DE102012216098A1 - Method for controlling an engine stop / start system - Google Patents

Abstract

A method for controlling the operation of an engine stop / start system is disclosed in which, when the time it takes to start an engine 10, which is controlled by the engine stop / start system, a predefined limit exceeds the operation of the engine stop / start system is disabled, so that a normal stop / start operation during at least the current driving cycle does not take place. This prevents the excessive use of a starting system for the internal combustion engine 10, which may lead to premature failure of the starting system, and also reduces negative reactions from a user of the motor vehicle 5 due to sluggish starting.

Description

This invention relates to a motor vehicle having an engine stop / start system for automatically stopping and starting an internal combustion engine of the motor vehicle, and more particularly to a method of controlling such an engine stop / start system.

It is known to provide a motor vehicle with an engine stop / start system for automatically stopping and starting the engine as soon as it is determined from driver actions that there is an opportunity to improve fuel economy and reduce emissions of the internal combustion engine.

Such engine stop / start systems have a problem that they significantly increase the wear and / or wear of components associated with an engine starting system, such as a starter motor and a battery.

Another problem is that if the time it takes to restart the engine after a stop is excessively long due to a malfunction of the starting system or for some other reason, this will further reduce the wear and / or wear of the starting system components increases and often leads to dissatisfaction with a user of the motor vehicle and also leads to actual usage problems, due to the fact that the driver fully engages the clutch before the internal combustion engine is completely restarted, resulting in a stalling of the internal combustion engine.

It is an object of this invention to provide a method of controlling the operation of an engine stop / start system to minimize the problems associated with the prior art.

According to a first aspect of the invention, there is provided a method of controlling an engine stop / start system of a motor vehicle, the method comprising measuring the time it takes for an engine controlled by the engine stop / start system to start, and controlling the operation of the engine stop / start system based on the result of the measuring step, wherein if the time it takes for the engine to start is longer than a first predefined limit, the operation of the engine Stop / Start system is controlled so that the stop / start operation is disabled, and if the time it takes for the engine to start, is longer than a second predefined limit, which is longer than the first predefined limit, the operation of the engine stop / start system is controlled so that the stop / start operation is deactivated.

The method may further comprise only disabling the stop / start operation if the first predefined limit has been exceeded more than a predefined number of times.

If the time it takes for the engine to start is less than the first predefined limit, the operation of the engine stop / start system may be controlled to allow a normal stop / start operation.

Each start time may be combined with an average of previous start times to produce a start time of a rolling average that is compared to the first predefined limit.

The method may further include warning a user of the internal combustion engine when the operation of the engine stop / start system is either disabled or deactivated.

The time for starting the internal combustion engine may be measured for a period of time which starts when a command to restart the internal combustion engine is generated until a time when a predetermined criterion has been met.

The criterion may be the achievement of a predefined speed by the internal combustion engine.

According to a second aspect of the invention, there is provided an engine stop / start system for a motor vehicle having an electronic processor arranged to automatically stop and start an internal combustion engine based on predefined criteria, and wherein the electronic processor is operable is to measure the time it takes after an engine start command to start the engine and to control the operation of the engine stop / start system based on the result of the measuring step, wherein when the time it lasts until the engine starts, is longer than a first predefined limit, the electronic processor is operable to inhibit a stop / start operation and if the time it takes to start is longer than a second one predefined limit, which is longer than the first predefined limit, the electronic processor operable i st to disable the stop / start operation.

Further, when the operation of the engine stop / start system is disabled or disabled, the electronic processor may be operable to activate a warning device to alert a user of the internal combustion engine.

According to a third aspect of the invention, there is provided a motor vehicle having an engine stop / start system constructed in accordance with the second aspect of the invention.

