Hybrid drive system with opposed piston internal combustion engine

Abstract

The hybrid drive system includes an opposed-piston internal combustion engine (52) having at least one cylinder (56) and a pair of pistons (57a, 57b) disposed within the bore of the cylinder and sliding oppositely within the cylinder, a power transducer device (53) coupled to be driven by the opposed-piston internal combustion engine (52), and a hybrid powertrain system (55) configured to receive electric power from the power transducer device (53).

Description

[Technical field]

[0001] The present invention relates to a hybrid drive system, and more particularly to a hybrid drive system for a vehicle in which a non-combustion drive device provides mechanical torque and rotation to a drive shaft and an opposed piston internal combustion engine device provides energy to the non-combustion drive system. [Background technology]

[0002] Various international considerations are driving the demand to increase energy efficiency and reduce undesirable emissions of vehicles powered by internal combustion engines. These objectives have led to the development of electric vehicles and hybrid electric powertrains for vehicles. Conventional internal combustion engines provide a low-cost platform with high power output and high energy density, thereby meeting consumer expectations of vehicle range, but continuing to offer low fuel consumption. Electric vehicles provide a low carbon signature (assuming a low CO2 grid) with good vehicle drivability characteristics. However, the energy impact of electric vehicles is low due to low sales volumes, high costs, less infrastructure support, and limited vehicle range. Hybrid electric vehicles increasingly offer a desirable combination of both drive technologies in terms of increased range, convenience, and efficiency. However, the efficiency and emission limitations of conventional internal combustion engines as currently configured increasingly inhibit the potential benefits of hybrid electric vehicles. Therefore, improving the internal combustion efficiency and emission characteristics of these vehicles can have a significant beneficial impact on global energy consumption and emissions.

[0003] Analytical studies have shown that opposed piston engines have fundamental fuel efficiency advantages over conventional internal combustion engines. Non-Patent Document 1 Other studies have confirmed the potential of opposed piston engines to meet stringent emissions regulations, especially those relating to NOx. Non-Patent Document 2 Recent advances in gasoline-powered opposed piston engine performance have shown that large margins in fuel efficiency and emissions are achievable over conventional two-stroke and four-stroke internal combustion engines used in hybrid applications. Non-Patent Document 3

[0004] However, to date, hybrid drive systems for vehicles such as cars, buses, and trucks have been designed and adapted for conventional internal combustion engine architectures based on single piston / cylinder configurations. Therefore, to achieve improved fuel efficiency and reduce undesirable emissions of the internal combustion components of hybrid drive systems, it is desirable to consider replacing the conventional internal combustion engine in a hybrid drive system with an opposed piston internal combustion engine. Summary of the Invention

[0005] In consideration of a drive to reduce or eliminate undesirable efficiency and emissions characteristics associated with conventional internal combustion engines, a hybrid drive system of the present invention having two power sources is configured such that a non-combustion drive device provides mechanical torque and rotation for a drive shaft and an opposed piston internal combustion engine device provides energy for the non-combustion drive device to an energy storage device that powers the non-combustion drive device.

[0006] In accordance with the present invention, a hybrid drive system may include an opposed piston internal combustion engine, a power transducer device coupled to be driven by the opposed piston internal combustion engine, and a hybrid powertrain system configured to receive power from the power transducer device.

[0007] Preferably, the hybrid powertrain system may comprise a first electric motor / generator arrangement and the power transducer arrangement may comprise a second electric motor / generator arrangement.

[0008] In some examples, the opposed piston internal combustion engine may include a first crankshaft, a second crankshaft, and a mechanical connection linking the first crankshaft and the second crankshaft, and a motor shaft of the second electric motor / generator unit may be coupled to one of the first crankshaft, the second crankshaft, and the mechanical connection.

