WO2008009045A1

WO2008009045A1 - Multi-purpose drive system for a combustion engine

Info

Publication number: WO2008009045A1
Application number: PCT/AU2007/000989
Authority: WO
Inventors: Michael Storey
Original assignee: Australian Customs Service
Priority date: 2006-07-19
Filing date: 2007-07-18
Publication date: 2008-01-24

Abstract

A multi-purpose drive system for a combustion engine, said drive system comprising: an AC motor adapted to drive the engine, a motor controller arranged for regulating at least one functional parameter of the motor and/or engine by controlling at least one operating characteristic of the motor; and a programmable supervising control system for controlling the driving engagement between the motor and the engine in a plurality of selectable modes o operation, each mode of operation being defined by stored reference values of the operating characteristic of the motor, and at least one of the selectable modes is a starting mode; wherein, to drive the engine in one of the selectable modes of operation, the supervising control system effects driving engagement between the motor and the engine, and provides the reference values, corresponding to the mode of operation, to the motor controller to control the corresponding the operating characteristic of the motor and, therefore, the functional parameter of the motor and/or engine.

Description

MULTI-PURPOSE DRIVE SYSTEM FOR A COMBUSTION ENGINE TECHNICAL FIELD

The present invention relates to a multi-purpose drive system for a combustion engine. BACKGROUND

It has long been known in the art to use DC electric motors to start combustion engines used in vehicles and maritime vessels. The automatically compensating characteristic of DC motors and their high starting torques are well suited to this application. Traditionally, a battery is used as the DC motors power source. After the engine attains self-sustaining combustion, the battery can be recharged using an engine driven alternator. In addition to the starter motors, the batteries are used to power an ever growing number of electronic loads including communications suites, security systems, navigation systems, control systems, auxiliary machines and the like. At least a portion of these electrical loads are essential, in that the vehicle or vessel is significantly limited without them being powered.

One of the problems with these DC systems is that the high starting currents required to satisfy the starting torque requirements of a combustion engine, can deplete the standing charge of batteries after just a few unsuccessful attempts to start the combustion engine. Thus, such high DC currents result in limited operational life and high maintenance of the battery system, battery charging systems and the DC starter motors.

In large applications, such as in maritime vessels using marine diesel engines, the batteries are large and expensive, often arranged in battery banks. There has been cases where depleting these large batteries has resulted in losses of normal power leading to hazardous situations and delays in vessel movements. Invariably the batteries must be replaced at significant expense in parts, labour and vessel availability. In addition, the short starting times of DC starter systems result in minimal lubricating oil pressure and fuel oil pressure being attained, prior to running of the engine.

Prior art starting systems using AC starter motors are also known. One advantage of using these systems relates to the fact that, by using AC speed controlled motors that match the static starting torque requirements of the engines, the AC power supply requirements can be kept to a minimum. Some prior art starting systems using AC starter motors are disclosed in US6462429(Dhyanchand et al), US4772802(Glennon et al.) and US4330743(Glennon). These arrangements are suited for engines which do not require a large amount of torque to start because of their size, such as aero engines. They are not suited to starting, turning or otherwise driving engines that require large amounts of torque.

AC induction motors have more complicated torque characteristics largely precluding their use in starting combustion engines, especially for meeting the high starting torque required in diesel engines. At the design stage, manipulating the features of AC induction motors results in corresponding variations in the variables of motor efficiency, starting torque, pull-out torque, power factor and starting current. An efficient AC motor has not yet been reported to simultaneously optimize these variables in order to be able to start a large standing combustion engine, such as a marine diesel engine. The torque generated by the motor has been less than required, drawing high currents and potentially damaging the motors.

The present invention seeks to provide a multi-purpose drive system for a combustion engine that will provide an alternative to the prior art.

SUMMARY OF THE INVENTION

According to a first aspect the present invention consists in a multi-purpose drive system for a combustion engine, said drive system comprising: an AC motor adapted to drive said combustion engine, said motor powered by an independent source of AC power; a motor controller arranged for regulating at least one functional parameter of said motor and/or combustion engine by controlling at least one operating characteristic of said motor; and a programmable supervising control system configured for controlling the driving engagement between said motor and said combustion engine in a plurality of selectable modes of operation of said drive system, each mode of operation being defined by stored reference values of the at least one operating characteristic of said motor, and at least one of said selectable modes of operation is a starting mode; wherein to drive said combustion engine in one of said modes of operation that has been selected, said supervising control system effects said driving engagement between said motor and said combustion engine, and provides the reference values, corresponding to the particular operation mode, to said motor controller so as to control the corresponding at least one operating characteristic of said motor and, therefore, said at least one functional parameter of said motor and/or combustion engine, according to that particular mode of operation . Preferably said multi-purpose drive system further comprising a feedback arrangement arranged to obtain and provide feedback related to said at least one functional parameter and of said motor and/or said combustion engine to said motor controller, so as to facilitate fine-tuning of said operating characteristics of said motor based on feedback from said feedback arrangement.

