control unit can determine that transitioning is more fuel-efficient and can transition the engine to the second water injection state. Additionally, the control unit can transition the engine to the knock-adapted engine speed-load profile by adjusting the engine speed-load ratio (EFT).Furthermore, the control device can transfer the machine and cover any difference between the machine's power output and the requested power output via battery power offsets.

[0078] With reference to Fig.Figure 7 shows exemplary fuel usage settings coordinated with hybrid transaxle transmission and engine torque settings in a hybrid vehicle system. Figure 700 depicts changes in engine speed (graphic 702), engine load (graphic 704), and engine power (graphic 706) in relation to driver demand (707).The characteristic map 700 further depicts the motor speed for an electric motor of the hybrid vehicle in graphical representation 708, changes in the state of charge of a battery coupled to the electric motor in graphical representation 710, water injection state selection (between a first state with water injection deactivated and a second state with water injection activated) in graphical representation 712, an indication of knocking in graphical representation 716, and water availability for water injection (such as based on the output of a level sensor coupled to the water tank) in graphical representation 718. All graphical representations are shown over time (along the x-axis). Significant time points during vehicle operation are shown at t1-t4. It is understood that, as used here, engine power is determined as the product of engine speed and engine load (or torque).Furthermore, the machine speed-load settings are achieved via adjustments to the speed ratio of an MHT coupled between the machine and an output shaft. In the present example, the water injection state is switchable between an active and an inactive state, although in alternative examples, multiple active states may be present, each representing a different mode / location of water injection (for example, direct, suction channel, or central water injection).

[0079] Before time t1, the hybrid vehicle operates in a machine mode where the vehicle wheels are driven using only machine torque (Plot 706). In one example, the vehicle operates in machine mode in response to increased driver demand (Plot 707, dashed line). Because the vehicle is driven using machine torque, one electric motor is deactivated (Plot 708), and the battery state of charge (SOC) can remain constant (Plot 710). Specifically, before t1, machine power output corresponding to the driver demand is delivered via the machine, which operates with the machine speed-load profile shown, and with water injection activated due to increased water availability (such as water levels in a water tank exceeding a threshold level).As a result of operation with active water injection, the water level in the water tank before t1 can constantly decrease, so that the water availability at t2 is lower.

[0080] At t1, in response to an increase in driver demand (such as due to a tip-in), the machine's power output can be increased to propel the vehicle and meet the driver demand. Based on driver demand, knock tendency, and battery state of charge (SOC) at t1, it may be more efficient to operate the machine with water injection actively maintained. However, due to the lower water availability at t1, water injection is deactivated to limit water consumption.

[0081] At t1, the machine speed-load profile is also set via MHT settings during operation in the inactive water injection state, thus optimizing the machine's power output. Specifically, a given machine power output is provided using a higher machine speed and a lower machine load than the standard machine load. The standard machine speed and load (for the given water injection state) are shown here as dashed lines 703a and 705a.The MHT settings can include the selection of a gear corresponding to a speed ratio that operates the machine at the target machine speed (for the inactive water injection state) and corresponding settings on one or more machine actuators (such as a throttle opener or cam timing control) that operate the machine with a target machine load based on the target machine speed while providing the given machine power output. Specifically, if the machine were operated with water injection disabled and at the standard machine speed load, the machine would be knock-limited, as indicated by the predicted knock sensor output 714 (dashed segment) exceeding the knock threshold (Knk_Thr).By switching to the disabled water injection state and higher engine speed via MHT settings, knocking at higher loads is countered, while improving overall engine fuel economy without compromising engine power output.

[0082] Efficient machine operation with the selected speed-load profile and deactivated water injection results in the machine power (plot 706) not reaching the operator demand (plot 707). This demand deficit is therefore compensated for by using engine torque. Specifically, the electric motor is turned using energy drawn from the system battery (plot 708) to provide sufficient engine torque to meet the operator demand, with a corresponding decrease in the battery state of charge (plot 710).

[0083] The machine can operate at a higher than standard machine speed and a lower than standard machine load with inactive water injection for a duration up to t2. At t2, in response to a drop in operator demand, the machine can operate with the inactive water injection state maintained, while the standard machine speed and load are resumed due to the fact that the machine is no longer knock-limited. This operation can be maintained up to t3.

