DE3839462A1 - Drive system with steplessly adjustable output transmission ratio - Google Patents

Abstract

In known drives which comprise an internal combustion engine and a transmission, a variation of the output speed of the transmission inevitably causes a variation of the output speed of the internal combustion engine. In this the said variation of the output speed of the internal combustion engine can occur only along predetermined characteristic curves, which are defined by the transmission ratio. Because, for a given, constant transmission output speed, the output speed of the internal combustion engine can be controlled as a function of operating parameters of the internal combustion engine and the transmission, an individual adjustment to certain requirements can be undertaken. For this purpose control systems are demonstrated which assume corresponding control of the internal combustion engine and the transmission. <IMAGE>

Description

The invention relates to a drive system and a method to regulate the drive system according to the generic terms of the independent claims.

Drive systems are known from vehicle construction which consist of an internal combustion engine and a downstream Gearboxes exist, from whose output shaft the drive wheels of the vehicle (power sink) are driven. Depending on the design and use of the Vehicle a number of gears that mechanically or can be switched automatically. So it changes inevitably with increasing or decreasing output rotation Number of gears at the same time according to the gear ratio defined in each gear nis the output speed of the internal combustion engine. Consequently are the according to the specified gear ratio different areas of internal combustion engine identification field. The gearbox design specifies whether the internal combustion engine map in the range of a gün specific fuel consumption, high Torque, lower noise emissions, lower Exhaust emissions or other parameters is run through. Therefore, each gearbox design relates to one predetermined map of an internal combustion engine one more or less bad compromise. In certain ones cases of one and the same drive unit can namely favorable specific fuel consumption is desirable  be, while in a subsequent use case low exhaust emissions is desired.

The invention has for its object a drive system stem and a method for controlling the drive system provide with the disadvantages described above be avoided.

This task is performed by the drive system according to Patentan spell 1 solved in that the output power of Internal combustion engine depending on the system: Gearbox power sink requested power adjustable is. Thus, the internal combustion engine does not determine that of power delivered to the transmission but the transmission requests a service. However, this allows characteristic curves same performance according to the requirement in the map the internal combustion engine are started and accordingly desired operating points of the internal combustion engine can be set.

According to the procedural claim, a control system is provided see this, according to a system performance requirement: Gearbox power sink the power output of the Brenn Engine controls such that the internal combustion engine performance to be delivered according to specifiable requirements is adjustable in the map of the internal combustion engine. Since the As is well known, the product of torque and Speed is determined, a change in performance can thus be achieved by changing the speed while maintaining the same speed Moment or vice versa or also with yourself at the same time Set changing torque and changing speed.

In a further development of the method, the transmission requested power in the gearbox to a desired one Set the torque and a desired speed. To this Way, the control process is simplified overall because only the information about the power to the internal combustion engine  machine forwarded or processed by the control system must be tet. The control system then searches accordingly the given boundary conditions which are correspondingly favorable speed with the corresponding torque from the Map of the internal combustion engine out.

According to an advantageous development of the invention Control system in an engine control system and one Transmission control system divided. This means that aufa Partially solve drive tasks. The internal combustion engine optimizes their operating conditions while another Electronics the behavior of the entire system: Gearbox power sink can optimize.

The specified in the further dependent claims NEN features represent advantageous developments of Invention is in the description of the drawing Embodiment of the invention described in more detail.

The individual shows:

Fig. 1 is a block diagram of the drive system with the inventive control system,

Fig. 2 shows an example of a possible Regelvor gear.

The A block of the block diagram of FIG. 1 is the internal combustion engine and block B standardize the transmission of Antriebsein. Block C contains the internal combustion engine control system, while block D houses the transmission control system. The internal combustion engine is, for example, a self-igniting internal combustion engine, the flywheel 1 of which is connected to the transmission by means of a shaft 2 . The transmission, which is preferably a continuously variable or hydraulic transmission, has an output which is an arbitrary drive (block B 1 ) for, for example, a vehicle, car, truck, tractor, machine or device (power sink).

The internal combustion engine has a fuel metering device 3 which, in the case of a self-igniting internal combustion engine, is an injection pump with a corresponding regulating device. The fuel metering device 3 has at least one control input 4 , via which the amount of fuel to be metered to the internal combustion engine can be changed. Wei terhin the internal combustion engine has a measuring system 5 , which continuously emits signals about the metered amount of fuel or suitable signals for its determination.

The invention is based on the following fundamental law regularities, considerations or regularities from:

A drive train with two is exemplified above regulated working groups (e.g. lifting and swiveling) shown.

P _x = power, M _x = torque, n _x = speed,
k _x = translation with x = 0 = internal combustion engine,
x = 1 = circle 1, x = 2 = circle 2

The following applies: P ₀ = P ₁ + P ₂ (+ P _v ) (1)

P _v = losses (are not taken into account when considering)

It is clear from this that such a system is clearly defined by the total power P ₀ (internal combustion engine power). If the internal combustion engine according to this invention receives a characteristic that allows the power to be set, the system (for example a hydraulic controller) that specifies the value “power request” knows the total power P ₀ .

