HK1227074B - Method for controlling the speed of an internal combustion engine - Google Patents

Description

Method for regulating the speed of an internal combustion engine

Technical Field

The invention relates to a method for regulating the speed of an internal combustion engine and a speed control circuit for carrying out the method.

Background Art

The speed of an internal combustion engine is defined as the frequency of its rotations per unit time. It is typically regulated during operation, in particular to keep it constant over a specific period of time. For this purpose, a speed controller is used. By specifying a control parameter, it influences the operation of the internal combustion engine in such a way that the speed remains as constant as possible at a given level corresponding to the target speed, while minimizing interference effects. Various types of controllers are known, whose characteristics are determined by the control parameter and influenced by its selection.

Document DE 10 2004 023 993 A1 describes a method for regulating the speed of an internal combustion engine-generator unit via a clutch during a starting process. In this method, after starting a first acceleration ramp, a switch is made from a first parameter set to a second parameter set upon detecting clutch engagement, and the first parameter set is subsequently deactivated. Within the second parameter set, the second acceleration ramp plays a significant role in determining the target speed.

Therefore, in the method, the controller parameters are converted based on the clutch signal. This clutch signal must be available as an external signal. The controlled variable of the speed controller is the fuel injection quantity. Therefore, it cannot be easily used in systems with more fuel.

Summary of the Invention

Against this background, a method for regulating the speed of an internal combustion engine and a speed control circuit for carrying out the method are described. In this method, at least one fuel is injected into the internal combustion engine, and a speed controller is provided. The speed controller is arranged in the speed control circuit and its characteristics are determined by a control parameter. The method is characterized in that a fuel energy of at least one fuel to be injected is generated as an output variable of the speed controller, and a component of the speed controller is calculated based on a steady-state proportionality factor, and the steady-state proportionality factor is calculated proportionally to the fuel energy and inversely proportional to the internal combustion engine speed. The speed control circuit includes a speed controller that is designed to generate the fuel energy as an output variable.

A method is described herein that allows the engine speed of an internal combustion engine, particularly one with a common rail injection system, to be controlled, even when one or more fuels of different types are injected into each cylinder. The fuel energy per injection is used as an output variable of a speed controller or as a control variable of a speed control loop, thereby enabling use in systems with two or more fuels. The control variable is tracked using internally available signals such as engine speed, fuel energy, and speed control deviation. Furthermore, a load signal can be used to improve the dynamic response of the speed controller. Fuel energy is understood to mean the fuel energy per injection that is typical for the fuel type.

The speed regulator can automatically adapt to the control path characteristics depending on the operating point. By calculating the proportionality factor based on the speed control deviation and by using the load signal, an improved dynamic response of the speed control loop is achieved.

It should be noted that the total fuel energy is used as the correcting variable of the speed controller and not the setpoint torque or the injection quantity as in previously known speed controllers.

The proposed method has the following overall features, at least in its expanded structure:

The speed control loop is based on fuel energy. In other words, its controlled variable is the total fuel energy injected per cylinder during the combustion process. The controller characteristic is calculated based on the controller parameters. The steady-state proportionality factor is calculated proportionally to the fuel energy and inversely proportional to the engine speed. The steady-state proportionality factor can be limited downward.

Furthermore, the controller characteristic can be adapted as a function of a second control variable, a dynamic proportionality factor, wherein the dynamic proportionality factor is additionally dependent on the speed control deviation.

The scaling factor of the steady-state scaling coefficient consists of two multipliers, wherein the first multiplier depends on the application and takes the value 2 when applied to a ship and takes the value 1 when applied to a generator.

The second multiplier reflects the loop amplifier of the open-loop speed control loop specified by the operator and is independent of the application.

The proportional component of the speed controller is calculated based on the dynamic proportional coefficient.

The integral component of the speed regulator is calculated based on the steady-state proportional coefficient.

The differential component of the speed regulator is calculated based on the proportional coefficient in the steady state.

Another controller parameter, the lead time, can be linearly tracked via the fuel energy for calculating the derivative component.

A fuel energy charge signal for improving the dynamic response of the speed controller can be added to the output signal of the speed controller, wherein the fuel energy charge signal is calculated from the system signal generated when a load is switched on.

The dynamic proportionality factor depends on the speed control deviation and improves the dynamic response of the speed control loop.

