Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02D—CONTROLLING COMBUSTION ENGINES
  • F02D31/00—Use of speed-sensing governors to control combustion engines, not otherwise provided for
  • F02D31/001—Electric control of rotation speed
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02D—CONTROLLING COMBUSTION ENGINES
  • F02D41/00—Electrical control of supply of combustible mixture or its constituents
  • F02D41/02—Circuit arrangements for generating control signals
  • F02D41/04—Introducing corrections for particular operating conditions
  • F02D41/06—Introducing corrections for particular operating conditions for engine starting or warming up
  • F02D41/062—Introducing corrections for particular operating conditions for engine starting or warming up for starting
  • F02D41/064—Introducing corrections for particular operating conditions for engine starting or warming up for starting at cold start
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
  • F02B75/00—Other engines
  • F02B75/16—Engines characterised by number of cylinders, e.g. single-cylinder engines
  • F02B75/18—Multi-cylinder engines
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02D—CONTROLLING COMBUSTION ENGINES
  • F02D2200/00—Input parameters for engine control
  • F02D2200/02—Input parameters for engine control the parameters being related to the engine
  • F02D2200/021—Engine temperature
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02D—CONTROLLING COMBUSTION ENGINES
  • F02D2200/00—Input parameters for engine control
  • F02D2200/02—Input parameters for engine control the parameters being related to the engine
  • F02D2200/04—Engine intake system parameters
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02D—CONTROLLING COMBUSTION ENGINES
  • F02D2200/00—Input parameters for engine control
  • F02D2200/02—Input parameters for engine control the parameters being related to the engine
  • F02D2200/10—Parameters related to the engine output, e.g. engine torque or engine speed
  • F02D2200/101—Engine speed
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02D—CONTROLLING COMBUSTION ENGINES
  • F02D2250/00—Engine control related to specific problems or objectives
  • F02D2250/18—Control of the engine output torque
  • F02D2250/26—Control of the engine output torque by applying a torque limit