Now z. B. the gear ratios can be determined by determining the engine speed. This means that M _{0 can also be} calculated.

From (1) follows:

M ₀ * n ₀ = M ₁ * n ₁ + M ₂ * n ₂ (2)

To avoid internal combustion engine overload is a Information about the torque reserve in the internal combustion engine seem necessary. Because the absolute amount of internal combustion machine torque by the engine controller is to be influenced, is a relative statement here required.

M _res = M _max (n₀) - M _ist (n₀) / M _max (n₀) (3)

The actual torque reserve of the internal combustion engine at the engine speed n ₀ at the current time is set in relation to the maximum possible torque of the internal combustion engine at n ₀ . If the value approaches zero, there is a risk of instability. This method requires the storage of the torque curve in a memory of the internal combustion engine electronics.

Signal overview of the interface

Adaptive determination of the full load line

The full load limit is set for mechanical injection systems adjustable. The data stored in the controller must agree with the mechanical adjustment. For the Service must find a procedure that transfers mechanical adjustment into the electronics.

An electrical contact (full load contact) is provided with the help of which it can be recognized when the mechanical controller reaches full load. So that is exactly the point for

M _res = 0 determined.

This digital switching signal of the full load contact can be used for the following applications are used:

• - Limit load regulation
• - Driver information
• - Gear shift information
• - Service / adjustment
• - Adaptive determination of the full load line

A self-learning, adaptive system at Internal combustion engine assembly a basic data set. With help the full load contact is with running internal combustion made an individual adjustment. In order to can output an analog signal "torque reserve" be the corrections to the mechanical setting balancing.

An internal combustion engine compares this signal at be agreed speeds and closed contact with the stored data. A correction can be made if these values are secured with a suitable algorithm are.

Another method observes the maximum control rods positions and recognizes new highs. These values can then also be used as shown above.

The internal combustion engine control system is as follows builds:

The internal combustion engine control system includes a position / quantity controller 6 , the output of which is connected to the control input 4 of the internal combustion engine and controls the fuel metering device 3 . It should be noted that the output of the position / quantity controller, if necessary, can also influence a valve control of the internal combustion engine in addition to the fuel metering device 3 .

The internal combustion engine delivers a signal by means of a measuring system 5 , which is suitable for determining the amount of fuel consumed. This is connected to the input of the position / quantity controller 6 and to the input of a memory 7 . In the memory 7 , the map of the internal combustion engine efficiency as a function of the control path and the speed of the internal combustion engine is saved. The current speed signal is transmitted to the memory 7 by a sensor 8 , which measures the speed of the shaft 2 . The speed signal is also fed to a speed controller 9 , an integrator 10 , a multiplier 11 and a comparator 12 . The speed controller 9 controls the speed of the internal combustion engine depending on the state of a power control circuit 13 . For example, if the required power is too low, speed controller 9 increases the speed requirement. The moment increases until either the desired performance is reached or is accelerated accordingly along the full load curve of the internal combustion engine.

The power that is currently delivered by the internal combustion engine is calculated with the multiplier 11 from the engine torque and the speed. The current output is constantly compared with the output requested by the output side. In addition, however, the internal combustion engine control system in the characteristic diagram 14 determines an optimum speed for this power and, via the integrator 10 , performs the power control circuit 13 as long as an additional power for acceleration or deceleration until the most favorable speed for this operating point has been set. The map 14 , in which the optimum speed for an output is stored, can be set according to the required boundary conditions, so that cheaper consumption, cheap exhaust gas emissions or other parameters serve for the selection of the speed.

The transmission control system is transmitted information about the instantaneous torque reserve 16 from the output of the calculation and storage stage 12 and a signal 17 of the engine speed from the output of the standardization member 15 . Information is supplied to the internal combustion engine control system about the internal combustion engine output 18 requested by the system: transmission power sink.

In Fig. 2, the full load curve of the internal combustion engine is plotted against the speed and the internal combustion engine torque. The operation of the invention is explained using the example of acceleration. The instantaneous operating point of the internal combustion engine is I. Due to the increased demand on the part of the transmission or the power sink, the internal combustion engine torque increases to II. Since the quantity limitation of the fuel metering element 3 has been reached, a further increase in performance can only be achieved through the Acceleration of the internal combustion engine to point III can be achieved. This is the currently requested engine power. The integrator 10 now lets the internal combustion engine drif th to the optimal operating point IV along the power hyperbolic. The transmission continuously converts the incoming constant power with changing speed and changing torque into a desired constant speed and a corresponding constant torque .