Preferably said supervising control system is arranged to receive from said motor controller information about at least one functional parameter of said motor and/ or said combustion engine, the information being based on information received from said motor controller from said feedback arrangement, so as to effect a predetermined event with said motor and/or said combustion engine when a predetermined functional parameter reaches a predetermined value.

Preferably said supervising control system is arranged to receive information about said at least one functional parameter of said motor and/or said combustion engine from said motor controller so as to effect the disconnection of said motor from said combustion engine when said motor and/or said combustion engine reaches a predetermined speed.

Preferably said starting mode includes increasing the speed of said motor at a predetermined rate of acceleration.

Preferably at least one functional parameter comprises the speed and/or the angular position of said motor and/or said combustion engine.

Preferably at least one of said selectable modes of operation of said drive system includes turning the engine slowly for pre-start lubrication.

In one embodiment pre-start lubrication is preferably achieved by delivering lubricant to the engine by an independently driven lubrication delivery system.

Preferably at least one of said selectable modes of operation of said drive system includes turning the engine slowly prior to shut down for cooling purposes.

Preferably at least one of said selectable modes of operation of said drive system includes turning the engine for extended periods at or near firing speeds for the purpose of bleeding fuel lines.

Preferably in one embodiment said plurality of selectable operation modes, includes any one or more of lubrication mode, cooling down mode, fuel line bleed mode, a maintenance mode or a diagnostic mode.

Preferably said multi-purpose drive system further comprising an actuation gear arranged to facilitate said driving engagement between said motor and said combustion engine, said actuation gear being controlled by said supervising control system.

Preferably said actuation gear is arranged to provide feedback indicative of the status of the actuation gear to the supervising control system, so that the motor is started only when the actuation gear is fully engaged.

Preferably said operating characteristics includes one or more of the following set: synchronous frequency, applied voltage, starting current, starting torque, pull-out torque and power factor.

Preferably said motor is powered up by a pulse width modulated rectangular wave AC signal, said motor controller being arranged to vary at least the voltage and the frequency of the AC signal.

Preferably said combustion engine is a diesel engine.

Preferably said motor is of a permanent magnet synchronous type.

Preferably said motor controller is a variable speed drive controller.

According to a second aspect the present invention consists in a multi-purpose drive system for a diesel combustion engine, said drive system comprising: an AC motor adapted to drive said combustion engine, said motor powered by an independent source of AC power; a motor controller arranged for regulating the speed and/or angular position of said motor and/or combustion engine by varying at least the frequency and/or voltage of said motor; and a programmable supervising control system configured for controlling the driving engagement between said motor and said combustion engine in a plurality of selectable modes of operation of said drive system, each mode of operation being defined by stored reference values of the at least one operating characteristic of said motor, and said selectable modes of operation include at least a starting mode; wherein to drive said combustion engine in one of said modes of operation that has been selected, said supervising control system effects said driving engagement between said motor and said combustion engine, and provides the reference values, corresponding to the particular operation mode, to said motor controller so as to vary said frequency and/or voltage of said motor and, therefore, said speed and/or angular position of said motor and/or combustion engine, according to that particular mode of operation .

Preferably said multi-purpose drive system further comprising a feedback arrangement arranged to obtain and provide feedback related to said at speed and/or angular position and of said motor and/or said combustion engine to said motor controller, so as to facilitate fine-tuning of said frequency and/or voltage of said motor based on feedback from said feedback arrangement.

Preferably said supervising control system is arranged to receive from said motor controller information about said speed and/or angular position of said motor and/or said combustion engine, the information being based on information received from said motor controller from said feedback arrangement, so as to effect a predetermined event with said motor and/or said combustion engine when a predetermined speed and/or angular position reaches a predetermined value

Preferably said plurality of selectable operation modes, includes any one or more of a lubrication mode, a cooling down mode, a fuel line bleed mode, a maintenance mode or a diagnostic mode.

