DE102019202238A1 - Method for controlling a vehicle with an internal combustion engine and method and device for controlling an internal combustion engine - Google Patents

Abstract

A method for controlling a vehicle (10) with an internal combustion engine (1) is proposed, with heating operation of the internal combustion engine (1) being implemented by a deterioration in the efficiency of the combustion in the internal combustion engine (1). The deterioration in efficiency is achieved by advancing the ignition angle of the combustion. Furthermore, a method and a device for controlling an internal combustion engine are proposed.

Description

The invention is based on a method for controlling a vehicle with an internal combustion engine and a method and a device for controlling an internal combustion engine according to the preamble of the independent claims.

From the DE 10 2007 027053 A1 a method for controlling a vehicle with an internal combustion engine is already known in which, for a heating operation of the catalytic converter, a deterioration in efficiency takes place by adjusting the ignition angle. Usually, the ignition angle is adjusted in the direction of later combustion.

Advantages of the invention

The method according to the invention and the device according to the invention result in a deterioration in the efficiency of the internal combustion engine through an advance adjustment of the ignition angle. Such an advance adjustment of the ignition angle realizes a heating operation in which the combustion chamber of the internal combustion engine is heated up more intensely. This measure achieves, in particular, better evaporation of the injected fuel, as a result of which the formation of particles in the heating phase of the internal combustion engine is reduced. In this way, the number of particles produced can be significantly reduced for heating up the internal combustion engine. Since a disproportionate number of particles are generated precisely in this first operating phase of the internal combustion engine, the exhaust gas from the internal combustion engine in particular can be significantly improved even when considering a longer period of time.

Further advantages and improvements result from the measures of the dependent claims. In order to ensure that the vehicle reaches a target torque despite the deterioration in efficiency, the deterioration in the efficiency of the combustion in the internal combustion engine can be compensated for by an electrical machine in the vehicle. In particular, it can be provided that the internal combustion engine is operated with a predetermined, for example, a constant torque output in order to select an operating point which is optimal for a heating operation of the internal combustion engine and at which particularly few particles arise. The variable portion of the torque output is then completely generated by the electric machine.

Furthermore, the state of charge of a battery in the vehicle can also be taken into account. In particular, a first operating state can be provided in which the torque is only output by the electrical machine. Only in a second operating state, in which the state of charge of the battery is low, is a torque output by the internal combustion engine. The heating operation according to the invention is then provided in a transitional operating state from the 1st to the 2nd operating state.

Alternatively, provision can also be made for a torque output by the internal combustion engine with a torque which is above a minimum torque to be provided for heating operation. The minimum torque can then be implemented by a negative torque of the electrical machine. This procedure enables additional freedom when operating the internal combustion engine, which enables further optimization of the heating of the internal combustion engine. The selection of the ignition angles used for the advance adjustment should take into account a knocking tendency or smooth running of the internal combustion engine. This can also take place as a function of the operating parameters of the internal combustion engine, for example load or speed. Further possible operating parameters are a residual gas in the combustion chamber, a lambda value or a division of the injection into the combustion chamber. This enables the internal combustion engine to be operated which is not associated with any loss of comfort for a user of the vehicle or the internal combustion engine.

drawings

Exemplary embodiments of the inventions are shown in the drawings and explained in more detail in the following description.

• 1 ein Fahrzeug mit einer Brennkraftmaschine und einer elektrischen Maschine,
• 2 einen idealisierten Verlauf des erzeugten Moments der Brennkraftmaschine aufgetragen gegen den Zündwinkel,
• 3 verschiedene Momente die von einer Brennkraftmaschine und einer elektrischen Maschine erzeugt werden, und
• 4 verschiedene Momente die von einer Brennkraftmaschine und einer elektrischen Maschine erzeugt werden und einen Ladungszustand einer Fahrzeugbatterie.