The method can be used in speed control loops, in particular also in systems in which two or more fuels of different types (diesel, gasoline, . . . ) are injected into the combustion process.

The proposed method offers a number of advantages, at least in some exemplary embodiments. Because the regulating variable of the speed control loop is the total fuel energy, the speed control loop can be used in engines in which two or more fuels are also injected. By tracking the steady-state proportionality factor, the steady-state engine amplification factor, which depends on the operating point, is inverted using the fuel energy and the engine speed, thereby adapting the speed controller to the control path. This makes the behavior of the speed control loop largely independent of the operating point. Furthermore, by using a dynamic proportionality factor that depends on the speed control deviation when calculating the proportional component, the dynamic response of the speed control loop can be improved. Furthermore, by connecting the fuel energy loading signal to the output of the PI( _DT1 ) speed controller in series, the dynamic response of the speed control loop can be improved.

Further advantages and developments of the invention will become apparent from the description and the drawings.

It goes without saying that the features listed above and still to be explained below can be used not only in the combination specified but also in other combinations or alone without departing from the scope of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is schematically illustrated by means of exemplary embodiments in the drawings and is described in more detail below with reference to the drawings.

FIG. 1 shows the structure of a speed control loop for carrying out the presented method.

FIG2 shows the discrete algorithm of the PI (DT ₁ ) speed regulator.

FIG3 illustrates the calculation of the dynamic scaling factor.

FIG4 illustrates the calculation of the static scaling factor.

FIG5 shows the calculation of the advance time tv.

FIG6 shows the calculation of the loading signal.

DETAILED DESCRIPTION

FIG1 shows a speed control loop in a block diagram, which is designated overall by reference numeral 10. This speed control loop 10 operates based on fuel energy. The diagram shows a controller 12, in this case a PI( _DT1 ) controller, a module 14 for calculating fuel energy, a filter 16, a speed filter 18, an engine management unit 20, and an internal combustion engine 22. In place of the PI( _DT1 ) controller, a PI controller, a PID controller, or a (PID) _T1 controller could also be used.

The input signal of the speed control loop 10 is the setpoint speed 30. The difference between this setpoint speed 30 and the measured engine speed 32 is the speed control deviation 34. The speed control deviation 34 is the input variable of the PI (DT ₁ ) speed controller 12. The output variable of the PI (DT ₁ ) speed controller is the PI (DT ₁ ) fuel energy 36, which relates to the injection into the combustion process of the internal combustion engine cylinder. A charge signal fuel energy 38 is added to the output variable 36 of the speed controller 12. This addition is a series interference variable. It serves to improve the dynamic response of the speed controller 12. The sum of the speed controller output 36 and the charge signal fuel energy 38 is then limited by the module 14 to a maximum fuel energy 40 and to a negative fuel friction energy 42 per cylinder.

Here, the maximum fuel energy 40 depends on the engine speed, intake pressure, and other parameters. The limited fuel energy 44 is a control parameter of the speed control loop and also affects injection. Fuel friction energy 46 is then added to the limited fuel energy. Fuel friction energy 46 is understood to be the fuel energy corresponding to the friction losses of the internal combustion engine. These friction losses may be friction losses within the internal combustion engine cylinders. The required total fuel energy is ultimately transferred to the engine management 20 and converted by the engine management into an injection quantity. In a diesel injection system, this is injection quantity 48, and in an injection system with diesel and gasoline injection (dual fuel injection), it is additionally gasoline injection quantity 50. The engine speed 52 is detected and filtered using the speed filter 18. The output variable of the speed filter 18 is the measured speed 32.

FIG2 shows the discrete-time algorithm of the PI (DT ₁ ) speed controller, which is generally designated by reference numeral 12 . The output variable 36 of the speed controller algorithm is the sum of three components: a proportional component 74 , an integral component 76 , and a DT ₁ component 78 . Proportional component 74 is the product of the speed control deviation 34 and a so-called dynamic proportionality factor 80 . Dynamic proportionality factor 80 is a control parameter of the speed controller algorithm, the calculation of which is shown in detail in FIG3 .

The integral component 76, I component, of the speed controller is the product of the current, limited integral component delayed by the sampling step (delay element 82), an amplification factor 84, and the sum of the current and delayed speed control deviation 34 by the sampling step (delay element 86). The integral component of the speed controller is limited upward to the maximum fuel energy 40 and downward to the negative fuel friction energy 42.