BRIEF DESCRIPTION OF THE DRAWINGS

A preferred embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawings in which:

Fig 1 is a schematic diagram of an embodiment of a multi-purpose drive system for a combustion engine in accordance with the present invention.

Fig 2 is further schematic diagram of the multi-purpose drive system in accordance with the present invention.

BEST MODE OF CARRYING OUT INVENTION

The multi-purpose drive system of the preferred embodiment is intended for driving a diesel combustion engine 2 in various modes of operation, including a mode to start the engine. As shown in Fig 1, the multi-purpose drive system comprises an AC motor 1 that is adapted to drive combustion engine 2.

In the preferred embodiment, AC motor 1 is a permanent magnet motor. The multi-purpose drive system also comprises a variable speed drive (VSD) motor controller 3 arranged for controlling one or more operating characteristics of AC motor 1, in accordance with externally provided reference values. The operating characteristics include one or more of the following: synchronous frequency, applied voltage, starting current, starting torque, pull-out torque and power factor. By controlling one or more operating characteristics of AC motor 1, such as the frequency and voltage of the AC power supply provided to the motor 1, motor controller 3 in fact controls various functional parameters of the motor, such as its speed and angular position.

The multi-purpose drive system of the preferred embodiment also includes a supervising control system 4. This supervising system controls the driving engagement between AC motor 1 and the combustion engine 2. The supervising control system 4 is also programmed with one or more modes of operation, each mode being associated with reference values, stored in the supervising control system 4, of at least one operating characteristic of the motor 1. To run the system in a particular mode, supervising control system 4 provides the stored reference values corresponding to the particular operation mode to motor controller 3. The motor controller uses these reference values to control the operating characteristics of AC motor 1, thus defining the peculiar mode of operation of the entire system, The motor controller 3 can be arranged to control all or some of the operating characteristics of the AC motor 1. Similarly, the control of all or only some of the controlled characteristics can be based on the reference values provided by supervising control system 4.

The multi-purpose drive system preferably further comprises a feedback arrangement 5, mounted on the shaft of motor 1. Arrangement 5 is configured to obtain and provide feedback related to various functional parameters, such as the speed and/or the angular position, of AC motor 1 or combustion engine 2 to motor controller 3. Based on this feedback, motor controller 3 periodically or continuously fine-tunes the operating characteristics of AC motor 1 to allow accurate speed and position control of the motor. It should be clear that the feedback arrangement can be configured to monitor functional parameters of the AC motor 1, combustion engine 2 or both.

The multi-purpose drive system preferably further comprises an actuation gear 6 allowing connection/disconnection between the starter motor shaft and the engine's ring gear. The AC motor 1, the position feedback device and the actuation gear 6 are mounted on a common shaft. Supervising control system 4 controls actuation gear 6 to effect the engagement between starter motor 1 and combustion engine 2.

In a "starting mode" the supervising control system 4 initially provides a signal to operate the actuation gear 6 and engage AC motor 1 and combustion engine 2. It then provides a signal for the motor controller 3 to increase the speed of motor 1 at a predetermined rate of acceleration. Once engine 2 starts operating, the supervising control system 4 disengages the actuation gear 6. In this preferred embodiment, supervising control system 4 is further arranged to receive information from motor controller 3 about the speed of motor 1. This information is based on information received by the motor controller 3 from feedback arrangement 5. The supervising control system 4 uses this information to effect the disconnection of the motor from the combustion engine 2 when AC motor 1 reaches a predetermined speed or the load current drops. Alternatively, if the engine is fitted with an "engine management system", a signal from such system may be sent to supervising control system 4 when the engine is running, to effect the disconnection of motor 1. The multi-purpose drive system of the preferred embodiment uses an independent AC electrical power source for powering up AC motor 1. The provided AC signal, which is typically a 3 phase AC signal, is modified by motor controller 3 into a rectangular wave-shaped pulse width modulated AC signal that is provided to AC motor 1. As mentioned above, the frequency and the voltage of the modulated AC signal are among the operating characteristics controlled by motor controller 3. The independent AC power source 7 for providing power to starter motor 1 can be a standby generator.

The preferred embodiment uses an AC motor 1 of a permanent magnet synchronous type as this optimises the size verses output torque of the motor. The AC motor 1 is supplied with variable voltage and variable frequency from the motor controller 3.

This together with the output current rating of the controller 3 allows motor 1 to be operated if necessary, at the maximum or breakdown torque capability of motor 1.