[0009] In another example, the opposed piston internal combustion engine may include a first crankshaft, a second crankshaft, and a mechanical connection linking the first crankshaft and the second crankshaft, and the power transducer apparatus may include a third electric motor / generator apparatus, a motor shaft of the second electric motor / generator apparatus may be coupled to the first crankshaft, and a motor shaft of the third electric motor / generator apparatus may be coupled to the second crankshaft.

[0010] In a further example, the opposed piston internal combustion engine may include a first crankshaft and a second crankshaft, and the power transducer arrangement may further include a third electric motor / generator arrangement, the motor shaft of the second electric motor / generator arrangement may be coupled to the first crankshaft, and the motor shaft of the third electric motor / generator arrangement may be coupled to the second crankshaft.

[0011] From another aspect, the invention can relate to a serial hybrid system or extended range electric engine system in which an electric drive device is configured to provide mechanical torque and rotation to a drive shaft and an opposed-piston internal combustion engine device, the internal combustion engine device being configured to provide electrical energy for the electric drive device to an electric energy storage device to power the electric drive device. [Brief description of the drawings]

[0012] [Figure 1] 1 is a schematic diagram of a typical opposed piston internal combustion engine of the prior art;

[0013] [Diagram 2] 1 is a schematic diagram of an opposed piston internal combustion engine arrangement configured for use in a hybrid drive system according to the present invention;

[0014] [Diagram 3] 1 is a schematic diagram of a first embodiment of a hybrid drive system configured in a series arrangement according to the present invention;

[0015] [Figure 4] FIG. 2 is a schematic diagram of a second embodiment of a hybrid drive system configured in a series arrangement according to the present invention.

[0016] [Diagram 5] FIG. 4 is a schematic diagram of a third embodiment of a hybrid drive system configured in a series arrangement according to the present invention.

[0017] [Figure 6] 2 is a flow chart illustrating an example of a general control procedure for operating a hybrid vehicle powered by a hybrid drive system including an opposed piston internal combustion engine according to the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] An opposed piston engine is an internal combustion engine characterized by an arrangement of two pistons disposed in a bore of a cylinder for reciprocating motion in opposite directions along the longitudinal axis of the cylinder. Opposed piston internal combustion engines differ in many respects from conventional internal combustion engines having a single piston in the cylinder. In opposed piston engines, a combustion chamber is formed in the cylinder between the end faces of two opposed pistons moving in the cylinder, whereas in conventional engines, the combustion chamber is formed between the cylinder head and the end face of the single piston moving in the cylinder. In opposed piston engines, air enters the cylinder through a piston-controlled intake port opening through the cylinder near one of its two ends, and exhaust exits the cylinder through a piston-controlled exhaust port opening through the cylinder near the other of its two ends. In conventional engines, air and exhaust pass through one end of the cylinder through respective valve-controlled intake and exhaust ports in the cylinder head.

[0019] Generally, opposed piston engines complete their operating cycle with a single complete revolution of the crankshaft and two strokes of the pistons connected to the crankshaft. The strokes are designated as compression and power strokes. Each piston moves between a bottom dead center (BC) region in the cylinder nearest the respective end of the cylinder and furthest from the other piston, and a top dead center (TC) region in the cylinder furthest from the respective end and nearest the other piston. The cylinders have ports near their respective BC regions. Each of the opposed pistons controls a corresponding one of the ports, opening the port as it moves to its BC region and closing the port as it moves from BC to its TC region. One port serves to admit charge air (sometimes called "scavenging air") to the bore, and the other port provides a passage for combustion products from the bore, and these are called the "intake" and "exhaust" ports, respectively (in some descriptions, the intake port is called the "air" or "scavenging" port). In a uniflow scavenged opposed-piston engine, pressurized air enters the cylinder through an intake port near one end of the cylinder and exhaust gases exit through its exhaust port near the opposite end. Thus, gases flow through the cylinder in one direction ("uniflow"), from the intake port to the exhaust port.

