Series hybrid generator

An electric generator has an outer rotor supported on a housing for rotation about an axis and a shaft input end lying on the axis at a first end of the housing. An inner rotor is supported on the housing for rotation about the axis and has a shaft input end lying on the axis at a second end of the housing. The outer rotor has an outer rotor generator winding. The inner rotor has an inner rotor generator winding. An outer rotor one-way clutch allows the outer rotor to be rotated by its shaft input end only in one direction. An inner rotor one-way clutch allows the inner rotor to be rotated by its shaft input end only in a direction which is opposite the direction of the outer rotor allowed by the outer rotor one-way clutch. Respective internal combustion engines operate the respective rotors.

FIELD OF THE INVENTION

This invention relates to a series hybrid generator, one use for which is in a dual-engine, variable-power drive.

SPONSORSHIP

This invention has been sponsored by the National Research Council Canada but is solely owned by the inventor.

BACKGROUND OF THE INVENTION

Achieving future fuel efficiency improvements in medium and heavy duty commercial trucks and buses will be a challenging task for commercial truck and diesel engine manufacturers. Over the past several decades, fuel efficiency improvements have been realized largely through the application of computer technology to the design and development of engines and powertrains and through the adoption of sophisticated engine control systems in commercial trucks. Hybrid powertrains have contributed to fuel economy improvements, but at significantly increased manufacturing costs that raise prices that purchasers must pay. The inventor believes that further improvements in conventional single-engine/powertrain design and development and in engine control systems are unlikely to yield more than minimal fuel economy improvements.

Currently manufactured long haul commercial trucks commonly use large diesel engines in the range of 400-600 maximum horsepower as their prime movers. An engine having such a maximum power output is necessary to accommodate the peak power requirement for typical vocation drive cycles of those vehicles.

The current cost of hybrid powertrains does not justify their wide-spread adoption by the commercial trucking industry. Current sales of hybrid truck, buses, and coaches are predominantly in fulfillment of governmental contracts which use taxpayer funds as a subsidy for the additional costs of such “green” technologies in purchased vehicles.

Current large displacement fixed horsepower diesel engines operate within sub-optimal efficiencies, commonly within ranges between 800 and 2200 revolutions per minute (RPM). Because they accommodate changes in torque and power demand by varying engine RPM, such engines are inherently incapable of achieving optimum performance and best fuel economy.

Failure of a current diesel engine while a vehicle is on the road may create a hazardous condition for the driver and surrounding traffic and/or disable the vehicle to such an extent that unexpected delay, economic losses, and/or customer dissatisfaction become inevitable results of the failure.

Virtually all commercial trucks, buses and coaches on the roads today use conventional brake pads exclusively to decelerate the vehicle, converting the kinetic energy into wasteful heat. While such waste can be partially mitigated by a hybrid powertrain, hybrid powertrains are, as mentioned earlier, not currently cost-justifiable. A hybrid powertrain also inherently adds weight to a vehicle, a fact that adversely impacts fuel economy.

The inventor's U.S. Patent Publication No. 2012 0152631 discloses a drive which when used to propel a vehicle, especially a large commercial vehicle such as a truck or bus for example, selectively uses one or both of two internal combustion engines, especially turbocharged diesel engines, depending on torque and power demands being imposed on the vehicle as it is being driven. The inventor's analysis of that drive shows that this selective use of the engines can enable a vehicle to achieve significant fuel economy improvements in comparison to improvement which is likely to be obtained in engines and engine controls through use of conventional single-engine/powertrain design and development techniques which were mentioned earlier.

The inventor's analysis shows that a single one of two V8 engines can provide sufficient power and torque for approximately 80% of a typical long haul drive cycle. During portions of a drive cycle where demand is greater, such as climbing a grade or accelerating the vehicle, a controller automatically starts a second V8 engine to provide the additional power required. Once the drive cycle returns to lesser demand, the controller automatically turns off one of the engines. In this way the invented drive is capable of maximizing efficiency through optimized variable power delivery.

Each of the two engines is more compact than a single large engine which is capable of delivering maximum power comparable to that of the drive disclosed in when both of its engines are operating the invented drive at maximum power.

