EP2075443A2 - Method and device for operating a combustion engine of a vehicle - Google Patents

Abstract

The method involves detecting a stop and go situation by using sensors (6). An electronic accelerator pedal (1) is pressed by an operator for requesting power of an internal combustion engine depending on a position of the accelerator pedal. Maximum internal combustion engine speed (4) is limited to a predetermined value, if the stop and go situation exists, where the maximum engine speed is limited to 50 to 60 percentage of rated speed. The limitation of the maximum internal combustion engine speed is cancelled, if no stop and go situation exists. Independent claims are also included for the following: (1) a method for emptying garbage containers using an internal combustion engine operated-bin lorry (2) a controller for operating an internal combustion engine of a vehicle, comprising an electronic accelerator pedal.

Description

The invention relates to a method for operating an internal combustion engine of a vehicle, as well as to a control device for carrying out the method. The method or control unit can be used particularly sensibly in vehicles in distribution traffic, which are mainly used in stop-and-go operation.

Within the meaning of the invention, stop-and-go traffic is not understood to be the normal participation in road traffic, in which frequent starts and stops occur as a result of increased traffic density. Rather, it is about operating vehicles with optimum fuel consumption, which, as a result of their intended task, must repeatedly approach destinations only a few meters apart for longer periods of time. Such vehicles are in particular refuse vehicles, postal distribution vehicles in metropolitan areas or newspaper deliveries. A stop-and-go situation is z. B. characterized in that at least 5 times repeated only very short distances of about 5 to 50 m are covered. As a result of the often repetitive starting and braking operations, the driver is understandably inclined to cover the corresponding route with maximum acceleration / deceleration. For this purpose, the accelerator pedal is briefly fully depressed, so that high speeds are achieved with correspondingly high fuel consumption. In automatic vehicles, therefore, late or not at all switched to the next higher gear. In semi-automatic or manual circuits, the next higher gear is not inserted for reasons of convenience because of the short route. The loads are enormous for engine, transmission and brakes, which leads to high wear.

For some vehicles used in the distribution service, eg. B, for refuse vehicles, a speed limit of 30 km / h is activated when the rear footpegs are extended. However, this safety measure for the protection of the traveling worker rarely intervenes in stop-and-go operation, since the speed limit is not reached anyway within a few meters of the next wheelie bin. This measure is not the fuel savings.

DE 39 18 971 relates to a similar speed limitation, wherein during the loading of the foot pegs the path of the accelerator pedal is limited, wherein a timer is provided, which allows a rapid initial acceleration without speed limitation.

DE-A-10 2004 057 511 describes a motor control method which detects a motor vehicle start-up operation and limits the speed during the start-up process to protect the manually shiftable clutch or transmission. The acceleration behavior after engagement is not limited.

DE-A 31 35 479 relates to an electromechanical accelerator pedal, which passes the position of the accelerator pedal by means of an electric motor to the carburetor, wherein the movement of the accelerator pedal is slowed down in the direction of full throttle position.

DE 698 15 775 discloses a vehicle speed control provided in the signal path between the electric accelerator pedal and the engine controller.

It is therefore an object of the present invention to provide an improved method for operating an internal combustion engine of a vehicle or a corresponding device.

This object is achieved by a method or a device having the features of the corresponding independent claims. Further advantageous embodiments of the invention are the subject of the dependent claims.

According to the invention, it has been recognized that by recognizing a stop-and-go situation and thereby limiting the maximum engine speed, a considerable reduction in consumption and reduction in wear can be achieved. In the tests described in more detail below, fuel consumption was reduced by at least 20%.

A person skilled in the art will come to numerous methods for detecting a stop-and-go situation, or corresponding sensors for detecting the same, which are not described in greater detail here. By way of example, the following are enumerated: In particular, in garbage trucks, the hydraulic system for the garbage compactor and the garbage can lifter is known as auxiliary unit. As long as this unit is running, you are in stop-and-go operation. In order to prevent the inventively provided speed limitation is manipulated by repeated short-term switching off the ancillaries, advantageously, the period since the shutdown of the auxiliary unit can be used. Thus, the stop-and-go situation ends, for example, only 15-60 seconds, preferably 25-45 seconds after switching off the auxiliary unit. It is therefore not worth to switch off the accessory for every 30-meter sprint.