[0084] At t3, the machine's power output can be reduced in response to a decrease in operator demand. Here, the power output is reduced while transitioning to operating the machine with water injection activated, because the active water injection state is more fuel-efficient. Further fuel-saving benefits are also achieved by adjusting the machine speed-load profile via MHT settings, so that the same machine power is provided using a lower machine speed than the standard machine speed and a higher machine load than the standard machine load. The standard machine speed and load (for the given fuel) are shown here as dashed lines 703b and 705b. In particular, if the machine were transitioned to the active water injection state and operated at the standard machine speed load, the machine could have been friction-limited.By switching to lower engine speed and higher engine load via MHT settings during the transition to water injection operation, friction losses at lower loads are reduced, while overall engine fuel savings are improved, without compromising engine power output. Knocking is also prevented.

[0085] The efficient operation of the machine with the selected speed-load profile and with reactivated water injection results in the machine power (plot 706) exceeding the operator demand (plot 707). The difference in demand is therefore compensated for by using engine torque and / or battery power offset. Specifically, the electric motor is run as a generator (plot 708), with excess energy stored in the system battery, resulting in a corresponding increase in the battery state of charge (plot 710). Machine operation with activated water injection and the speed-load system optimized for the given water injection state then continues until t4.

[0086] At t4, in response to increased operator demand, the machine's power output is increased while maintaining operation with water injection enabled, as the active water injection state is more fuel-efficient. Additionally, the machine speed-load profile is reset to the standard speed-load profile via MHT settings. By transitioning to the lower machine speed and higher machine load via MHT settings during the transition to water injection operation, friction losses at lower loads are reduced, while overall machine fuel savings are improved, without compromising machine power output. At this point, the machine power output is sufficient to meet operator demand, and no further battery offset is required.

[0087] In this way, fuel-saving losses in a hybrid vehicle system due to frequent engine acceleration and deceleration (such as in a city cycle) can be reduced by integrating water injection technology with hybrid transaxle transmission technology. By using engine torque and battery power to meet driver demand while maintaining the machine in a more efficient water injection state and operating range for that state, frequent switching between water injection states is reduced, even when the driver pedal position changes or oscillates frequently.Even if the engine load fluctuates excessively between the optimal range of different water injection states, fuel savings can be improved by remaining in a more efficient setting while applying a small amount of battery power offset to meet driver demand. As a result, synergistic fuel-saving benefits are achieved by utilizing the electrical components of a hybrid vehicle system during water injection state selection. By leveraging the different engine speed-load combinations achievable for a given engine power output via MHT settings, a hybrid vehicle control device can better address engine constraints, such as knock limits, associated with water injection state transitions.This therefore allows for a more precise determination of the costs associated with a transfer, and a reduction in the frequency of inefficient switching operations in response to frequent changes in driver or wheel torque demand, or due to changes in water availability. Overall, the fuel savings of a hybrid vehicle can be enhanced.

[0088] An exemplary procedure for a hybrid vehicle incorporating an engine configured with water injection and a hybrid transaxle (MHT) transmission comprises: for a given power level, comparing an initial fuel saving without water injection and an initial amount of stored power offset from an energy storage system with a second fuel saving with water injection at an initial set engine speed load and a second amount of stored power offset; in response to the second fuel saving exceeding the first fuel saving and to a higher water availability than threshold, injecting a quantity of water into the engine and changing the initial set engine speed load; and in response to the first fuel saving exceeding the second fuel saving or to a water availability lower than threshold,Operating the machine without water injection and changing the machine speed load to a second set machine speed load. In the preceding example, the method additionally or optionally further includes: in response to the second fuel saving exceeding the first fuel saving and to water availability being lower than the threshold water availability, maintaining machine operation without water injection, changing the machine speed load to the second set machine speed load, and using stored power from the energy storage system.to cover a deficit between machine output and the power level. In all the preceding examples, the first and second amounts of stored power offset are additionally or optionally based on the state of charge of the energy storage system and the power level. In any of the preceding examples, the first set machine speed load is additionally or optionally based on a knock limit and friction limit of machine operation with water injection, and the second set machine speed load is based on a knock limit and friction limit of machine operation without water injection. In any of the preceding examples, switching to the first or second set machine speed load additionally or optionally involves transitioning from a standard machine speed load via settings on a speed ratio of the MHT,wherein the first set machine speed load has a lower machine speed and a higher machine load compared to the standard machine speed load, and the second set machine speed load has a higher machine speed and a lower machine load compared to the standard machine speed load. In any of the preceding examples, additionally or optionally, a machine power output with water injection enabled and the first set machine speed load is equal to the machine output power with water injection disabled and the second set machine speed load. In any of the preceding examples, the lower water availability than the threshold water availability is additionally or optionally set to a water level lower than the threshold water level in a water reservoir of a water injection system coupled to the machine.or due to a water quality lower than the threshold water quality in the water tank and a deterioration of a component of the water injection system, wherein the component comprises a water injection nozzle and a water pump.