The invention will now be described by way of example with reference to the accompanying drawings, in which:

1 a schematic representation of a motor vehicle with an engine stop / start system according to a second aspect of the invention;

2 10 shows a flowchart illustrating the actions performed by the engine stop / start system, including steps that constitute a first embodiment of a method for controlling the engine stop / start system according to a first aspect of the invention; and

3 Fig. 10 shows a flowchart illustrating actions performed by the engine stop / start system, including steps constituting a second embodiment of a method for controlling the engine stop / start system according to the first aspect of the invention.

Regarding 1 is a motor vehicle 5 with an internal combustion engine 10 shown a multi-speed transmission 11 drives. The gear 11 is with the internal combustion engine 10 by a clutch (not shown) provided by a driver of the motor vehicle 5 is manually engaged or disengaged and a gear selector lever (not shown), driveably connected. The gear selector lever is movable between a plurality of positions including at least one position where a gear forming part of the multi-speed transmission is selected and a neutral position where no gears of the multi-speed gear are selected. When the gear selector lever is moved to the neutral position, it is said that the multi-speed gearbox 11 is in a neutral state in which no drive can be transmitted by the multi-speed transmission, and when the gear selector lever is moved to a position in the course, it is said that the multi-speed transmission 11 is in a state in transition in which a drive can be transmitted through the multi-speed transmission.

An internal combustion engine starter in the form of an integrated starter generator 13 is drivable with the internal combustion engine 10 connected in this case by a flexible drive in the form of a drive belt or chain drive 14 with a crankshaft of the internal combustion engine 10 connected. The starter generator 13 is with a source of electrical energy in the form of a battery 15 Connected and is used to the internal combustion engine 10 which is recharged by the starter generator when operating as an electric generator.

The invention is not based on the use of a starter generator 13 limited and the starter generator 13 could be through a starter motor to start the engine 10 be replaced.

It can be seen that during the start of the internal combustion engine 10 the starter generator 13 the crankshaft of the internal combustion engine 10 drives and that at other times the starter generator by the internal combustion engine 10 is driven to generate electrical power.

A driver-operable on / off device in the form of a key-operated ignition switch (not shown) is used to control the overall operation of the internal combustion engine 10 to control. That is, when the internal combustion engine 10 is running, the ignition switch is in a "switched on" position, and when the ignition switch is in a "switched off" position, the internal combustion engine 10 do not walk. The ignition switch also includes a third instantaneous position that is used to drive the internal combustion engine 10 to start manually. It will be appreciated that other devices may be used to provide this functionality, and that the invention is not limited to the use of an ignition switch.

An electronic control unit 16 is with the starter generator 13 , with the internal combustion engine 10 , with a gear selector lever sensor 12 who is watching to see if the transmission 11 in neutral or in-gear is used with an engine speed sensor 21 , which measures the speed of a crankshaft 20 the internal combustion engine 10 is used with a brake pedal position sensor 24 to monitor the position of a brake pedal 23 is used with a clutch pedal position sensor 26 To monitor the position of a clutch pedal 25 is used, and with a throttle position sensor 19 to monitor the position of an accelerator pedal 18 used, connected. The accelerator pedal 18 provides driver input of the required output from the engine 10 , When the accelerator pedal 18 is moved from a rest position, it is said that it is in a stepped position or in a stepped state.

It will be appreciated that the term gear selector lever sensor is not limited to a sensor that monitors the position of the gear selector lever, but rather is any device that can provide feedback as to whether the transmission is running 11 in gear or in neutral position.

Likewise, the term brake pedal sensor is not limited to a sensor that monitors the position of the brake pedal, but rather is any device that provides feedback whether a driver of the motor vehicle 5 a pressure on the brake pedal 23 has applied to the brakes of the motor vehicle 5 apply. For example, the brake pedal sensor could monitor the pressure of the fluid in one or more brake lines. When the brake pedal 23 enough has been entered to apply the brakes, it is said that it is in a trodden state or in a stepped position.