[0020] FIG. 1 is a schematic diagram of a typical opposed-piston engine. Preferably, the engine is a two-stroke uniflow scavenged opposed-piston engine (hereinafter "opposed-piston engine 8") including at least one cylinder. The opposed-piston engine may operate on a compression ignition principle or with electronic or optical ignition assistance. The opposed-piston engine 8 may have one cylinder or may comprise two cylinders or more than two cylinders. In either case, the cylinder 10 corresponds to both the single-cylinder and multi-cylinder configurations of the opposed-piston engine 8. The cylinder 10 includes a bore 12 and longitudinally spaced apart intake and exhaust ports 14 and 16 machined, molded, or otherwise formed in the cylinder near each end of the cylinder. An air handling system 15 of the opposed-piston engine 8 manages the transport of charge air 34 into and exhaust from the engine by means of these ports. Each of the intake and exhaust ports includes one or more openings communicating between the cylinder bore and an associated manifold or plenum. In many cases, the ports comprise one or more circumferential arrays of openings, with adjacent openings separated by solid portions of the cylinder wall (also called "bridges" or "bars"). In some descriptions, each opening is called a "port", but the structure of the circumferential array of such "ports" is no different from the port structure shown in FIG. 1. The fuel injector 17 includes a nozzle fixed to a hole leading into the cylinder. The fuel system 18 of the opposed-piston engine 8 provides fuel for direct side injection into the cylinder by the injector 17. Two pistons 20, 22 are disposed in the bore 12 with their end faces 20e, 22e facing each other. For convenience, the piston 20 is called the "intake" piston, since it opens and closes the intake port 14. Similarly, the piston 22 is called the "exhaust" piston, since it opens and closes the exhaust port 16. Preferably, but not necessarily, intake piston 20 and all other intake pistons are coupled to crankshaft 30 of opposed-piston engine 8, and exhaust piston 22 and all other exhaust pistons are coupled to crankshaft 32 of engine 8.

[0021] In response to combustion occurring between their ends, the opposing pistons move away from their respective TC locations where the pistons are at their innermost positions within the cylinder 10. While moving from their TC locations, the pistons keep their associated ports closed until they approach their respective BC locations where the pistons are at their outermost positions within the cylinder and their associated ports are open. As charge air enters the cylinder 10 through the intake port 14, the shape of the intake port openings and the surface features of the opposing piston end faces induce turbulent charge air flow that promotes air / fuel mixing, efficient combustion, and reduced pollutants.

[0022] FIG. 2 illustrates an opposed-piston internal combustion engine arrangement ("opposed-piston engine arrangement") in a hybrid drive system according to the present invention. The opposed-piston engine arrangement 50 includes an opposed-piston engine 52 configured and operated as shown in FIG. 1, and a power transducer arrangement 53 operated by mechanical power transmitted from the opposed-piston engine. The opposed-piston engine 52 may include an engine block 54 housing at least one cylinder 56 disposed between two spaced apart crankshafts 58, 59. For example, the opposed-piston engine 52 may include one, two, or three or more cylinders. In any case, the cylinder 56 corresponds to both the single-cylinder and multiple-cylinder configurations of the opposed-piston engine 52. The two crankshafts 58, 59 are rotatably supported in respective crankcase portions 60, 61 of the engine block 54. The power transducer device 53 is adapted to convert the mechanical rotation of the crankshaft into a form of electrical power output for use by the non-combustion elements of an electric hybrid drive system type, a hydraulic hybrid drive system type, or a pneumatic hybrid drive system type. Two pistons 57a, 57b are disposed within the bore of the cylinder 56 for reciprocating movement in opposite directions along the longitudinal axis of the cylinder 56. The piston 57a ​​is coupled to a crankshaft 58 and the piston 57b is coupled to a crankshaft 59.

