Title of Invention	"A METHOD OF CONTROLLING THE FUELLING RATE TO AN INTERNAL COMBUSTION ENGINE"
Abstract	A method of controlling the fuelling rate to an internal combustion engine during start-up of the engine comprising: determining whether the engine is started by way of a manual arrangement or by way of an automated starting means; and selecting an appropriate fuelling rate for the engine based on this determination.

Full Text

The present invention relates to a method of controlling the fuelling rate to an internal combustion engine. The present invention is directed at the control of the fuelling rate to an internal combustion engine at start-up of the engine. More particularly, the present invention is directed at controlling the fueling rate at start-up as a function of the particular mode of starting that is used for the engine. It is well known in the prior art for motorcycles and motorised scooters to use "kick start" arrangements to start the engine of the motor vehicle. Similarly, the use of "pull-start" arrangements for certain vehicles such as snowmobiles and all-terrain-vehicles (ATVs) and on other motorised equipment such as certain lawn mowers and other garden/industrial equipment is also well known. More recently, starter motors have also or alternatively been added to such engines as an alternative mode of starting the engine as compared to the aforementioned known "manual start" arrangements. As a result, it is not uncommon for motor-scooters or other vehicles which use the same or similar engine power-plants to be offered to buyers with one or the other mode of starting. Furthermore, it has also become commonplace for certain motor-scooters or other vehicles to be offered with both means to start the engine. In particular regard to this latter scenario, this provides a built in redundancy for the scooter or vehicle so that it can still be started using the manual start if the battery is dead or some other electrical problem exists such that the starter motor cannot be used to start the engine. It has been found however that the amount of fuel required during a kick or manual starting of an engine is typically significantly lower than the fuel required to start the engine using a starter motor. Such a manual starting has also been found to in general produce an initially faster rotational start speed. In some vehicle applications where both modes of starting are provided for the engine, it has been found that as little as 1/3 of the fuel required for starter motor starting is required for satisfactory manual starting via a kick or pull-start arrangement. Accordingly, if a respective engine management system is programmed to provide a fuelling rate sufficient for a starter motor start-up, then excessive fuel would be provided to the engine if a kick start arrangement is instead used to start the engine. This can result in flooding of the engine resulting in engine starting difficulties. Furthermore, and in light of the fact that significantly different levels of fuelling are typically required for starter motor versus manual start modes of starting, it may be very difficult to program the engine management system to provide a suitable compromised fuelling rate for start-up that would be acceptable for both manual start and starter motor modes of starting. It is therefore an object of the present invention to provide a method of determining the mode of starting for an internal combustion engine and controlling the fuelling rate during engine start-up based on this determination. With this in mind, according to one aspect of the present invention, there is provided a method of controlling the fuelling rate to an internal combustion engine during start-up of the engine including: a) determining whether the engine is started by way of a manual arrangement or by way of an automated starting means; and b) selecting an appropriate fuelling rate for the engine based on this determination. There is also provided according to another aspect of the present invention, a method of determining the mode of starting for an internal combustion engine including: (a) determining whether the engine is started by way of a manual arrangement or by way of an automated starting; means; and (b) providing an appropriate fuelling rate to the engine during start-up based on this determination. More particularly, according to a further aspect of the present invention, there is provided a method of controlling the fuelling rate to an internal combustion engine during engine start-up based on a determination of the mode of starting used for the engine, the engine having a battery operatively associated therewith, and the method including: a) detecting if there is a drop in the voltage across the battery during engine start-up; (b) providing a fuelling rate to the engine suitable for a manual start of the engine if there is no effective drop in the battery voltage; and (c) providing a fuelling rate to the engine suitable for an automated start of the engine if there is an effective drop in the battery voltage. Preferably, a "manual start" of the engine equates to the use of a "kick start" arrangement to start the engine. Conveniently, a "manual start" of the engine may also or alternatively equate to the use of a "pull-start" arrangement to start the engine. Preferably, an "automated starting means" equates to an electrical means such as starter motor or like device. Typically, a starter motor needs to be provided with current from the battery at start-up leading to a drop in the battery voltage during engine starting. Hence, this battery current flow or voltage drain is one means of providing an indication that a starter motor is being used. The use of a kick or pull-start arrangement to start the engine however typically does not require any current from the battery, and there is therefore