In this case, the clutch pedal position sensor includes first and second switches SW1 and SW2 (not shown) arranged to give an indication when the clutch pedal 25 towards one end of its stroke. This is done by opening or closing the switches SW1 and SW2 when the clutch pedal 25 achieved certain positions achieved. When it is said that the stroke of the clutch pedal 25 zero percent is when it is not actuated, that is, when it is in a non-pedaling state, and one hundred percent is when it has entered the limit of its stroke, that is, when it is in a trodden state, then, in one example, the switch positions may correspond to 10% lift percentages for the first switch and 75% for the second switch. When the clutch pedal 25 is at 10% or less than 10% of its stroke, the first switch is closed (SW1 = 1 and a high side signal becomes the electronic control unit 16 sent that confirms this, and when the clutch pedal 25 is 75% or more than 75% of its stroke, the second switch is closed SW2 = 1 and a low side signal becomes the electronic control unit 16 sent that confirms this. When the clutch pedal 25 is between 10% and 75% of its stroke, no signal is sent through both the switch SW1 and SW2 = 0. When the clutch pedal is in the stepped state, it is said that it is in a stepped position and the clutch is disengaged, and when it is in the non-stepped state, it is said that it is released or in a non-stepped position is located and the clutch is engaged.

It should be noted that when the signal SW = 1 is sent from the first switch, the clutch is clearly engaged, and when the signal SW2 = 1 is sent from the second switch, the clutch is clearly disengaged.

As an alternative to this arrangement, the current position of the clutch pedal using a single sensor such. B. a rotary potentiometer and the determination of when the clutch is engaged or disengaged, can then by the electronic control unit 16 using the signal received from the position sensor. In this case, the high and low clutch signals would be the positions of the clutch pedal 25 represent, in which it is known that the clutch is engaged or disengaged, by the electronic control unit 16 are determined on the basis of the signal received from the clutch pedal position sensor.

The electronic control unit 16 receives several signals from the internal combustion engine 10 including a signal indicating the speed of the internal combustion engine 10 indicates, from the engine speed sensor 21 , and sends signals to the internal combustion engine 10 that are used to shutdown and start the engine 10 to control. In this case, the internal combustion engine 10 a spark-ignited internal combustion engine 10 and from the electronic control unit 16 transmitted signals are used to a fuel supply system (not shown) for the internal combustion engine 10 and an ignition system (not shown) for the internal combustion engine 10 to control. When the internal combustion engine 10 a diesel engine should be, then only the fuel supply to the engine would be controlled.

The electronic control unit 16 includes various components, including a central processing unit, memory devices, one or more electronic processors, timers and signal processing devices, for receiving the signals from the sensors connected to the electronic control unit 16 are connected to convert data from the electronic control unit 16 used to control the operation and in particular the automatic stopping and starting of the internal combustion engine 10 to control.

The electronic control unit 16 is also connected to a driver warning device, in this case in the form of a man-machine interface 17 present at a control panel of the motor vehicle 5 is arranged.

During normal engine operation, the electronic control unit is 16 operable to the internal combustion engine 10 to control supplied fuel and to adjust the ignition system, so that spark to the internal combustion engine 10 of spark plugs are supplied at the correct time to produce the desired engine torque.

The electronic control unit 16 controls the operation of the internal combustion engine 10 operating in two modes, a first or stop / start mode of operation and a second or continuous mode of operation. However, it will be appreciated that one or more separate electronic control units could be used to control the normal operation of the internal combustion engine 10 to control, and the electronic control unit 16 only the switching of the internal combustion engine 10 between the two operating modes and the automatic stopping and starting of the internal combustion engine 10 can control.

All components used to stop and start the engine in response to driver actions combine to form the engine stop / start system from which the electronic control unit 16 is a major component.

A factor that is used in the case of a conventional engine stop / start system to determine if the internal combustion engine 10 is operated in the second mode or in the first mode, is whether the motor vehicle 5 emotional. When the motor vehicle 5 moved, the internal combustion engine is operated in the second mode and the internal combustion engine 10 runs continuously, and when the motor vehicle 5 not moved, the internal combustion engine 10 normally operated in the first mode in which an automatic stop / start operation of the internal combustion engine takes place. The electronic control unit 16 However, in accordance with this invention, it is further operable to determine, by testing one or more engine operating parameters, such as engine operating parameters. As the time it takes to the internal combustion engine 10 start to determine if it is suitable to the internal combustion engine 10 in the first mode before operating in the first mode, as described below with reference to FIG 2 and 3 discussed in more detail.