[0089] Another exemplary procedure for a hybrid vehicle includes: powering the vehicle via a machine operating with a water injection state selected based on driver demand and onboard water availability; and, in response to a change in driver demand, adjusting the water injection state based on each change in driver demand, the state of charge of an energy storage system, and water availability. In the preceding example, the adjusting additionally or optionally involves selecting between maintaining a current water injection state and switching to an alternative water injection state based on fuel savings for each of the current and alternative water injection states, with a stored power offset based on the state of charge.wherein the current water injection state has one of an enabled water injection state and one of a disabled water injection state, and wherein the alternative water injection state has the other of the enabled water injection state and one of the disabled water injection state. In any of the preceding examples, additionally or optionally, the stored power offset applied with the first water injection state is different from the stored power offset applied with the alternative water injection state.and wherein the stored power offset features an increase in the state of charge by charging the energy storage system using machine torque and a decrease in the state of charge by discharging the stored power to supplement the machine torque. In any of the preceding examples, the selection additionally or optionally features: transitioning to the alternative water injection state when the fuel saving associated with the alternative water injection state with the stored power offset is more than a threshold quantity higher than the fuel saving associated with the current water injection state with the stored power offset, and a level of water higher than the threshold level is available in a water reservoir; and maintaining the current water injection state when the fuel savingthe fuel savings associated with the alternative water injection state with the stored power offset are lower than the fuel savings associated with the current water injection state with the stored power offset, or are higher by less than the threshold quantity, or a lower water level is available in the water reservoir. In any of the preceding examples, the method further includes, additionally or optionally: while maintaining the current water injection state, compensating for a driver demand deficit via torque from an engine coupled to the energy storage system. In any of the preceding examples, the method further includes, additionally or in response to maintaining the current water injection state,Operating the machine with a first set speed-load profile while maintaining a vehicle performance level using engine torque, and in response to transitioning to the alternative water injection state, operating the machine with a second set speed-load profile,while maintaining the vehicle's performance level using engine torque. In any of the preceding examples, the first set engine speed-load profile is additionally or optionally based on a knock limit of engine operation with the current water injection state, and the second set engine speed-load profile is based on a knock limit of engine operation with the alternative water injection state. In any of the preceding examples, the current water injection state additionally or optionally includes the activated water injection state, and the first set engine speed-load profile has a lower engine speed than the standard engine speed and a higher engine load than the standard engine load.and wherein the alternative water injection state is the deactivated water injection state, and the second set machine speed-load profile is a machine speed higher than the standard machine speed and a machine load lower than the standard machine load. In any of the preceding examples, the hybrid vehicle additionally or optionally has a modular hybrid transaxle (MHT) transmission, and wherein operating with the first set speed-load profile involves selecting a first speed ratio of the MHT that corresponds to the first set speed-load profile, and wherein operating with the second set speed-load profile involves selecting a second different speed ratio of the MHT that corresponds to the second set speed-load profile.exhibits. In any of the preceding examples, a machine power level is additionally or optionally maintained during each machine operation in the current water injection state with the first set speed-load profile and machine operation with the alternative water injection state with the second set machine speed-load, and wherein the power level is a drivetrain output of the machine, which is determined as a product of the machine load and the machine speed. In any of the preceding examples, operating the machine in the activated water injection state involves injecting a quantity of water into the machine via one or more direct injection points into a machine cylinder via a direct water injection nozzle.Intake manifold injection into an intake manifold upstream of an intake valve via an intake manifold water injection nozzle and central injection into an intake pipe upstream or downstream of an intake throttle via a central water injection nozzle.