Show it:

• 1 a vehicle with an internal combustion engine and an electric machine,
• 2 an idealized curve of the torque generated by the internal combustion engine plotted against the ignition angle,
• 3 different torques generated by an internal combustion engine and an electrical machine, and
• 4th different torques generated by an internal combustion engine and an electric machine and a state of charge of a vehicle battery.

description

in the 1 is schematically a motor vehicle 10 with an internal combustion engine 1 and an electric machine 2 shown. The control of both the internal combustion engine 1 as well as the electric machine 2 is done by a control unit 3 . Control lines with which the control unit 3 with the internal combustion engine 1 and the electric machine 2 is not shown in the drawing. By the internal combustion engine 1 a moment can be generated, which by means of power transmission means, such as a gearbox, to the wheels 11 is transmitted. Because of that on the wheels 11 transmitted torque or torque of the internal combustion engine 1 the vehicle is propelled 1 . There is also an electrical machine 2 provided, which also generates a moment on the wheels 11 can be given. In the vehicle after the 1 it is therefore a hybrid vehicle which can be selected using the internal combustion engine 1 or the electrical machine 2 or can be driven with both at the same time. The electric machine 2 Such a hybrid vehicle can not only have a positive torque to drive the wheels 11 make available, but can also make a braking torque available by the electrical machine 2 operated as a generator. By the electric machine 2 both a positive and a negative moment can thus be generated.

In the 2 that is idealized by the internal combustion engine 1 generated torque M am shown against an ignition angle ZW. The ignition angle of an internal combustion engine is usually represented as degrees of the crankshaft angle of the internal combustion engine. Furthermore, in the 2 an optimal ignition angle ZW _{OPT is} shown. At the optimum ignition angle ZW _OPT , the internal combustion engine is 1 a maximum moment M is generated. In a typical combustion in an internal combustion engine, the optimum ignition angle ZW _{OPT is} before the top dead center of the piston in the combustion chamber.

Ignition angles to the left of the optimal ignition angle ZW _OPT are earlier ignition angles and to the right of the optimal ignition angle are later ignition angles. If ignition in the internal combustion engine takes place at an earlier ignition angle, then combustion in the internal combustion engine takes place significantly earlier, that is, before top dead center. In the case of combustion well after the optimum ignition angle, the combustion takes place later, that is, well after top dead center. In the 2 the influence of the ignition angle ZW on the output torque M of a combustion is shown. It was already known from the document cited in the introduction that in the case of later combustions, that is to say in the case of an ignition angle later than the optimal ignition angle, a deterioration in efficiency occurs. It is reduced so that the moment generated during combustion.

According to the invention, it is now provided to use earlier ignition angles in order to reduce the torque generated during the combustion and thus to reduce the efficiency. This fact is in the 2 shown. A reduction in the efficiency of combustion of an internal combustion engine means that a smaller part of the energy released during combustion is converted into mechanical propulsion, ie into mechanical work. This also means that the amount of heat generated in the internal combustion engine increases with decreasing efficiency.

The selection of the ignition angle in the direction of earlier or later combustion influences, however, in which part of the internal combustion engine this amount of heat increasingly leads to heating. At a later ignition angle, the exhaust system is mainly heated up, since the combustion chamber itself only has brief contact with the hot gas. At an earlier ignition angle, the combustion chamber is predominantly heated, since the combustion chamber is in contact with the hot gas over a longer period of time. In the case of a cold combustion chamber of an internal combustion engine, there is an inhomogeneous distribution of the fuel that is introduced into the combustion chamber and thus promotes the generation of particles. By using an earlier ignition angle, well before the optimal ignition angle, the internal combustion engine can thus be heated up significantly faster and the number of particles occurring in the early operating phase can be significantly reduced.

It is essential that the advanced ignition angle can be well before the optimal ignition angle ZW _OPT . In real operation of the internal combustion engine, ignition angles of -40 ° crankshaft angle can be used before the optimal ignition angle ZW _OPT . However, there are limits to the advance shift in the ignition angle depending on the load and speed. In particular, knocking events can be generated in the combustion chamber if the ignition angle is too early. However, these should be avoided for safe operation of the internal combustion engine. Furthermore, ignition angles that are too early can also lead to a significant increase in the uneven running of an internal combustion engine. This limit must therefore also be taken into account when selecting the suitable ignition angle in the direction of earlier ignition. These two operating limits, the knocking limit and the smooth running limit, are selected when the control units are adjusted 3 to the respective internal combustion engine 1 .