In the first or stop / start mode, the internal combustion engine 10 through the electronic control unit 16 selectively stopped and started without driver intervention when one or more predetermined engine stop and engine start conditions exist. These stop and start conditions are based on the actions of the driver as provided by the signals provided by the electronic control unit 16 from the throttle sensor 19 , from the brake sensor 24 , from the clutch sensor 26 and the gear selector lever sensor 12 be received. The position or condition of the clutch pedal 25 , the accelerator pedal 18 , the brake pedal 23 and the transmission 11 are all different motor vehicle variables that can be used to control the operation of the internal combustion engine 10 to control.

The specific conditions used for the purpose of this example are that the internal combustion engine 10 is stopped when the gearbox 11 is in the neutral position and the clutch pedal 25 not lowered, SW1 = 1, and started when the clutch pedal 25 SW2 = 1. Such a system is often referred to as a neutral stop system. However, it will be appreciated by those skilled in the art that various other combinations of driver action could be used to control the stopping and starting of the internal combustion engine.

The sequence of events for an engine stop / start cycle are the state changes of switch SW1 from SW1 = 1 to SW1 = 0 and the state changes of switch SW2 from SW2 = 0 to SW2 = 1 in response to the driver depressing the clutch pedal 25 occurs, then a neutral position in the transmission 11 is selected. The driver then leaves the clutch pedal 25 so that the state of the switch SW1 changes from SW1 = 0 to SW1 = 1, and the state of the switch SW2 changes from SW2 = 1 to SW2 = 0, and the internal combustion engine 10 is stopped when the neutral position is detected at SW1 = 1.

When the driver depresses the clutch pedal 25 If a shift occurs, the state of the switch SW1 changes from SW1 = 1 to SW1 = 0, and the state of the switch SW2 changes from SW2 = 0 to SW2 = 1, changing the state of the switch SW2 from SW2 = 0 to SW2 = 1 is used as an indication that a start is required.

It can be seen that the time it takes for the driver to depress the clutch pedal 25 enters and makes a drive while the state of the switch SW2 remains at SW2 = 1 is when the internal combustion engine 10 ideally restarted, since during this period no additional resistance to the internal combustion engine 10 consists. Until the state of the switch SW2 changes to SW2 = 0, therefore, the internal combustion engine should 10 preferably restarted and run, if this is not the case, then an invalid start results and in some cases could stall the engine 10 occurrence. For a normal restart, the amount of time is during the clutch pedal 25 is sufficiently stepped to keep the clutch disengaged (the SW2 state remains SW2 = 1), in the range of 2 seconds and thus the internal combustion engine 10 in Start less than this time if you want to avoid problems.

When the internal combustion engine 10 operating in the second mode, it is operated continuously as long as the ignition switch remains in the "on" position.

The measurement of vehicle speed may be via the use of an impeller sensor or some other convenient means.

A first embodiment of a method according to the invention will now be described with reference to FIG 2 described.

The procedure starts in the box 100 which is a power-on event.

Then the process checks in step 110 Whether the engine stop / start system is currently "disabled" or "disabled".

The term "disabled" as used herein is that the normal operation of the engine stop / start system has been completed so that the engine is permanently operated in the second mode of operation until an external intervention has taken place, such as resetting of the engine stop / start system.

The term "disabled" as used herein is that the normal operation of the engine stop / start system has been temporarily terminated so that the internal combustion engine is operated in the second operating mode during the current operating cycle. However, in this case, the engine stop / start system is reset by a turn-off event and thus returns to normal operation (engine operates in the first mode) when the next turn-on event occurs.

