CROSS REFERENCE TO RELATED APPLICATIONS

[0001] The present patent application is related to and claims the benefit of priority from the Indian Provisional Patent Application with Serial No. 21 14/CHE/201 3 titled Ά COMPACT PORTABLE DIESEL GENERATOR SET WITH REDUCED VIBRATION AND NOISE', filed on 13 ^th May, 2103 and subsequently deferred by six months, that is, up to 13 ^th November 2013, the contents of which are incorporated in entirety by the way of reference.

BACKGROUN D

Technical field

[0002] The present disclosure generally relates to a motor-generator for generating electrical energy and particularly relates to a diesel generator. The present disclosure more particularly relates to a diesel generator with minimized noise level and minimized vibrations.

Description of the Related Art

[0003] Diesel engine powered electrical generators are used in the event that the availability of conventional electrical energy/primary electrical power source is disrupted. Diesel motor generators or diesel engine generators generate electricity are typically used in populated locations such as hospitals, and malls to ensure uninterrupted supply of electrical power. A diesel generator is typically driven by an internal combustion engine.

[0004] Diesel engine powered generator assemblies are typically situated indoors, such as, inside domestic buildings, inside factories and the like. The power generator assemblies are typically provided with an engine and a generator mounted on a unitary base plate in-line, preferably adjacent to one another on a same level. The transmission of electrical energy from the engine to the generator is typically accomplished using an elastic coupling and, in certain cases, through speed reduction gears. An elastic coupling is required for transmission of electrical energy, in order to compensate for the vibration of the diesel engine. The speed reduction gears are typically used when the generator comprises a four-pole machine in which the rotor is rotated at a speed of about 1 ,500 rpm, since the speed of rotation of the diesel engine is usually higher. A cardan shaft may also be used to transmit electrical energy between the diesel engine and the generator.

[0005] An assembly with aforementioned construction is typically large and therefore requires a significant amount of floor space. Further, the noise level accompanying the operation of a generator assembly, in which the engine and the generator are not enclosed within an acoustically insulated housing, is high and typically close to 100 decibels (dB). In conventional generator arrangements, noise generated by the exhaust gases being released into open air from the generator can be suppressed by means of a silencer suspended from the ceiling using a special piping and suspension members. The fuel tank for the generator is general ly provided as a standalone unit requiring an installation of separate fuel conduits and the like.

[0006] The in-line placement of the engine and the generator further requires two separate air circulating ports at the place of assembly (typically an engine room). One port is used for the intake air and another port is used for the exhaust air. An engine driven generator assembly as described above may be enclosed in a housing provided with a heat and sound insulation. In such cases, the dimensions of the assembly are even greater and the required floor area is also correspondingly increased. Moreover, an enclosed assembly of this type necessitates an arrangement of two air circulating ports at the place where the assembly is located. [0007] Hence, there was felt a need for a diesel generator with low noise level and reduced vibrations. There was also felt a need for a compact diesel generator that can be used in places having space related constraints.

OBJECTS OF THE EMBODIMENTS

[0008] The primary object of the present disclosure is to provide a compact portable diesel generator.

[0009] Another object of the present disclosure is to provide a diesel generator with an inlet noise inhibiting device to limit inlet air pressure pulse cycle intensity and a crankcase breather system to partially damp a pressure pulse at airbox from engine cylinder air inlet.

[0010] Yet another object of the present disclosure is to provide a compact portable diesel generator with a cooling system designed for noise reduction.

[001 1 ] Yet another object of the present disclosure is to provide a compact portable diesel generator with an improved air impellor volute casing profile to enable a highly efficient air flow with an even mass distribution at the radiator inlet for optimizing a heat transfer capacity within a minimum weight and volume.

[0012] Yet another object of the present disclosure is to provide safety characteristics in a compact portable diesel generator for preventing air entrapment in the fuel suction lines on fuel level in the tank reaching "empty ^" '.

[0013] Yet another object of the present disclosure is to provide a simplified method for manufacturing an alternator used in the diesel generator.

[0014] Yet another object of the present disclosure is to provide a compact automotive diesel engine as part of a Hybrid drive pack 501 for retro-fitting to existing IC engine powered vehicles. [0015] These and other objects and advantages of the present disclosure will become readily apparent from the following detailed description taken in conjunction with the accompanying drawings.

SUMMARY

[0016] The various embodiments of the present disclosure provide a compact, portable diesel generator with reduced vibration and noise, for preferably domestic use. The diesel generator comprises a single cylinder diesel engine for burning the fuel to convert chemical energy into mechanical energy which results in rotating a crankshaft. The diesel generator further comprises an alternator connected to the crankshaft for converting the mechanical energy into electrical energy.

[0017] The diesel generator further comprises an air box and an air filter, which are arranged for limiting inlet air pressure pulse cycle intensity. A water cool ing arrangement is provided in the diesel generator for maintaining appropriate working temperature inside the internal combustion engine. A radiator is provided in the diesel generator assembly for cooling the internal combustion engine. A control panel is provided for monitoring, metering and protecting the diesel generator.