no drop in the battery voltage when such a manual start is used. The battery voltage that is measured is typically the unfiltered battery voltage as could be read across the terminals of the battery by way of a sensor of a suitable engine management system. The engine is typically operatively arranged within a motor-scooter or other suitable vehicle or device which includes a key operated ignition switch. Where a starter motor is arranged as the or one of the means for starting the engine, the vehicle or motor-scooter generally also includes a starter button or switch to actuate the starter motor and the operator must initially turn the ignition on before pressing the starter button. Conveniently, the engine management system measures the initial battery voltage once the ignition switch has been turned on and prior to starting of the engine. The engine management system becomes aware of the impending startup of the engine when the starter button is activated or a manual start arrangement is used. Upon or subsequent to the commencement of engine rotation, the engine management system then measures the prevailing battery voltage. Preferably, the difference or delta between the initial battery voltage and the prevailing battery voltage subsequent to the commencement of engine rotation is compared against a predetermined threshold battery voltage value. The threshold value is conveniently selected so as to clearly provide an indication of the mode of starting that is being used for the engine. Where delta is less than the threshold value, the engine management system determines that a manual start arrangement is being used to start the engine and thus selects a first low fuelling level for the engine. Where delta is greater than the threshold value (ie. as a result of a drain or drop in the battery voltage), the engine management system determines that a starter motor is being used to start the engine and thus selects a second higher fuelling level for the engine. Conveniently, the engine management system may be initially set to provide an amount of fuel suitable for a manual or kick start of the engine. However, if a drop in the battery voltage is detected during start-up, then the engine management system may reset the amount of fuel to be provided to the engine such that the amount is suitable for a starter motor start-up of the engine. In this way, the minimum fuelling level at start-up is used unless it is determined a starter motor or like device is being used. The engine management system may typically include an electronic control unit (ECU) for controlling the fuelling rate to the engine and the timing of the ignition and fuel delivery to the engine. One advantage of the method according to the present invention is that the ECU can detect the change in battery voltage at start-up, and hence there is no need to provide additional hardware on the engine to determine the mode of starting which is used. That is, the method is typically able to be implemented by way of code or software in the ECU. A further advantage of the present invention is that, to a certain extent, the same engine management system and/or ECU are able to be used across a range of vehicle applications where a first group of vehicles only incorporate one mode of starting for the engine and a second group of vehicles only incorporate the other mode of starting for the engine. Scooter engines and other vehicle engines typically include crankshaft position sensing means for determining engine speed and the crankangle of the engine. Such means typically include a toothed encoder disc or wheel arranged on the crankshaft and a corresponding sensor to provide encoder tooth signals to the ECU as the crankshaft rotates. In respect of the present invention, the battery voltage may be timed to be measured at a predetermined tooth occurrence following start-up of the engine. For a typical scooter arrangement, the battery voltage may for example be measured at the occurrence of the first or second tooth after the start of engine rotation. In certain arrangements, the second tooth can be chosen to avoid any erroneous signals, due to rocking of the scooter while stationary or other movement not associated with the engine operation. Otherwise, the first tooth can be used to help ensure that the correct amount of fuel for start-up is determined as soon as possible. The method according to the present invention therefore ensures that the engine management system of a scooter or other vehicle having both a kick start arrangement and an electrical starter motor is able to provide the correct fuelling level to the engine during engine start-up. As alluded to hereinbefore, it should however be appreciated that the ECU of the engine management system programmed to achieve the method according to the present invention could be equally used on a scooter or other vehicle only having a kick start or only having a starter motor starting means. This, for example, means that it is not necessary to use different ECUs for differently set up scooters. Conveniently, the method of the present invention is employed on fuel injected engines and in particular direct fuel injected engines. More particularly, the method is conveniently implemented on dual fluid or air-assist fuel injected engines wherein a compressed gas, typically air, is used to entrain and deliver a metered quantity of fuel into one or more combustion chambers of the engine. In such dual fluid fuel injection systems, it is known to assist in pressurising a gas chamber or rail of the fuel injection system during engine start-up by delivering pressurised gas from within a combustion chamber or cylinder into the gas rail. Typically, a delivery injector associated with the cylinder is opened at an appropriate time in the cylinder cycle so that compressed gas within the cylinder