The calculation of DT ₁ component 78 is shown in the lower portion of FIG. DT ₁ component 78 is obtained by the sum of two products. First product 92 is formed by multiplying DT ₁ component 78 delayed by the sampling step (delay element 96) by coefficient 94. Second product 98 is obtained by multiplying the output of switch 102 by coefficient 100. Depending on the position of switch 102, coefficient 100 is multiplied either by the difference between the current speed control deviation 34 and the speed control deviation delayed by the sampling step (delay element 96) (switch position 1) or by the difference between the measured generator speed delayed by the sampling step (delay element 108) and the current measured generator speed 32 (switch position 2).

In this case, if the target engine speed 30 does not change or changes only slightly, such as in generator applications, switch position 2 is always preferred. The amplification factors 84 and 100 of the I component and the DT ₁ component depend on the so-called steady-state proportionality factor kpStat, while the proportional component depends on the dynamic proportionality factor 80. The steady-state proportionality factor kpStat is calculated as follows:

kpStat=（f*v*E ^I _Soll ）/n _ist .

The measured engine speed n _is represented by reference numeral 32, and the integral component E ^I _Soll is represented by reference numeral 76. Therefore, the steady-state proportionality factor is proportional to the integral component E ^I _Soll and _inversely proportional to the measured engine speed n . The proportionality factor is the product of two multipliers: the first multiplier is the coefficient f, and the second multiplier is the loop gain v.

The coefficient depends on the application. For ship applications, f takes the value 2, and for generator applications, it takes the value 1. The loop gain factor v can be specified by the operator and is the dimensionless loop gain of the open-loop speed control loop. Large values of v increase the dynamic response of the speed control loop, while small values of v reduce the dynamic response of the speed control loop. The steady-state proportionality factor kpStat is limited to a specified minimum proportionality factor kpmin:

kpStat≥kpmin.

FIG3 illustrates the calculation of the dynamic proportionality factor 80. The dynamic proportionality factor 80 is calculated from the steady-state proportionality factor kpStat 152 plus a component 154 that depends on the speed control deviation 34. This component is effective when the switch 156 is in position 1. If the switch 156 is in position 0, the dynamic proportionality factor 80 corresponds to the steady-state proportionality factor kpStat 152.

When switch 158 is switched to position 2, switch 156 assumes position 1. In this case, switch 158 connects a logical 1 to switch 156, thereby placing it in position 1. When signal 160 has a logical value of 1, switch 158 is in position 2. This is the case when measured engine speed 32 is greater than or equal to setpoint effective speed 164, while speed control deviation 34 is less than or equal to 0. For an engine starting process, this means that after the engine starts, when engine speed 32 reaches effective speed 164, for example, 1500 rpm, and engine speed 32 reaches setpoint speed 30 (speed control deviation equal to 0), switch 156 switches to position 1, whereby dynamic proportionality factor 80 is calculated from steady-state proportionality factor kpStat 152 plus component 154 dependent on speed control deviation 34. If engine shutdown is detected, logic signal 165 has a value of 1, and switch 158 is in position 1. Consequently, switch 158 connects a logical 0, placing switch 156 in position 0. In this case, the dynamic proportionality factor 80 again corresponds to the steady-state proportionality factor kpStat 152 .

Component 154 dependent on speed control deviation 34 is calculated as follows: If speed control deviation 34 is greater than a set value e ^min _pos , component 154 dependent on the added dynamic proportional coefficient 80 of speed control deviation 34 increases linearly until speed control deviation 34 reaches value e _max . As speed control deviation increases further, added component 154 remains constant. If speed control deviation 34 is negative and less than a set value e ^min _neg , added component 154 increases linearly until speed control deviation 34 reaches the negative set value e _max . If the speed control deviation decreases further, added component 154 remains constant again.

By calculating the dynamic proportionality factor 80 as a function of the speed control deviation 34 , the dynamic response of the speed control loop during unstable processes, in particular load switching on and off processes, can be significantly improved, since the proportionality factor and the associated proportional component of the speed controller increase when a speed control deviation occurs.