[0018] A fuel tank for storing fuel, fuel filler for filling fuel and an engine lube oil filler for filling engine lube oil are also provided in the diesel generator assembly. A battery enclosure is installed for storing and safeguarding one or more batteries. External sound attenuation panels are mounted on the diesel generator assembly for reducing the intensity of sound waves. Further, anti-vibration mountings are installed for reducing the vibrations. One or more lifting handles are provided for lifting and transporting the diesel generator. The diesel generator comprises twin balancer shafts and respective gear assemblies which are arranged for achieving a full primary balance of the diesel engine. An air-cooling system for damping noise and a water cooling arrangement for cooling the diesel engine are also provided.

[0019] According to one embodiment herein, the single cylinder diesel engine is a 10 bhp single cylinder four stroke 3000 rpm diesel engine which drives a 230 volt two- pole single-phase alternator.

[0020] According to one embodiment herein, a rotor of the alternator is integrated to the engine crankshaft and mounted directly to a drive plate on the crankshaft to replace the substantial flywheel normally required for the single cylinder diesel engine. The arrangement saves both the space as well as the weight of the diesel generator.

[0021] According to one embodiment herein, the diesel generator includes a plurality of features such as: setting speed control (to maintain correct current frequency), setting wave form compensation (to ensure alternating current to be within specified limits for mains supply quality).

[0022] According to one embodiment herein, the twin balancer shafts used for achieving a full primary balance of the diesel engine (referred to as 'engine' hereafter) further comprise a first balancer shaft and a second balancer shaft. The first balancer shaft and the second balancer shaft are controlled by the main crankshaft of the engine with the help of a timing gear drive arrangement. The timing gear drive arrangement is enclosed in a timing gear cover.

[0023] According to one embodiment herein, the use of twin balancer shafts provides a full primary reciprocating balance of the single-cylinder diesel engine without a residual unbalanced moment. As a result, the engine of the present disclosure effectively has primary reciprocating balance equivalent to a normal four cylinder inline arrangement normally used in small cars. [0024] According to one embodiment herein, the crankshaft counter weights are designed for a full rotating balance and 50% reciprocating primary balance. The twin balancer shafts are arranged to be rotated in a direction opposite to the rotation of the crankshaft. The weight of each of the balancer shafts is equal to 25% of primary reciprocating unbalance of the reciprocating components of the engine. The above arrangement hence enables a full primary balance of the engine, leaving only the secondary unbalanced as in an inline four cylinder engine arrangement.

[0025] According to one embodiment herein, the timing gear drive arrangement further comprises a first balancer shaft drive gear, a second balancer shaft drive gear, an overhead cam shaft gear, an idler gear, a cooling fan shaft gear, a fuel cam shaft gear and a crankshaft main gear. The first balancer shaft drive gear and the second balancer shaft drive gear are driven by the crankshaft main gear at a speed equivalent to the speed of the crankshaft.

[0026] According to one embodiment herein, the first balancer shaft drive gear is connected to the fuel pump of the engine for controlling the fuel supply to the engine and is known as fuel pump side balancer shaft gear. Similarly, the second balancer shaft drive gear is connected to the water pump of the engine for controlling the water flow in the engine and is known as water pump side balancer shaft gear.

[0027] According to one embodiment herein, the use of fully geared timing drive arrangement provides a long working life of these sections of the diesel generator and the components thereof.

[0028] According to one embodiment herein, the air box and air filter of the diesel generator act as an inlet noise inhibiting device by limiting the inlet air pressure pulse cycle intensity. The airbox enclosure is connected to the crankshaft breather system for damping the inlet pressure pulse in the airbox by using and transmitting an opposite timing gear cover and rocker cover, are convex surfaces. This design results in avoiding any focused concentration of sound waves generated from the elastic deformations of the engine structure during the operation of the diesel generator. The aforementioned structural design characteristic is also found to provide favorable stress distributions. This results in reduced overall noise radiation from the vibrating assemblies of the diesel generator.

[0034] According to one embodiment herein, the overal l noise of the diesel generator is further reduced by the use of the external sound proofing panels (external sound attenuation panels) lined with an acoustic damping media designed for the specific frequency ranges as applicable for a maximum effectiveness in the various locations of the equipment.

[0035] According to one embodiment herein, the external covers of the generator is made of cast aluminum components and the outer surfaces are specially shaped to minimize a propagation of the operational deflections and vibration from the engine power system to the outside environment.

[0036] According to one embodiment herein, the alternator of the compact diesel generator is designed to be highly integrated with the engine for functional advantages. The alternator design further includes an assembly tooling design for locating the stator with respect to a spigot on an external casing of the alternator which is itself located on an engine flywheel bell housing counter bore. A rotor of the alternator is located on the flywheel flange of the engine crankshaft by means of the stepped seats on the flywheel plate, which comprises a precision fit to the outer laminations carrying the rotor magnets. The said arrangement provides a simple assembly of the alternator to the engine and also enables a precise assembly with highly reliable repeatability at an economical cost of manufacturing. [0037] According to one embodiment herein, the alternator of the compact diesel generator further comprises a plurality of magnets mounted in a recessed seat in the rotor lamination assembly for a secure retention against torsional shock due to an engine firing event. This method provides a risk-free transmission of the electromagnetic torque.

[0038] According to one embodiment herein, the rotor laminations are fixed to the crankshaft carrier plate. The rotor laminations are lined with a High Conductivity Sheet Shield (Copper or Aluminum or any other high conductivity material) to reduce the reverse rotating component of magnetic field that is inherently produced by the load current due to the single-phase structure of the winding.