[0090] Another exemplary vehicle system comprises: a machine; an engine powered by an energy storage system; a fuel injector for supplying fuel from a fuel tank to the machine; a water injector for supplying water from a water reservoir to the machine; a modular hybrid transaxle (MHT) transmission coupling the machine and engine to vehicle wheels, the MHT having a variety of speed ratios; and a control device. The control device may be configured with computer-readable instructions stored on non-volatile memory to: estimate a first efficiency associated with operating the machine with the water injector disabled and a first power offset from the energy storage system; estimate a second efficiency,which is associated with operating the machine with the water injection nozzle activated and a second different power offset; if the second efficiency is higher than the first efficiency and a water level in the water tank is higher than a threshold, to activate the water injection nozzle, to set an output of the motor to provide the second power offset, and to select one of the many speed ratios of the MHT to operate the machine with a first modified machine speed-load profile; and, if the second efficiency is lower than the first efficiency or the water level in the water tank is lower than the threshold, to deactivate the water injection nozzle, to set the output of the motor to provide the first power offset, and to select another of the many speed ratios of the MHT to provide a second modified machine speed-load profile.to provide a profile that differs from the first modified machine speed-load profile. In the preceding example, the first modified machine speed-load profile is additionally or optionally based on a machine knock limit and machine friction when operating with water injection, wherein the second modified machine speed-load profile is based on a machine knock limit and machine friction when operating without water injection, wherein the first modified machine speed-load profile has a lower machine speed and a higher machine load than the second modified machine speed-load profile, and wherein the output power of the machine with the water injection nozzle activated and the first modified machine speed-load profile is equal to the power output of the machine with the water injection nozzle deactivated and the second modified machine speed-load profile.

[0091] In another embodiment, a method for a hybrid vehicle comprising an engine configured with water injection and a modular hybrid transaxle (MHT) transmission includes: comparing, for a desired power level, the fuel savings of operating the engine in each water injection state at a first, unset engine speed-load and a second, set engine speed-load; selecting the combination of a water injection state and one of the first and second engine speed-load that results in greater fuel savings; and operating the engine with the selected water injection state and engine speed-load. The method further includes providing a battery power offset based on the difference between the engine power output at the selected water injection state and the selected engine speed-load relative to the desired power level.The method further features a positive battery power offset, with a decrease in the battery state of charge when the machine power output at the selected water injection condition and speed-load is lower than the desired power level. Alternatively, the method also features a negative battery power offset, with an increase in the battery state of charge when the machine power output at the selected water injection condition and speed-load is higher than the desired power level. It should be noted that the control and estimation routines contained herein can be used with various machine and / or vehicle system designs. The control methods and routines disclosed herein can be stored as executable instructions in non-volatile memory and implemented by the control system, including the control device, in combination with the various sensors, actuators, and other machine hardware.The specific routines described here can represent one or more of any number of processing strategies, such as event-driven, interrupt-driven, multitasking, multithreading, and the like. Therefore, different actions, operations, and / or functions shown in the sequence can be performed in parallel or, in some cases, omitted. Likewise, the processing order is not necessarily required to achieve the features and benefits of the implementations described here, but is provided for ease of presentation and description. Depending on the strategy used, one or more of the actions, operations, and / or functions shown can be performed repeatedly.Furthermore, the described actions, processes and / or functions can graphically represent code that is to be programmed into non-volatile memory of the computer-readable storage medium in the machine control system, whereby the described actions are implemented by executing the instructions in a system including the various machine hardware components in combination with the electronic control device.

[0092] It is understood that the interpretations and routines disclosed herein are exemplary in nature and that these specific embodiments are not to be interpreted in a limiting sense, as numerous variations are possible. For example, the technology described above can be applied to the V-6, I-4, I-6, V-12, Boxer 4, and other machine types. The subject matter of this disclosure includes all novel and non-obvious combinations and sub-combinations of the different systems and interpretations, as well as other features, functions, and / or properties disclosed herein.

