Title of Invention

OPERATING CONDITION DETERMINATION APPARATUS FOR INTERNAL COMBUSTION ENGINES

Abstract

Intake pressure in an intake passage (2) is detected at a plurality of different predetermined crank angles set outside an intake stroke in one combustion cycle of an engine (1). An acceleration/deceleration condition and a steady-state condition of the engine (1) are determined based on the amount of change between a preceding intake pressure and a present intake pressure detected at the same crank angle. Thus, even if no throttle angle sensor is used, there is a plurality of time points of detecting the intake pressure in one combustion cycle of the engine (1). The operating condition is determined from the pressure change in other than the intake stroke. (Fig. 1 for Publication)

Full Text

The present invention relates to an operating condition determination apparatus for internal combustion engines that determines operating conditions of engines for use in, for instance, controlling fuel injection and ignition. BACKGROUND OF THE INVENTION It is known to determine operating conditions of an internal combustion engine by detecting changes of throttle angles of a throttle valve which regulates the intake air to the engine, and correct, for instance, injection amount of fuel or ignition time point. The throttle angle is detected by a throttle angle sensor coupled with the throttle shaft of the throttle valve. The operating conditions of the engine can be determined based on the amount of change of the throttle angle in the case that the system is constructed to detect the throttle angle by the throttle angle sensor. A considerable cost reduction can be attained in the case that the system is constructed in a simplified structure in which no expensive throttle angle sensor is used. Here, a change amount of intake pressure is effective as an alternative to determine the operating conditions of the engine without using the throttle angle sensor. It is known that the intake pressure changes largely in the intake stroke among the intake, compression, power (explosion) and exhaust strokes of the engine. Therefore, if the operating condition of the engine is determined based on the intake pressures detected at predetermined detection time points in the intake stroke in one combustion cycle of the engine, the operating condition can be determined easily because of large amounts of changes. However, the operating condition is likely to be determined erroneously, if the detection time points vary and the error of change amounts increases- SUMMARY OF THE INVENTION It is an object of the present invention to provide an operating condition determination apparatus for internal combustion engines that is capable of quickly and accurately determining operating conditions of an engine without using throttle angle sensors. According to the present invention, intake pressure in an intake passage is detected at a plurality of predetermined crank angles in one combustion cycle of an engine, and an acceleration/deceleration condition and a steady-state condition of the engine is determined from the amount of change between a preceding intake pressure and a present intake pressure that are detected at the same crank angle or same crank angle time point. Thus, because the intake pressure is detected a plurality of times in one combustion cycle of the engine, the operating condition of the engine can be determined quickly. Preferably, the predetermined crank angle or crank angle time point is set at an angle outside an intake stroke, that is. in the compression stroke, power stroke or exhaust stroke. Thus, because the detection time point is set in the compression stroke, power stroke or exhaust stroke, errors of the change amounts caused by variations of the intake pressure detection time points can be reduced in comparison with the detection in the intake stroke. More preferably, the acceleration/deceleration condition or the steady-state condition of the engine is determined from a sum of each change amount between the preceding intake pressure and the present intake pressure detected at each of the plurality of predetermined crank angles. BRIEF DESCRIPTION OF THE DRAWINGS The above and other objects, features and advantages of the present invention will become more apparent from the following detailed description made with reference to the accompanying drawings. In the drawings: Fig. 1 is a schematic diagram showing an engine and its peripheral devices to which an operating condition determination apparatus for internal combustion engines according to the first embodiment of the present invention is applied; Fig. 2 is a time chart showing a transition condition of intake pressure in the acceleration condition of the engine; Fig. 3 is a flow chart showing fuel injection correction coefficient calculation routine executed in the first embodiment; Fig. 4 is a flow chart showing fuel injection correction coefficient calculation routine executed in correspondence with an acceleration condition of the engine in the first embodiment; Fig. 5 is a flow chart showing fuel injection correction coefficient calculation routine executed in correspondence with a deceleration condition of the engine in the first embodiment; Fig. 6 is a flow chart showing fuel injection correction coefficient calculation routine executed in correspondence with a steady-state condition of the engine in the first embodiment; Fig- 7 is