A further enhancement relates to providing a feedback from the actuation gear 6 to the supervising control system 4 about the status of the actuation gear 6. This is especially easily implemented in standard gear arrangements, such as Bendix™ gear, which are provided with a switch that closes when the gear is fully engaged. This switch can be used to switch power to the motor 1 only when the actuation gear 6 is fully engaged, thus preventing damage to the engine ring gear.

In some embodiments, the multi-purpose drive system can also include, as a part of the motor controller 3 or as a separate device, a soft start controller to adjust one or more of the functional parameters in a predetermined manner that is well known in the art. This, however, may not be possible where high currents are required.

In operation, to drive combustion engine 2 in a particular mode of operation, supervising control system 4 triggers actuation gear 6 to engage AC motor 1 and the combustion engine 2. The supervising control system 4 also provides the reference values, corresponding to the particular operation mode, to motor controller 3 to facilitate the operation of the multi-purpose drive system in the particular mode of operation. There could be many operating modes, depending on the particular applications. The modes of operations can, for example, include "speed control only" or "speed and position" control.

A "speed only" mode does not require feedback arrangement 5, but relies for speed control solely on the reference values provided by supervising control system 4. One "speed control only" sub- mode includes starting combustion engine 2 in a controlled manner, where the speed is controlled in order to provide efficient torque matching or sufficient duration of the starting process to ensure the build up of adequate oil pressure in combustion engine 2. In another "speed control only" sub-mode, the engine is turned slowly at selected speeds for maintenance. Depending on the type of actuation gear 6 utilised, it may be possible to turn the engine slowly in either direction, possibly via a remote control wand.

In a "speed and position" control mode, the combustion engine 2 cannot only be turned in a required direction, but also to a selected rotational angle. To be able to index the crankshaft to a precise angle, the multi-purpose drive system has to incorporate feedback arrangement 5, as discussed above. This mode can be really useful during manufacture and engine maintenance.

Apart from minimizing the power requirements in a start mode, the multi-purpose drive system can be used in a way to ensure that good engine lubrication is achieved. One method includes extending the starting time for the engine to allow sufficient time for the required engine oil pressures to be achieved. A second method uses the motor as a turning motor with lubricating oil (lubricant) being supplied by an external auxiliary lubricant pump.

The foregoing describes only a preferred embodiment of the present invention and modifications, obvious to those skilled in the art, can be made thereto without departing from the scope of the present invention. For example, it should be understood that, whilst the abovementioned embodiment is particularly suited to diesel engines that require high starting loads, such as those used in marine application and the like, the present invention may be used to start other types and sizes of combustion engines. In the abovementioned preferred embodiment the AC motor 1 is of a permanent magnet synchronous type, however it should be understood that other motors could be used. For example, an induction motor could be used, however, with use of such induction motor it may not be possible to utilize a feedback aiτangement as described earlier. Other gearing arrangements can also be used for engaging motor 1 and the combustion engine 2, depending on the size of the engine, cranking speed and torque required. Furthermore, instead of information regarding the angular position and speed of the starter motor driving shaft, driving feedback arrangement 5 may be arranged to provide information related to the engine crank shaft, or other interconnected element, as long as the information is indicative of the speed, position or other functional parameter of combustion engine 2 or the AC motor 1.

It should be understood that a feature of the multi-purpose drive system of the present invention, is that the supervising control system 4 is programmable with various selectable modes of operation. These modes not only include slow turning of the engine for lubrication purposes, but also slow turning of engine 2 for cooling purposes before shutdown. A slow turning maintenance mode as mentioned earlier may also be employed. A further mode may be a "fuel line bleed" mode where the engine 2 is turned at higher speeds (at or near firing speeds) for extended periods, say for example in the order of 120 seconds for a marine diesel engine, for the 'bleeding" of fuel lines.

The present embodiment is shown in alternative schematic of Fig 2. In this schematic the "multipurpose drive system" comprising the motor 1 , controller 3 and supervising control system 4 are depicted as a "single box" for ease of reference. A mode selection device 20 is operably connected to the supervising control system 4 of the multi-purpose drive system to allow an operator to selectively choose an operating mode. The mode selection device 20 may be a touch panel, computer, remote control wand (or other hand held device), or alternatively may be a panel with an array of buttons or switches.

An important feature of the present invention is that its programmability changes the function of the motor and controls the load on the motor thereby providing the drive system with its "multipurpose" capability.