[0039] According to one embodiment herein, the shielding effect is achieved by means of the eddy currents which lead to additional Joule losses. The shield is deployed between the magnets and the rotor core, instead of being mounted between the magnets and the main air gap to permit a reduction of such losses.

[0040] According to one embodiment herein, the stator laminations arrangement has an assembly in sections to reduce a space required for the turns on the windings to provide a better compactness and also to reduce the cost of assembly due to the simplified winding process.

[0041 ] According to one embodiment herein, the alternator assembly further provides a special uneven distribution of the armature winding in a set of suitably unevenly spaced slots for improving the voltage wave-form.

[0042] According to one embodiment herein, the diesel generator further comprises safety characteristics for preventing air entrapment in fuel suction lines. The air entrapment in the fuel suction lines is prevented by adopting a level switch in a localized well provided in the fuel tank at the point of the outlet to the fuel pump suction. When a low fuel level is detected in the fuel tank, the level switch is operated to turn off the fuel supply valve on the pump suction to stop the engine. The fuel line from the tank to pump is hence protected against air entrapment. The engine can therefore be started without a need for priming and bleeding when the fuel tank is refilled.

[0043] The various embodiments herein provide for a Turbo-charged version of the Diesel engine as part of a Hybrid drive pack, which is retro-fitted to existing IC engine vehicles. The hybrid drive pack is engineered to replace an existing engine with the minimal changes in the base vehicle thereby enabling a huge saving of fuel consumption (the overall fuel consumption is typically less than half of the fuel consumption of equivalent gasoline driven cars).

[0044] According to one embodiment herein, the Hybrid drive pack comprises a single cylinder diesel engine for burning the fuel to convert chemical energy into mechanical energy which results in rotating a crankshaft. A generator is an electromechanical device connected to the crankshaft for converting the mechanical energy into electrical energy. A battery enclosure is provided for storing and safeguarding batteries.

[0045] According to one embodiment herein, the single cylinder diesel engine is a 10 bhp single cylinder four stroke 3000 rpm diesel engine which drives a 230 volt two- pole single-phase alternator.

[0046] According to one embodiment herein, the diesel engine of the Parallel Hybrid drive pack is designed to have an automotive power output of 22 kW at 4300 rpm corresponding to approximately 40% of the usual engine power for the same size of the vehicle. The reduced power capacity of the engine enables it to operate for the most part close to its optimum brake specific fuel consumption of about 200 gm/kW hr compared with well over double that figure for the 56 kW diesel engines it replaces which would be running almost entirely at a very small proportion of their rated power. [0047] According to one embodiment herein, maximum direct use of power drawn from the engine is carried out with as little as possible use of battery stored energy to minimize the attendant losses of charging and discharging of the battery system in order to optimize the overall thermal efficiencies for minimum vehicle fuel consumption.

[0048] According to one embodiment herein, a torque demand from the base engine (of a compact single cylinder diesel engine) is pitched at a near optimum fuel consumption as far as possible.

[0049] According to one embodiment herein, a surplus torque available in the power/torque requirement for the VCA Mixed Cycle is used for recharging the battery pack comprising pluralities of batteries in a variety of configurations during the test cycle along with an energy recovery from regenerative braking.

[0050] According to one embodiment herein, the Parallel Hybrid drive pack comprises a compact single cylinder diesel engine as a primary drive unit, an electric motor as a secondary drive unit, a clutch to engage /decouple vehicle gearbox, electric generator, a device for interface of Hybrid Unit with standard vehicle gearbox and a clutch to engage/decouple electric generator.

[0051] According to one embodiment herein, the clutches for engaging/decoupling vehicle gearbox and electric generator respectively are electronically controlled and linked to the ECU of the vehicle.

BRIEF DESCRIPTION OF THE DRAWINGS

[0052] The other objects, features and advantages will occur to those skilled in the art from the following description of the preferred embodiment and the accompanying drawings in which: [0053] FIG. l A-l F illustrate various perspective views of the compact portable diesel generator, accord ing to one embodiment of the present disclosure.

[0054] FIG. 2A-2D illustrate cross sectional views of the compact portable diesel generator, according to one embodiment of the present disclosure.

[0055] FIG. 3A-3B illustrate a front view of air cooling system of the compact portable diesel generator with a cover and without a cover respectively, according to one embodiment of the present disclosure.

[0056] FIG. 4A-4C illustrate top, side and front views of various engine external covers and surfaces of the compact portable diesel generator, according to one embodiment of the present disclosure.

[0057] FIG. 5A-5E illustrate various views of the Diesel Electric Parallel Hybrid drive pack 501 , according to one embodiment of the present disclosure.

[0058] FIG. 6A-6B illustrate side views of the Diesel Electric Parallel Hybrid drive pack 501 showing the comparison of space claim of Hybrid Drive when replacing typical 4-cylinder inline petrol/diesel engine, according to one embodiment of the present disclosure.

[0059] FIG. 7 illustrates a cross sectional view of an alternator, according to one embodiment of the present disclosure.

[0060] FIG. 8 illustrates a cross section view of an alternator with special optimized profile adopted in the rotor laminations, according to one embodiment of the present disclosure.