can flow through the open injector and into the gas rail to increase the gas pressure therein. Various "pump-up" methods of this type are disclosed in the Applicant's US Patent No's. 4936279 and 6164268, the contents of which are incorporated herein by way of reference. Conveniently, the method of the present invention is employed together with a pump-up strategy for pressurising a gas rail or chamber of a dual fluid fuel injection system at engine start-up. Conveniently, the pump-up strategy includes a predetermined plurality or sequence of pump-up events which are effected upon start-up of the engine. Preferably, upon detecting that there is a drop in voltage across the battery during engine start-up, the sequence of pump-up events is re-initialised. That is, when a determination is made that an automated starting means is being used to start the engine, the complete sequence of pump-up events is used to ensure that sufficient gas pressure is developed in the gas rail to support the subsequent delivery of fuel. Preferably, upon detecting that there has not been an effective drop in voltage across the battery during engine start-up, the sequence of pump-up events is continued from where it last finished. That is, when a determination is made that a manual staring arrangement is being used to start the engine, the sequence of pump-ups is not pre-initialised. This avoids the need to go through a full pump-up sequence upon every manual start attempt and hence avoids the situation where fuel may never be injected (ie. as only a finite number of engine revolutions typically result from a kick or pull-start event and some fuel needs to be delivered and combusted during these finite number of cylinder cycles to try and get the engine to fire). According to yet another aspect of the present invention there is provided an electronic control unit (ECU) for controlling the fuelling rate to an internal combustion engine during start-up of the engine, the ECU determining whether the engine is started by way of a manual starting arrangement or by way of an automated starting means and then selecting an appropriate fuelling rate for the engine based on this determination. According to a further aspect of the present invention, there is provided an electronic control unit (ECU) for determining the mode of starting for an internal combustion engine including the ECU determining whether the engine is started by way of a manual starting arrangement or by way of an automated starting means; such that an appropriate fuelling rate is then provided to the engine during start-up based on this determination. According to another aspect of the present invention, there is provided an electronic control unit (ECU) for controlling the fuelling rate to an internal combustion engine during engine start-up based on a determination of the mode of starting used for the engine, the engine having a battery operatively associated therewith, and the ECU including: (a) means for detecting if there is a drop in the voltage across the battery during engine start-up; (b) means for providing a fuelling rate to the engine suitable for a manual start of the engine if there is no effective drop in the battery voltage; and (c) means for providing a fuelling rate to the engine suitable for an automated start of the engine if there is an effective drop in the battery voltage. It will be convenient to further describe the invention with respect to the accompanying drawing which illustrates one possible embodiment of the method according to the present invention. Other embodiments of the invention are of course possible, and consequently, the particularity of the accompanying drawing is not to be understood as superceding the generality of the preceding description of the invention. The drawing depicts a flow diagram showing the operational sequence followed by an ECU of an engine management system to determine the fuelling level required at start-up of the engine. The ECU initially detects when the ignition switch of the engine is turned to the "on" position (step 1). Knowing that the ignition is on, the ECU measures the initial battery voltage (V1) (step 2), this being the voltage read across the terminals of the battery prior to any rotational movement of the engine. By way of signals received from the crankshaft position sensor, the ECU is then able to determine that engine rotation has commended (step 3) and can hence proceed to make a determination of which mode of starting has been used. As alluded to hereinbefore, the crankshaft position sensor forms part of the overall engine management system and typically includes a toothed encoder wheel arranged on the crankshaft and a corresponding sensor. Measurement of the crankshaft position can typically occur as soon as a first encoder tooth is detected by the sensor following commencement of engine rotation or movement. With the engine management system aware of an impending start-up of the engine, the ECU makes a further measurement of the battery voltage (V2) (step 4) in order to enable a comparison between the prevailing battery voltage (V2) and the initial battery voltage (V1). This comparison is effected by the ECU then determining whether the difference in measured battery voltages (V1-V2) (step 5) is greater than a predetermined or threshold value (step 6). In this way, the ECU is able to assess whether the battery has experienced a voltage drain or drop due to actuation of a starter motor. The predetermined or threshold value may simply be the battery voltage immediately prior to the start-up sequence of the engine (ie V1). Alternatively, the threshold value may be set at some other suitable level which would enable a clear distinction to be made between different modes of starting for the engine. If the difference in the battery voltages (ie. Delta) is less than