The test in the box 110 can therefore include:
Checking the value of two flags F1 and F2;
if F1 and F2 use <1, then normal (first) mode;
if F1 = 1, then disable operation; and
if F2 = 1 then disable operation.

Other tests could be used and the invention is not limited to the use of such a test.

If the test result from the box 110 such that the engine stop / start system is to be disabled or disabled, therefore, no further action is taken and the process goes over the box 115 to the box 280 to check if a shutdown event has occurred, if so, the procedure ends in the box 300 by storing values for the two flags F1 and F2 after setting the flag F1 equal to zero and holding the flag F2 at its current value.

If no power off event in the box 280 has occurred, the method returns to the box 110 back, in which the flags F1 and F2 are read again, and when the engine system has been deactivated, it runs continuously through the boxes in one cycle 110 . 115 and 280 until the flag F2 is reset to zero by external engagement.

In the case where no shutdown event in the box 280 and the engine stop / start system has been locked, the process continues to run continuously through the bins in one cycle as before 110 . 115 and 280 but in this case, the flag F1 is finally reset to zero when a turn-off event, as in the box 300 indicated, occurs.

If the test result from the box 110 indicates that the engine stop / start system is not currently disabled or disabled, the procedure moves to the box 120 Next, a test to determine if the internal combustion engine 10 is to be stopped automatically is. When the internal combustion engine 10 should not be stopped, the procedure goes from the box 120 to the box 280 to check if a shutdown event has occurred, if so, the procedure ends in the box 300 and if not, the method returns to the box 110 back.

If you go to the box 120 returns and if the conditions for an engine stop exist, the process goes to step 130 Continue and the internal combustion engine 10 is stopped.

Then be in the box 140 the engine restart conditions are checked and this process continues until a positive result is achieved, at which point the process to the box 150 continues. In this case, the engine restart conditions are a single condition, namely that the clutch pedal 25 is kicked.

The generation of an engine start request in the box 150 simultaneously starts a timer in the electronic control unit 16 runs to measure the time it takes for the engine to start, as in the box 200 and this starts the key steps of the Procedure, which also in the boxes 210 to 275 include specified steps.

In the case of this example, the time it takes to start is the time from the point where the engine start signal is generated until a time when the internal combustion engine 10 has reached a predetermined speed which is 700 min ^-1 in this case, but a different speed could be for other engine types. When the internal combustion engine 10 reaches this speed, as by the engine speed sensor 21 indicated, the timer in the electronic control unit 16 stopped and the elapsed time (Ts) is stored in memory.

The procedure then goes to the box 210 continue, in which the validity of the time measurement is checked. For example, starts that are disturbed by the driver are ignored (eg, if the clutch is pulled up too fast before the engine has started). If the start is not valid, the procedure moves from the box 210 to the box 280 to check if a shutdown event has occurred, if so, the method ends in the box 300 as discussed above, otherwise it returns to the box 110 back.

When in the box 210 the start is confirmed as valid, then the procedure goes to the box 220 to compare the measured start time with a predefined maximum time (Ts Max).

Ts Max is a period of time that is much longer than it normally would take the engine 10 to start, and that indicates that a serious problem exists, which is an efficient starting of the internal combustion engine 10 prevented. For example, and without limitation, if the expected time to start the engine when all components are in a new or fully functional state is 0.6 seconds, then Ts Max could be set to 2.0 seconds.

When the time it takes the internal combustion engine 10 to start, Ts Max exceeds, then the procedure goes to the box 230 continue, in which the operation of the engine stop / start system is deactivated (second mode selected), and then in the box 235 the flag F2 is set to 1 and in memory for reading in the box 110 saved when in the box 110 will be entered next time. The procedure then moves from the box 235 to the box 270 in which a driver is de-activated via the man-machine interface 17 under the control of the electronic control unit 16 is warned, and then goes to the box 275 Continue, where it to the box 280 continues. Control options for the box 280 are described above and will not be described again.