Failure of one of the two engines while the vehicle is on the road is unlikely to disable the vehicle because the other engine can be used in most driving situations to drive the vehicle directly to a service facility or to a suitable off-road location.

The drive disclosed in U.S. Patent Publication No. 2012 0152631 can recover substantial brake energy by charging an on-board energy storage system, examples of which are electric energy storage in a battery, battery bank, or ultra-capacitor and hydraulic energy storage in an accumulator. Refuse collection and package delivery vocations present perhaps the largest market opportunity for energy recapture due to low average speeds with frequent stop and start driving. Line haul vocations offer less opportunity for brake energy recapture due to continuous, high speed, non-start-and-stop drive cycles.

An example of the dual-engine, variable-power drive disclosed in U.S. Patent Publication No. 2012 0152631 comprises two generic V8 diesel engines having opposite flywheel rotation which can operate concurrently to deliver power through one or more drive axles to driven wheels that propel a wheeled vehicle such as a commercial truck. When both engines are running at the same power output level, engine torque reaction is cancelled through the respective engine mountings. The SAE (Society of Automotive Engineers) standard diesel engine has counter-clockwise flywheel rotation. The inventor is unaware of any electric generator, other than one embodiment disclosed in his U.S. Patent Publication No. 2012 0152631, which can accommodate counter-clockwise mechanical rotation energy of two standard diesel engines. In that embodiment the engines do not rotate about a common axis.

Although the inventor's publication discloses another embodiment which also uses two diesel engines, one at each end, rotating about a common axis, such a configuration requires one engine to rotate in the clockwise direction and the other in the counterclockwise direction. Clockwise rotation diesel engines are not commonly manufactured. Although such an engine could be manufactured, it would be a special order low volume product that would significantly increase the total cost of manufacturing and maintenance for the two-engine, single-generator configuration.

SUMMARY OF THE INVENTION

The present disclosure introduces a generator which accommodates two standard counter-clockwise rotation, mass-produced, off-the-shelf diesel engines so as to enable their flywheels to rotate about a common axis. A more costly, non-standard engine is not needed; neither is a power-inversion gear box for one of the two engines.

The generator includes one-way mechanical clutches which function to prevent energy losses from a running one of the two engines to the other engine when the latter engine is not running. The generator is always coupled to the engines through torque convertors.

The generator absorbs and cancels out all of the engine torque through the generator housing when both engines are running, thereby eliminating right front wheel overloading resulting from the engine torque transfer to a truck vehicle frame when the engine is mounted at the front of the vehicle with its axis running lengthwise of the vehicle.

The generator is scalable in diameter and length in multiple ways to accommodate various vehicle frame architectures and power generation level requirements; and it allows the vehicle to be propelled should one engine break down.

The foregoing summary, accompanied by further detail of the disclosure, will be presented in the Detailed Description below with reference to the following drawings that are part of this disclosure.

DETAILED DESCRIPTION

FIG. 1is a representative truck drive cycle power diagram (HWFET) showing engine power requirement as a function of drive time during a specified drive cycle. It shows a peak power requirement near 600 horsepower (hp.). The average power requirement is much lower.

FIG. 2is a representative truck drive cycle power diagram (WVU Interstate) showing engine power requirement as a function of drive time during a specified drive cycle. It shows a peak power requirement near 500 horsepower (hp.). The average power requirement is much lower.

FIGS. 3 and 4are engine torque/speed, torque/power diagrams for respective turbocharged diesel engines rated at about 131 hp and 475 hp respectively. The trace T in each diagram represents torque, and the trace P, power.

FIGS. 1-4are presented to show how a vehicle's fuel economy can be substantially improved by a power unit embodying a dual-engine, variable-power drive having the series hybrid generator disclosed herein.

FIGS. 5-8show an embodiment of dual-engine, variable-power drive100which, when used to propel a truck vehicle and referenced to locations in a chassis frame F of such a vehicle as inFIGS. 6 and 7, comprises: a starboard side turbodiesel propulsion engine1; a starboard side torque converter2; a series hybrid generator3; a port side torque converter4; a port side turbodiesel propulsion engine5; a starboard side engine exhaust stack6, including a diesel particulate filter (DPF) and optional exhaust treatment apparatus; and a port side engine exhaust stack7, including a diesel particulate filter (DPF) and optional exhaust treatment apparatus.