[0061] FIG. 9A-9C illustrate cross sectional views of an alternator illustrating magnets mounting in a recessed seat in rotor lamination assembly for a secure retention against torsional shock due to engine firing event, according to one embodiment of the present disclosure. [0062] FIG. lOA-lOC illustrate cross sectional views of an alternator indicating a cooling arrangement of the alternator, according to one embodiment of the present disclosure.

[0063] FIG. 1 lA-1 I B illustrate cross sectional views of an alternator indicating a teeth arrangement provided on the rotor laminations to clean up dust deposits, according to one embodiment of the present disclosure.

[0064] Although the specific features of the present disclosure are shown in some drawings and not in others, this is done for convenience only as each feature may be combined with any or all of the other features in accordance with the present disclosure. DETAILED DESCRIPTION OF THE EMBODIMENTS HEREIN

[0065] In the following detailed description, a reference is made to the accompanying drawings that form a part hereof, and in which the specific embodiments that may be practiced is shown by way of illustration. These embodiments are described in sufficient detail to enable those skilled in the art to practice the embodiments and it is to be understood that the logical, mechanical and other changes may be made without departing from the scope of the embodiments. The following detailed description is therefore not to be taken in a limiting sense.

[0066] FIG. lA- lF illustrate the various perspective views of the diesel generator 100, according to one embodiment herein. FIG. 1 A is a top perspective view with a cover, FIG. 1 B is a side perspective view with a cover, FIG. 1 C is a side perspective view with a cover, FIG. I D is a side perspective view without a cover, FIG. I E is a bottom perspective view without a cover and FIG. I F is a cross sectional view of the diesel generator 100. The diesel generator 100 comprises a single cylinder diesel engine 1 13 (as shown in FIG. I F) for burning the fuel in order to convert the chem ical energy into mechanical energy which results in rotating a crankshaft. An alternator 101 (as shown in FIG. 1 A) is an electromechanical device connected to the crankshaft (not shown in figures) for converting the mechanical energy into electrical energy. An airbox enclosure comprises an air box and an air filter 109 (as shown in FIG. I C and FIG. I E) for limiting an inlet air pressure pulse cycle intensity. An air-cooling system comprises a cooling fan 1 14 (as shown in FIG. I F) for maintaining a constant temperature inside the radiator to in turn maintain correct temperature inside the internal combustion engine 1 13. A water cooling arrangement comprises a radiator 1 10 (as shown in FIG. I C and FIG. I E) for cooling water/coolant/suitable fluid circulated inside the internal combustion engine 1 1 3. The diesel generator 100 includes a control panel 104 (as shown in FIG. 1 A, FIG. I B and FIG. ID) for monitoring, metering, protecting and control system, a fuel tank (not shown) for storing fuel, a fuel filler 106 for filling fuel (as shown in FIG. 1 A, FIG. I C and FIG. I D), an engine lube oil filler 107 (as shown in FIG. 1 A and FIG. I C) for filling engine lube oil, a battery enclosure 102 (as shown in FIG. 1 A and FIG. I B) for storing and safeguarding one or more batteries, external sound attenuation panels 108 (as shown in FIG. 1 A. FIG. I B and FIG. I C) for reducing the intensity of sound waves, anti- vibration mountings 1 12 (as shown in FIG. I E) for reducing vibrations, one or more lifting handles 105 (as shown in FIG. 1 A, FIG. I B, FIG. I C, FIG. I D, FIG. I E and FIG. I F) for lifting and transporting diesel generator 100. An exhaust system enclosure 103 (as shown in FIG. 1 A, FIG. I C and FIG. I E) for noise attenuation, storing and safeguarding exhaust system comprises a 2-stage silencer, twin balancer shafts and their respective gear assemblies for achieving full primary balance of the engine 1 13 have also been provided in the diesel engine 100.

[0067] According to one embodiment herein, the single cylinder diesel engine 1 13 is a 10 BHP (Brake Horse Power) single cylinder four stroke 3000 rpm diesel engine which drives a 230 volt two-pole single-phase alternator 101 . [0068] According to one embodiment herein, a rotor of the alternator 101 is integrated to the engine crankshaft and mounted directly to a drive plate on the crankshaft to replace the substantial flywheel which is normally required for the single cylinder diesel engine. The arrangement saves both overall space and weight of the diesel diesel generator 100.

[0069] According to one embodiment herein, the diesel generator includes various features such as but not limited to: setting speed control (to maintain correct current frequency), setting wave form compensation (to ensure alternating current to specified limits for mains supply quality) and also safeguarding for the ease of use by lay persons without the need for attention by trained technicians.

[0070] According to one embodiment herein, the air box and air filter 109 (as shown in FIG. 1C and FIG. IE) of the generator 100 act as an inlet noise inhibiting device by limiting the inlet air pressure pulse cycle intensity. The airbox enclosure is connected with a crankshaft breather system for damping the inlet pressure pulse in the airbox, to be transmitted to airbox during the cycle for compensation of inlet pulse by using an opposite phase of pressure inside crankcase.

[0071 ] According to one embodiment herein, the air-cooling system comprises a cooling fan 1 14 (as shown in FIG. I F) of the generator 100 which is designed for reduced noise by lowering the rotational speed of the impellor along with an impellor casing located laterally in front of timing gear cover, which acts as an acoustic barrier to reduce noise radiation and radiator 1 10 is also positioned in-front of the engine and beside the cooling fan impeller casing to reduce noise emission as shown in FIG. 1 C and FIG. I E.