When in "start mode" the system builds up speed slowly, three to four times longer than prior art systems. In a typical marine diesel engine this may typically be over a period of 6-8 seconds, however it may in some instances be up to 12 seconds. The advantages of this are: a) A very low starting current and as a consequence only a small motor is required to be used, which is of particular importance for combustion engines used in marine vessels and vehicles.

b) If there is a mechanical problem with the engine, for example, fluid in a cylinder, damage will be minimised because of the low starting speed and power.

c) The relatively slow build up to firing speed allows oil pressures to build in the fuel system and lubricating system. That allows more time for a lubricating oil wedge to form between bearings and j ournals .

As the multi-purpose drive system sources its power from mains power. This means that stored energy systems are not required. The reductions in cost, weight and space savings are significant, particularly for marine vessel applications. Stored energy, be it electricity in the form of batteries, compressed air or pressurised hydraulic oil all have to have systems in place to recharge the stored energy. Stored energy systems must start the engine quickly in order to preserve their starting capability.

In trials carried out to date for driving a marine diesel combustion engine, the multi-purpose drive system of the present invention enable an AC permanent magnet synchronous type motor 1 to be of a small size, by use of the programmable VSD controller (controller 3), and a reduction gear box inline before the Bendix™ gear (actuation gear 6) . The final drive ratio in the trial version was 40:1. This compares to about 11:1 in current DC systems for the same size diesel engine.

It should be noted that it is possible by means of using a notebook, laptop or other computer device, all the functions of the driving cycle can be logged and graphed. This notebook, laptop, or computer may be the same device that is used as mode selection device 20 in Fig 2, or may be a separate device. For example, in starting mode, the time of the starting sequence as a base can be compared against starting current; speed of the motor 1 (and therefore the engine 2)and speed called for from the controller 3. This can be interfaced with the engine management system so that starting current can be compared with crank angle from 0 to 720 degrees (this is for a four stroke engine as firing cycle takes two revolutions to complete and the engine management system must already know this information to control the injection timing). With this capability any abnormal starting load can be detected.

If the current drops for a particular cylinder this could indicate low compression i.e. a burnt out exhaust valve or worn rings. If the current increases it could be indicate a tight spot or some fluid leakage into the cylinder causing higher compression pressures.

Another function that may be graphed is a "diagnostic mode" of operation. In this diagnostic mode you may for example drive the engine at 50rpm and hold it there with no fuel being injected and compare the load against crank angle. This "diagnostic mode" would point to further investigation of the engine and which cylinders to investigate, if there were any abnormal readings. However, in order to include such a diagnostic mode it may require the co-operation of the engine manufacturer to interface its data, or alternatively use a separate crank angle sensor fitted to the engine. The latter would be required for non electronic engines.

The terms "comprising" and "including" (and their grammatical variations) as used herein are used in inclusive sense and not in the exclusive sense of "consisting only of.

Claims

CLAIMS:

1. A multi-purpose drive system for a combustion engine, said drive system comprising: an AC motor adapted to drive said combustion engine, said motor powered by an independent source of AC power; a motor controller arranged for regulating at least one functional parameter of said motor and/or combustion engine by controlling at least one operating characteristic of said motor; and a programmable supervising control system configured for controlling the driving engagement between said motor and said combustion engine in a plurality of selectable modes of operation of said drive system, each mode of operation being defined by stored reference values of the at least one operating characteristic of said motor, and at least one of said selectable modes of operation is a starting mode; wherein to drive said combustion engine in one of said modes of operation that has been selected, said supervising control system effects said driving engagement between said motor and said combustion engine, and provides the reference values, corresponding to the particular operation mode, to said motor controller so as to control the corresponding at least one operating characteristic of said motor and, therefore, said at least one functional parameter of said motor and/or combustion engine, according to that particular mode of operation .

2. A multi-purpose drive system as claimed in claim 1, said system further comprising a feedback arrangement arranged to obtain and provide feedback related to said at least one functional parameter and of said motor and/or said combustion engine to said motor controller, so as to facilitate fine-tuning of said operating characteristics of said motor based on feedback from said feedback arrangement.

3. A multi-purpose drive system as claimed in claim 2, wherein said supervising control system is arranged to receive from said motor controller information about at least one functional parameter of said motor and/ or said combustion engine, the information being based on information received from said motor controller from said feedback arrangement, so as to effect a predetermined event with said motor and/or said combustion engine when a predetermined functional parameter reaches a predetermined value.