If on the other hand in the box 220 the engine start time Ts is not longer than Ts Max, then the process goes to the box 240 Next, in which the current value of the start time is added to an existing average start time for the current engine operating cycle.

Ts Avg_old

= existierender Wert der mittleren Startzeit;

Ts_new

= neuer erfasster Wert der Startzeit; und

N

= eine Zahl gleich oder größer als 1.

This may be a simple averaging of an existing average Ts Avg with the new value Ts, such as. B. [(Ts Avg + Ts) / 2] or can be on an equation such. Based on the following equation: Ts Avg = Ts Avg _old + [(Ts _new - Ts Avg _old ) / N] in which:

Ts Avg _old

= existing value of the middle start time;

Ts _new

= new recorded value of the start time; and

N

= a number equal to or greater than 1.

For example, if Ts Avg _old = 0.65 s, Ts _new = 0.67 s and N = 5
then Ts Avg = 0.65 + [(0.67-0.65) / 5] = 0.654 seconds

Compared to a result of 0.66 seconds, when a simple averaging is used.

The use of such an equation reduces the risk of a system error if an erroneous value of Ts _{new is} generated.

The procedure then goes from the box 240 to the box 250 in which the value TS Avg is compared with a predefined limit, which in this case is a value much closer to the expected start time and which defines a start time that produces wear or deterioration of the starting system for the internal combustion engine or a significant one Driver dissatisfaction generated.

For example, the test may be Ts Avg> 0.85 using the data listed above for a start.

If the value of Ts Avg exceeds the limit Ts Avg Max, then the procedure goes to the box 260 continue, in which the operation of the engine stop / start system is locked by operating the internal combustion engine in the second operating mode for the rest of the current operating cycle. That is, the operation of the engine stop / start system is disabled until a "turn off" and a subsequent "turn on" event has occurred. This is achieved by putting in the box 260 the flag F1 is set to a value of 1 and in the box 300 the flag F1 = 0 is reset.

The value of the F1 flag is read as soon as the procedure moves to the box 110 returns, which is why in this case causes the process in a loop through the boxes 110 . 115 and 280 for the current operating cycle, once the flag F1 has been set to one, until a power-off event in the box 280 takes place.

When going to the box after completing the locking of the engine stop / start system 260 returns, the procedure goes to the box 270 Next, in which the driver with respect to the blocking of the operation via the man-machine interface 17 under the control of the electronic control unit 16 is warned, and then goes to the box 275 and from there to the box 280 continue whose control options are described above.

It can be seen that in the box 270 provided warning for a deactivation event and a locking event may be different.

A second embodiment of a method according to the invention will now be described with reference to FIG 3 described.

The second embodiment is identical to that with reference to the above with respect to the boxes 100 . 115 . 120 . 130 . 140 . 150 . 200 . 210 and 280 described first embodiment, but in this case takes place only the locking of the engine stop / start system, there is no deactivation in the disclosed method, although this could be added if necessary. The same reference numerals have been used for these boxes and the operations performed in these boxes will not be described again in detail.

The procedure starts in the box 100 , which is a power-on event, and goes to the box 1110 continue to the previously described box 110 is equivalent, and in step 1110 the method checks whether the engine stop / start system is currently "locked".

The term "locked" has the same meaning as described above.

The test in the box 1110 therefore, involves checking the value of the flag F1, and if F1 <1, using the normal stop / start system stop / start mode of operation for the engine stop / start system. On the other hand, when F1 = 1, the operation of the engine stop / start system is inhibited.

Other tests could be used and the invention is not limited to the use of such a test.

If the test result from the box 1110 such that the engine stop / start system should be disabled, therefore, no further action is taken and the process goes over the box 115 to the box 280 to check if a shutdown event has occurred, if so, the procedure ends in the box 1300 by setting the flag F1 and the counter N equal to zero.

When in the box 280 no shutdown event has occurred, the process returns to the box 1110 back, in which the flag F1 is read again, and the method runs continuously through the boxes in one cycle 1110 . 115 and 280 until a turn-off event occurs, at which time the flag F1 and the counter N are reset to zero, as in the box 1300 specified.