[0072] According to one embodiment herein, the overal l noise of the diesel generator is reduced by the use of external sound proofing panels (external sound attenuation panels 108 (as shown in FIG. 1 A. FIG. I B and FIG. 1 C) lined with acoustic damping media designed for the specific frequency ranges as applicable for the maximum effectiveness in the various locations of the equipment.

[0073] FIG. 2A-2D illustrates the cross sectional views of the diesel generator 100, according to one embodiment herein. FIG. 2Aa and FIG. 2Ab illustrates a cross section view of the diesel generator 100 indicating an arrangement of water pump side balancer shaft (1 15), FIG. 2Ba and FIG. 2Bb illustrate a cross sectional view of the diesel generator 100 indicating an arrangement of fuel pump side balancer shaft ( 1 18), FIG. 2Ca and FIG. 2Cb show a cross sectional view of the diesel generator 100 indicating the cooling air impeller drive arrangement and FIG. 2D shows a cross sectional view of the diesel generator 100 indicating an engine timing gear arrangement. The twin balancer shafts and their respective gear assemblies are provided in the diesel generator 100 for achieving full primary balance of the engine. The twin balancer shafts further comprises a first balancer shaft and a second balancer shaft. The first balancer shaft and the second balancer shaft are controlled by the main crankshaft of the engine with the help of a timing gear drive arrangement. The timing gear drive arrangement is enclosed in a timing gear cover. The first balancer shaft is a water pump side balancer shaft 1 1 5 (as shown in FIG. 2Ba and FIG. 2Bb) and the second balancer shaft is a fuel pump side balancer shaft 1 18 (as shown in FIG. 2Aa and FIG. 2Ab).

[0074] According to one embodiment herein, the use of twin balancer shafts ( 1 15 and 1 18) provides a full primary reciprocating balance of the single-cylinder diesel engine without any residual unbalanced moments so that, the engine of the present disclosure effectively has reciprocating balance equivalent to a normal four cylinder inline arrangement which is normally used in smaller motor vehicles.

[0075] According to one embodiment herein, the crankshaft counter weights are designed for full rotating balance and 50% reciprocating primary balance. The twin balancer shafts (1 15 and 1 1 8 as shown in FIG. 2A and FIG. 2B) are arranged to be rotated in the same direction, which is preferably opposite to the direction of rotation of the crankshaft. The twin balancer shafts ( 1 15 and 1 1 8) are coupled to the balancer shaft drive gear 1 17 as shown in FIG. 2Aa, FIG. 2Ab and FIG. 2Bb. The balancer shaft drive gear 1 17 drives both the twin balancer shafts (1 15 and 1 18). The weighting of each of the balancer shafts is equal to 25% of primary reciprocating unbalance of the reciprocating components of the engine. The above arrangement hence enables a full primary balance of the engine, leaving only secondary's unbalanced as in an inline four cylinder engine arrangement.

[0076] According to one embodiment herein, the air-cooling system of the diesel generator 100 comprises a cooling fan for maintaining a constant temperature of the cooling water circulating in the internal combustion engine. The cooling fan is provided with a specific impeller configuration 120 (as shown in FIG. 2Ca and FIG. 2Cb) suitable for the compact generator 100. The cooling fan impeller 120 is located inside the cooling fan impeller casing. The cooling fan impellor casing profile is designed in such a manner, to enable a highly efficient air flow with even mass distribution at the radiator inlet for optimizing a heat transfer capacity within minimum weight and volume. The cooling fan drive spindle 1 19 is adopted in the portable compact generator 100 for driving the cooling fan impeller 120 as shown in FIG. 2Ca and FIG. 2Cb.

[0077] According to one embodiment herein, the timing gear drive arrangement of the portable generator 100 further comprises a first balancer shaft drive gear 123 (water pump side balancer shaft gear), a second balancer shaft drive gear 124 (fuel pump side balancer shaft gear), an overhead cam shaft gear, an idler gear, a cooling fan drive gear 125, a fuel pump drive gear 121 and a crankshaft main gear 122. The first balancer shaft drive gear 123 and the second balancer shaft drive gear 124 are controlled by the crankshaft mean gear 122.

[0078] According to one embodiment herein, the use of fully geared timing drive arrangement is to increase the working life and remove need for maintenance of this area of the generator 100 and its components.

[0079] FIG. 3A-3B illustrate an air cooling system of the diesel generator 100, according to one embodiment herein. The air-cooling system of the diesel generator 100 comprises a cooling fan 1 14 (as shown in FIG. 3Aand FIG. 3B) for maintaining a constant temperature inside the internal combustion engine. The cooling fan 1 14 is provided with a specific impeller configuration 120 (as shown in FIG. 3 A and FIG. 3B) suitable for the compact generator 100. The cool ing fan impeller 120 is adopted inside the cooling fan impeller casing. The cooling fan impellor casing profile is designed in such a manner, to enable a highly efficient air flow with even mass distribution at the radiator 1 10 inlet for optimizing a heat transfer capacity within minimum weight and volume (direction of air flow into the impeller 127 and direction of air flow to the radiator 126 is as shown in FIG. 3A and FIG. 3B). The cooling fan drive spindle is adopted in the portable compact generator 100 for driving the cooling fan impeller 120 as shown in FIG. 3A and FIG. 3B.