[0093] The following claims specifically indicate certain combinations and subcombinations that are considered novel and not obvious. These claims may refer to "one" element or "a first" element, or the equivalent thereof. Such claims should be understood as including one or more such elements, without requiring or excluding two or more such elements. Other combinations and subcombinations of the disclosed features, functions, elements, and / or properties may be claimed by amendment of the present claims or by filing new claims in this or a related application. Such claims, whether their scope of protection is broader, narrower, the same, or different from that of the original claims, shall also be considered to be included in the subject matter of the present disclosure. Reference sign 10 Internal combustion engine 12 Electronic Control Unit (ECU) 13 turbochargers 14 compressors 18 Hybrid power transmission 19th wave 20 Throttle valve 23 MCT sensor 26 Electric motor 28 Tax system 30 sensors 31 air purifiers 33 Sensor 35 Exhaust pipe 44 gearboxes 45-48 water injection nozzles 50 coolers 52 drive wheels 54 Battery 60 torque converters 61 Water canal 62 Release clutch 63 Water tank 64 Torque sensor 65 Water level sensor 66 TCU 67 Water temperature sensor 68 Control device 69 Water filling channel 70 starters 72 Collection system 74 vehicle components 76 Water tank filling channel 91 Drain valve 92 Derivative 100 Hybrid drive system 102 Motor vehicle 104 machine system 116 Turbine 118 CRC 122 Intake manifold 124 Boost pressure sensor 125 air charge temperature sensor, ACT sensor 126 UEGO probe 136 Exhaust manifold 142 Inlet channel 151 EGR channel 152 EGR valve 160 Water injection system 161 lines 162 Valve 164 Water lifting pump 168 filters 170 Emission control device 179 Fuel injector 180 combustion chamber 182 Cylinder head 183 Knock sensor 185 Intake manifold 224 Intake manifold pressure (MAP) sensor