a flow chart showing fuel injection correction coefficient calculation routine executed in the second embodiment of the present invention; and Fig. 8 is a flow chart showing fuel injection correction coefficient calculation routine executed in the third embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT [First Embodiment] Referring to Fig. 1, a single-cylinder water-cooled engine is designated with numeral 1. Air is drawn into an intake passage 2 of the engine 1 from an air cleaner 3. A throttle valve 11, which is opened and closed in correspondence with the operation of an accelerator pedal (not shown), is provided in the midway of the intake passage 2. The amount of intake air into the intake passage 2 is varied with opening and closing of the throttle valve 11. In addition to the intake air, fuel is injected in the engine 1 from an injector (fuel injection valve) 5 provided near an intake port 4 in the intake passage 2. Mixture of fuel and air is taken into a combustion chamber 7 through an intake valve 6. Further, an intake pressure sensor 21 is provided downstream the throttle valve 11 provided in the midway of the intake passage 2 to detect intake pressure PM in the intake passage 2. A crank angle sensor 22 is provided near the crankshaft 12 of the engine 1 to detect crank angles [°CA] corresponding to crankshaft rotation The engine rotation speed NE of the engine 1 is calculated based on crank angle signals generated by the crank angle sensor 22. Further, a coolant temperature sensor 23 is provided on the engine 1 to detect coolant temperature THW, An ignition plug 13 is provided in a direction to the combustion chamber 7 of the engine. A high voltage is applied to the ignition plug 13 from an ignition coil/igniter 14 in response to an ignition command signal generated form an electronic control unit (ECU) 30 in synchronization with the crank angle detected by the crank angle sensor 22, so that the mixture in the combustion chamber 7 is ignited for combustion- When the mixture in the combustion chamber 7 is combusted (exploded) to produce a driving force, and the exhaust gas after the combustion is exhausted from an exhaust manifold through an exhaust valve 8 to an exhaust passage 9 and then outside. The ECU 3 0 is constructed as a logic arithmetic circuit that includes a CPU 31 for executing various calculation routine, a ROM 3 2 for storing a control program, a RAM 32 for storing various data, a B/U (back-up) RAM 34, an input/output circuit 35, a bus line 36 for connecting those circuit components, and the like. The intake pressure PM detected by the intake pressure sensor 21, the crank angle detected by the crank angle sensor 22, the coolant temperature THW detected by the coolant temperature sensor 23 and the like are applied to the ECU 30. In accordance with the output signals of the ECU 30 produced based on those various sensor information, the time point and amount of fuel injection of the injector 5, the time point of ignition by an ignition plug 13 controlled by a coil/igniter 14, and the like are appropriately controlled. The ECU 30, particularly CPU 31, is programmed to execute various processing including fuel injection correction coefficient calculation routine shown in Figs. 2 and 4 to 6 with regard to fuel injection control. This calculation routine is executed repeatedly by the CPU 31 at every interrupt synchronized with the crank angle signal generated by the crank angle sensor 22. As shown in Fig. 2, in the acceleration condition, the intake pressure PM [kPa (kilo Pascal)] of the engine 1 changes in the increasing direction. Although not shown, in the deceleration condition, the intake pressure PM [kPa] changes in the decreasing direction opposite to the acceleration condition. Here, "n" of PMn and APMn means 1, 2, 3, that is, PMl, APMl, PM2, APM2, PM3, APM3. As shown in Fig. 2, the predetermined crank angle is set to a [°CA] in the compression stroke, P [°CA] in the power stroke and Y [°CA] in the exhaust stroke relative to the reference crank angle in other than the suction stroke of the engine 1, that is, to three different crank angles in one combustion cycle (intake, compression, power and exhaust). The ECU 30, particularly CPU 31 is programmed to execute various control routines including fuel injection correction coefficient calculation routine shown in Figs. 3 to 6. Referring to Fig. 3, it is first determined at step 101 whether it is the detection timing of the intake pressure PMn. At this step^ specifically, it is determined which one of the predetermined crank angles a, p and Y [°CA] which are detection time points of the intake pressure PMl (PMlO), PM2 {PM20) and PM3 (PM30) shown in Fig. 2. If the determination result is NO at step 101, that is, it is other than the predetermined crank angles a, p and Y [°CA] which are the detection time points of the intake pressure PMn, the execution of this routine ends. On the other hand, if the determination result is YES at step 101, that is, it is either one of the predetermined crank angles a, p and Y [°CA] which are the detection time points of the intake pressure PMn, the processing proceeds to step 102 to read the intake pressure PMn at that time. Then at step 103, an intake pressure change APMn is calculated by subtracting the preceding intake pressure PMnO stored in the RAM 33 from the present intake pressure PMn read in at step 102. Then at step 104, it is determined whether the intake pressure