[0023] The examples and embodiments of the invention shown and described below are directed to electric hybrid drive system types, but this is not intended to exclude the application of the invention to other hybrid drive system types. Also, these examples and embodiments are directed to applications including wheeled hybrid vehicles. This application is for illustrative purposes only and is not intended to exclude other types of platform applications, which may include, without limitation, wheeled hybrid vehicles such as cars, vans, trucks, and buses, agricultural vehicles, construction vehicles, mining vehicles, military vehicles, marine and freshwater vessels, locomotives, and aircraft.

[0024] With further reference to FIG. 2 , the power transducer arrangement 53 is adapted to convert mechanical rotation of the crankshafts 58, 59 into electrical energy that the power transducer arrangement 53 outputs to an electric hybrid powertrain system. The electric hybrid powertrain system may include a battery arrangement 65 and at least one electric motor arrangement, in this case a motor / generator arrangement 67. The power transducer arrangement 53 is coupled to provide electrical power to the hybrid powertrain system 55 by an electric bus line 62. The AC motor portion of the electric motor / generator arrangement 67 has an associated rotating motor shaft 69 that may be coupled to provide mechanical torque and rotation to one or more wheels of the hybrid vehicle by one or more of a drive shaft, an axle, and a hub flange. For example, the electric motor / generator arrangement 67 may be coupled to a drive shaft 72 via a transmission assembly 71 for providing to one or more wheels 73 of the hybrid vehicle. Alternatively, the hybrid powertrain system may include one or more motor / generator arrangements for driving each of a plurality of wheels of a multi-wheel hybrid vehicle via a hub flange at each wheel.

[0025] The hybrid drive system of the present invention may also include a control mechanism, which is a computer-based system that includes a programmed controller, a number of sensors, several actuators, and other mechanical devices distributed throughout the hybrid drive system and / or the hybrid vehicle. The control mechanism manages the operation of the various components of the hybrid drive system. The programmed controller includes one or more control units (CUs) that are electrically connected to the associated sensors, actuators, and other mechanical devices. As shown in FIG. 2, control of the opposed piston engine arrangement 50 and the hybrid powertrain system 55 (and possibly other systems associated with the hybrid drive system) is performed by the control mechanism that includes a programmed electronic control unit (ECU) 80. The ECU 80 may be comprised of one or more microprocessors, memory, I / O, converters, drivers, etc., and is programmed to execute control algorithms under various hybrid drive system operating conditions. Such algorithms may be embodied in control modules that are part of a system control program executed by the ECU 80 to regulate the operation of the hybrid drive system. In some cases, the algorithms may be developed and executed in conjunction with a wheeled hybrid vehicle operated in a manual mode or an autonomous self-driving mode.

[0026] In addition to the ECU 80, the control mechanism may include various sensors (physical and / or virtual). These may include vehicle motion sensors (key, shift, acceleration request, braking request, vehicle speed, etc.). Hybrid drive system sensors may include engine sensors (engine operating state, engine speed, engine system, etc.), motor sensors (motor speed, generator current, etc.), and battery status sensors (state of charge, voltage, current, temperature, etc.). Additionally, the control mechanism may include various actuators such as those found in the fuel system, air handling system, and cooling system of an opposed piston engine. See, for example, PCT Publications WO2013 / 062921A1 and WO2015 / 026628A1. The control mechanism may further include various actuators for the motor, generator, and battery devices (converters, inverters, etc.).

[0027] In the example shown in Fig. 2, the power transducer arrangement 53 may comprise one or more motor / generator arrangements with a rotating motor shaft mechanically coupled to the opposed-piston engine 52. Furthermore, the two crankshafts 58, 59 of the opposed-piston engine 52 may or may not be mechanically coupled. An embodiment of a hybrid drive system according to Fig. 2 is shown in Figs. 3, 4 and 5.