Those seven components1through7form an assembly (shown by itself inFIG. 5) which is supported on an engine and cooling module support frame7A shown inFIG. 6.

A torque converter is a type of fluid coupling which allows an engine to spin somewhat independently of the series hybrid generator at times such as when a vehicle is stopped with the engine idling and the service brakes applied. When the engine is accelerated to accelerate the vehicle, the torque converter delivers engine torque to accelerate the vehicle.

Support frame7A comprises a starboard side upright8A and a port side upright8B for supporting a cooling module8which comprises a radiator located forwardly along the chassis frame in relation to components1through5. Support frame7A also comprises a starboard side upright9for supporting starboard side exhaust stack6and a port side upright10for supporting port side exhaust stack7. Cooling module8comprises multiple electric-driven fans11directly rearward of its radiator. When operated, fans11draw air through the radiator to cool liquid coolant passing through the radiator.

A starboard side supply coolant conduit12supplies liquid coolant to the radiator after having been circulated through coolant passageways in engine1. A starboard side return coolant conduit which supplies liquid which has been cooled by passage through the radiator back to engine1is present but cannot be seen. A port side supply coolant conduit13supplies liquid coolant to the radiator after having been circulated through coolant passageways in engine5. A port side return coolant conduit which supplies liquid which has been cooled by passage through the radiator back to engine5is present but cannot be seen.

Engine mounts14(only one of which is seen inFIG. 6) support engine1at opposite sides of its engine block (front and rear sides as referenced to chassis frame F) on horizontal members14A (only one of which can be seen inFIG. 6) of support frame7A. Engine mounts15(only one of which can be seen inFIG. 6) support engine5at opposite sides of its engine block on members14A. What would be commonly understood as the front of starboard engine1and the front of port engine5face in opposite directions at the far ends of drive100. Each engine has counter-clockwise (CCW) rotation as viewed from its front.

Members14A are disposed atop chassis frame F at right angles to the length of chassis frame F and are fastened to right (starboard side) and left (port side) side rails19and20of chassis frame F by starboard side mounts16and port side mounts17respectively using fasteners18.

The truck vehicle which is propelled by drive100comprises a cab C (FIGS. 7 and 8) having an interior compartment for a driver of the vehicle. A wind deflector present on the exterior of cab C comprises an upper wind deflector21which is smoothly contoured upwardly and rearwardly along the length of the cab when looking rearward from the front of the vehicle as inFIG. 8. Starboard side and port side wind deflectors22of the wind deflector join with upper wind deflector21and are smoothly contoured laterally outwardly and rearwardly. Upper wind deflector21comprises an air intake grille23directly in front of cooling module8to allow air to be drawn through the radiator of the cooling module, by ram air effect and/or use of fans11. Cab C comprises a front windshield24through which the driver has a frontal view from the cab interior.

A cover comprising movable starboard and port side clamshell halves27,28covers support frame7A and the components which it supports when the clamshell is closed while exhaust stacks6,7are shaped to place their tailpipes outside the cover when the cover is closed.FIG. 7shows the clamshell halves swung open to provide service access.

The truck vehicle also has a rotary electric machine29for operating a tandem rear axle which comprises a front tandem drive axle32and a rear tandem drive axle33. Rotary electric machine29has a shaft which is coupled to a differential mechanism of front drive axle32, and through that differential mechanism, to a differential mechanism of rear drive axle33.

FIG. 7shows a port side charge air cooler line30running to the radiator of cooling module8from a charge air cooler that cools boost air created by the engine turbocharger before entering engine5and a starboard side charge air cooler line31running to the radiator from a charge air cooler that cools boost air created by the turbocharger before entering engine1. The return lines from the radiator to the respective charge air coolers which complete the respective coolant loops cannot be seen inFIG. 7.

Right and left front steerable wheels68,70respectively are suspended from chassis frame F on right and left sides for steering the truck. Front and rear tandem drive axles32,33are suspended from chassis frame F rearward of front steerable wheels68,70. Axle32has at least one driven wheel74on the right side and at least one driven wheel76on the left side, and axle33has at least one driven wheel80on the right side and at least one driven wheel82on the left side. All wheels comprise pneumatic tires. The truck vehicle which is illustrated is an example of a highway tractor which has a fifth wheel34to which a trailer can be coupled for towing by the tractor.