Definitions

• the invention relates to a method for operating an internal combustion engine with a plurality of cylinders, a warm-up operation being carried out after the internal combustion engine has started, during which a rotational speed of the internal combustion engine is limited to a limit value.
• the invention further relates to an internal combustion engine.
• the publication DE 42 19 362 B4 is known from the prior art.
• This describes an engine speed control unit for an engine that is equipped with an automatic transmission.
• the engine speed control device includes an overspeed lock device that is actuated at a predetermined limit speed.
• the overspeed lock device is actuated in such a way that it reduces the engine output, for example by interrupting the fuel supply to the engine, thereby preventing the engine from operating at speeds which are greater than the limit speed.
• the limit speed is changed depending on engine operating conditions, for example depending on engine temperatures.
• a regular upshift vehicle speed which is ideally determined by shift control curves, in order to carry out upshifts of the automatic transmission as a function of throttle openings, is changed or adjusted as a function of engine temperatures. It is an object of the invention to propose a method for operating an internal combustion engine, which has advantages over known methods, in particular enables operation of the internal combustion engine with low emissions, preferably during a warm-up operation of the internal combustion engine.
• the limit value is selected at least temporarily as a function of a starting temperature of the internal combustion engine during warm-up operation.
• the described method is used to operate the internal combustion engine, which in turn is preferably used to drive a motor vehicle, that is to say to provide a torque aimed at driving the motor vehicle.
• the internal combustion engine has the plurality of cylinders, each of which has a combustion chamber.
• the engine is started at the start.
• the start can include increasing the speed of the internal combustion engine and / or switching on a fuel supply to the internal combustion engine, for example.
• the speed is particularly preferably increased starting from a standstill of the internal combustion engine, that is to say a speed of zero, up to a minimum speed or an idling speed of the internal combustion engine.
• the minimum speed of the internal combustion engine corresponds to the speed from which the internal combustion engine can further increase its speed automatically, that is to say without an external torque supply.
• the idling speed is the speed at which the engine is operated, provided that it is not used to provide a torque.
• the idle speed is preferably higher than the minimum speed.
• the idling speed is selected such that the engine has as smooth a running as possible with at the same time as little fuel consumption as possible.
• the start of the internal combustion engine takes place, for example, after switching off the internal combustion engine, in particular in the context of parking the motor vehicle.
• the internal combustion engine can also be started by an automatic stop-start system.
• Switching off the internal combustion engine includes, for example, reducing the speed of the internal combustion engine, in particular to zero, that is to say when the internal combustion engine is at a standstill, and / or switching off the fuel supply.
• the internal combustion engine can initially have any speed.
• the internal combustion engine can be towed when the fuel supply is switched off, that is to say driven by means of an external torque.
• the internal combustion engine can, for example, be switched off if the motor vehicle is switched off. Parking the motor vehicle means that the motor vehicle is stopped, that is, its speed is reduced to zero. In particular, when the motor vehicle is switched off, the driver leaves the motor vehicle at least temporarily. It is particularly preferred to get back into the motor vehicle before starting.
• the motor vehicle can be designed as a hybrid vehicle.
• the internal combustion engine can also be started while the motor vehicle is moving, for example when the internal combustion engine is switched on in a controlled manner.
• the start of the internal combustion engine can also take place after a temporary shutdown of the fuel supply, for example during a towing operation or a fuel cut-off of the internal combustion engine.
• a speed of the internal combustion engine can be increased to the minimum speed by an electrical machine, for example a starter. After the minimum speed has been reached or before, the fuel supply is switched on, so that after the start the internal combustion engine can operate on its own. After the internal combustion engine has started, the warm-up operation is carried out.
• the internal combustion engine is operated in such a way that the speed of the internal combustion engine is limited to a limit value.
• the rotational speed is preferably a rotational number of a shaft assigned to the internal combustion engine, in particular a crankshaft or a camshaft.
• the internal combustion engine is operated at least outside of the warm-up mode in such a way that the speed corresponds to a target speed.
• the target speed is determined, for example, from the instructions of the driver of the motor vehicle and / or the driver assistance device of the motor vehicle. For example, the target speed is determined using an accelerator pedal position.
• the internal combustion engine is operated in such a way that the speed is limited to the limit value during the warm-up operation, so the speed of the internal combustion engine cannot exceed the limit value. At least during the warm-up operation, the speed of the internal combustion engine can be less than the target speed, namely if the limit value is less than the target speed.
• the limit value of the speed during warm-up operation is selected at least temporarily depending on the starting temperature of the internal combustion engine.
• the start temperature is a temperature, for example a combustion chamber temperature, at the time the internal combustion engine starts.
• the starting temperature can also be a temperature of the internal combustion engine that corresponds to the combustion chamber temperature or at least approximately correlates with it.
• the start temperature can be measured directly by a temperature sensor or indirectly determined based on a model calculation.
• the model calculation can take into account available sensor data, such as, for example, an outside temperature, a previous operating time of the internal combustion engine, or the duration of a shutdown of the internal combustion engine before the start.
• the model calculation can be carried out in a control unit assigned to the internal combustion engine.