[0028] FIG. 3 is a schematic diagram of a first embodiment of the invention in which an opposed piston internal combustion engine arrangement 50 is arranged in series with a hybrid powertrain system 55 in a hybrid drive system capable of transmitting power to one or more wheels of a hybrid vehicle. In this embodiment, the opposed piston engine 52 includes a mechanical connection 63 connecting the crankshafts 58, 59. The mechanical connection 63 may comprise a belt, a chain, a gear train, or possibly another type of link. The power transducer arrangement 53 includes a motor / generator (M / G) arrangement 90 that can supply power to and receive power from a battery arrangement 65 via an inverter 91. A rotating motor shaft 93 of the AC motor portion of the motor / generator arrangement 90 may be directly coupled to the opposed piston internal combustion engine 52 or to either of the crankshafts 58, 59, for example via an idler gear of a gear train, or may be coupled by a transmission assembly (not shown).

[0029] The opposed piston engine 52 is of the internal combustion type that generates power by burning gasoline, diesel fuel, gaseous fuel, or any combination thereof, depending on fuel and air regulation by the ECU 80. The motor / generator unit 67 (referred to as the first motor / generator unit) is a power transducer that can be operated as either an electric motor or a generator. Similarly, the motor / generator unit 90 (referred to as the second motor / generator unit) is a power transducer that can be operated as either an electric motor or a generator. In this regard, the motor / generator unit 67 is primarily operated as a motor, thereby providing output power of the hybrid drive system via its motor shaft 69 when provided with electrical energy stored in the battery unit 65. The motor / generator unit 67 may also be capable of operating as a generator in certain hybrid vehicle applications that include a regenerative braking system. The motor / generator unit 67 can receive power from the battery unit 65 via an inverter 68 and provide power to the battery unit. The motor / generator arrangement 90 operates as a generator when its motor components are driven by the opposed-piston engine 52 via its motor shaft 93. Electrical power generated thereby may be directed to the battery arrangement 65, to the motor / generator arrangement 67 (via inverter 68), or to both. The motor / generator arrangement 90 can supply power to and receive power from the battery arrangement 65 via an inverter 91. Each inverter 68, 91 is connected to the battery arrangement 65 via an electrical bus line 62. The inverters 68, 91 are configured to enable either of the motor / generator arrangements 67, 90 to supply power to the other and / or to the battery arrangement 65 directly. The motor function of each motor / generator arrangement is regulated by its associated inverter.Thus, inverter 68 controls the amount of power supplied to or obtained from motor / generator arrangement 67 in accordance with the magnitude and polarity of a first torque command issued by ECU 80, and inverter 91 controls the amount of power supplied to or obtained from motor / generator arrangement 90 in accordance with the magnitude and polarity of a second torque command issued by ECU 80.

[0030] The hybrid drive system shown in FIG. 3 may be controlled in a series hybrid manner by the ECU 80, which may coordinate the switching of each of the motor / generator devices 67, 90 between operation as a motor and as a generator via respective torque commands. In a first mode of operation of the hybrid drive system in which the opposed piston internal combustion engine is off, the motor / generator device 67 may operate in a motor mode powered by the battery device 65. When the hybrid drive system powers a hybrid vehicle, the motor / generator device 67, powered by the battery device 65, operates in a motor mode with its output coupled to drive one or more wheels 71. When the hybrid vehicle is equipped with a regenerative braking system, the motor / generator device 67 may operate in a generator mode to charge the battery device 65. In a second mode of operation of the hybrid drive system in which the opposed piston engine 52 is operating, the motor / generator device 67 may operate in a motor mode powered by the battery device 65, while the motor / generator device 90, operated in a generator mode, maintains or replenishes the charge of the battery device 65. In a third mode of hybrid drive system operation with opposed piston engine 52 operating, motor / generator device 67 may operate in a motor mode powered by battery device 65 and motor / generator device 90 operating in a generator mode. When opposed piston engine 52 operation is initiated, motor / generator device 90 may operate in a motor mode to crank opposed piston engine 52.