If the test result from the box 1110 indicates that the engine stop / start system is not currently disabled, the procedure moves to the box 120 Next, which is a test to determine if the internal combustion engine 10 should be stopped automatically. When the internal combustion engine 10 should not be stopped, the procedure goes from the box 120 to the box 280 to check if a shutdown event has occurred, if so, the procedure ends in the box 1300 and if not, the method returns to the box 1110 back.

If you go to the box 120 returns and if the conditions for an engine stop exist, the process goes to step 130 Continue and the internal combustion engine 10 is stopped.

Then be in the box 140 the engine restart conditions (clutch stepped) are checked and this process continues until a positive result is achieved, at which point the procedure goes to the box 150 continues. The generation of an engine start request in the box 150 simultaneously starts a timer in the electronic control unit 16 runs to measure the time it takes for the engine to start, as in the box 200 specified. As before, the time it takes to start, the time from the point at which the engine start signal is generated, to a time when the Internal combustion engine 10 has reached a predefined rotational speed, which in this case is 700 min ^-1. The value of 700 ^min-1 is a stable engine speed of which can be expected that a normal operation of the internal combustion engine 10 results.

When the internal combustion engine 10 Reached 700 min ^-1 , as by the engine speed sensor 21 indicated, the timer in the electronic control unit 16 stopped and the elapsed time (Ts) is stored in memory.

In the box 210 the validity of the time measurement is checked as before, and if the start is not valid, the procedure moves from the box 210 to the box 280 whose tax options were previously discussed, and if in the box 210 the start is confirmed as valid, then the procedure goes to the box 1220 continue to perform a comparison of the measured start time with a predefined time limit (TsLim).

TsLim is a period of time that is longer than would normally take the engine 10 to start, and that indicates that a problem exists that allows the engine to start efficiently 10 prevented. For example, and without limitation, if the expected time to start the engine when all components are in a new or fully functional state is 0.6 seconds, then TsLim may be set to 0.9 seconds.

When the time it takes to start the engine 10 takes, TsLim exceeds, then the procedure goes to the box 1230 continue, in which a counter is incremented by one (N = N + 1). Then in the box 1240 checked whether the counter has exceeded a predefined limit NLim.

For example, NLim could be set to 2 if the test was at 1220 is met more than twice, this is therefore taken as indication that a persistent deterioration in take-off performance occurs, and the procedure goes to the box 1250 further, otherwise it returns from the box 1240 to the box 280 back, and if no power off event has occurred, go to the box 1110 with a flag value of F1 = 0, so that the operation is not disabled and the steps of 1110 to 1240 be repeated.

If, however, the test in the box 1240 is met, the procedure goes from the box 1240 to the box 1250 continue, in which the operation of the engine stop / start system is locked by operating the internal combustion engine in the second operating mode for the rest of the current operating cycle. That is, the operation of the engine stop / start system is disabled until a "turn off" and then "turn on" event has occurred. This is achieved by putting in the box 1250 the flag F1 is set to a value of 1, which is read when the procedure is over the box 280 to the box 1110 returns and by in the box 1300 after a switch-off event in the box 280 the flag F1 and the counter N are reset equal to zero.

If the value of the F1 flag in the box 1110 is read, this causes the process in a loop through the boxes 1110 . 115 and 280 for the current operating cycle runs as soon as it has been set to F1 = 1, that is until a switch-off event in the box 280 occurs.

When you go to the box 1250 returns after completing the engine stop / start system lock, the method moves to the box 1260 Next, in which the driver with respect to the blocking of the operation via the man-machine interface 17 under the control of the electronic control unit 16 is warned, and then goes to the box 12805 and from there to the box 280 continue whose control options are described above.