the predetermined value, then the ECU determines that the fuelling level to be supplied to the engine during the start-up sequence is that required for a manual or kick start (step 7). However, if the difference in the battery voltages or the Delta is greater than the predetermined value, then the ECU determines that the fuelling level to be supplied to the engine during the start-up sequence is that required for start-up using a starter motor (step 8), this fuelling level being higher than that supplied in respect of a kick start. Depending upon the selection of the threshold value, it is also possible for the ECU to proceed to step 7 (ie. fuelling level to be supplied is that required for engine starting via a kick start) where the difference in the battery voltages (ie. Delta) is equal to the threshold value. Hence, by way of the present invention, an appropriate fuelling rate is able to be provided to the engine at start-up based on whether one mode of starting is used over a different mode of starting. This hence enables improved and more reliable starting. Monitoring battery voltage is one preferred way of distinguishing between different modes of starting for the engine, but it is to be appreciated that other methods may also be implemented. For example, the provision of suitable sensors operatively arranged with respect to the kick start arrangement and starter motor where both are implemented on a scooter or vehicle is perhaps a different way by which the fuelling level at start-up can be determined based on the mode of starting that is used. In relation to the use of battery voltage to determine the particular mode of starting which is used, it is to be appreciated that the predetermined value could also relate to, for example, a range of values to take into account the change in battery voltage over the life of the battery. Similarly, the predetermined value could be selected or adapted so as to offer a certain level of compensation for situations where the scooter or vehicle is operated at temperatures significantly colder than normal. The method of the present invention is particularly suited for use with fuel injected engines and in particular direct fuel injected engines. However, it is to be appreciated that the invention is equally applicable to engines which are not fuel injected and regardless of whether the engines are of the 4-stroke or 2-stroke type. Furthermore, whilst in the main described with respect to motor-scooter and other vehicles, the method may be applicable to a wider spectrum of engine applications where there is a requirement to have pull-start or kick-start as an option for starting the engine. As alluded to hereinbefore, the method of the present invention may be used in conjunction with a suitable pump-up strategy as may be desirous for an engine equipped with a two fluid or air assisted fuel injection system. Examples of such a two fluid fuel injection system and different pump-up strategies are disclosed in the Applicant's US Patent No's. 4936279 and 6164268, the contents of which are included herein by way of reference. The main purpose of such a pump-up strategy is to ensure that, following engine start-up, fuel may be subsequently transported with sufficient air/gas pressure into the engine cylinders for combustion to occur when the first fuel injection event occurs. Where the particular pump-up strategy implemented in such a two fluid fuel injection system involves a sequence for pressure pump-up events, it has been found that certain slight modifications may be desirable to the pump-up strategy depending on whether a manual starting arrangement or automated starting means is implemented to start the engine. Typically, a prime pump-up event is one where the sole purpose is to increase the pressure in a gas or air rail and hence fuel is not injected into a cylinder during the cylinder cycle. The pump-up strategy would generally be one which includes a predetermined plurality or sequence of such pressure pump-up events. Hence, no fuel would typically be delivered to the engine until the full sequence of prime pump-up events has been completed and thus resulted in the attainment of a certain level of pressurisation of a gas or air rail of the two fluid fuel injection system. However, in light of the fact that a typical kick or pull-start event will only result in a finite number of engine revolutions, there is some risk of never injecting fuel if the prime pump-up sequence is re-initialised for every kick or pull-start event. Accordingly, upon detecting that a manual starting arrangement is being used (step 7), the ECU of the engine management system may be programmed to ensure that the pressure pump-up sequence, which is generally a one-way sequence, is only performed once per power up (ie. after ignition is switched "ON" as at step 1). In this way, if a first kick or pull-start event only enables, for example, half of the pump-up sequence to be completed during the few engine revolutions which have resulted, the rest of the pump-up sequence will then be continued upon the next kick or pull-start event. That is, following the ignition being switched to "ON", the pump-up sequence is only effected from its starting point once if a manual starting arrangement is used. Conversely, where it is detected that an automated starting means is being used to start the engine (step 8), the ECU may be programmed to ensure that the pressure pump-up sequence is re-initialised each time a start event occurs. Hence, the complete sequence of pump-up events will be re-initiated each time an electrical starter motor or like device is used to start the engine, regardless of how many start events are required to start the engine. In this way, it is ensured that there is sufficient pressure in the gas or air rail of the two fluid fuel injection system to effect subsequent fuel delivery and hence provide a better chance for the engine to fire. This is particularly beneficial where several start events may be required as a previous failed starting attempt may have depleted the air pressure in the gas or air rail in the process of trying to achieve engine starting and/or start combustion. Modifications and variations as would be deemed obvious to the person skilled in the art are included within the ambit of the present invention as defined in the appended claims. We claim: 1. A method of controlling the fuelling rate to an internal combustion engine during start-up of the engine comprising: determining whether the engine is started by way of a manual arrangement or by way of an automated starting means; and selecting an appropriate fuelling rate for the engine based on this determination. 