A total of three time periods have to be defined:

• 1. Response time to setpoint changes.
  This is essentially determined by the delays of the fuel metering device 3 . For solenoid valves, this corresponds to the interval between two injections, for control rod systems approx. 50 to 100 ms, for servomotors 0.1 s to 0.5 s. This means that the engine torque can run through its full range of values during these periods.
• 2. The acceleration time.
  If a change in speed is required to change the power, the flywheel masses act as a delay in the entire primary working group.
• 3. The time constant for speed setting.
  An integrator leads the engine speed to the optimal working point. It must be designed in such a way that the malfunction caused by it is safely controlled by the regulation on the output side. The "flow" of the speed must not be uncomfortable for the driver either.

In summary it can be stated that it is with the present ing invention without restricting the scope the internal combustion engine is possible continuously an optimal control line, which depending on the requirements for example, consumption, service life, noise can run optimally.

A performance requirement from the system: transmission performance sink directly increases the amount of fuel. A high dynamic can be achieved when dynamic signals (e.g. dn / dt) are activated.

The formation of the "power request" signal can in different ways and ultimately has to Based on an analysis of the drive task. Common is the process of giving a driver one more "drive lever" or less actuated to a desired work result to reach. So far, however, was the internal combustion engine cha characteristics not freely definable, so that depending on Internal combustion engine type showed different behavior. It therefore makes sense to request the driver as a performance request change.

Are certain jobs independent of the driver's will do so, the performance request must be electronic  be determined. Here is a known, constant decrease performance to be mentioned as a constant to or away is switched. If there is a control loop, the Control deviation provide a measure on the basis of which the Performance is increased or decreased. Are there higher requirements? changes to the control accuracy, there is a lei performance measurement or calculation of performance (e.g. Pressure and speed measurement if the control deviation increases Should become zero.

Is the setpoint specification and switching on the hydraulics System acceleration can be time-controlled be optimized.

A control line (no area) is defined, which is always aimed at integrally. That’s why Internal combustion engine operating points over the speed in statistical means known.

The speed controller behavior regarding the P degree can go to zero.

On the hydraulic side, the total power is based on the Target value can be estimated.

This gives the opportunity to see the current performance in the To estimate the hydraulic circuit (no pressure measurement!) And to Use control of the work result.

The engine-specific data, like the rule line are only stored in the engine control system.

Claims (12)

1. Drive system, at least consisting of an internal combustion engine and at least one transmission and a consumer (power sink), the output speeds and output torques of the internal combustion engine and the transmission being changeable, characterized in that the output power of the internal combustion engine is dependent on the system: Gearbox power sink requested power ( 18 ) is controllable and wherein the gearbox converts the power ( 18 ) into a desired speed-torque ratio. 2. Drive system according to claim 1, characterized in that the output speed of the internal combustion engine as a function of the system: gearbox power sink requested power ( 18 ) is regulatable, the speed control of the internal combustion engine being carried out at least as a function of operating parameters of the internal combustion engine. 3. Drive system according to claim 1 or claim 2, characterized in that the output torque of the internal combustion engine as a function of the system: gearbox power sink requested power ( 18 ) is regulatable, the torque control of the internal combustion engine at least depending on the operating parameters of the internal combustion engine he follows. 4. Drive system according to one of claims 1 to 3, characterized in that the gearbox has a fine, is continuously variable or hydraulic transmission. 5. Drive system according to one of claims 1 to 4, characterized in that at least the Brennkraftma machine and the gearbox operating data to a control system transmit and the tax system from the transmitted Operating data control values for controlling the internal combustion engine machine derives and according to the control values Internal combustion engine controls. 6. Drive system according to claim 5, characterized in that the control system into a focal engine control system and a transmission control system is divided. 7. Drive system according to claim 6, characterized in that the internal combustion engine control system information about the system: transmission Lei stungssenke requested power ( 18 ) and the instantaneous output of the engine are supplied. 8. Drive system according to claim 7, characterized in that the currently delivered Power from a speed signal and a fuel supply measurement signal is determined. 9. Drive system according to one of claims 6 to 8, characterized in that the internal combustion engine control system emits signals for adjusting a fuel metering organ ( 3 ) and the transmission control system information on the internal combustion engine output speed ( 17 ) and the instantaneous available torque reserve ( 16 ) via averaged. 10. Drive system according to one of claims 6 to 9, characterized in that the internal combustion engine control system has at least one memory ( 7 ) in which the map of the internal combustion engine can be stored. 11. Method for regulating an internal combustion engine performance to be delivered with changing performance Requirements of one of the internal combustion engine systems: gearbox power sink, characterized in that a tax system according to a System performance requirement: Transmission power sink regulates the power output of the internal combustion engine in such a way that the power to be delivered by the internal combustion engine according to specifiable requirements in the map of the internal combustion engine machine in a corresponding speed-torque Ratio is set. 12. The method according to claim 11, characterized in that by the internal combustion engine power to be output from the transmission into a desired one Moment and a desired speed according to the lei performance requirement is implemented.