Activation response of injectors of an internal combustion engine

Abstract

A control device is provided for a cooling liquid injection system for an internal combustion engine of a motor vehicle. The cooling liquid injection system includes at least two activatable injectors for introducing a cooling liquid into the internal combustion engine, which injectors can be controlled by the control device. The injectors can be supplied with cooling liquid by way of a common rail, and the control device is designed to receive an inclination variable, which characterizes an inclination of the rail, to determine an activation response for the injectors in dependence on the inclination variable, and to activate the injectors using the determined activation response in order to empty or fill the rail.

Claims

1. A device for a coolant injection system for an internal combustion engine of a motor vehicle, wherein the coolant injection system comprises at least two activatable injectors which are controllable so as to introduce a coolant into the internal combustion engine, and a common rail by which the injectors are supplied with coolant, wherein the device comprises: a control device configured to: receive an inclination variable characteristic of an inclination of the rail, determine an activation response of the injectors as a function of the inclination variable, and activate the injectors using the determined activation response in order to empty or fill the rail.

2. The device according to claim 1, wherein the control device is further configured to: select the activation response of the injectors from a set of at least two predetermined activation responses for the injectors as a function of the inclination variable.

3. The device according to claim 1, wherein the control device is further configured to: determine the activation response of the injectors as a function of the inclination variable such that a first injector which is located at a relatively high point owing to the inclination is activated earlier when the rail empties than a second injector which is located at a relatively low point with respect thereto owing to the inclination.

4. The device according to claim 3, wherein the control device is further configured to: determine the activation response of the injectors as a function of the inclination variable, such that a first injector which is located at a relatively high point owing to the inclination is activated later when the rail is filled than a second injector which is located at a relatively low point with respect thereto owing to the inclination.

5. The device according to claim 1, wherein the control device is further configured to: determine the activation response of the injectors as a function of the inclination variable, such that a first injector which is located at a relatively high point owing to the inclination is activated later when the rail is filled than a second injector which is located at a relatively low point with respect thereto owing to the inclination.

6. The device according to claim 1, wherein the control device is further configured to: determine the activation response of the injectors additionally as a function of whether the rail is emptied or filled.

7. The device according to claim 1, wherein the control device is further configured to: determine the activation response of the injectors additionally as a function of a distance of the respective injector from a rail inflow and/or from a geometric configuration of the rail.

8. The device according to claim 1, wherein the activation response of the injectors comprises a sequence and/or points in time at which the injectors are activated.

9. The device according to claim 1, wherein the control device is further configured to: receive a pressure variable which is characteristic of pressure in the rail, determine an activation time for at least one injector as a function of the pressure variable, and activate the injector at the determined activation time.

10. A coolant injection system for an internal combustion engine for a motor vehicle, comprising: at least two activatable injectors which are controlled so as to introduce a coolant into an intake section of the internal combustion engine; a common rail by which the injectors are supplied with coolant; and a control device configured to: receive an inclination variable characteristic of an inclination of the rail, determine an activation response of the injectors as a function of the inclination variable, and activate the injectors using the determined activation response in order to empty or fill the rail.

11. The coolant injection system according to claim 10, wherein the rail comprises a valve for sucking in fresh air.

12. A method for controlling a coolant injection system for an internal combustion engine of a motor vehicle, wherein the coolant injection system comprises at least two activatable injectors for introducing coolant into the internal combustion engine, wherein the injectors are supplied with coolant via a common rail, the method comprising the steps of: receiving an inclination variable which is characteristic of an inclination of the rail; determining an activation response for the injectors as a function of the inclination variable, and activating the injectors with the determined activation response in order to empty or fill the rail.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 shows an exemplary embodiment of a coolant injection system according to the invention.

(2) FIG. 2 shows an exemplary embodiment of a method according to the invention for controlling the coolant injection system.

(3) FIG. 3 shows a further exemplary embodiment of a method according to the invention for controlling the coolant injection system.

DETAILED DESCRIPTION OF THE DRAWINGS

(4) FIG. 1 shows an internal combustion engine VM of a motor vehicle. The internal combustion engine is connected to a coolant injection system, wherein the coolant injection system comprises three activatable injectors I1, I2, I3 which can be controlled by a control device SV and have the purpose of introducing a coolant into the internal combustion engine VM. In particular, the injectors I1, I2, I3 are connected here to the internal combustion engine VM in such a way that each injector I1, I2, I3 is assigned a cylinder Z1, Z2, Z3 of the internal combustion engine VM.