change APMn calculated at step 103 is more than a threshold A in the positive side for the deteinnination of acceleration. It is thus determined whether the intake pressure change APMn shown in Fig. 2 has changed largely to the positive side in excess of the positive-side threshold A. If the determination result at step 104 is YES, that is, the intake pressure change APMn has changed largely to the positive side in excess of the positive-side threshold A, the correction coefficient calculation routine is executed in accordance with the acceleration condition of the engine 1 at step 105 as described below. On the other hand, if the determination result of step 104 is NO, that is, if the intake pressure change APMn is less than the positive-side threshold A, the processing proceeds to step 106 and determines whether the intake pressure change APMn is less than a negative-side threshold B for the determination of deceleration. If the determination result of step S106 is YES, that is, the intake pressure change APMn has changed largely to the negative side in excess of the negative-side threshold B, the processing proceeds to step 107 to execute the correction coefficient calculation in accordance with the deceleration condition. On the other hand, if the determination result of step 106 is NO, that is, if the on the more positive side than the negative-side threshold B, in other words, the intake pressure change APMn changes between the positive-side threshold A and the negative-side threshold B, the processing proceeds to step 108 and executes the correction coefficient calculation routine based on the steady-state condition of the engine 1. After step 105, S107 or S108, the processing proceeds to step 109 to update the preceding intake pressure PMnO by storing the present intake pressure PMn in the RAM 33, thus ending this routine. After the processing of this routine, a basic fuel injection amount which is calculated in the known manner based on the engine rotation speed NE and the intake pressure PMn of the engine 1 in a main routine (not shown) is corrected with either one of fuel injection correction coefficients corresponding to the acceleration/deceleration condition or the steady-state condition of the engine, so that the injection amount of fuel actually injected from the injector 5 is regulated. In the case of the acceleration condition, the fuel injection correction coefficient is calculated as shown in Fig. 4 in correspondence with the acceleration condition of the engine 1. At step 201, an acceleration fuel increasing correction coefficient FACC is calculated by multiplying the intake pressure change APMn by a predetermined conversion gain C and adding a correction value D which is set in accordance with parameters such the engine rotation speed NE and the coolant temperature THW, Then at step 202, an asynchronous injection correction coefficient TIASY is calculated by multiplying the pressure change APMn by a predetermined conversion gain E and adding a correction value F which is set in accordance with the parameters such the engine rotation speed NE and the coolant temperature THW. In the case of the deceleration condition, the fuel injection correction coefficient is calculated as shown in Fig. 5 in correspondence with the deceleration condition of the engine 1. At step 301, it is determined whether the intake pressure change APMn is less than a negative-side threshold G. This negative-side threshold G is set to be larger in the negative side than the negative-side threshold B used at step 106 in Fig. 3. If the determination result of step 3 01 is YES, that is, the intake pressure change APMn changes to the negative side in excess of the negative-side threshold G, the processing proceeds to step 302. Thus, the engine 1 is determined to be in the large deceleration condition and the supply of fuel is cut off, thereby ending this routine-On the other hand, if the determination result of step 301 is NO, that is, the intake pressure change APMn is on the more positive side than the negative-side threshold G and is not so large in the negative side, the engine 1 is determined to be in the normal deceleration condition and the processing proceeds to step 303. A deceleration fuel decreasing correction coefficient FDEC is calculated by multiplying the intake pressure change APMn by a predetermined conversion gain H and adding a correction value I set in accordance with parameters such as the engine rotation speed NE and the coolant temperature THW, thus ending this routine • In the case of the steady-state condition, the fuel injection correction coefficient is calculated as shown in Fig. 6 in correspondence with the steady-state condition of the engine 1. At step 401, it is determined whether the fuel supply is being cut off. If the determination result of step 401 is YES, that is, it is in the fuel cut-off condition, processing of returning from the fuel cut-off is executed. On the other hand, if the determination result of step 401 is NO, that is, it is not the fuel cut-off condition, the processing skips step 402. Then at step 4 03, it is determined whether the acceleration fuel increasing correction coefficient FACC stored in the RAM 33 is larger than 0 (zero). If the determination result of step 403 is YES, that is, the acceleration fuel increasing correction coefficient FACC is larger than 0, the processing proceeds to step 404 so that the acceleration fuel increasing