[0080] According to one embodiment herein, the cooling fan impellor rotational speed is reduced to a little over 50% of crank speed to minimize noise generated from operation of the impellor.

[0081 ] According to one embodiment herein, the diesel generator further comprises a water cooling arrangement used in the prime mover diesel engine. The water cooling is adopted to provide a greater compactness than that of the air cooling system of the single cylinder diesel engine. The cooling air flow arrangement is designed to be passed towards the water filled radiator 1 10 in a uniformly distributed manner to provide the maximum heat transfer efficiency of surface and provides a great compactness of the overall arrangement. The design further allows a diversion of small quantities of air at the impellor outlet into subsidiary cooling circuits as required for further applications with higher power ratings.

[0082] FIG. 4A-4C illustrates the different views of the diesel generator 100, indicating the various shapes of engine external covers and surfaces, according to one embodiment herein. The external surfaces of the main engine 1 13 components like timing gear cover and rocker cover are made in the form of convex surfaces. The convex surfaces are adopted for the engine cylinder block 128a and engine cylinder head 128b as shown in FIG. 4A, FIG. 4B and FIG. 4C. The design results in preventing any focused concentration of sound waves generated from elastic deformations of the engine structure during operation. The convex surface structural design characteristic reduces the sound by providing a favorable stress distribution under the designed conditions in any case. This further result in reducing the overall noise radiation from the vibrating assemblies of the diesel generator.

[0083] According to one embodiment herein, the external covers (such as timing gear cover and rocker cover, of engine cylinder block 128a and engine cylinder head 128b) of the generator 100 is made of cast aluminum components and outer surfaces are specially shaped to minimize a propagation of the operational deflections and vibrations from the engine power system to the outside environment.

[0084] The diesel generator 100 is retro-fitted to existing IC engine vehicles (naturally aspirated or turbo charged) to provide a Parallel Hybrid drive pack 501 as shown in FIG. 5A and FIG. 5E. [0085] FIG. 5A and FIG. 5B show an isometric view of the Diesel Electric Parallel Hybrid drive pack 501 . FIG. 5C and FIG. 5D show a perspective view of the Diesel Electric Parallel Hybrid drive pack 501 .

[0086] FIG. 5C and FIG. 5D illustrate the base engine of the diesel generator 100 in Turbo Charged version (turbo charger 504) in a hybrid drive pack 501 which replaces an existing engine with minimal changes in the base vehicle, and which results in reduced fuel consumption (fuel consumption being typical ly less than half the fuel consumption of equivalent gasoline driven cars).

[0087] According to one embodiment herein, the Diesel Parallel Hybrid drive pack 501 comprises a single cylinder diesel engine 1 13 for burning the fuel to convert chemical energy into mechanical energy which results in rotating a crankshaft, a battery enclosure for storing and safeguarding one or more batteries, the twin balancer shafts and their respective gear assemblies 503 for achieving full primary balance of the engine, a air-cooling system for damping noise, a water cooling arrangement for cooling internal combustion engine, a turbo charger 504 for increasing power output and efficiency by forcing more intake air and proportionately more fuel into the combustion chamber of the diesel engine 1 13 and Hybrid power pack 502 comprising a motor 51 1 and generator which are electro-mechanical devices connected to the rotating crankshaft of the single cylinder diesel engine 1 13 for converting mechanical energy into electrical energy (and vice-versa).

[0088] FIG. 5E shows a cross sectional view of the Diesel Electric Parallel Hybrid drive pack 501. The Hybrid drive pack 501 comprises a generator 505 for generating an electric current, an electric motor 51 1 acting as a secondary drive unit (by converting electric current into mechanical energy) for driving the vehicle, a first clutch 507 for engaging/decoupling the electric generator and a second clutch 506 for engaging/decoupling a vehicle gearbox. The rotor of the motor 51 1 is engineered with the flywheel of the single cylinder diesel engine 1 13. The Hybrid Power Pack 502 is coupled to the existing gearbox of the vehicle, for driving the vehicle. The interface 508 of the Hybrid Power Pack 502 with the standard vehicle gearbox is shown in FIG. 5E.

[0089] FIG. 6A-6B illustrates a side view of the Diesel Electric Paral lel Hybrid drive pack 501 indicating the comparison of space claim of Hybrid Drive when replacing a typical 4-cylinder inline petrol/diesel engine, according to one embodiment of the present disclosure. The existing 4-cylinder inline petrol/diesel engine 509 is replaced with the Diesel Electric Parallel Hybrid drive pack 501 as shown in FIG. 6A and FIG. 6B. The Hybrid Power Pack is coupled to the existing gearbox 510 of the vehicle, for driving the vehicle on the electric motor as well as on single cylinder inline petrol/diesel engine 1 13 of the present disclosure. Retro fitting of the diesel generator 100 in the existing IC engine 509 with minimal changes in the base vehicle, results in huge savings in terms of fuel consumption as wel l as space, as shown in FIG. 6A and FIG. 6B.

[0090] According to one embodiment herein, the mass and inertia of the rotor of the generator is referenced to the inertia of the engine flywheel to combine both of these to be available as flywheel inertia.