[0031] FIG. 4 is a schematic diagram of a second embodiment of the invention, which is a variation of the first embodiment shown in FIG. 3, in which an opposed-piston internal combustion engine arrangement 50 is arranged in series with a hybrid powertrain system 55 in a hybrid drive system capable of transmitting power to one or more wheels of a hybrid vehicle. In this embodiment, a motor shaft 93 of a second motor / generator arrangement 90 is coupled to a crankshaft 58 (referred to as a first crankshaft) and a third motor / generator arrangement 95 with a motor shaft 96 is coupled via its motor shaft 96 to a crankshaft 59 (referred to as a second crankshaft). Thus, in the second embodiment, the power transducer arrangement 53 comprises a second motor / generator arrangement (M / G) 90 and a third motor / generator arrangement (M / G) 95 with an associated inverter 97. In the second embodiment, the opposed-piston engine 52 includes a mechanical connection 63 connecting the crankshafts 58, 59. As with the first embodiment, the mechanical connection 63 may comprise a belt, a chain, a gear train, or possibly another type of linkage.

[0032] The motor / generator arrangement 95 operates as a generator when its motor component is driven by the opposed-piston engine 52 via its motor shaft 96. Electrical power generated thereby is directed to the battery arrangement 65 or to the generator portion of the motor / generator arrangement 67 (via inverter 68), or both. The motor / generator arrangement 95 can supply power to and receive power from the battery arrangement 65 via an inverter 97 that is connected to the battery arrangement 65 by an electrical bus line 62. The inverter 97 is configured to enable the motor / generator arrangement 96 to supply power directly to or receive power from either or both of the other motor / generator arrangements 67, 90. The motor function of the motor / generator arrangement 95 is regulated by its associated inverter 97. The inverter 97 thus controls the amount of electrical power supplied to or obtained from the motor / generator arrangement 95 according to the magnitude and polarity of a third torque command issued by the control unit 80.

[0033] The hybrid drive system shown in FIG. 4 may be controlled in a series hybrid manner by the ECU 80, which may coordinate the switching of each of the motor / generator units 67, 90, 95 between operation as a motor and as a generator via respective torque commands. In a first mode of hybrid drive system operation in which the opposed-piston engine 52 is off, the motor / generator unit 67 may operate in a motor mode powered by the battery unit 65. When the hybrid drive system powers a hybrid vehicle, the motor / generator unit 67, powered by the battery unit 65, operates in a motor mode with its output coupled to drive one or more wheels 71. When the hybrid vehicle is equipped with a regenerative braking system, the motor / generator unit 67 may operate in a generator mode to charge the battery unit 65. In a second mode of hybrid drive system operation with the opposed piston engine 52 in operation, the motor / generator arrangement 67 can be operated in a motor mode powered by the battery arrangement 65, while both the motor / generator arrangement 90 and the motor / generator arrangement 95 are operated in a generator mode to maintain the charge of the battery arrangement 65. In a third mode of hybrid drive system operation with the opposed piston engine 52 in operation, the motor / generator arrangement 67 can be operated in a motor mode powered by the battery arrangement 65, the motor / generator arrangement 90, and the motor / generator arrangement 95, while the motor / generator arrangement 90 and the motor / generator arrangement 95 are operated in a generator mode. When operation of the opposed piston 52 is to commence, either the motor / generator arrangement 90 or the motor / generator arrangement 95 can be operated in a motor mode to crank the opposed piston engine 52.

[0034] Figure 5 is a schematic diagram of a third embodiment of the invention which is a variation of the second embodiment shown in Figure 4, in which an opposed-piston internal combustion engine arrangement 50 is placed in series with a hybrid powertrain system 55 in a hybrid drive system capable of transmitting power to one or more wheels of a hybrid vehicle. In this embodiment, a motor shaft 93 of a second motor / generator arrangement 90 is coupled to a first crankshaft 58 and a motor shaft 96 of a third motor / generator arrangement 95 is coupled to a second crankshaft 59. However, in the third embodiment, the opposed-piston engine 52 does not include, and therefore excludes, any mechanical connection linking the crankshafts 58, 59.