FIG4 illustrates the calculation of the steady-state proportionality factor kpStat 152. If the engine speed n _ist 32 is equal to 0, switch 200 is in position 1, thereby switching on the value 80. However, if the engine speed n _ist 32 is not equal to 0, the engine speed n _ist 32 is limited downward to a given value n _min 202 and switched on by switch 200, since this switch is in position 0 in this case. The output value of switch 200 then forms an inverse 206 (block 204). This inverse 206 is multiplied by the factor f 208, the loop gain v 209, and the I component E ^I _Soll 212, which is limited downward to a given value E _min 210. The result 214 of this multiplication is also limited to a given value kpmin 216 and represents the steady-state proportionality factor kpStat 152. In summary, kpStat 152 is calculated as follows:

kpStat=（f*v*E ^I _Soll ）/n _ist （1）

E ^I _Soll ≥E _min

n _ist ≥n _min

kpStat≥kpmin

Where f=1 (generator)

f=2 (ship).

The I component E ^I _Soll must be limited downward to the value E _min so that the proportionality factor kpStat in the steady state is not too low or equal to 0, and so that the speed controller does not have an excessively slow dynamic response. If the proportionality factor is 0, the proportional component of the speed controller is no longer active. The engine speed n _ist must be limited downward at least to the engine speed detection limit, which is, for example, 80 rpm. For additional safety, kpStat is ultimately also limited overall to a lower limiting value kpmin.

Instead of the I component E ^I _Soll, the filtered fuel energy E _Soll ^Gefiltert 53 can be used to calculate the steady-state proportionality factor kpStat:

KpStat=（f*v*E _Soll ^Gefiltert ）/n _ist

in

E _Soll ^Gefiltert ≥E _min

n _ist ≥n _min

kpStat≥kpmin

in

f=1 (generator)

f=2 (ship).

Equation (1) is the control law for a speed regulator based on fuel energy. This control law describes the calculation of the steady-state proportionality factor kpStat. The steady-state proportionality factor kpStat is proportional to the fuel energy E ^I _Soll and E _Soll ^Gefiltert and inversely proportional to the engine speed n _ist . The proportionality factor is the product of two multipliers: the coefficient f and the loop gain v, where the coefficient f depends on the application and the loop gain v is specified by the operator.

To derive the regulation laws, the engine and the equipment are modeled as a single-mass oscillator. If the law of conservation of angular momentum is applied to this single-mass oscillator, the following equation is obtained for the case of propeller drive (applicable to ships):

Θ*dw/dt=M _m -k _B *n _ist ²

in

Θ=Θ _Moto +Θ _Last

Θ - total moment of inertia [kgm ² ]

w - angular velocity [1/s]

M _m - engine torque [Nm]

k _B - scaling factor [Nm min ² ]

n _ist - engine speed [1/min]

The angular velocity w is calculated as follows:

w=2*pi*n _ist

This results in the following nonlinear model of a single-mass vibrator:

Θ*2pi*dn _ist /dt+k _B *n _ist ² =M _m

If this equation is linearized, the following linear model for a single-mass vibrator is obtained:

Θ*2*pi*d（Δn）/dt+2*k _B *n _Bet *Δn=ΔM _m

in

n _Bet : Engine speed operating point at which linearization is performed

Δn, ΔM _m : Deviation of engine speed and engine torque at the operating point

Therefore, the transfer function for a single-mass vibrator applies:

G(s)=Δn(s)/ΔM _m (s)=k _m /(1+T _m *s)

in

k _m =1/(2*k _B * n _Bet ) (2)

T _m = (pi*Θ)/(k _B * n _Bet )

The relationship between the fuel energy E _Soll per injection and the engine torque M _m is as follows:

E _Soll = (pi*M _m )/(250*z*η)

in

E _Soll - fuel energy per injection [kJ]

M _m - engine torque [Nm]

z-number of cylinders[ ]

η-efficiency[ ]

For the engine torque M _m, the following applies:

M _m =kv*E _Soll (3)

in

kv=（250*z*η）/pi

Therefore, at the operating point (M _m ^Bet , E _Soll ^Bet ) the following applies:

M _m ^Bet =k _v *E _Soll ^Bet (4)

For load torques, the following applies:

M _m ^Bet =k _B *n _Bet ²

Therefore, it is applicable to

k _B *n _Bet =M _L ^Bet /n _Bet (5)

For engine magnification, apply to:

v _m = k _v * k _m

By (2) applies to:

v _m =k _v *[1/（2*k _B * n _Bet )]