[0091] According to one embodiment herein, the diesel engine of the Diesel Parallel Hybrid drive pack 501 is designed to have an automotive power output of 22 kW at 4300 rpm corresponding to approximately 40% of the usual engine power for the same size of vehicle. The reduced power capacity of the engine enables it to operate for the most part at a level which is close to its optimum brake specific fuel consumption of about 200 gm/kW hr compared with a well over double that figure for the 56 kW diesel engine that is being replaced by it operating at very light loads. [0092] According to one embodiment herein, to further optimize overall thermal efficiencies for minimum vehicle fuel consumption, maximum direct use of power drawn from the engine is made with the use of battery stored energy as little as possible to minimize the attendant losses of charging and discharging of the battery system.

[0093] According to one embodiment herein, a torque demand from the base engine (compact single cylinder diesel engine) is designed to be near optimum fuel consumption.

[0094] According to one embodiment herein, a surplus torque available in the power/torque requirement for VCA Mixed Cycle is used for recharging a battery pack comprising pluralities of batteries in a variety of configurations during the test cycle along with energy recovered from regenerative braking.

[0095] According to one embodiment herein, the Diesel Parallel Hybrid drive pack 501 comprises a compact single cylinder diesel engine as a primary drive unit, an electric motor as a secondary drive unit, an electric generator, a clutch to engage /decouple vehicle gearbox, a device for interface of Hybrid drive pack 501 with standard vehicle gearbox and a clutch to engage/decouple electric motor.

[0096] According to one embodiment herein, the clutches for engaging/decoupling vehicle gearbox and electric generator respectively are optimized and controlled electronically with the complete system interacting with the ECU of the vehicle.

[0097] According to one embodiment herein, the Diesel Electric Parallel Hybrid drive pack 501 comprises: a structure with an overall length x height x width being approximately equal to 680mm x 590mm x 580mm. The automotive Engine power rating is 22kW and the Engine peak torque is 55-60 Nm. The max torque of Electric motor is 150Nm and the total weight of hybrid drive pack 501 is 75 g. The Battery storage capacity is 250 Amp Hr and the Total weight of a general battery such as Lead Acid/NiMH battery pack is 80Kg/70 g.

[0098] According to one embodiment herein, an "averaged" power of a little over one-third of the typical automotive rating of a passenger road vehicle is required for more than 90% of usage. The diesei engine of the above Hybrid drive pack 501 is hence designed to have an automotive power output of 22 kW at 4300 rpm corresponding to approximately 40% of the usual engine power for this size of vehicle. The reduced power capacity of the engine enables it to operate for the most part close to its optimum level of brake fuel consumption of about 200 gm/kW hr when compared with well over double that figure for the 56 kW diesei engines being replaced by it. To further optimize the overall thermal efficiencies for minimum vehicle road fuel consumption, a maximum direct use of power drawn from the engine is made with the use of battery stored energy as little as possible to minimize the attendant losses of charging and discharging of the battery system.

[0099] According to one embodiment herein, pluralities of measures are considered to yield the best overall results. The measures comprise a torque demand from base engine which is designed at near optimum fuel consumption as far as possible and the surplus torque available in the power/torque requirement (as illustrated for the mixed cycle road fuel consumption test published by the Vehicle Certification Agency (VCA) of the UK Government Department for Transport (DfT)) is used for recharging the battery pack during the test cycle along with energy recovery from regenerative braking.

[00100] FIG. 7 illustrates a cross sectional view of an alternator connected to the engine crankshaft, according to one embodiment herein. The alternator comprises a rotor 701, a rotor mounting 703 to mount the rotor to the flywheel plate, a stator 702, windings in the stator704, a flywheel carrier plate 706, stator mounting 707 to an external casing of the alternator and magnets 708 located in the rotor laminations. The alternator is connected to the crankshaft 705 of the existing engine. According to one embodiment of the present disclosure, the alternator of the present disclosure is mounted with an external rotor 701, so that the mass and inertia of the rotor 701 serves as the required single cylinder diesel engine flywheel mass. The moment of inertia of the rotor 701 is brought to an optimum level to obviate a need for additional flywheel mass by the rotor laminations used in this section to optimize the magnetic performance of the rotor 701 . This combination allows a substantial reduction in overall space envelope and weight of the compact diesel generator.

[00101 ] According to one embodiment herein, the rotor windings are designed to enable compensation and correction of the output waveform.

[00102] FIG. 8 illustrates a cross sectional view of an alternator with special optimized profile adopted in the rotor laminations, according to one embodiment herein. The FIG. 8 shows an alternator with a special optimized profile in the rotor laminations. The alternator further comprises an external casing 709, stator windings 714, stator assembly 713, magnets in rotor 712 and rotor assembly 71 1 . The profile of laminations 710 is relieved On the sides as shown in the FIG. 8. The special optimized profile saves material weight and cost while providing the correct magnetic properties required by the electro-magnetic design parameters of the alternator along with flow passages for providing a most effective exit path for the cooling air.

[00103] FIG. 9A-9C illustrate a cross sectional view of an alternator indicating the magnets mounted in a recessed seat in the rotor lamination assembly for a secure retention against torsional shock due to engine firing event, according to one embodiment herein. The magnets 712 are mounted in a recessed seat in the rotor lamination assembly for providing a secure retention against torsional shock due to the engine firing event as shown in FIG. 9A. This method of fixing the magnets also provides the benefits in terms of magnetic impact but is mainly intended to secure them for operating under the engine firing torque loads. This method also provides a risk-free transmission of the electromagnetic torque.

