Brake control for stop-start vehicle

Abstract

Vehicle that includes the following: an engine with auto-stop and auto-start conditions; a braking system with an auto-hold function configured to automatically apply braking torque after the vehicle has decelerated to a complete standstill, regardless of the brake pedal position; and a control device configured to automatically apply braking torque in response to the activation of the engine's auto-stop condition, and to control the automatic restart of the engine in response to the movement of a gearshift lever from PARK, with the automatic restart of the engine being controlled before the gearshift lever reaches an end position.

Description

Technical field

[0001] One or more embodiments relate to a vehicle system and method for controlling braking systems and engine shutdown and restart during a driving cycle. Background of the invention

[0002] In many cases, a vehicle needs to stop during a typical driving event before reaching its destination. This can occur, for example, when the vehicle stops at traffic lights, pedestrian crossings, stop signs, and similar locations. A stop-start vehicle can activate a stop-start strategy to start and stop the vehicle's engine during a driving cycle. When no power is required (e.g., while waiting at a traffic light), the engine is switched off. As soon as power is requested, the engine restarts automatically. The engine can also be automatically restarted in response to other conditions, such as a decrease in battery charge or a gearshift lever being moved from one gear position to another. By avoiding unnecessary engine idling, the vehicle's fuel economy is improved.For this reason, it is desirable to use the engine shutdown function as much as possible when engine stop conditions are met.

[0003] Conventional vehicles typically include a primary and a secondary braking system. The primary braking system is hydraulic, where pressing a brake pedal increases hydraulic pressure in the system, causing one or more brake shoes to be applied against a rotating element (such as a rotor) of each wheel to produce friction braking. The secondary braking system, or parking brake system, is mechanical, where releasing a lever moves a cable that applies one or more brake shoes against a rotating element of each rear wheel.

[0004] An electric or electronic parking brake (EPB) system replaces one or more components of the parking brake system with an actuator. Generally, there are two different types of electric parking brake systems: cable-operated electric parking brake systems and wheel-mounted electric parking brake systems. A cable-operated electric parking brake system replaces the parking brake lever with an actuator. The actuator is controlled by a switch inside the passenger compartment to move or pull the mechanical cables and apply the brake shoes. Wheel-mounted electric parking brake systems include an actuator integrated into a wheel-mounted brake caliper. These systems replace the parking brake lever and the mechanical cables.

[0005] DE 10 2014 217 541 A1 discloses a vehicle comprising an engine with auto-stop and auto-start conditions and a braking system with an auto-hold function. DE 10 2013 223 881 A1 discloses a stop-start system for a vehicle's engine. DE 11 2008 000 460 T5 relates to a shift control system and method. DE 10 2010 040 700 A1 discloses a brake-assisted control of an engine restart event. Summary description

[0006] According to the invention, a vehicle according to claim 1 is proposed. Advantageous embodiments of the invention are specified in the dependent claim and the following description.

[0007] A vehicle as described in this disclosure includes an engine with auto-stop and auto-start conditions. The vehicle further includes a braking system with an auto-hold function. The auto-hold function is configured to automatically apply braking torque, regardless of the brake pedal position, once the vehicle has been decelerated to a complete stop. The vehicle also includes a control device configured to automatically apply braking torque in response to the engine being in the auto-stop condition, and to maintain the engine in the auto-stop condition when a gear selector is moved from a gear position other than PARK.

[0008] In some embodiments, the control device is further configured to control the engine, so that in response to the engine being automatically stopped, it automatically restarts, the auto-hold function automatically applies braking torque, and the gear selector is moved out of the PARK position. The automatic restart of the engine can be initiated before the gear selector reaches an end position.

[0009] A method for controlling a vehicle with a braking system, a gearshift lever, and an engine with auto-stop and auto-start conditions includes automatically restarting the engine in response to the engine being in the auto-stop condition and the gearshift lever being moved. The method further includes automatically applying braking torque according to an auto-hold function in response to the engine being automatically shut off and the gearshift lever being moved, thus maintaining the engine in the auto-stop condition.

[0010] In some embodiments, the engine is held in the auto-hold condition in response to the gear selector being moved from a gear position other than PARK. In such embodiments, the engine can be controlled to automatically restart in response to the engine being automatically shut down, the braking system automatically applying braking torque according to an auto-hold function, and the gear selector being moved to a gear position other than PARK. The automatic restart of the engine can be initiated before the gear selector reaches an end position.

[0011] A vehicle according to the present disclosure includes an internal combustion engine, a gearshift lever, a braking system with an auto-hold function, and a control device. The control device is configured to automatically shut off the engine in response to a first condition during a driving cycle and to automatically restart the engine in response to a second condition during the driving cycle. The control device is further configured to keep the engine off in response to the second condition, with the braking system providing an auto-hold function.

[0012] In some embodiments, the second condition includes the movement of a shift lever from an initial gear position to a subsequent gear position. In such embodiments, the initial gear position may be a gear position other than PARK. The control device may further be configured to automatically restart the engine in response to the shift lever being moved from PARK to a gear position other than PARK, with the braking system providing an auto-hold function. The control device may further be configured to instruct the engine to perform an auto-start before the shift lever is moved to a gear position other than PARK.