2. A method as claimed in claim 1, wherein the engine has a battery operatively associated therewith, the mode of starting being determined by detecting any drop in the voltage across the battery during engine start-up. 3. A method of determining the mode of starting for an internal combustion engine comprising: a) determining whether the engine is started by way of a manual arrangement or by way of an automated starting means; and b) providing an appropriate fuelling rate to the engine during start-up based on this determination. 4. A method as claimed in claim 3, wherein the engine has a battery operatively associated therewith, the mode of starting being determined by detecting any drop in the voltage across the battery during engine start-up. 5. A method of controlling the fuelling rate to an internal combustion engine during engine start-up based on a determination of the mode of starting used for the engine, the engine having a battery operatively associated therewith, and the method comprising: (a) detecting if there is a drop in the voltage across the battery during engine start-up; (b) providing a fuelling rate to the engine suitable for a manual start of the engine if there is no effective drop in the battery voltage; and (c) providing a fuelling rate to the engine suitable for an automated start of the engine if there is an effective drop in the battery voltage. 6. A method as claimed in claim 5, wherein the battery voltage that is measured is the unfiltered battery voltage as read across terminals of the battery. 7. A method as claimed in claim 5 or 6, wherein the difference between an initial battery voltage and a prevailing battery voltage subsequent to the commencement of engine rotation is compared against a predetermined threshold battery voltage value, such that when the difference is less than the threshold value, a first fuelling rate suitable for said manual start is provided to the engine, and such that when the difference is greater than the threshold value, a second higher fuelling rate suitable for said automated start is provided to the engine. 8. A method as claimed in any one of claims 5 to 7, including initially setting the fuelling rate to the engine at the amount suitable for said manual start of the engine and resetting the fuelling rate to the amount suitable for said automated start of the engine if a drop in voltage across the battery is detected. 9. A method as claimed in claim 7, wherein the threshold battery voltage value is varied depending on at least operating parameter of the battery including the age of the battery or the ambient temperature. 10. A method as claimed in any one of claims 5 to 7, the engine having a crankshaft position sensing means, the battery voltage being measured at a predetermined crankshaft position following start-up of the engine. 11. A method as claimed in any one of the preceding claims, the engine having a dual fluid fuel injection system, and the method being implemented in conjunction with a pump-up strategy for pressurising a gas rail of the dual fluid injection system upon engine start-up. 12. A method as claimed in claim 11, wherein the pump-up strategy has a predetermined sequence of pump-up events which are effected upon start-up of the engine. 13. A method as claimed in claim 12, wherein upon detecting a drop in voltage across the battery during engine start-up, the sequence of pump-up events is re-initialised. 14. A method according to claim 12, wherein upon detecting no effective drop in voltage across the battery during engine start-up, the sequence of pump-up is not re-initialised. 15. An electronic control unit (ECU) for controlling the fuelling rate to an internal combustion engine during start-up of the engine, the ECU determining whether the engine is started by way of a manual starting arrangement or by way of an automated starting means and then selecting an appropriate fuelling rate for the engine based on this determination. 16. An electronic control unit (ECU) for determining the mode of starting for an internal combustion engine including the ECU determining whether the engine is started by way of a manual starting arrangement or by way of an automated starting means such that an appropriate fuelling rate is then provided to the engine during start-up based on this determination. 17. An electronic control unit (ECU) for controlling the fuelling rate to an internal combustion engine during engine start-up based on a determination of the mode of starting used for the engine, the engine having a battery operatively associated therewith, and the ECU comprising: (a) means for detecting if there is a drop in the voltage across the battery during engine start-up; (b) means for providing a fuelling rate to the engine suitable for a manual start of the engine if there is no effective drop in the battery voltage; and (c) means for providing a fuelling rate to the engine suitable for an automated start of the engine if there is an effective drop in the battery voltage.