A controller38controls which one, or ones, of engines1and5is, or are, used at any given time when the vehicle is being operated. Controller38comprises a control strategy for coordinating control of the engines acting through the torque converters and of the series hybrid drive to manage powerflow to the driven wheels.

When the truck vehicle is being propelled, one or both engines are operated depending on the amount of torque being requested by the driver. The torque request is commonly provided by depression of an accelerator pedal in cab C. A sensor which tracks pedal depression provides an input to controller38which has a control strategy that acts on the input to control drive100in a manner which leads to satisfaction of the request.

A flywheel is coupled for rotation with the respective engine crankshaft near a respective rear main bearing for the crankshaft. Each flywheel stores rotational energy created by the power impulses of the respective engine that occur during each combustion event in the cylinders of the respective engine, and releases stored energy between power impulses, thus assuring less fluctuation in engine speed and smoother engine operation. The size of the flywheel depends on the number of engine cylinders and the general construction of the engine. With a large number of cylinders and the consequent overlapping of power impulses, there is less need for a flywheel and consequently a flywheel can be relatively smaller.

Each flywheel is coupled through the respective torque converter to an input end of a respective rotor shaft of series hybrid generator3, as will be more fully explained later.

When driven wheels74,76,80,82are driven to propel the vehicle, they become loads on rotary electric machine29. Electric machine29and those driven wheels then become the load on series hybrid generator3. When propelling the vehicle, electric machine29operates as an electric propulsion, or drive, motor.

The mechanical energy input applied to a rotor shaft of series hybrid generator3causes series hybrid generator3to deliver electric current to electric machine29, causing the latter to operate as an electric motor that provides torque to the driven wheels74,76,80,82of the tandem axle for satisfying a torque request by the driver.

Controller38can also coordinate control of electric machine29with that of series hybrid generator3and of engines1,5. By controlling electric machine29to regulate the load on series hybrid generator3, engine speed and that of the rotor shaft(s) of series hybrid generator3can be held constant while accelerating the truck, thereby providing acceleration in the same manner as an infinitely variable mechanical transmission.

By making the electric machine29reversible, the truck vehicle can be driven either forward or in reverse.

The truck vehicle can also provide brake energy recovery by using the driven axle wheels to operate electric machine29as an electric generator to charge an energy storage device or system, such as a battery, battery bank, or ultra-capacitor39.

FIGS. 9 and 10illustrate a truck vehicle chassis50having a length extending from front to rear, a right side, and a left side. Chassis50comprises a frame52having a right side rail54extending from front to rear, a left side rail56extending from front to rear, and various cross-members58,60,62,64,66,67bridging the side rails. The cross-members are securely fastened to the side rails by Huck fasteners69.

Right and left front steerable wheels68,70respectively are suspended from frame52on the right and left sides for steering the truck vehicle. A tandem rear axle72is suspended from frame52rearward of front steerable wheels68,70. Tandem rear axle72is illustrated by way of example to comprise two electric drive axles, one of which is a first (front tandem) drive axle72having at least one driven wheel74on the right side and at least one driven wheel76on the left side and the other of which is a second (rear tandem) drive axle78rearward of first drive axle72and having at least one driven wheel80on the right side and at least one driven wheel82on the left side. All wheels comprise pneumatic tires.

Each drive axle72,74comprises a respective differential gear mechanism which is operated by a respective rotary electric machine housed within a respective casing within which respective right and left axle shafts extend from the respective differential gear mechanism to the respective axle's right and left driven wheels.

A dual-engine, variable-power drive100drives the rotary electric machine of each electric drive axle to deliver torque to wheels74,76,80,82to propel the vehicle. Dual-engine, variable-power drive100comprises a rear internal combustion engine102and a front internal combustion engine104at opposite lengthwise ends. Drive100also comprises a rear torque converter103, a front torque converter105, and a series hybrid generator106. A respective flywheel is coupled for rotation with the respective engine crankshaft as explained in the description of earlier Figures.

