SYSTEM AND METHOD FOR CONTROLLING AN ENGINE SYSTEM WITH START-STOP AUTOMATIC IN A MOTOR VEHICLE WITH ELECTRIC PARKING BRAKE

Abstract

Method for controlling a start-stop system of a motor vehicle with an engine and an electrically operated parking brake, comprising: Monitoring the parking brake to determine whether the parking brake is in a transitional stage between an engaged state and a released state; and Suppression of the automatic restart of the engine until a point when the parking brake is not in a transitional stage, wherein the transition state comprises a transition from a state in which the parking brake is applied to a state in which the parking brake is released.

Description

[0001] Certain motor vehicles are equipped with an "automatic start-stop system" that automatically stops and restarts the vehicle's engine to reduce the vehicle's fuel consumption under certain conditions, for example, when the vehicle would otherwise be idling. In operation, a motor vehicle's automatic start-stop system detects that the vehicle has stopped (where the engine would otherwise be idling), and the system then turns off the engine. When engine power is needed, for example, when the driver releases their foot from the brake, the engine is automatically restarted. Other examples are also possible where an automatic start-stop system could be used. When a vehicle with an automatic start-stop system is in automatic stop mode, i.e. when the engine is switched off, the vehicle's battery must still supply power to the electrical devices and components in the vehicle.In motor vehicles with an electrically operated parking brake, the electrical energy required to apply the electric brake (i.e., to brake or release the brake) can be significant (on the order of approximately 45 amps) over a relatively short period of time (approximately 1 second). Under certain battery conditions, the battery current may be insufficient to simultaneously power the electric brake actuator and the starter motor (to restart the vehicle).

[0002] In known vehicles with automatic start-stop systems, the automatic start-stop system would be deactivated if the amount of current in the vehicle battery fell below a certain threshold, sufficient to enable the system to simultaneously activate the electric parking brake and the vehicle starter. The inventors of the present invention have developed a system and method for controlling an automatic start-stop system of a motor vehicle that allows the vehicle's automatic start-stop system to operate with less battery power than is the case with previously known systems.

[0003] US 2012 / 0 330 522 A1 discloses systems and methods for restarting an engine that can be selectively deactivated during idle-stop conditions. To this end, power can be sequentially directed to a starter motor and an electric brake by limiting the current supplied to one while power is supplied to the other, the order of power delivery being based on the timing of a restart request relative to an electric brake request, as well as the operating conditions of the vehicle at the time the requests are received.

[0004] US 2007 / 0 170 775 A1 describes a brake control section with which an automatic mode can be selected in which a mechanical brake is automatically transferred from a released state to a braking state in response to the driving state of a vehicle. A diagnostic section outputs an error signal when an abnormal condition of the brake control section is detected. A power control section automatically stops a drive power source of the vehicle when the driving state of the vehicle meets a predetermined condition for determining a vehicle stop. When the automatic mode of the brake control section is released or when the diagnostic section outputs an error signal of the brake control section, the power control section is prevented from automatically stopping the drive power source. A method for controlling an automatic start-stop system of a motor vehicle having an engine and an electrically operated parking brake is disclosed, which has the features of claim 1. Furthermore, a system for controlling an automatic start-stop system of a motor vehicle is provided, which has the features of claim 6.

[0005] The method includes the steps of monitoring the parking brake to determine whether the parking brake is in a transitional state between an applied state and a released state, and inhibiting automatic restart of the engine until the parking brake is no longer in a transitional state. Fig. Figure 1 is a simple schematic representation of a motor vehicle in which an embodiment of the invention may be used. Fig. Figure 2 is a functional block diagram of the components of the vehicle's automatic start-stop control system. Fig. Figure 3 is a flowchart of an example algorithm for controlling the deactivation of the vehicle's reverse brake assist system and Host Messaging Interface (MHI) messages / alerts.

[0006] A system and method for controlling the operation of a motor vehicle's automatic start-stop system are disclosed. The system monitors the state of the parking brake. If the parking brake is about to be applied, i.e., if the parking brake is in a transitional state, when a command is given to restart the vehicle, the restart of the vehicle engine is suppressed until the parking brake is no longer in a transitional state. As a result, the vehicle battery does not simultaneously receive the command to deliver energy to start the engine and to apply or release the parking brake.

[0007] Fig. 1 is a simple diagram of an exemplary motor vehicle in which the system and method for controlling the vehicle's automatic start-stop system may be implemented. The vehicle 10 is equipped with an electronic control unit (ECU) 100 that communicates with an ABS module 102 and a vehicle starter 106 (among others, not shown). The vehicle starter 106 is electrically connected to the vehicle engine 110. The ABS module communicates with a parking brake (including a parking brake actuator) 104 and a parking brake switch 108 located within the vehicle interior. The ECU 100, the ABS module 102, the parking brake 104, the parking brake switch 108, the vehicle starter 106, and the vehicle engine 110 may each be conventional components known to those skilled in the art and may be connected in various ways, e.g., electrically or wirelessly, as described above.

[0008] Fig. Figure 2 is a simple functional block diagram that also shows the components described above. That is, the parking brake switch 108 communicates with the ABS module 102, which communicates with both the parking brake 104 and the vehicle ECU 100. Functionally, a driver inside the vehicle can actuate the parking brake switch 108 when the driver wishes to apply the parking brake 104. The parking brake switch 108 sends a signal to the ABS module 102, which in turn sends a signal to the parking brake actuator to actuate the parking brake 104.