• the limit value is selected as a function of the start temperature during warm-up operation. In other words, the limit value is dependent on the combustion chamber temperature at the time of starting Internal combustion engine selected, which is measured directly or estimated by the model calculation.
• the pollutant emissions of the internal combustion engine which occur at the start or after the start of the internal combustion engine, can be significantly reduced, namely by reducing the speed of the internal combustion engine during warm-up operation.
• An externally ignited internal combustion engine in particular an Otto engine, is preferably used as the internal combustion engine.
• a particularly preferred embodiment of the invention provides that during the warm-up operation, a cylinder charge of the cylinders is at least temporarily limited to a limit value.
• the fresh gas can consist entirely of fresh air or at least have fresh air.
• the fresh gas is composed of fresh air and exhaust gas, namely if an exhaust gas recirculation is carried out.
• the introduction of the fresh gas takes place at least outside the warm-up mode in such a way that after the introduction there is an amount of the mixture in the combustion chamber which corresponds to a desired amount.
• This target quantity is determined, for example, from a specification by a driver of the motor vehicle and / or a driver assistance device of the motor vehicle.
• the cylinder filling is limited to the limit value.
• the cylinder charge can therefore be at least temporarily smaller than the target quantity, namely if the limit value is smaller than the target quantity.
• the limit value is exceeded by the Cylinder filling prevented during warm-up operation.
• the limitation can be achieved by means of the control device assigned to the internal combustion engine, which adjusts the cylinder charge by actuating a corresponding control element, for example a throttle valve.
• the cylinder filling is preferably the filling of each of the cylinders, that is to say not the cylinder filling of all the cylinders together.
• the cylinder filling of each of the cylinders is limited to the limit.
• the limit values are always dealt with in the following explanations, however, the explanations apply in the case of several limit values accordingly both to the limit value of the speed and to the limit value of the cylinder charge.
• the warm-up operation is only carried out when the starting temperature of the internal combustion engine is below a minimum temperature.
• the speed of the internal combustion engine is limited to the limit value during warm-up operation.
• the torque directed to driving the motor vehicle is also limited during warm-up operation.
• the minimum temperature is provided in order not to limit the torque that can be called up for driving the internal combustion engine after a very brief standstill of the internal combustion engine, during which the cooling of the internal combustion engine progresses only slightly.
• the minimum temperature can be selected depending on the ambient temperature. For example, a lower minimum temperature can be provided at a lower ambient temperature, while a higher minimum temperature is provided at a higher ambient temperature. If the start temperature determined at the time of the start is below the minimum temperature, the warm-up operation described above is carried out when the internal combustion engine starts. If the starting temperature determined at the time of starting the internal combustion engine is above the minimum temperature, the warm-up mode is started not carried out, but, for example, normal operation in which the speed is not limited to the limit value.
• the limit value at the start of the warm-up operation is set to a start value selected as a function of the start temperature of the internal combustion engine.
• the starting temperature describes the combustion chamber temperature of the internal combustion engine and can thus be used as a measure of the progressive cooling of the internal combustion engine. It may make sense to choose the limit value of the speed selected during warm-up operation as a function of the starting temperature and thus the cooling of the internal combustion engine.
• the start value is set for the limit value, which is set at the start of warm-up operation.
• a minimum value can also be determined for this start value in order to limit the choice of the limit value.
• the starting value is therefore not exclusively selected as a function of the starting temperature of the internal combustion engine, in particular the selection of the starting value for providing a minimum torque can be limited by the minimum value.
• provision can be made to select the starting value as a function of the ambient temperature. For example, a lower start value can be set at a lower ambient temperature and a higher start value at a higher ambient temperature.
• a further embodiment of the invention provides that the limit value is increased during the warm-up operation starting from the start value in the direction of an end value.
• a limit value is set for the limit value, which may be a maximum permissible value which may be present during continuous operation of the internal combustion engine as intended, without causing damage to the internal combustion engine or are to be expected.
• the end value will always be higher than the start value and the limit value will increase towards the end value during warm-up operation.
• the final value is selected as a function of the starting temperature of the internal combustion engine.
• the final value is not set to the maximum permissible value, but is selected as a function of the starting temperature. Since the starting temperature describes the combustion chamber temperature of the internal combustion engine, a lower final value can be selected if cooling has already progressed further. Alternatively or additionally, the final value can be selected depending on the ambient temperature.
• a further development of the invention provides that the increase takes place linearly or in steps.
• the limit value is increased in the direction of the end value during warm-up operation.
• This increase can be linear, for example with a fixed rate of increase, in particular with a constant rate of increase during warm-up operation.
• the increase can also be done in stages.
• the incremental increase can take place in fixed time steps, with the limit being increased by a fixed value in each time step.
• Another additional or alternative embodiment of the invention provides that the increase takes place as a function of an air quantity supplied to the internal combustion engine and / or a further temperature of the internal combustion engine.
• the cumulative amount of air supplied to the cylinders since the start of the internal combustion engine can be used as a measure of the amount of heat generated by the internal combustion engine during its operation.
• the cumulative amount of air supplied, in particular fresh gas is understood to mean the total amount of air or fresh gas supplied to the cylinders since the start of the internal combustion engine.