coefficient FACC is updated by multiplying the acceleration fuel increasing correction coefficient FACC by a predetermined gain J and subtracting a correction value K which is set in accordance with parameters such as the engine rotation speed NE and the coolant temperature THW. On the other hand, if the determination result of step 403 is NO, that is, the acceleration fuel increasing coefficient FACC is 0, the processing skips step 404. Then at step 405, it is determined whether the deceleration fuel decreasing correction coefficient FDEC stored in the RAM 33 is larger than 0 (zero). If the determination result of step 405^is YES, that is, the deceleration fuel decreasing correction coefficient FDEC is larger than 0, the processing proceeds to step 406 so that the deceleration fuel decreasing coefficient FDEC is updated by multiplying the deceleration fuel decreasing correction coefficient FDEC by a predetermined gain L and subtracting a correction value M which is set in accordance with parameters such as the engine rotation speed NE and the coolant temperature THW. On the other hand, if the determination result of step 405 is NO, that is, the deceleration fuel decreasing coefficient FDEC is 0, the processing skips step 406 and ends this routine. According to the first embodiment, the intake pressure PMn in the intake passage 2 is detected at the crank angle corresponding to the detection time point among a plurality of different crank angles a, p, y [°CA] in one combustion cycles of the engine 1. The acceleration/deceleration condition or the steady-state condition of the engine 1 is determined based on the change amount APMn between the preceding intake pressure PMnO and the present intake pressure PMn detected at the same crank angle. Thus, as there is a plurality of detection time points (a, (3, y) of detecting the intake pressure in one combustion cycle of the engine 1, the operating condition of the engine 1 can be determined quickly. Further, the predetermined crank angles a, p, y [°CA] of the operating condition determination apparatus according to the present embodiment is set in the compression stroke, the power stroke and the exhaust stroke other than the intake stroke, respectively. As the time points of detecting the intake pressure are set in the compression stroke, the power stroke and the exhaust stroke other than the intake stroke, error in the change amount due to variations in the time points of detecting the intakepressure can be reduced. Thus, even if the system is constructed simply without us ing a throttle angle sensor, it can be determined accurately whether the engine 1 is in the acceleration/deceleration condition or in the steady-state condition. In the above embodiment, it is determined whether the engine 1 is in the acceleration/deceleration condition or the steady-state condition based on one change amount of each intake pressure APMl, APM2 and APM3 detected at the detection time points among the intake pressures PMl, PM2 and PM3 detected at crank angles a, P, y [°CA] in one combustion cycle of the engine 1. However, the determination may be made by using a plurality of the intake pressure change, for instance, by using a sum of the change amounts of intake pressures. In the case of using the sum of change amounts, the determination of the operating condition of the engine 1 is delayed a little. However, the determination becomes more accurate and more appropriate fuel injection correction coefficient can be determined based on the sum of change amounts. [Second Embodiment] In the second embodiment, the correction coefficient calculation routine is executed repeatedly at every interrupt in synchronism with the crank angle signal generated by the crank angle sensor 22. Specifically, as shown in Pig. 7, the intake pressure PM at the same crank angle is read at step 501. Then at step 502, the intake pressure PM read in at step 501 is stored in a latest intake pressure storage area of the RAM 33 as the present intake pressure PMa. Then at step 503, determination is made whether it is the acceleration/deceleration determination time point. This acceleration/deceleration determination time point means a plurality of different crank angles predetermined in one combustion cycle of the engine 1. If the determination result of step 503 is NO, that is, it is not the acceleration/deceleration determination time point, this routine is terminated without executing any other steps. On the other hand, if the determination result of step 503 is YES, that is, it is the acceleration/deceleration determination time point, the processing proceeds to step 504 so that the intake pressure change APM is calculated by subtracting the preceding intake pressure PMb from the present intake pressure PMa. The intake pressure PMa is a value that is stored in the latest intake pressure storage area of the RAM 33 at step 502, and the intake pressure PMb is a value that is stored in the preceding intake pressure storage area of the RAM 33 after having been used in the determination at the preceding acceleration/deceleration determination time point. Then at step 505, it is determined whether the intake pressure change APM calculated at step 504 is more than a positive-side threshold P provided for acceleration determination. If the determination result of step 505 is YES, that is, the intake pressure change APM has changed largely to the positive side in excess of the positive-side threshold