In a hybrid vehicle is next to the internal combustion engine 1 another electric machine 2 intended. Both machines, both the internal combustion engine 1 as does the electric machine 2 , generate a moment which is used to propel the vehicle 10 serves. The torque contribution of the electrical machine 2 can also be used are the operation of the internal combustion engine 1 , especially in a warm-up phase.

In the 3 the moment M the vehicle is plotted against the time t. The torque output of the internal combustion engine is determined by the course of the curve 31 shown. The torque output of the electrical machine 2 is determined by the course of the curve 32 shown. The total torque of the vehicle, ie the sum of the torque outputs 31 and 32 , will be in the curve 33 shown.

At time t0 the vehicle will 10 put into operation. The entire moment output 33 of the vehicle 10 then increases continuously in the time window from t0 to t1. The torque output increases accordingly 31 the internal combustion engine 1 and 32 the electric machine 2 in the time window t0 to t1. The total torque output remains in the time window t1 to t2 33 The respective torque outputs of the internal combustion engine also remain continuous and accordingly 1 and the electric machine 2 constant. From the time T2 however, the total torque output varies 33 . However, the variation is only achieved by a corresponding variation in the torque output 32 the electric machine 2 causes. The torque output of the internal combustion engine 1 remains continuous as on the course of the curve 31 you can see.

The entire moment 33 of the vehicle results from a large number of requirements that a target torque of the vehicle 10 realize. On the one hand, there is a desire of the user of the vehicle 10 , for example according to a driving speed of the vehicle. In addition to these requirements of a user of the vehicle 10 However, other influencing variables also flow into the target torque of the vehicle 10 a. If a user of the vehicle wishes to keep the same speed, different target moments result, for example, depending on whether the vehicle is driving up or down a mountain. Furthermore, auxiliary units such as an electric heater or an air conditioning system or other parts of a vehicle can be used 10 , have additional torque requirements, all of which lead to an increased output of a total torque 33 to lead. The moment of the internal combustion engine 1 is used in the representation of the 3 Optimized with regard to heating the internal combustion engine. An optimal torque of the internal combustion engine is used for this 1 used whichever is the one in the 3 torque output shown 31 leads. Variations of the vehicle 10 The required target torque is provided exclusively by the electrical machine 2 causes, so that the optimal continuous operating state for heating up the internal combustion engine 1 does not have to be left.

The Indian 3 The course shown with a constant torque of the internal combustion engine 1 , which for heating up the internal combustion engine 1 is optimal, it becomes, for example, when the vehicle is started 10 used. This can be both a first start, for example at the beginning of the day, and a restart in which the internal combustion engine still has residual heat, but this is not sufficient.

In the 4th the torque outputs of the internal combustion engine 1 , the electric machine 2 and a total moment 33 also applied very much against time. Furthermore, the state of charge of the battery SOC (State of Charge) is shown compared to time t. The 4th it is assumed that, up to a point in time t4, the charge in the battery is sufficiently high that purely electrical operation takes place. This can also be easily recognized from the fact that up to the point in time t4 the moments are released 31 the internal combustion engine 1 the value 0 Has. As can be easily seen by looking at the upper curve SOC, the state of charge of the battery drops continuously as a result of the electrical operation, until a state of charge is reached at time t4 that enables the internal combustion engine to be started up 1 requires. The state of charge 41 However, at time t4 it still has a sufficient height so that there is still a heating up, as it was already for 3 can be done.

The internal combustion engine is used for this purpose at time t4 1 put into operation and creates a continuous moment 31 . Correspondingly, the moments can be output 32 the electric machine 2 from the time T4 be reduced. The by the internal combustion engine 1 in the 4th moment output performed 31 is in turn for heating up the internal combustion engine 1 optimized. The amount of moment output 31 but is such that it already contributes to the overall moment 33 supplies so that the moment contribution 32 the electric machine 2 can be reduced accordingly from time t4. The moment transfer 31 the internal combustion engine 1 will be from the time E5 held continuously in order to optimally heat up the internal combustion engine 1 to ensure. A variation of the total torque is corresponding in turn 33 exclusively by the electrical machine 2 causes.