(5) The injectors I1, I2, I3 can be supplied with coolant by means of a common rail R, wherein the coolant can be pumped out of a coolant tank W, for example, through an inflow Z.

(6) The control device SV is also coupled to an inclination sensor NS which determines an inclination variable which is characteristic of an inclination of the rail R, such as, for example, the inclination of the motor vehicle in the longitudinal direction and transverse direction. Furthermore, the control device SV is coupled to a valve V which forms part of the rail R and has the purpose of sucking in fresh air.

(7) FIG. 2 shows an exemplary embodiment of a method according to the invention for controlling the coolant injection system.

(8) At the start of the method sequence, the rail R is completely emptied here and there is therefore no coolant in the rail R. All the injectors I1, I2, I3 are opened so that when any possible filling of the rail R with coolant occurs the air which is located in the rail R can escape through the opened injectors I1, I2, I3.

(9) In step 100, the control device SV receives an inclination variable which is characteristic of an inclination of the rail R. This may be, for example, an inclination of the motor vehicle in the longitudinal direction of the vehicle, which is determined by an inclination sensor NS.

(10) In the following step 110, the control device SV determines an activation response for the injectors I1, I2, I3 as a function of the inclination variable. The activation response comprises here, in particular, the sequence in which the injectors I1, I2, I3 are to be activated.

(11) For example, the control device SV can select here an activation response for the injectors I1, I2, I3 from a set of at least two predetermined activation responses for the injectors I1, I2, I3. These predetermined activation responses can be determined empirically, for example during the development of the coolant injection system.

(12) In addition, during the determination of the activation response of the injectors I1, I2, I3 the control device SV can also take into account whether the R is emptied or filled.

(13) For example, the control device SV is configured to determine the activation response for the injectors I1, I2, I3 in such a way that a first injector I1 which is located at a relatively high point owing to the inclination, is activated later when the rail R is filled then a second injector I2 which is located at a relatively low point with respect thereto owing to the inclination.

(14) During the filling process of the rail R, the control device can receive, in step 120, a pressure variable which is characteristic of the pressure in the rail R. Depending on the pressure variable, an activation time is determined for the injector I1, I2, I3 which is next according to the determined activation response, and the next injector I1, I2, I3 is closed in step 130 at the specific activation time as soon as the rise in pressure which is characteristic of the time when coolant is present at the injectors I1, I2, I3 can be observed.

(15) After the closing of the last injector I1, I2, I3, the rail can be completely filled.

(16) FIG. 3 shows a further exemplary embodiment of a method according to the invention for controlling the coolant injection system.

(17) For the start of the method sequence, the rail R is completely filled with coolant here. All the injectors I1, I2, I3 are closed so that cooling fluid is not introduced into the internal combustion engine VM.

(18) In order to empty the rail R, the valve V which forms part of the rail R is opened by the control device SV in step 200.

(19) In the following step 210, the rail R and part of the coolant supply system are emptied in that the coolant which is located therein is pumped into the coolant tank W. Owing to the open valve V the corresponding volume is filled with fresh air here.

(20) As soon as the rail R is completely emptied, in step 220 the valve V is closed by the control device SV.

(21) In step 230, the control device SV receives an inclination variable which is characteristic of an inclination of the rail R. This may be, for example, an inclination of the motor vehicle in the longitudinal direction of the vehicle, which is determined by the control device SV itself.

(22) In the following step 240, the control device SV determines, as a function of the inclination variable, an activation response for the injectors I1, I2, I3. The activation response comprises here, in particular, the sequence in which the injectors I1, I2, I3 are to be activated, and the time at which the injectors I1, I2, I3 are to be activated.

(23) In step 250, the injectors I1, I2, I3 are then activated in the determined sequence and at the determined times, and the air in the system is used to push out the coolant from the injectors and into the intake system so that after the method is concluded the injectors and the rail are filled with fresh air.

(24) If necessary, in the following step 260 the coolant supply system is again filled with fresh air up to the provided proportion of the volume when the injectors are closed and the valve is opened.