InFIG. 9the front of front engine104and the front of rear engine102face in opposite directions at the far ends of drive100. A cooling module111for engine104is mounted on chassis frame52frontally of engine104, and a cooling module113for engine102is mounted on chassis frame52rearward of engine102.

The top half of each of four engine mounts108is fastened to the block of each engine at the four locations shown, and the bottom half of each engine mount is permanently secured to one of the frame side rails using Huck fasteners. The four-point mounting of each engine to the chassis frame contributes to rigidity of the chassis frame.

When one engine, such as front engine104for example, can provide sufficient power and torque for propelling a truck (approximately 80% of a typical long haul drive cycle), only front engine104, and not rear engine102, operates. During portions of a drive cycle where demand is greater, a controller like controller38automatically starts rear engine102to provide the additional power required. Once the drive cycle returns to lesser demand, the controller automatically turns off rear engine102.

Controller38provides control of either engine102,104when only one engine is used, and of both engines102,104when both are used, to provide output torque corresponding to a torque request from the driver.

The engine output torque operates series hybrid generator106, causing series hybrid generator106to deliver electric current to the electric drive axle motors so that they provide torque to the driven wheels correlated with the torque request. The driven wheels at the ends of the electric drive axles are loads on the electric drive axle motors. The electric drive axle motors and the driven wheels at the ends of the axles are loads on series hybrid generator106.

The controller also coordinates control of series hybrid generator106and of the motors of the electric drive axles with control of engines102,104. By controlling the electric axle drive motors to regulate the load on series hybrid generator106, engine speed and that of the series hybrid generator's rotor shaft(s) can be held constant while accelerating the truck, thereby providing acceleration in the same manner as an infinitely variable mechanical transmission.

By making the electric axle drive motors reversible, a truck can be driven either forward or in reverse.

The truck can also provide brake energy recovery by using the driven axle wheels to operate the electric motors of the drive axles as electric generators to charge a battery, a battery bank, or an ultra-capacitor.

Shown in phantom inFIG. 9are a front hood115covering engine104and having a grill frontally of cooling module111. The rear of a day cab is marked at117and that of a sleeper cab at119. A rear hood121covers engine102and has a grill rearward of cooling module113. The rear hood will extend to the rear of either type of cab.

Preferably each engine102,104is a standard production engine with approximately 131 hp, more or less, with CCW flywheel rotation. An example of such an engine is a MaxxForce 8 engine weighing approximately 1200 lbs, about half that of a 460 hp MaxxForce 13 engine.

The disclosed drive100can be used as the power unit of a propulsion system in numerous mobile vocations which include, on-road (commercial vehicles, for example), off-road (construction shovels, creepers, for example), agricultural (combines, for example), light and heavy rail (passenger and freight locomotives, for example), load trains such as those used to haul freight across remote areas of some countries such as Australia, marine (naval vessels and icebreakers, for example), and military vehicles. It can also stand alone as an electric generator station, such as a back-up electric generator that is used during electric utility power outages.

FIG. 3is representative of the torque/power capability of each individual engine1,5,102,104. Each engine has approximately one-half the peak power capability of a single engine having the torque/power capability shown inFIG. 4. Drive100can provide ample torque and power most of a typical drive cycle by operating only one engine, using both engines only when extra power is needed. This will accomplish significant fuel economy improvement.

FIGS. 11 and 12show structural detail of a series hybrid generator123like the ones described above.

Series hybrid generator3comprises a housing125which comprises a generator casting127, an outer rotor engine mount casting129, and an inner rotor engine mount casting131. To save weight, these castings may be compressed graphite.

Generator casting127has opposite longitudinal ends, to a first of which outer rotor engine mount casting129is assembled and to a second of which inner rotor engine mount casting131is assembled. A first gasket130seals the housing interior between outer rotor engine mount casting129and generator casting127, and a second gasket132seals the housing interior between inner rotor engine mount casting131and generator casting127.

Housing125houses an electric generator assembly133, a first one-way clutch assembly135, and a second one-way clutch assembly137.

Electric generator assembly133comprises an outer rotor assembly139and an inner rotor assembly141both of which are supported on housing125for rotation about an axis143.