Documents:

1130-DELNP-2003-Abstract-(16-07-2008).pdf

1130-delnp-2003-abstract.pdf

1130-DELNP-2003-Claims-(16-07-2008).pdf

1130-delnp-2003-claims.pdf

1130-DELNP-2003-Correspondence-Others-(16-07-2008).pdf

1130-delnp-2003-correspondence-others.pdf

1130-delnp-2003-description (complete)-16-07-2008.pdf

1130-delnp-2003-description (complete).pdf

1130-DELNP-2003-Drawings-(16-07-2008).pdf

1130-delnp-2003-drawings.pdf

1130-DELNP-2003-Form-1-(16-07-2008).pdf

1130-delnp-2003-form-1.pdf

1130-delnp-2003-form-18.pdf

1130-DELNP-2003-Form-2-(16-07-2008).pdf

1130-delnp-2003-form-2.pdf

1130-DELNP-2003-Form-3-(16-07-2008).pdf

1130-delnp-2003-form-3.pdf

1130-delnp-2003-form-5.pdf

1130-DELNP-2003-GPA-(16-07-2008).pdf

1130-delnp-2003-pct-101.pdf

1130-delnp-2003-pct-210.pdf

1130-delnp-2003-pct-304.pdf

1130-delnp-2003-pct-401.pdf

1130-delnp-2003-pct-402.pdf

1130-delnp-2003-pct-408.pdf

1130-delnp-2003-pct-409.pdf

1130-delnp-2003-pct-416.pdf

1130-DELNP-2003-Petition-137-(16-07-2008).pdf

1130-DELNP-2003-Petition-138-(16-07-2008).pdf