[0035] 2-5, crankshafts 58, 59 are coupled to one or more motor / generator units. How such coupling is configured is a matter of design choice. In this regard, the rotating motor shaft of each motor / generator unit may be directly coupled to the crankshaft or may be coupled to a crankshaft coupling device by a belt, by a gearing arrangement, possibly including a clutch, or by other transmission.

[0036] A hybrid drive system comprising an opposed piston internal combustion engine according to any one of the three embodiments of Figures 3, 4 and 5 uses both of the two crankshafts 58, 59 to generate electricity, making the system suitable for operation in series hybrid or range extender hybrid applications.

[0037] FIG. 6 is a flow chart illustrating an example of a general control procedure for operating a hybrid vehicle including a hybrid drive system according to any of the embodiments shown in FIGS. 2-5. If the hybrid vehicle is off, a vehicle "key on" signal (ignition signal, start signal) input to (received by) ECU 80 in step S605 initiates operation of the hybrid drive system. Initialization of the hybrid vehicle includes a determination by ECU 80 of the level of charge (state of charge, or SOC) held by battery device 65. This is done by execution of a GET SOC procedure in step S610 in which the level of charge held by battery device 65 is measured by ECU 80. In step S615, ECU 80 evaluates whether the level of charge (SOC) is sufficient to enable movement of the hybrid vehicle by motor / generator device 67 and to power various other vehicle systems. The evaluation performed by ECU 80 in step S615 compares the measured SOC with an initial state of charge threshold SOC. t1 The level of charge held by the battery device 65 (measured SOC) may be compared to an initial state of charge threshold SOC. t1 , then in step S617, the ECU 80 issues a torque command Tm1 to the motor / generator 67 conditioned to move the hybrid vehicle when requested by the driver or by the autonomous vehicle. Step S620 corresponds to a continuous check by the ECU 80 for a vehicle "key on" signal being received by the ECU 80, in the absence of which the ECU 80 issues a torque command Tm1 to the motor / generator 67 conditioned to stop operation, thereby preventing movement of the hybrid vehicle. Returning to step S615, it is determined whether the level of charge held by the battery device 65 (measured SOC) is greater than or equal to the initial state of charge threshold SOC. t1If so, then in step S625, the ECU 80 commences operation of the opposed piston internal combustion engine 52 to generate electrical power for supplying the hybrid power system 55. The ECU 80 starts the engine 52 by cranking the engine 52 via the power transducer arrangement 53. Once the opposed piston internal combustion engine 52 is cranked, the ECU 80 in step S630 sets the operating parameters (engine speed, boost, airflow, fuel, etc.) that will operate the engine 52 at a desired operating point. Once the engine 52 is at the desired operating point, the ECU 80 in step S635 switches the power transducer arrangement 53 to provide generator operation for the opposed piston internal combustion engine 52 and to supply electrical power to the electrical bus line 62, thereby replenishing the level of charge in the battery arrangement 65. Depending on the structure of the power transducer arrangement 53, the ECU 80 may enable such switching with one torque command (Tm2 in the embodiment of FIG. 3) or with two torque commands (Tm2 and Tm3 in either of the embodiments of FIGS. 4 and 5). At this point in the general control procedure, if the ECU 80 has received a torque request from the driver or an autonomous driving controller, the ECU 80 may also drive the motor / generator 67 with a torque command (Tm1). With the engine 52 running and generating power for the hybrid powertrain system 55, the ECU 80 may, in step S637, adjust the level of charge (SOC) of the battery arrangement 65 to a second state of charge threshold SOC. t2 In this case, the SOC t2 is SOC t1 (SOC t2 >SOC t1 ) is preferably determined based on whether the level of charge held by the battery device 65 (measured SOC) is greater than or equal to a second state of charge threshold SOC t2As long as the "key on" signal is maintained (step S640), the ECU 80 maintains the engine 52 in operation via the loop S630, S635, S637, S40 (the "charging loop") until the level of charge held by the battery pack 65 (measured SOC) is below the second state of charge threshold SOC t2 If so, the ECU 80 follows the negative exit from step S637 and turns off the engine 52 in step S645. Similarly, if the ECU 80 does not detect a vehicle "key on" signal in step S640, the ECU 80 follows the negative exit from step S640 and turns off the engine 52 in step S645.