Outer rotor assembly139has an outer rotor shaft145which comprises, in succession starting at an input end: an outer rotor torque converter spline147, an outer rotor one-way clutch spline149, and a first bearing mount151. Outer rotor shaft145ends in a second bearing mount153. Between first and second bearing mounts151,153, outer rotor shaft145supports an outer rotor electric generator155.

Inner rotor assembly141has an inner rotor shaft157which comprises, in succession starting at an input end: an inner rotor torque converter spline159, an inner rotor one-way clutch spline161, a first bearing mount163, and a slip ring wheel mount165on which are disposed first and second electric terminals167,169.

Second bearing mount153of outer rotor assembly139has a through-hole which is concentric with axis143and which provides clearance for inner rotor shaft157to pass through to an inner rotor electric generator171which is within an interior space surrounded circumferentially by outer rotor electric generator155. A seal172seals the outer diameter of inner rotor shaft157to the through-hole in second bearing mount153. Inner rotor shaft157ends beyond inner rotor electric generator171in a second bearing mount174. While the drawing shows the inner rotor generator disposed completely within a space which is circumferentially surrounded by the outer rotor generator so that the latter completely axially overlaps the former, the inner rotor generator may be only partially circumferentially surrounded by the outer rotor generator so that they only partially axially overlap.

Taper bearing assemblies173,175are mounted on outer rotor engine mount casting129and generator casting127respectively to support outer rotor assembly139at bearing mounts151,153for low-friction rotation about axis143.

Inner rotor assembly141is supported by taper bearing assemblies177,179at bearing mounts163,174for low-friction rotation about axis143.

The construction of outer rotor electric generator155comprises a frame on which taper bearing assembly179is mounted. Taper bearing assembly177is mounted on inner rotor engine mount casting131.

Consequently, inner rotor shaft157is supported for rotation about axis143at opposite ends of inner rotor electric generator171, and outer rotor shaft145is supported for rotation about axis143at opposite ends of outer rotor electric generator155.

One-way clutch assembly135comprises a circular mounting ring183and a circular clutch rotor185. Mounting ring183fits within a circular recess187of outer rotor engine mount casting129and is fastened to outer rotor engine mount casting129. Clutch rotor185is disposed within mounting ring183and comprises an internal spline which meshes with outer rotor one-way clutch spline149to rotationally couple outer rotor shaft145and clutch rotor185.

One-way clutch assembly135comprises a mechanism which acts between mounting ring183and clutch rotor185to allow the clutch rotor to free wheel in a clockwise direction of rotation as viewed in the direction of arrow189while disallowing counter-clockwise rotation.

One-way clutch assembly137fits within a circular recess188of inner rotor engine mount casting131and has a construction like that of one-way clutch assembly135, allowing free-wheeling clockwise clutch rotor rotation as viewed in the direction of arrow191but disallowing counter-clockwise rotation.

From the foregoing description, it can be understood that clockwise rotation of outer rotor shaft145imparts clockwise rotation to outer rotor electric generator155, with the rotating mass being supported on housing125via taper bearings173,175and that clockwise rotation of inner rotor shaft157imparts clockwise rotation to inner rotor electric generator171, with the rotating mass being supported on housing125via taper bearing177and on the frame of outer rotor electric generator155. The clockwise rotation of each rotor assembly139,141is however counter-clockwise to the clockwise rotation of the other rotor assembly.

The frame of outer rotor electric generator155on which taper bearing assembly179is mounted also mounts an outer rotor electric generator winding having terminations connected to respective outer rotor slip rings201,203which are axially spaced apart and extend circumferentially around the outside of outer rotor electric generator155. Outer rotor electric brushes205,207on the interior of generator casting127are biased into contact with respective slip rings201,203providing connection of the outer rotor electric generator winding to electric terminals on the housing exterior which are parts of an electric interface which provides for selectively connecting the outer rotor winding to one of an electric current source and an electric load.

An inner rotor slip ring wheel209is disposed on inner rotator shaft157, and keyed to that shaft via a slot211in the shaft and a key213which fits to both slot211and a slot in the wheel.