[0009] The ABS module 102 sends a parking brake status signal to the ECM 100 so that the ECM 100 can monitor the condition of the parking brake. The ECM 100 uses the Fig.3, for controlling the automatic start-stop system of the vehicle, with respect to controlling the restart of the vehicle during times when the parking brake is applied, i.e., when it is in a transitional state. In particular, the ECM 100 determines (in step 300) from the parking brake status signal (provided by the ABS module 102) whether the parking brake is transitioning from one state to another (from an applied state to a released state or from a released state to an applied state). In this case, the ECM 100 determines (in step 310) whether the vehicle engine 110 is off. If so, the ECM 100 suppresses (in step 330) the automatic start of the engine 110 until the parking brake 104 is fully applied or, if earlier, until a predetermined period of time has elapsed.On the other hand, if the parking brake does not transition from one state to another, the ECM 100 inhibits (in step 320) the automatic stop function of the engine 110 until the parking brake 104 is fully applied or, if earlier, until a predetermined period of time has elapsed.

[0010] According to the system and method described above, the initiation of restarting the vehicle engine is prevented during a transient parking brake condition. As a result, the vehicle battery does not experience the combined stress of simultaneous operation of the vehicle starter and parking brake, allowing the vehicle's automatic start / stop system to remain activated when battery current is lower than in known prior art systems.

[0011] With regard to the methods, systems, methods, heuristics, etc. described herein, it is to be understood that although the steps of such methods, etc., have been described as occurring in a particular ordered sequence, these methods could also be practiced if the described steps were performed in a different order than that described herein. It is further understood that certain steps could be performed concurrently, that other steps could be added, or that certain steps described herein could be omitted. In other words, the descriptions of methods herein are intended to illustrate particular embodiments and are in no way to be construed as limiting the claimed invention.

[0012] Accordingly, it is to be understood that the above description is illustrative and not restrictive. Many embodiments and applications other than the described examples will become apparent upon reading the above description. The scope of the invention is to be determined not with reference to the above description, but with reference to the appended claims and the full scope of equivalents of such claims. It is anticipated and intended that future developments will occur in the technologies discussed herein and that the disclosed systems and methods will be incorporated into such future embodiments. In summary, it is to be understood that the invention is susceptible to modification and variation. For example, the system and method described above could be used for forward movement (in addition to, or instead of, reverse movement).

[0013] All terms used in the claims are to be construed as broadly as possible and have the ordinary meanings understood by one of ordinary skill in the art to which the technologies described herein belong, unless expressly stated to the contrary herein. In particular, the use of singular articles, e.g., "a," "a," "the," "said," etc., should be read as meaning one or more of the specified elements, unless a claim contains an express limitation to the contrary.

Claims

[1] Method for controlling an automatic start-stop system of a motor vehicle with an engine and an electrically operated parking brake, comprising: Monitoring the parking brake to determine whether the parking brake is in a transition state between an applied state and a released state; and Suppression of automatic restart of the engine until the parking brake is not in a transitional state, wherein the transition state comprises a transition from a state in which the parking brake is applied to a state in which the parking brake is released. [2] The method of claim 1, wherein the transition state comprises a transition from a state in which the parking brake is in a released state to a state in which the parking brake is applied. [3] The method of claim 1, further comprising the step of inhibiting automatic engine shutdown until such time as the parking brake is not in a transient state. [4] A method according to claim 3, wherein the step of inhibiting automatic engine shutdown comprises inhibiting automatic engine shutdown until at least one of the following conditions is met: (i) the parking brake is not in a transient state, and (ii) a predetermined period of time has elapsed. [5] The method of claim 1, wherein the step of inhibiting automatic restart of the engine comprises inhibiting automatic restart of the engine until at least one of the following conditions is met: (i) the parking brake is not in a transient state, and (ii) a predetermined period of time has elapsed. [6] System for controlling an automatic start-stop system of a motor vehicle, comprising: an engine configured to be automatically stopped and started in response to a control signal from an electronic control unit; an electrically actuated parking brake configured to be selectively applied and released in response to a control signal from the electronic control unit; and wherein the electronic control unit is configured to receive information indicative of the status of the parking brake and, in response to the status information, to suppress restart of the engine until the parking brake is no longer in a transition state between an applied state and a released state, wherein the transition state comprises a transition from a state in which the parking brake is applied to a state in which the parking brake is released. [7] The system of claim 6, wherein the transition state comprises a transition from a state in which the parking brake is in a released state to a state in which the parking brake is applied. [8] The system of claim 6, wherein the electronic control unit is further configured to inhibit automatic engine shutdown until the parking brake is not in a transient state. [9] The system of claim 8, wherein the electronic control unit is further configured to inhibit automatic engine shutdown until at least one of the following conditions is met: (i) the parking brake is not in a transient state, and (ii) a predetermined period of time has elapsed. [10] The system of claim 6, wherein the electronic control unit is further configured to inhibit automatic restart of the engine until at least one of the following conditions is met: (i) the parking brake is not in a transient state, and (ii) a predetermined period of time has elapsed.

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