The above-mentioned periods have proven to be particularly suitable in this regard, since on the one hand the improper termination of a stop-and-go situation is prevented and on the other hand, the vehicle can quickly re-participate in regular traffic.

The above statement also applies mutatis mutandis to comparable operating means, for example, provided for the refuse workers footrests for riding at the rear. Transferred to other vehicles in distribution traffic will come to the expert comparable sensors that allow to determine whether there is just stop-and-go traffic or driving. In the case of postal delivery vehicles, this may be the door to the cargo compartment, the driver's door and / or the seat occupancy of the driver's seat, for example - also in combination - preferably with the time delay described above. The time delay always has to be calculated in such a way that it is unattractive for the respective application to wait for the timer to expire.

A sensor for detecting a stop-and-go situation in the sense of the invention does not necessarily have to be a special component. Rather, it is sufficient that states already detected in the system of the original vehicle are included as well, e.g. Speed or speed or course of the same. Some vehicles, even in the original state, determine certain vehicle states from which a stop-and-go situation can be derived, such as, for example, the "speed-limited mode" of a garbage truck with the footrests unfolded or the accessory running.

In the following, a preferred embodiment will be explained in a refuse vehicle. The method for detecting a stop-and-go situation described here has the advantage that it can be used with minimal adjustments in a large number of vehicles, adapts to different loading situations and is easy to retrofit. Only the speed and the speed are tapped, ie data that is readily available on every vehicle.

The existence of a stop-and-go situation can, for. B. by detecting an increase in the idle speed to an increased idle speed while the vehicle is stopped without the accelerator pedal is pressed, are detected. In the case of a refuse compactor, an increase of an idling speed of 25-120%, in particular 35-100%, preferably to an increased idling speed takes place. For a reliable determination of such an increased idle speed associated with the press, the skilled person is well aware of measures, z. B. can be determined whether the speed is sufficiently constant for a suitable period, z. For example, the speed should fluctuate at least 5 sec. Less than 10%, preferably 5%, especially preferably 2.5%, around the increased idle speed.

The existence of a stop-and-go situation can also be detected by the following steps. It is repeated an increase in idle speed to an increased idle speed while the vehicle is stopped without the accelerator pedal is actuated detected and a subsequent reduction to idle speed detected within a certain period. The vehicle can be moved in between. It is therefore recognized when the vehicle is in collective service and travels only very short distances between the collection points. For reliable determination of the lowering to idle speed, the skilled person is well aware of measures, for. B. can be determined whether the speed is sufficiently constant for a suitable period, z. For example, the speed should fluctuate at least 1 sec, less than 10%, preferably 5%, most preferably 2.5%, around the idle speed.

It is best if the presence of a stop-and-go situation is detected by the following steps: repeatedly detecting an increase in idle speed to an increased idle speed while the vehicle is stationary without the accelerator pedal is depressed and detecting a reduction to idle speed, wherein every time between the repeated recognition a certain period is not exceeded. It makes sense to measure the period between the lowering to idle speed and the increase to increased speed in the state without the accelerator pedal is pressed. This is related to the distance of the collected collection points. If this period is less than an appropriate value, e.g. If less than 45 sec. Or 30 sec., A counter with the value 1 starts. If, on the way to the next collection point, the value falls below the time value again, the counter increases by 1, otherwise it is reset to 0. If the counter is a setpoint, z. B. 5, is a stop-and-go situation given. A small setpoint, z. B. l, allows a very economical operation, the speed limit is already active at two nearby collection points. Preferred is a nominal value of 3-6.

The vehicle is within the meaning of the invention if the speed is less than 10, preferably 3, in particular preferably 2 km / h.