P, the processing proceeds to step 506 and executes the correction coefficient calculation routine in correspondence with the acceleration condition of the engine 1. The intake pressure change APM in this modification corresponds to the intake pressure change APMn in Fig. 4. On the other hand, if the determination result of step 505 is NO, that is, the intake pressure change APM is less than the positive-side threshold P, the processing proceeds to step 507 and determines whether the intake pressure change APM is less than a negative-side threshold Q provided for determination of deceleration. If the determination result of step 507 is YES, that is, the intake pressure change APM has changed largely to the negative side in excess of the negative-side threshold Q, the processing proceeds to step 508 and executes the correction coefficient calculation routine shown in Fig. 5 in correspondence with the deceleration condition of the engine 1. It is noted that the intake pressure change APM in this embodiment corresponds to the intake pressure change APMn in Fig. 5. On the other hand, if the determination result of step 507 is NO, that is, the intake pressure change APM is more positive than the negative-side threshold Q, in other words, if the intake pressure change APM is changing between the positive-side threshold P and the negative-side threshold Q, the processing proceeds to step 509 and executes the correction coefficient calculation routine of Fig. 6 in correspondence with the steady-state condition of the engine 1. The processing proceeds to step 510 after steps S506, S508 or S509 and the intake pressure PMa stored in the latest intake pressure storage area of the RAM 33 is stored in the preceding intake pressure storage area as the preceding intake pres sure PMb, thus ending this routine. After the processing of this routine, the fuel injection amount is corrected in the same manner as in the first embodiment. According to this second embodiment, the intake pressure PM in the intake passage 2 is detected at the crank angle corresponding to the detection time point among the intake pressures PM detected at every interrupt synchronized with the different crank angle signals in one combustion cycle of the engine 1. The acceleration/deceleration condition or the steady-state condition of the engine 1 is determined based on the change amount APM between the preceding intake pressure PMb and the present intake pressure PMa detected at the same crank angle time point. Thus, as the detection time points of detecting the intake pressure are the same in one combustion cycle of the engine 1, the operating condition of the engine 1 can be determined quickly. [Third Embodiment] In the third embodiment, the fuel injection correction coefficient is calculated repeatedly by the CPU 31 at every interrupt synchronized with the crank angle signal generated by the crank angle sensor 22 . As shown in Fig. 8, the intake pressure PM is read at step 601. Then at step 602, the intake pressure PM read in at step 601 is stored in the latest intake pressure storage area of the RAM 33 as the present intake pressure PMX. Then at step 603, determination is made whether it is an N-signal interrupt time point. This N-signal interrupt time point means a time point of interrupt made by an N-signal generated by the crank angle sensor 22 at a .predetermined crank angle. If the determination result of step 603 is NO, that is, it is not the N-signal interrupt time point, this routine is terminated without executing any steps. On the other hand, if the determination result of step 603 is YES, that is, it is the N-interrupt time point, the processing proceeds to step 604 so that an N-number indicative of the order of the N-signal is updated to a new N-number by adding "+1" to the stored N-number (preceding value). Then at step 605, it is determined whether the N-number equals a predetermined number R. If the determination result of step 605 is YES, that is, the N-number equals the predetermined number R, the phase of the engine 1 is considered to correspond to one combustion cycle and the N-number is returned to the initial value '0." If the determination result of step 605 is NO, that is, the N-number is not equal to the predetermined number R, the processing skips step 606. Then at step 607, the intake pressure PMX stored at step 602 is stored in a storage area of the RAM 33 as the intake pressure PMN of the time point of updating the N-nuraber, that is, of the time point of the predetermined crank angle in one combustion cycle of the engine 1. Then at step 608, it is determined whether the N-number equals a predetermined value S corresponding to the acceleration/deceleration determination time point. This acceleration/deceleration determination point means a plurality of different crank angles predetermined in one combustion cycle of the engine 1. If the determination result of step 608 is NO, that is, the N-number is not equal to the predetermined number S, this routine is terminated without executing any steps. On the other hand, if the determination condition of step 608 is YES, that is, the N-number equals the predetermined number S, the processing proceeds to step 609 and calculates an intake pressure change APMS by subtracting the preceding intake pressure PMSO from the present intake pressure PMS. Then at step 610, it is determined whether the intake pressure change APMS calculated at step 609 is more than a