4. A multi-purpose drive system as claimed in claim 3, wherein said supervising control system is arranged to receive information about said at least one functional parameter of said motor and/or said combustion engine from said motor controller so as to effect the disconnection of said motor from said combustion engine when said motor and/or said combustion engine reaches a predetermined speed.

5. A multi-purpose drive system as claimed in claim 1, wherein said starting mode includes increasing the speed of said motor at a predetermined rate of acceleration.

6. A multi-purpose drive system according to claim 1, wherein the at least one functional parameter comprises the speed and/or the angular position of said motor and/or said combustion engine.

7. A multi-purpose drive system as claimed in claim 1, wherein at least one of said selectable modes of operation of said drive system includes turning the engine slowly for pre-start lubrication.

8. A multi-purpose drive system as claimed in claim 7, wherein pre-start lubrication is achieved by delivering lubricant to the engine by an independently driven lubrication delivery system.

9. A multi-purpose drive system as claimed in claim 1, wherein at least one of said selectable modes of operation of said drive system includes turning the engine slowly prior to shut down for cooling purposes.

10. A multi-purpose drive system as claimed in claim 1, wherein at least one of said selectable modes of operation of said drive system includes turning the engine for extended periods at or near firing speeds for the purpose of bleeding fuel lines.

11. A multi-purpose drive system as claimed in claim 1, wherein said plurality of selectable operation modes, includes any one or more of lubrication mode, cooling down mode, fuel line bleed mode, a maintenance mode or a diagnostic mode.

12. A multi-purpose drive system as claimed in claim 1, wherein said system further comprising an actuation gear arranged to facilitate said driving engagement between said motor and said combustion engine, said actuation gear being controlled by said supervising control system.

13. A multi-purpose drive system as claimed in claim 12, wherein the actuation gear is arranged to provide feedback indicative of the status of the actuation gear to the supervising control system, so that the motor is started only when the actuation gear is fully engaged.

14. A multi-purpose drive system as claimed in claim I₅ wherein said operating characteristics includes one or more of the following set: synchronous frequency, applied voltage,¹ starting current, starting torque, pull-out torque and power factor.

15. A multi-purpose drive system as claimed in claim 1, wherein said motor is powered up by a pulse width modulated rectangular wave AC signal, said motor controller being arranged to vary at least the voltage and the frequency of the AC signal.

16. A multi-purpose drive system as claimed in claim I₅ wherein said combustion engine is a diesel engine.

17. A multi-purpose drive system according to claim 1, wherein said motor is of a permanent magnet synchronous type.

18. A multi-purpose drive system as claimed in claim I₅ wherein said motor controller is a variable speed drive controller.

19. A multi-purpose drive system for a diesel combustion engine, said drive system comprising: an AC motor adapted to drive said combustion engine, said motor powered by an independent source of AC power; a motor controller arranged for regulating the speed and/or angular position of said motor and/or combustion engine by varying at least the frequency and/or voltage of said motor; and a programmable supervising control system configured for controlling the driving engagement between said motor and said combustion engine in a plurality of selectable modes of operation of said drive system, each mode of operation being defined by stored reference values of the at least one operating characteristic of said motor, and said selectable modes of operation include at least a starting mode; wherein to drive said combustion engine in one of said modes of operation that has been selected, said supervising control system effects said driving engagement between said motor and said combustion engine, and provides the reference values, corresponding to the particular operation mode, to said motor controller so as to vary said frequency and/or voltage of said motor and, therefore, said speed and/or angular position of said motor and/or combustion engine, according to that particular mode of operation .

20. A multi-purpose drive system as claimed in claim 19, further comprising a feedback arrangement arranged to obtain and provide feedback related to said at speed and/or angular position and of said motor and/or said combustion engine to said motor controller, so as to facilitate fine-tuning of said frequency and/or voltage of said motor based on feedback from said feedback arrangement.

21. A multi-purpose drive system as claimed in claim 20, wherein said supervising control system is arranged to receive from said motor controller information about said speed and/or angular position of said motor and/or said combustion engine, the information being based on information received from said motor controller from said feedback arrangement, so as to effect a predetermined event with said motor and/or said combustion engine when a predetermined speed and/or angular position reaches a predetermined value.

22. A multi-purpose drive system as claimed in any one of claims 19 to 21, wherein said plurality of selectable operation modes, includes any one or more of a lubrication mode, a cooling down mode, a fuel line bleed mode, a maintenance mode or a diagnostic mode.