The specified areas for the maximum engine speed were determined by tests on MAN semi-automatic TGA 26.320 or Mercedes 950.60. This resulted in a consumption reduction of up to 27%, without the travel time being significantly increased. In a test with Mercedes 950.60 extended a 7-hour tour with 850 stops and a distance of 100 km by only 5 minutes, which corresponds to 0.35 seconds per stop. The fuel consumption dropped from 62 liters to 45 liters.

Advantageously, the accelerator pedal is designed as an electronic accelerator pedal, which facilitates the manipulation of the accelerator pedal signal by an additional inventive control device for performing the method. The retooling therefore essentially limited to the breaking of electrical connections. The electronic accelerator pedal is introduced only intermittently in the electronic signal path between the accelerator pedal and the engine's original engine control unit and connected to the sensors for detecting the stop-and-go situation. There are no time-consuming mechanical adjustments or interventions in the original engine control unit necessary. It is particularly advantageous if the vehicle already receives an electronic signal from which a stop-and-go situation can be derived.

Another advantage of the method according to the invention is that no permanent speed limitation is made, which causes a significant impairment in regular road traffic, since, for example, the refuse vehicle for threading can not accelerate fast enough.

• beim Anfahren das Gaspedal einen Wert U_ist größer als U_max aufweist und
• ab Erreichen einer durch Versuche ermittelten zweckmäßigen Drehzahl n_Grenz, die kleiner als die begrenzte maximal gewünschte Motordrehzahl ist,

wird U_ist verringert an das Motorsteuergerät weitergegeben. Um dabei Schwingungen zu vermeiden wird U_ist nicht schlagartig auf U_max zurückgenommen. Vielmehr wird U_ist vorzugsweise linear mit zunehmender Motordrehzahl derart zurückgenommen, dass bei Erreichen der begrenzten maximal gewünschten Motordrehzahl der Wert U_max erreicht wird. Die Gaspedalspannung wird also erfindungsgemäß in Abhängigkeit von der tatsächlichen Drehzahl n um den Betrag $$\frac{{\mathrm{U}}_{\mathrm{ist}}\mathrm{-}{\mathrm{U}}_{\max }}{{\mathrm{n}}_{\max }\mathrm{-}{\mathrm{n}}_{\mathrm{Grenz}}}\mathrm{\times }\left({\mathrm{n}}_{\mathrm{x}}\mathrm{-}{\mathrm{n}}_{\mathrm{Grenz}}\right)$$

reduziert.Preferably, the limitation of the max. Engine speed (n _max ) carried out as follows: First, it is determined by experiments, at which value (U _max ) of the electronic accelerator pedal, z. B. 2.5 V the limited maximum desired engine speed, z. B. 1900 U / min in 1, gear is reached. When starting the accelerator pedal position is now first, so the voltage U _{is passed} unchanged to the engine control unit. Only when

• when starting the accelerator pedal has a value U _is greater than U _max and
• after reaching a determined by tests appropriate speed _limit n that is less than the limited maximum desired engine speed,

U _is reduced is passed to the engine control unit. In order to avoid vibrations U _is not abruptly reduced to U _max . Rather, U _is preferably taken back linearly with increasing engine speed such that upon reaching the limited maximum desired engine speed, the value U _{max is} reached. The accelerator pedal voltage is thus according to the invention in dependence on the actual speed n by the amount $$\frac{{\mathrm{U}}_{\mathrm{is}}\mathrm{-}{\mathrm{U}}_{\mathrm{Max}}}{{\mathrm{n}}_{\mathrm{Max}}\mathrm{-}{\mathrm{n}}_{\mathrm{border}}}\mathrm{\times }\left({\mathrm{n}}_{\mathrm{x}}\mathrm{-}{\mathrm{n}}_{\mathrm{border}}\right)$$

reduced.

Fig. 5 shows in the diagram the inventively passed to the engine control accelerator pedal voltage U, which is reduced from a speed of 1,500 U / min to U _max .