Through (5) we can get:

v _m = (k _v *n _Bet )/(2*M _L ^Bet )

In steady-state operation the engine torque is identical to the load torque:

M _m ^Bet = M _L ^Bet

This applies to:

v _m = (k _v *n _Bet )/(2*M _m ^Bet )

By (4) applies to:

v _m = (k _v *n _Bet )/(2*k _v *E _Soll ^Bet )

The steady-state amplification factor for the engine thus applies:

v _m =n _Bet / (2* E _Soll ^Bet ) (6)

For an open-loop speed control loop, the loop gain applies:

v=kpStat*v _m

This results in the following regulation law:

kpStat=（2*v* E _Soll ^Bet ）/n _Bet

in

kpStat - steady-state proportionality coefficient [kJ min]

v-loop magnification[ ]

n _Bet - engine speed [1/min]

E _Soll ^Bet - theoretical energy of fuel [kJ]

If the I component of the rotational speed regulator is used for E _Soll ^Bet and the measured rotational speed n _ist is used for n _Bet , the following equation is obtained for application to ships:

kpStat=（2*v*E ^I _Soll ）/n _ist （ship）

When applied to the generator, a linear relationship between load torque _ML and engine speed _nst applies. This results in a variable multiplier in the control law:

kpStat=（v*E ^I _Soll ）/ _nist （generator）

In summary, the above regulation law (1) is obtained:

kpStat=（f*v*E ^I _Soll ）/n _ist

in

f=1 (generator)

f=2 (ship)

E ^I _Soll ≥E _min

n _ist ≥n _min

kpStat≥kpmin.

This control law keeps the loop gain of the open-loop speed control loop constant over the entire operating range. Equation (6) shows that the engine gain is small at low engine speeds and large at high engine speeds. The engine gain is large at low fuel energy and small at high fuel energy, i.e., high load. Because a large kpStat is calculated at low engine speeds and a small kpStat is calculated at high engine speeds according to the above-mentioned control law, the loop gain of the open-loop speed control loop is kept constant overall. The same applies to fuel energy: a small kpStat is calculated at low fuel energy and a large kpStat is calculated at high fuel energy, so that in this case, the loop gain can also be kept constant overall.

The loop gain is a predeterminable parameter. By increasing this parameter, the dynamic response of the speed control loop can be increased. The control law in the form described exhibits the following characteristics:

The steady-state proportionality factor kpStat is tracked linearly by the fuel energy.

-The steady-state proportionality factor is inversely proportional to the engine speed.

-The steady-state proportionality factor is proportional to the loop gain v, which can be given by the operator.

- The steady-state proportionality factor is twice as high when applied to a ship as when applied to a generator.

- The proportionality factor in the steady state is limited downward to a given value kpmin.

2, the advance time tv is used to calculate the amplification factor 100 of the DT ₁ component. The advance time tv can be constant or alternatively calculated from the fuel energy, as shown in FIG5. In this case, either the I component E ^I _Soll of the speed controller or the filtered target fuel energy E _Soll ^Gefiltert is used as the fuel energy.

FIG5 shows a graph of the relationship between the advance time tv 250 and the fuel energy 248. The figure shows that if the fuel energy is less than a given value E _min 254, the advance time tv 250 corresponds to a value tv _min 252. If the fuel energy is greater than a given value E _max 256, tv corresponds to a value tv _max 258. If the fuel energy is greater than E _min 254 and less than E _max 256, tv 250 tracks linearly through the fuel energy 248. The values tv _min 252 and tv _max 258 can be specified by the operator.

FIG1 shows that a charge signal fuel energy 38 is added to the output 36 of the PI (DT ₁ ) speed controller. Charge signal fuel energy 38 is a disturbance variable of the speed control loop. Its purpose is to improve the dynamic response of the speed controller during unstable processes, such as load switching on and off.

FIG6 illustrates calculation of the loading signal fuel energy 38. The loading signal fuel energy is calculated from a plant signal, such as a generator power signal. The plant signal is provided by the plant operator as a 0…10 volt or 4…20 mA signal. If switch 341 is in position 1, voltage signal U (0…10 volts) is used; if switch 341 is in position 2, current signal I (4…20 mA) is used.