Inner rotor slip rings215,217are axially spaced apart and extend circumferentially around the outside of inner rotor slip ring wheel209. Inner rotor electric brushes219,221on the interior of inner rotor engine mount casting131are biased into contact with respective slip rings215,217.

Inner rotor electric generator171comprises a frame on which an inner rotor electric generator winding is mounted. That winding has terminations at electric terminals167,169on inner rotor shaft157which connect with respective inner rotor slip rings215,217, enabling the winding to connect through the slip rings and brushes219,221with electric terminals on the housing exterior which are other parts of the electric interface which provides for selectively connecting the inner rotor winding to one of the electric current source and the electric load. When the outer rotor winding is connected to the electric current source, the inner rotor winding is connected to the electric load, and vice versa.

An outer longitudinal end of outer rotor engine mount casting129opposite generator casting127comprises a mounting flange191having a bolt hole pattern for fastening housing125to a matching end of a housing of torque converter2of engine1.

An outer longitudinal end of inner rotor engine mount casting131opposite generator casting127comprises a mounting flange193having a bolt hole pattern for fastening housing125to a matching end of a housing of torque converter2of engine5.

A series hybrid generator can be constructed to bolt onto conventional counter-clockwise rotation, mass-produced, diesel engines, eliminating the need for special engines built specifically for use with the series hybrid generator. The one-way clutches prevent one engine from rotating the other through magnetic interactions within the series hybrid generator.

The ability of the series hybrid generator to generate electric current occurs because of interactions between respective magnetic fields produced by the respective generator windings of the inner rotor electric generator171and the outer rotor electric generator155.

Magnetic field interactions can occur in the following ways.

Engine1operating, Engine2stopped: Electric current from an external source is supplied through brushes219,221and slip rings215,217to the winding of inner rotor generator171to create a magnetic field. As outer rotor generator155is rotated by engine1, the winding of the outer rotor generator delivers electric current through slip rings201,203for use in operating electric machine29. The interaction would rotate inner rotor generator171were it not for one-way clutch137preventing the rotation.

Engine1stopped, Engine2operating: Electric current from an external source is supplied through brushes205,207and slip rings201,203to the winding of outer rotor generator155to create a magnetic field. As inner rotor generator171is rotated by engine2, the winding of the inner rotor generator delivers electric current through slip rings215,217for use in operating electric machine29. The interaction would rotate outer rotor generator171were it not for one-way clutch135preventing the rotation.

Engine1operating, Engine2operating: Electric current from an external source is supplied through either brushes205,207and slip rings201,203to the winding of outer rotor generator155or through brushes219,221and slip rings215,217to the winding of inner rotor generator171, but not to both windings. The other winding not supplied with external current generates electric current for use in operating electric machine29. Because the inner and outer rotor generators are rotating in opposite senses relative to each other lines of magnet flux created by current from an external source are effectively cut more frequently than if one generator were not rotating, thereby causing the other generator to generate larger electric current than when the one generator is not rotating. The electrical energy that is generated, which may for example be AC current, is directly proportional to the summation of the rotational distance of the inner rotor added to that of the outer rotor.

When a first of the rotors is not being rotated by its engine, that rotor is stationary relative to the other (second) rotor which is being rotated by its engine, causing the electrical energy output of the generator from the second rotor to be proportional to the second rotor's speed. The electrical energy output is also a function of the electric current being input to the first rotor. The non-rotating rotor acts as a stator for the rotating rotor.

When the first rotor is also being rotated by its engine, the first rotor becomes a “rotating stator” for the rotating second rotor. This causes the electrical energy output of the generator from the second rotor to be proportional not only to the second rotor's speed but also to the first rotor's speed. The electrical energy output remains a function of the electric current being input to the first rotor. Because the rotors are rotating in opposite directions relative to each other, summation of their rotational distances is the primary quantitative parameter of electrical energy generated. In this way for a constant current input to the first rotor, electrical energy output from the second rotor increases with increasing speed difference between the two rotors.

In this disclosure, the windings are constructed as electromagnets rather than permanent magnets. When the vehicle is stopped in traffic, energy is conserved by having the generator not generate electricity. Accordingly, electromagnets will be activated and deactivated as appropriate during an entire drive cycle to control the total quantity of electrical energy generated during the drive cycle.