Essentially, the same time always sets in until n _{Max is} reached starting from n _limit . This time in a measure of the inertia of the vehicle and thus its weight or state of charge. If more time is needed, the car is heavier. Depending on the determined inertia or time, the value U _{max can be} increased.

The reverse is true when the car has been emptied. This allows the same acceleration behavior of loaded and unloaded vehicles. According to the invention, U _max can be increased or reduced as a function of the state of charge of the wagon, which is determined by means of acceleration behavior, such that an acceleration behavior which is approximately independent of the state of charge results.

Instead of voltages, the position of the accelerator pedal can also be passed on or modified differently, for. B. based on pulse width modulation, digital signals, etc.

Fig. 1:

eine konventionelle Drehzahlsteuerung eines Fahrzeugs;

Fig. 2:

die erfindungsgemäße Fahrzeugsteuerung mit zusätzlichem Steuergerät;

Fig. 3:

einen Fahrzyklus ohne erfindungsgemäßes Steuergerät;

Fig. 4:

einen Fahrzyklus mit erfindungsgemäßem Steuergerät, und

Fig. 5:

im Diagramm die erfindungsgemäß an die Motorsteuerung weitergegebene Gaspedalspannung U

Further advantages will become apparent from the following description and the accompanying drawings. Likewise, according to the invention, the features mentioned above and even further can be used individually or in any desired combinations with one another. The mentioned embodiments are not exhaustive and have exemplary character. Show

Fig. 1:

a conventional speed control of a vehicle;

Fig. 2:

the vehicle control according to the invention with additional control unit;

3:

a driving cycle without inventive control device;

4:

a driving cycle with inventive control device, and

Fig. 5:

in the diagram, the inventively passed to the engine control accelerator pedal voltage U

Fig. 1 shows an electronic accelerator pedal 1, which is connected via an electronic connection 2 with the original engine control unit 3 of a vehicle. The position of the accelerator pedal results in an electrical signal. In response, the engine control unit 3 controls the speed 4 of the engine. The power of the engine is thus requested by the accelerator pedal and the engine control unit calculates the required injection quantity to increase or decrease the speed. Under Considering the transmission, this results in a vehicle speed 5.

Accordingly shows Fig. 3 the speed or speed curve of a typical drive cycle over 100 seconds. Between the seconds 41 to 56 it can be seen that, despite a low speed of approx. 10 km / h, the engine turns at 2.700 rpm, very high, and is decelerated to a high level by the engine control unit. The driving cycle shown above thus describes a typical driving situation for garbage trucks, from garbage can to garbage bin. The driver is constantly full throttle when he drives to the next garbage can and leaves the engine mostly in 2, gear up to the rated speed. This is an essential factor for the high consumption of an average of 62 liters per 100 km, the loads in this area are enormous for the engine, transmission and brakes.

Fig. 2 shows that between the conventional electronic accelerator pedal 1 and the original engine control unit 3, the inventive control device / EDA 10 in the signal path 2a, 2b between accelerator pedal 1 and engine control unit 3 is connected. The EDA controls - here on the basis of the accessory NAG 6 or other signals (gear position, foot pegs, detection of recurrent acceleration phases in a certain time, etc.), whether the vehicle is in the stop-and-go cycle and controls on the basis of the accelerator pedal signal maximum permissible speed 4 by the accelerator pedal signal 2a is influenced by the EDA 10 so long 2b until the desired maximum allowable speed is reached. When the stop-and-go situation is over, the original accelerator pedal signal 2a is automatically directed to the engine control unit. The effect of this approach is that a consumption reduction of up to 27% is achieved. This not only works with trucks, but also with comparable used cars.

Fig. 4 shows the invention cut off speed peaks. Nevertheless, higher speeds than in Fig. 3 scored, through the speed limit is forced upshifting - whether manual or automatic - as seen at 30 seconds.