This measure can cause the internal combustion engine to heat up 1 be optimized, although in the picture after the 4th the internal combustion engine 1 a contribution to the overall moment 33 of the vehicle 10 supplies. If that is for the operation of the vehicle 10 required total torque 33 should assume a value below that in the 4th shown value for the torque output 31 the internal combustion engine 1 so can the electrical machine 2 can also be used to create a negative moment. This is done by the electrical machine 2 operated as a generator, making the electric machine 2 a negative moment, i.e. a braking moment, is generated.

It should also be noted that even when the internal combustion engine is operating with a deteriorated degree of efficiency, the torque output of the internal combustion engine can be influenced by the filling, ie by the amount of fuel and air introduced into the combustion chamber of the internal combustion engine. In the examples as shown in the 3 or 4th the torque output can be displayed 31 of the internal combustion engine can also be implemented by adjusting the ignition angle early and also setting a desired torque of the internal combustion engine by increasing the charge. It can thus reduce the torque output due to the deterioration in efficiency 31 the internal combustion engine are compensated. With this type of filling increase, of course, an optimized heating operation can also take place in which only the internal combustion engine itself is operated. For this purpose, the efficiency of the internal combustion engine is increased by advancing the ignition angle 1 and at the same time the torque output is set to the desired value by increasing the filling.

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• DE 102007027053 A1 [0002]

Claims (9)

Method for controlling a vehicle (10) with an internal combustion engine (1), wherein a heating operation of the internal combustion engine (1) is implemented by a deterioration in the efficiency of the combustion in the internal combustion engine (1), characterized in that the deterioration in efficiency is achieved by an advance adjustment of the ignition angle of the combustion is realized. Procedure according to Claim 1 , characterized in that the vehicle (10) realizes a target torque in that the deterioration in the efficiency of the combustion in the internal combustion engine (1) is compensated for by an electrical machine (2) of the vehicle during heating operation. Procedure according to Claim 2 , characterized in that the target torque of the vehicle (10) varies with time, and the internal combustion engine (1) is operated with a predetermined torque output and the electric machine (2) with a variable torque output. Procedure according to Claim 2 or 3 , characterized in that a charge state of a battery of the vehicle (10) is also taken into account, in that, in a first operating mode, when the battery is in a high state of charge, torque is output only by the electric machine (2) and in a second operating state when the state of charge is low the battery is a torque output by the internal combustion engine (1), and in a transitional operating state from the first to the second operating state, a heating operation according to one of the Claims 2 - 3 he follows. Procedure according to Claim 1 , characterized in that the vehicle (10) realizes a target torque in that the deterioration in efficiency and the filling of the internal combustion engine (1) are selected in the heating mode so that the internal combustion engine realizes a torque above a minimum torque for the operation of the internal combustion engine (1) in heating mode and that the electrical machine (2) realizes a negative torque so that a target torque of the size of the minimum torque for operating the internal combustion engine (1) in heating mode is realized. Procedure according to Claim 1 , characterized in that the vehicle (10) realizes a target torque by compensating for the deterioration in efficiency during heating operation by increasing the filling of the internal combustion engine (1). Method according to one of the preceding claims, characterized in that the advance adjustment of the ignition angle is determined as a function of a tendency to knock and a smooth running of the internal combustion engine (10) as a function of load and speed and other operating parameters of the internal combustion engine. Method for controlling an internal combustion engine (1), wherein a heating operation of the internal combustion engine (1) is implemented by a deterioration in the efficiency of the combustion in the internal combustion engine (1), characterized in that the deterioration in efficiency is achieved by advancing the ignition angle of the combustion. Device for controlling an internal combustion engine (1), with a heating operation of the internal combustion engine (1) being implemented by a deterioration in the efficiency of the combustion in the internal combustion engine (1), characterized in that means are provided which implement the deterioration in efficiency by advancing the ignition angle of the combustion.

Images