[0038] 6 illustrates controlling the operating state of the opposed piston internal combustion engine 52 in response to the SOC and vehicle key signals, this should not preclude the use of other control factors that require more detailed analysis by the ECU 80. In this regard, the ECU 80 may turn the opposed piston internal combustion engine 52 on or off in response to information received from a connected automated vehicle and / or in response to algorithmic machine learning activities that use predictive methods to analyze future vehicle requirements.

[0039] The embodiments of the invention have been described with reference to numerous specific details that may vary from implementation to implementation. Certain adaptations and modifications of the described embodiments may be made. Other embodiments will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the invention being indicated by the following claims. [Prior art documents] [Non-patent literature]

[0040] [Non-Patent Document 1] Herold, R., Wahl, M., Regner, G., Lemke, J., and Foster, D., (2011), "Thermodynamic Benefits of Opposed-Piston Two-Stroke Engines," SAE Technical Paper 2011-01-2216, 2011. [Non-Patent Document 2] Kalebjian, C., Redon, F., and Wahl, M., (2012), "Low Emissions and Rapid Catalyst Light-Off Capability for Upcoming Regulations with an Opposed-Piston, Two-Stroke Diesel Engine," Global Automotive Management Council and Emissions 2012, Ypsilanti, MI. [Non-Patent Document 3] Hanson, R., Strauss, S., Redon, F., Salvi, A., (2017), "Progress in Light-Duty OPGCI Engine Design and Testing," SIA Powertrain International Conference, Versailles.

Claims

1. A hybrid drive system, comprising: an opposed-piston internal combustion engine including at least one cylinder and a pair of pistons disposed in a bore of the cylinder and sliding in opposed relation within the cylinder; a power transducer device coupled to be driven by the opposed piston internal combustion engine; a hybrid powertrain system configured to receive power from the power transducer device; Equipped with the hybrid powertrain system comprising a battery arrangement and a first electric motor / generator arrangement, the power transducer arrangement comprising a second electric motor / generator arrangement; The opposed piston internal combustion engine comprises a first crankshaft and a second crankshaft, the power transducer arrangement further comprising a third electric motor / generator arrangement; a motor shaft of the second electric motor / generator unit coupled to the first crankshaft, a motor shaft of the third electric motor / generator unit coupled to the second crankshaft, and a motor shaft of the first electric motor / generator unit coupled to a transmission assembly; The hybrid drive system further includes a control mechanism, the control mechanism controlling the hybrid drive system as follows: a first mode of operation in which the first electric motor / generator device operates in a motoring mode powered by the battery device; a second mode of operation, with the opposed piston internal combustion engine operating, powered by the battery device, in which the first electric motor / generator device operates in a motor mode while both the second electric motor / generator device and the third electric motor / generator device operate in a generator mode to maintain a charge on the battery device; and in a third mode of operation, with the opposed piston internal combustion engine operating, power is supplied by the battery device, the second electric motor / generator device, and the third electric motor / generator device, such that the first electric motor / generator device operates in a motor mode while the second electric motor / generator device and the third electric motor / generator device operate in a generator mode; A hybrid drive system configured to operate.

2. A hybrid drive system as described in claim 1, wherein the control mechanism is further configured to initiate operation of the opposed piston internal combustion engine by operating either the second electric motor / generator device or the third electric motor / generator device in the motor mode to crank the opposed piston internal combustion engine.

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