Claims (12)

Method for operating an internal combustion engine of a vehicle, in particular a refuse vehicle, with the following steps: - Detecting a stop-and-go situation by sensors (6); - Pressing the accelerator pedal (1) by the operator to request power of the internal combustion engine in dependence on the position of the accelerator pedal; Limiting the maximum engine speed to a predetermined value when a stop-and-go situation exists; and - Canceling the limitation of the maximum engine speed when no stop-and-go situation exists. A method for emptying a plurality of refuse containers by means of an internal combustion engine powered refuse vehicle, comprising the following repetitive steps: - Approaching a garbage container and emptying it into the garbage truck; - Pressing the accelerator pedal (1) by the operator to request power of the internal combustion engine in response to the position of the accelerator pedal to approach a next refuse container, the refuse containers are less than 50 m, in particular less 25 m away; - Detecting a stop-and-go situation by sensors (6); Limiting the maximum engine speed to a predetermined value when a stop-and-go situation exists; and - Approach the next garbage container and emptying the same in the garbage truck. Method according to one of the preceding claims, wherein the presence of a stop-and-go situation is detected as a function of at least one of the following parameters: - operation of ancillary equipment (6), in particular period since the last use thereof; - Condition of doors, footpegs, seat occupancy, in particular period since last use thereof; - Speed, in particular speed curve; - period since the last engine start; Speed, in particular speed course; - presence of a speed-limited mode of the vehicle; Method according to one of the preceding claims, wherein the maximum engine speed is limited to 40-75%, preferably 45-65% and in particular preferably 50-60% of the rated speed. Method according to one of the preceding claims, wherein the presence of a stop-and-go situation is detected by the following steps: Detecting an increase in idle speed to an increased idle speed while the vehicle is stationary Method according to one of the preceding claims, wherein the presence of a stop-and-go situation is recognized by the following steps: Recognizing an increase in idle speed to an increased idle speed while the vehicle is stationary and Recognition of a reduction to idle speed within a period of time. Method according to one of the preceding claims, wherein the presence of a stop-and-go situation is detected by the following steps: Recognizing an increase in idle speed to an increased idle speed while the vehicle is stationary and Detecting a reduction to idle speed, each time between the repeated detection is not exceeded a certain period. Method according to one of the preceding claims, wherein as the accelerator pedal, an electronic accelerator pedal (1) is provided and for carrying out the method, a control device (10) between the accelerator pedal (1) and the engine control unit (3) of the vehicle is switched, soft in the absence of a stop and -Go situation the signal from the accelerator pedal (1) incoming signals (2a) to the engine control unit (3) and in the presence of a stop-and-go situation by the accelerator pedal (3) incoming signals (2a) speed-reducing changed (2b) the engine control unit (3) passes. Control unit (10) for operating an internal combustion engine of a vehicle with an electronic accelerator pedal (1) and an engine control unit (3) connected therewith via a signal line (2) for operating the engine in dependence on the position of the accelerator pedal,
characterized in that
the vehicle has sensors (6) for detecting a stop-and-go situation and is provided on the control unit (10): - A first input (11) for connecting to the signal coming from the accelerator pedal line (2a); - A second input (12) for connection to sensors (6) for detecting a stop-and-go situation; and - an output (13) for connection to the motor control unit (3) leading signal line (2b); wherein the signal line (2) is interrupted by the control unit. Control device according to claim 6, characterized in that the control device (10) is designed such that it makes a limitation of the maximum engine speed to a predetermined value, when there is a stop-and-go situation and there is the limitation of the maximum
Cancel engine speed when no stop-and-go situation exists. Control unit according to one of the preceding claims, characterized in that the sensors for detecting a stop-and-go situation are such that at least one of the following parameters is detected: - operation of ancillary equipment, in particular the period since its last use; - Condition of doors, footpegs, seat occupancy, in particular period since last use thereof; - Speed, in particular speed curve; - period since the last engine start; Speed, in particular speed course; - Presence of a speed-limited mode of the vehicle. Use of the control device according to one of the preceding claims for carrying out the method according to one of the preceding claims, in particular in a refuse vehicle.

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