It can be seen that when in the box 1300 the flag F1 is not set to zero and the counter N is not set to zero, then the method could be used to provide the deactivation of the engine stop / start system, and the flag F1 and the counter N by external intervention such as z. Reset by a customer service representative, a user of the vehicle would need to be reset, or the electronic control unit, which could be a powertrain control module that could monitor manual typed start times to determine if they are improving to a sufficient level, and then automatically could reactivate the stop / start process.

It will be appreciated that the steps described in the above-described methods are provided by way of example and that a different sequence of steps or a combination of steps of the two methods could be used.

In summary, therefore, using one of the methods described above, unnecessary wear or user dissatisfaction can be reduced or avoided by monitoring the starting performance of the internal combustion engine and preventing the operation of the internal combustion engine 10 in the first (stop / start) operating mode when the power has fallen below a predefined level. The use of simple timekeeping eliminates the need for complex diagnostic routines or equipment that would otherwise be required to provide an indication of degradation in takeoff performance.

It will be appreciated that many factors can cause such degradation of performance, such as: B. a low state of charge of the battery, which is used to operate the electric starter (starter motor), an error or problem in the operation of the starting device, ignition problems such. As a faulty spark plug or wrong ignition timing or fuel supply problems such. B. a faulty fuel injector or incorrect fuel timing. The inventors have recognized that instead of attempting to analyze all such potential problems involved in degraded starting performance, it is advantageous to measure only the consequence of such problems in the manner described above.

Further, it will be appreciated that only the operating characteristics of the engine stop / start system required to explain this invention are discussed in detail and that other factors may determine when operation in the first mode is enabled.

It will be appreciated by those skilled in the art that while the invention has been described by way of example with reference to one or more embodiments, it is not limited to the disclosed embodiments and one or more modifications to the disclosed embodiments or alternative embodiments could be constructed without departing from the scope of the invention.

Claims (10)

A method of controlling an engine stop / start system of a motor vehicle, the method comprising measuring the time it takes for an engine controlled by the engine stop / start system to start and controlling the operation of the engine stop / Start system based on the result of the measuring step, wherein, if the time it takes for the internal combustion engine starts, is longer than a first predefined limit, the operation of the engine stop / start system is controlled so that the stop / start operation is inhibited, and if the time it takes for the engine to start is longer than a second predefined limit, which is higher than the first predefined limit, the operation of the engine stop / start system is controlled so that the stop / start operation is deactivated. The method of claim 1, wherein the method further comprises only inhibiting the stop / start operation if the first predefined limit has been exceeded more than a predefined number of times. The method of claim 1 or claim 2, wherein, when the time it takes for the engine to start is less than the first predefined limit, the operation of the engine stop / start system is controlled to be the normal stop / start To allow operation. The method of any one of claims 1 to 3, wherein each start time is combined with an average of previous start times to produce a start time of a rolling average that is compared to the first predefined limit. The method of one of claims 1 to 4, wherein the method further comprises alerting a user of the engine when the operation of the engine stop / start system is either disabled or deactivated. Method according to one of claims 1 to 5, wherein the time for starting the internal combustion engine for a period of time, which starts when a command to restart the internal combustion engine is generated, until a time when a predetermined criterion has been met, is measured. The method of claim 6, wherein the criterion is the achievement of a predefined speed by the internal combustion engine. An engine stop / start system for a motor vehicle having an electronic processor arranged to automatically stop and start an internal combustion engine based on predefined criteria, and wherein the electronic processor is operable to time after a command for to measure an engine start that lasts until the engine starts, and to control the operation of the engine stop / start system based on the result of the measuring step, wherein if the time it takes for the engine to start, is longer than a first predefined limit, the electronic processor is operable to disable the stop / start operation and if the time it takes to start is longer than a second predefined limit that is longer than the first predefined limit Limit the electronic processor is operational to disable the stop / start operation. The system of claim 8, wherein when the operation of the engine stop / start system is either disabled or deactivated, the electronic processor is further operable to To activate warning device to warn a user of the internal combustion engine. Motor vehicle with an internal combustion engine stop / start system according to one of Claims 8 to 9.

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