Claims

[1] Method for a hybrid vehicle (102), comprising: Propelling the hybrid vehicle (102) via an internal combustion engine (10) operating with a water injection state selected based on driver demand and water availability on board the hybrid vehicle (102); and in response to a change in driver demand, adjusting the water injection state based on each of the changes in driver demand, a state of charge of an energy storage system (54) and water availability, wherein The setting includes the selection between maintaining a current water injection state and switching to an alternative water injection state based on fuel saving in each of the current and alternative water injection states with a stored power offset based on the state of charge, wherein the current water injection state has one of an activated water injection state and one of a deactivated water injection state, and wherein the alternative water injection state has the other of the activated water injection state and the deactivated water injection state. [2] Method according to claim 1, wherein the stored power offset applied with the current water injection state is different from the stored power offset applied with the alternative water injection state, and wherein the stored power offset comprises an increase in the state of charge by charging the energy storage system (54) using machine torque and a decrease in the state of charge by discharging the stored power to supplement the machine torque. [3] System according to claim 1, wherein the selection comprises: Switch to the alternative water injection state if the fuel saving associated with the alternative water injection state with the stored power offset is higher than a threshold amount than the fuel saving associated with the current water injection state with the stored power offset, and a level of water higher than the threshold level is available in a water reservoir (63); and Maintaining the current water injection state when the fuel saving associated with the alternative water injection state with the stored power offset is lower than the fuel saving associated with the current water injection state with the stored power offset, or is higher by less than the threshold amount, or a lower water level than the threshold level is available in the water reservoir (63). [4] Method according to the preceding claim, further comprising, while maintaining the current water injection state, compensating for a deficit in driver demand via torque from a motor (26) coupled to the energy storage system (54). [5] The method of claim 1, further comprising operating the internal combustion engine (10) with a first set speed-load profile in response to maintaining the current water injection state, while maintaining a power level of the hybrid vehicle (102) using engine torque, and operating the internal combustion engine (10) with a second set speed-load profile in response to switching to the alternative water injection state, while maintaining the power level of the hybrid vehicle (102) using engine torque. [6] Method according to the preceding claim, wherein the first set machine speed-load profile is based on a knock limit of the machine operation with the current water injection condition and the second set machine speed-load profile is based on a knock limit of the machine operation with the alternative water injection condition. [7] Method according to claim 5, wherein the current water injection state is the activated water injection state, and the first set machine speed load is a lower machine speed than standard machine speed and a higher machine load than standard machine load, and wherein the alternative water injection state is the deactivated water injection state and the second set machine speed load is a higher machine speed than standard machine speed and a lower machine load than standard machine load. [8] Method according to claim 5, wherein the hybrid vehicle (102) has a modular hybrid transaxle transmission (44) and wherein operation with the first set speed-load profile comprises selecting a first speed ratio of the hybrid transaxle transmission (44) corresponding to the first set speed-load profile, and wherein operation with the second set speed-load profile comprises selecting a second different speed ratio of the hybrid transaxle transmission (44) corresponding to the second set speed-load profile. [9] Method according to claim 5, wherein a power level of the internal combustion engine (10) is maintained during each machine operation in the current water injection state with the first set speed-load profile and machine operation with the alternative water injection state with the second set machine speed-load, and wherein the power level is a drive train output of the internal combustion engine (10) which is determined as a product of the machine load and the machine speed. [10] Method according to claim 1, wherein the operation of the internal combustion engine (10) in the activated water injection state comprises the injection of a quantity of water into the internal combustion engine (10) via one or more of the direct injection into a machine cylinder via a direct water injection nozzle (47), intake port injection into an intake port upstream of an intake valve via an intake port water injection nozzle (48) and central injection into an intake manifold upstream or downstream of an intake throttle via a central water injection nozzle (45, 46). [11] Vehicle system, comprising: an internal combustion engine (10); a motor (26) which is supplied with power via an energy storage system (54); a fuel injector (179) for supplying fuel from a fuel tank to the internal combustion engine (10); a water injection nozzle (45, 46, 47, 48) for supplying water from a water reservoir (63) to the internal combustion engine (10); a modular hybrid transaxle transmission (44) that couples the internal combustion engine (10) and the motor (26) to vehicle wheels (52), wherein the hybrid transaxle transmission (44) has a plurality of speed ratios; and a control device (68) with computer-readable instructions stored on non-volatile memory to: to estimate an initial efficiency associated with operating the internal combustion engine (10) with the deactivated water injection nozzle (45, 46, 47, 48) and an initial power offset from the energy storage system (54); to estimate a second efficiency associated with operating the internal combustion engine (10) with the activated water injection nozzle (45, 46, 47, 48) and a second, different power offset; if the second efficiency is higher than the first efficiency and a water level in the water tank (63) is higher than a threshold, to activate the water injection nozzle (45, 46, 47, 48), to adjust an output of the engine (26) to provide the second power offset, and to select one of the multiple speed ratios of the hybrid transaxle transmission (44) to operate the internal combustion engine (10) with a first modified engine speed-load profile; and If the second efficiency is lower than the first efficiency or the water level in the water tank (63) is lower than the threshold, the water injection nozzle (45, 46, 47, 48) is deactivated, the motor output (26) is adjusted to provide the first power offset, and another is selected from the multitude of speed ratios of the hybrid transaxle transmission (44) to provide a second modified machine speed-load profile that is different from the first modified machine speed-load profile. [12] System according to the preceding claim, wherein the first modified machine speed-load profile is based on a machine knock limit and machine friction when operated with water injection, and wherein the second modified machine speed-load profile is based on a machine knock limit and machine friction when operated without water injection, wherein the first modified machine speed-load profile has a lower machine speed and a higher machine load than the second modified machine speed-load profile, and wherein an output power of the internal combustion engine (10) with the activated water injection nozzle (45, 46, 47, 48) and the first modified engine speed-load profile is equal to the output power of the internal combustion engine (10) with the deactivated water injection nozzle (45, 46, 47, 48) and the second modified engine speed-load profile. [13] Method for a hybrid vehicle (102) comprising an internal combustion engine (10) configured with water injection and a modular hybrid transaxle transmission (44), comprising: Propelling the hybrid vehicle (102) via an internal combustion engine (10) which operates with a water injection state selected based on driver demand and water availability on board the hybrid vehicle (102); in response to a change in driver demand, adjusting the water injection state based on each of the changes in driver demand, a state of charge of an energy storage system (54) and water availability; for a desired performance level, comparing an initial fuel saving without water injection and an initial quantity of stored power offsets from an energy storage system (54) to a second fuel saving with water injection at an initial set machine speed load and a second quantity of stored power offsets; in response to the fact that the second fuel saving exceeds the first fuel saving and to a water availability higher than a threshold water availability, injecting a quantity of water into the internal combustion engine (10) and changing the first set engine speed load; and in response to the fact that the first fuel saving exceeds the second fuel saving or to a water availability lower than the threshold water availability, operating the internal combustion engine (10) without water injection and changing the engine speed load to a second set engine speed load. [14] Method according to the preceding claim, further comprising: in response to the fact that the second fuel saving exceeds the first fuel saving and the water availability is lower than the threshold water availability, Maintaining the operation of the internal combustion engine (10) without water injection, Changing the machine speed load to the second set machine speed load and Use of stored energy from the energy storage system (54) to compensate for a deficit between the power of the internal combustion engine (10) and the desired power level. [15] Method according to claim 13, wherein the first and second amounts of stored power offset are based on a state of charge of the energy storage system (54) and the desired power level.

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