Each input signal 302 or 304 is first converted into a percentage using a two-dimensional curve 306 or 308. This results in a signal 310 defined as a percentage. A given maximum load signal, fuel energy 312, corresponding to a value of 20,000 J, for example, is divided by 100 and multiplied by this converted percentage value. The result of this multiplication 316 is then amplified by a DT ₁ element 318. The given DT ₁ algorithm parameters are the lead time tv _Load and the delay time t1 _Load . These two parameters serve as input parameters for module 318. The output 320 of the DT ₁ system 318 is processed by the "Hysteresis" module 322 as follows: If the output of the DT ₁ system exceeds an upper limit value, such as 1,000 J, or if it falls below a lower limit value, such as -1,000 J, the output of the DT ₁ system is switched on, i.e., activated. In this case, the output 324 of the hysteresis module corresponds to the output of the DT _{1 system. If the output of the DT 1 system} falls below another limit value, such as 50 J, the output is switched off, i.e., the output of the hysteresis module is equal to 0 in this case. The limit value is an input parameter of module 322 .

If switch 330 is in position 1, load signal fuel energy 38 corresponds to output 324 of hysteresis module 322. This is the case when engine speed 32 is greater than or equal to setpoint speed 334 and parameter "load signal active" 340 is equal to 1. This means that load signal fuel energy 38 is disconnected when engine speed 32 reaches setpoint speed 334 and setpoint parameter "load signal active" 340 is set to value 1. In all other cases, load signal fuel energy 38 is equal to 0. The purpose of load signal fuel energy 38 is to support the speed controller during load switching operations. If a load is switched on or off in the case of a generator, the generator power increases or decreases. If this generator power is detected and read out from the engine circuit as a 0...10 volt or 4...20 mA signal, the signal is amplified using DT ₁ and fed to the speed controller as a disturbance variable, thereby improving the dynamic response, or responsiveness, of the speed control loop.

Claims (12)

1. A method for regulating the speed (32) of an internal combustion engine (22), comprising injecting at least one fuel of a fuel into the internal combustion engine, having a speed regulator (12) disposed in a speed regulation loop (10) and the characteristics thereof determined by a regulation parameter, characterized in that the output parameter (36) of the speed regulator (12) generates fuel energy of at least one fuel to be injected, and the components (74,76,78) of the speed regulator (12) are calculated according to a steady-state proportionality coefficient (152) and the steady-state proportionality coefficient (152) is calculated proportionally to the fuel energy (76,53) and inversely proportional to the speed (32) of the internal combustion engine (22). 2. The method for adjusting the speed of an internal combustion engine as claimed in claim 1, characterized in that the components (74, 76, 78) of the speed regulator (12) are calculated based on a dynamic proportional coefficient (80), wherein the dynamic proportional coefficient (80) additionally depends on the speed adjustment deviation (34). 3. The method as claimed in claim 1 or 2, wherein the scaling factor of the steady-state scaling factor (152) consists of two multipliers (208, 209), wherein the first multiplier (208) depends on the application, taking a value of 2 when applied to a ship and a value of 1 when applied to a generator. 4. The method as claimed in claim 3, wherein the second multiplier (209) reflects the loop amplification of the open-loop speed regulation loop given by the operator and is independent of the application. 5. The method as described in claim 2, characterized in that the proportional component (74) of the speed regulator is calculated based on the dynamic proportional coefficient (80). 6. The method as described in claim 1 or 2, characterized in that the integral component (76) of the speed regulator is calculated based on the steady-state proportional coefficient (152). 7. The method as described in claim 1 or 2, characterized in that the differential component (78) of the speed regulator is calculated based on the steady-state proportional coefficient (152). 8. The method as claimed in claim 7, wherein the advance time (250) for calculating the differential component (78) is linearly tracked by the fuel energy (248, 76, 53). 9. The method as claimed in claim 1 or 2, characterized in that a fuel energy-load signal (38) for improving the dynamic response of the speed regulator (12) is added to the output signal (36) of the speed regulator (12). 10. The method as claimed in claim 9, wherein the fuel energy-load signal (38) is calculated from the equipment signal generated when the load is turned on. 11. The method as claimed in claim 1 or 2, characterized in that a variety of different types of fuels are injected into the cylinder and burned during the combustion process. 12. A speed regulation circuit (10) for performing the method as claimed in any one of claims 1 to 11, having a speed regulator (12) designed to generate fuel energy as an output parameter (36).