[00104] According to one embodiment herein, the rotor laminations are fixed (71 5) to the crankshaft carrier plate 706 as shown in FIG. 9B. FIG. 9C illustrates fixing ring (716) for the rotor laminations 717. The rotor laminations (717) are lined with a High Conductivity Sheet Shield (Copper or Aluminum or other high conductivity material) to reduce the reverse rotating component of magnetic field that is inherently produced by the load current due to the single-phase structure of the winding.

[00105] According to one embodiment herein, the shielding effect is achieved by means of the eddy currents which lead to additional Joule losses. The shield is deployed between the magnets and the rotor core, instead of mounting it between the magnets and the main air gap to permit a reduction of such losses.

[00106] According to one embodiment herein, the stator laminations arrangement has an assembly in sections to reduce a space required for the turns on the windings to provide a better compactness and also to reduce the cost of assembly due to the simplified winding process.

[00107] According to one embodiment herein, the alternator assembly further provides a special uneven distribution of the armature winding in a set of suitably unevenly spaced slots for improving the voltage wave-form.

[00108] According to one embodiment herein, the stator laminations are split into several parts, whose shape is purposely designed to permit an assembling of the core after having put the coils which constitute the armature (stator) winding, in place. These separate parts of the armature are then wound in advance onto the special supports directly for achieving their final shape whilst minimizing the length of end-turns, to save on the total conductor weight and Joule losses. (The said construction design is used for wider application in electrical machines). Similarly the design of magnets of the present disclosure provides a provision for varying the thicknesses of the individual segments. The appropriately selected profile gives the benefit of improved output voltage waveform from the alternator.

[00109] According to one embodiment herein, the excitation of the machine is provided only by magnets and output voltage variation due to load current is limited to resemble the performance of a normal mains electric supply for domestic applications.

[001 10] According to one embodiment herein, the excitation of the machine is provided by a dedicated winding located in the rotor and the output voltage variation due to load current is controlled accurately.

[001 1 1] According to one embodiment herein, the excitation of the machine is achieved by means of a hybrid excitation solution with rotor windings being used along with the rotor magnets. The wound-field or hybrid-excitation versions of the machine are designed to compensate the output voltage variation due to a load by adjusting the field current to effectively control the RMS value of output voltage control.

[001 12] FIG. 1 OA- IOC illustrate the cross sectional views of an alternator indicating a cooling arrangement of the alternator, according to one embodiment herein. FIG. 10A shows the protrusions 719 provided in the stator laminations with the slots in a support and the protrusions in the internal support 720 for stator laminations. FIG. 10B shows the protrusions in the internal support 720 for stator laminations and the air induction (cooling air flow) 721 through an inner diameter of the stator laminations which are arranged to conduct a waste heat to a core former. The protrusions also are used to support and locate stator laminations. in FIG. I OC. The cooling air flowing inside the stator tube also discharges the dust particles 725, if any accumulated inside the alternator as shown in FIG. I OC.

[001 1 7] According to one embodiment herein, the dust and heavier particles are separated and removed away from the alternator electromagnetic working zones by using the centripetal field of a differential airflow. The radial flow cooling fan pulls the air through the stator bore as described above. The airflow at the fan discharge provides a high value centrifugal field which allows a separation of the dust particles with a higher density than air and diverting these away from the outer diameter of the rotor laminations which are then cooled by the air stream as shown in FIG. I OC.

[001 18] According to one embodiment herein, the air flow is also cleared of the dust particles in the rotor and stator gap zone as the air flow through this area is redirected inward from the higher angular velocity of the impellor discharge, which inhibits an entrainment of the dust particles as shown in FIG. 1 0C.

[001 19] FIG. 1 1 A- 1 I B show the cross sectional views of an alternator indicating a teeth arrangement provided on the rotor laminations to clean up the dust deposits, according to one embodiment herein. The alternator design of the present disclosure provides an additional feature as a measure of "abundant caution" against any build-up of dust deposits inside the casing, which could be damaging the rotor laminations. The alternator design comprises projecting "teeth" provided locally on the outer diameter of the rotor laminations to clean up any dust deposits ahead of passage of the main lamination profile in the area of minimum radial clearance as shown in FIG. 1 1 A and FIG. 1 I B.

[00120] According to one embodiment herein, the projecting "Teeth" on the outer diameter of the rotor laminations form a ridge to dislodge any build-up of dust deposits inside alternator casing as shown in FIG. 1 1 A and FIG. 1 1 B. TECHNICAL ADVANTAGES

[00121 ] The technical advantages of the present disclosure include the realization of a portable, compact diesel generator. The diesel generator envisaged by the present disclosure provides for prolonged work life between two consecutive service intervals. Further, the diesel generator provides for lower levels of vibration due to the presence of full reciprocating primary balance. Further, the diesel generator envisaged by the present disclosure is light-weighted and compact. The diesel generator envisaged by the present disclosure uses the components/peripherals thereof as acoustic barriers, thereby providing for substantial (operational) noise reduction. The diesel generator envisaged by the present disclosure incorporates a water cooling arrangement that provides for maximum cooling efficiency from a small space envelope, while still being used as an acoustic shield for the diesel engine.