positive-side threshold T provided for the acceleration determination. If the determination result is YES, that is, the intake pressure change APMS has changed largely to the positive side in excess of the positive-side threshold T, the processing proceeds to step 611 and executes the correction coefficient calculation routine of Fig. 4 in correspondence with the acceleration condition of the engine 1. It is noted that the intake pressure change APMS in this modification corresponds to the intake pressure change APMn in Fig. 4. On the other hand, if the determination result of step 610 is NO, that is, the intake pressure change APMS is less than the positive-side threshold T, the processing proceeds to step 612 and determines whether the intake pressure change APMS is less than a negative-side threshold U provided for determination of deceleration. If the determination result of step 612 is YES, that is, the intake pressure change APMS has changed largely in the negative side in excess of the negative-side threshold U, the processing proceeds to step 613 and executes the correction coefficient calculation routine shown in Fig. 5 in correspondence with the deceleration condition of the engine 1. It is noted that the intake pressure change APMS in this modification corresponds to the intake pressure change APMn in Fig. 5. On the other hand, if the determination result of step 612 is NO, that is, the intake pressure change APMS is more positive than the negative-side threshold U, in other words, if the intake pressure change APMS is changing between the positive-side threshold T and the negative-side threshold U, the processing proceeds to step 614 and executes the correction coefficient calculation routine of Fig. 6 in correspondence with the steady-state condition of the engine 1. The processing proceeds to step 615 after step 611, S613 or S614 and the present intake pressure PMS is stored in the intake pressure storage area of the RAM 33 as the preceding intake pressure PMSO, thus ending this routine. After the processing of this routine, the basic fuel injection amount which is calculated in the known manner based on the engine rotation speed NE and the intake pressure PM of the engine 1 in the main routine (not shown) is corrected with each fuel injection correction coefficient corresponding to the acceleration/deceleration condition or the steady-state condition of the engine, so that the injection amount of fuel actually injected from the injector 5 is regulated. Thus, the acceleration/deceleration condition or the steady-state condition of the engine 1 is determined based on the change amount APMS between the preceding intake pressure PMSO and the present intake pressure PMS detected at the same crank angle time point. Thus, as the detection time points of detecting the intake pressure are the same in one combustion cycle of the engine 1, the operating condition of the engine 1 can be determined quickly. CLAIM !• An operating condition determination apparatus (30) for internal combustion engines (1) comprising: intake pressure detecting means (21, 30) for detecting intake pressure in an intake passage (2) at a plurality of predetermined crank angles in one combustion cycle of an internal combustion engine (1); and operating condition determining means (30) for determining an acceleration/deceleration condition and a steady-state condition of the engine from a change amount between a preceding intake pressure and a present intake pressure detected by the intake pressure detecting means (21, 30) at the same crank angle of the engine (1). 2. An operation condition determination apparatus (30) for internal combustion engines (1) comprising: intake pressure detecting means (21, 30) for detecting intake pressure in an intake passage (2) at a plurality of predetermined crank angles in one combustion cycle of an internal combustion engine (1); and operating condition determining means (30) for determining an acceleration/deceleration condition and a steady-state condition of the engine from a change amount between a preceding intake pressure and a present intake pressure detected by the intake pressure detecting means (21, 30) at the substantially same crank angle of the internal combustion engine. 3. The operation condition determination apparatus (30) for engines as set forth in claim 1 or 2, wherein the predetermined crank angle is set at an angle outside an intake stroke. 4 . The operation condition determination apparatus (30) for engines as set forth in any of claims 1 to 3, wherein the operating condition determining means (30) determines the acceleration/deceleration condition and the steady-state condition of the engine (1) from a sum of each change amount between the preceding intake pressure and the present intake pressure detected at each of the plurality of predetermined crank angles. 5. An operating coodition determination apparatus for internal combustion engines substantially as herein described with reference to the accompanying drawings.

Documents:

107-che-2003-abstract.pdf

107-che-2003-claims duplicate.pdf

107-che-2003-claims original.pdf

107-che-2003-correspondnece-others.pdf

107-che-2003-correspondnece-po.pdf

107-che-2003-description(complete) duplicate.pdf

107-che-2003-description(complete) original.pdf

107-che-2003-drawings.pdf

107-che-2003-form 1.pdf

107-che-2003-form 26.pdf

107-che-2003-form 3.pdf

107-che-2003-form 5.pdf

107-che-2003-other documents.pdf