• the amount can be a mass or a volume.
• the amount of air supplied to cylinders in each intake stroke is cumulative or cumulatively added.
• the internal combustion engine If the internal combustion engine is operated with a higher load, it will heat up faster and the cumulative air quantity will increase more rapidly than with a lower load. It may therefore make sense to increase the limit value depending on the amount of air supplied to the cylinders cumulatively, in order to take into account the speed at which the internal combustion engine is warmed up during operation.
• a further temperature of the internal combustion engine can be used as a measure of the progress of the warming-up process, for example a coolant temperature or a temperature of an exhaust system.
• the warm-up operation is ended when the limit value reaches the end value and / or the air quantity supplied to the cylinders exceeds a threshold value.
• the limit value is increased in the direction of the end value during warm-up operation. It may therefore make sense to stop warming up if the limit value reaches or exceeds the end value.
• the internal combustion engine can be operated in normal operation, during which the measures described above are no longer carried out. If there is a limit value for both the cylinder charge and the speed, the warm-up mode can be ended when one of the limit values reaches the final value. Alternatively, it can be provided that the warm-up operation is only ended when both limit values have reached their respective end values.
• the amount of air supplied to the cylinders cumulatively since the start is used as a measure of the thermal energy converted by the internal combustion engine and to stop the warm-up operation as soon as this amount of air reaches or exceeds the threshold value. From the time it is exceeded, it can be assumed that the internal combustion engine is at its operating temperature has reached. After the internal combustion engine has been switched off again, the warm-up operation can be carried out again using the method described above. In particular, the warm-up operation can be carried out after each start using the above statements.
• the invention further relates to an internal combustion engine with a plurality of cylinders, in particular for carrying out the method according to one or more of the preceding claims, with a warm-up operation being carried out after a start of the internal combustion engine, during which egg speed of the internal combustion engine is limited to a limit value.
• the internal combustion engine is designed to select the limit value during warm-up operation at least temporarily depending on a starting temperature of the internal combustion engine.
• the internal combustion engine can have an engine control unit for implementing the method.
• Figure is a schematic representation of an internal combustion engine.
• the figure shows a schematic representation of an internal combustion engine 1, which has a plurality of cylinders 2 in the exemplary embodiment shown here.
• Each of the cylinders 2 has at least one intake valve 3 and at least one exhaust valve 4.
• Fresh gas from an intake tract 5 can be supplied to the respective cylinder 2 via each of the intake valves 3, whereas exhaust gas from the corresponding exhaust gas can be fed through each of the exhaust valves 4.
• the cylinder 2 can escape, namely in the direction of an exhaust tract 6.
• the exhaust gas purification device 8 can have, for example, at least one catalyst.
• the internal combustion engine 1 is operated by means of a method according to which a warm-up operation is carried out after the internal combustion engine has started.
• the speed of the internal combustion engine 1 is limited to the limit value.
• the cylinders 2 is supplied with fresh gas via the intake tract 5, this fresh gas supply during the Warmlaufbe operation can also be limited to a limit value.
• two limit values can exist, namely one for the speed of the internal combustion engine and one for the cylinder charge.
• the one or more limit values are selected at least temporarily during warm-up operation depending on a starting temperature of the internal combustion engine 1.
• the internal combustion engine 1 is designed to determine the combustion chamber temperature at the time when the internal combustion engine 1 starts, in order to use this as the start temperature.
• the combustion chamber temperature 1 temperature sensors can be provided in the internal combustion engine.
• the combustion chamber temperature can be determined on the basis of a model calculation.
• the model calculation can calculate sensor data, such as an outside temperature, as well as the time course of a standstill of the internal combustion engine 1 prior to the start of the internal combustion engine 1, the combustion chamber temperature or the start temperature. If the measured or calculated start temperature is below a minimum temperature, the warm-up mode is carried out.
• the limit value is set to a start value.
• the limit value is increased from the start value in the direction of an end value.
• the end value is selected, for example, so that the limit value of the speed is a maximum casual speed reached, which may be present in an intended operation after reaching the operating temperature without damage to the internal combustion engine 1 occur or are expected.
• a maximum permissible end value can also be set for the limit value of the cylinder charge.
• the limit value is increased in the direction of the final value, the increase taking place as a function of the amount of air supplied cumulatively to the cylinders 2 via the intake tract 5 since the start.
• the warm-up mode is ended. Additionally or alternatively, it can be provided to end the warm-up operation as soon as the amount of air supplied to the cylinders 2 cumulatively since the start exceeds a threshold value. In this way, the internal combustion engine 1 is heated to an operating temperature in a controlled manner during the warm-up operation, and the pollutant emissions of the internal combustion engine 1 are correspondingly significantly reduced during the warm-up operation.

Landscapes

• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Output Control And Ontrol Of Special Type Engine (AREA)
• Electrical Control Of Air Or Fuel Supplied To Internal-Combustion Engine (AREA)
• Combined Controls Of Internal Combustion Engines (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=68699430

Family Applications (1)

Country Status (5)

Families Citing this family (1)

Family Cites Families (61)

• 2018
  • 2018-12-20 DE DE102018222510.9A patent/DE102018222510A1/de active Pending
• 2019
  • 2019-11-25 EP EP19809787.5A patent/EP3899232A1/de active Pending
  • 2019-11-25 CN CN201980082924.1A patent/CN113195882B/zh active Active
  • 2019-11-25 US US17/283,117 patent/US11624330B2/en active Active
  • 2019-11-25 WO PCT/EP2019/082456 patent/WO2020126335A1/de unknown

Also Published As

Similar Documents

Legal Events