[0013] Embodiments according to the present disclosure offer several advantages. For example, embodiments according to the present disclosure can avoid unnecessary engine restarts due to shifting into PARK while the brake's auto-hold function is active. Avoiding unnecessary engine restarts can provide various benefits, including improved fuel economy, reduced wear and tear on vehicle components, and improved driver satisfaction.

[0014] The aforementioned advantages and other advantages and features of the present disclosure will become apparent from the detailed description below of preferred embodiments in conjunction with the accompanying drawings. Brief description of the characters Fig. 1 is a side view of a vehicle depicted on a road that slopes downwards; Fig. Figure 2 is a schematic diagram of a vehicle system for controlling braking systems during a shutdown and restart of an engine according to one or more embodiments; Fig. Figure 3 is a flowchart illustrating a method for controlling braking systems during engine shutdown according to one or more embodiments; and Fig. Figure 4 is a flowchart that illustrates a method for coordinating brake systems and engine systems according to one or more embodiments. Detailed description

[0015] As specified, detailed embodiments of the present invention are disclosed below; however, it is understood that the disclosed embodiments serve only as examples of the invention, which can be implemented in various and alternative forms. The figures are not necessarily drawn to scale; some features may be enlarged or reduced to show details of certain components. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely serve as a basis for illustrating various implementations of the present invention to those skilled in the art.

[0016] Referring to Fig. Figure 1 is a vehicle system for controlling braking systems during engine shutdown and restart, shown according to one or more embodiments and generally referenced by reference numeral 10. The vehicle system 10 is shown within a vehicle 12. In the Fig. In the illustrated example 1, vehicle 12 is stopped on an inclined surface and subjected to various forces and moments. The surface has a gradient θ, which can also be described as a road gradient. The resulting torque, T veh , at the wheels of the vehicle can be calculated using equation 1 as shown below: Tveh=Tcreep+Tbrk−Trl=0

[0017] T embodies creep The output torque provided by the engine at idle is T brk the total braking torque provided by the vehicle braking system(s) and is Trl The torque acting on the vehicle due to "driving resistance" or external forces. T creep is represented as a positive or clockwise rotating moment, and T rl and T brk are represented as negative or counterclockwise rotating moments. T brk acts against the rotation of the wheels and would therefore act as a clockwise moment around the wheels if the vehicle were moving in a backward direction from T rl is powered, and T brk would act as a counterclockwise moment around the wheels when the vehicle is driven by the motor 16 in a forward direction. Although each moment is shown about a front axle of the vehicle 12, both T rl as well as T brk both the front and rear axles are affected. In a front-wheel drive vehicle, such as in Fig. 1 shown and in detail in Fig. 2 shown, T appearscreep only around the front axle, since the engine is not mechanically connected to the rear axle. Since vehicle 12 is stationary, T veh is zero, and the primary driving resistance is due to gravity. Equation 2 represents an equation for calculating the driving resistance torque (T). rl ): Trl=MgSin(θ)∗Rw

[0018] Here, M is the vehicle mass; g is the acceleration due to gravity; θ is the road gradient; and R w the radius of the drive wheels.

[0019] Referring to Fig. 2 The vehicle includes an engine control module (ECM) 14 for controlling an internal combustion engine (ICE) 16. The vehicle 12 is a stop-start vehicle according to one or more embodiments and includes an engine 16 that can be controlled by the engine control module 14 to repeatedly start and stop during a driving cycle to reduce fuel consumption. The vehicle 12 also includes a vehicle system control device (VSC) 18 that communicates with the engine control module 14 and the vehicle system 10. The vehicle system 10 includes a brake control device 20 that communicates with the engine control module 14 and the vehicle system control device 18. The vehicle system also includes a primary brake system 22 and a secondary brake system 24.

[0020] Referring back to Fig. 1 and equation 1 must be the vehicle torque (T veh) be equal to zero in order to hold the vehicle 12 stationary on an inclined surface. However, if the motor control module 14 switches off the motor 16, the creep torque (T) decreases. creep ) to zero. In order to keep the vehicle 12 stationary without restarting the engine 16, the vehicle system 10 can apply the braking torque (T). brk ) increase to reduce T creep to compensate. The brake control device 20 coordinates the control of the primary brake system 22 and the secondary brake system 24 in order to compensate. brk to increase when the engine 16 is switched off in order to maintain the position of the vehicle 12 and prevent it from rolling backward.

[0021] The vehicle 12 includes an improved starter 26, which is coupled to an engine crankshaft. The starter 26 receives electrical power and provides output torque to the crankshaft for starting the engine 16.

[0022] The vehicle 12 includes a gearbox 28 for adjusting the output torque of the motor 16. Torque from the motor 16 is transmitted via a gearbox output shaft through the gearbox 28 to a differential 30. Axle half-shafts 32 extend from the differential 30 to a pair of drive wheels 34 to provide drive torque for propelling the vehicle 12 forward.

[0023] The vehicle 12 includes a shift lever 36 for selecting a transmission gear. The shift lever 36 includes a sensor (not shown) to provide an output signal corresponding to a selected transmission gear (e.g., PRNDL). A transmission control module (TCM) 37 communicates with the shift lever 36 and the transmission 28 to adjust the transmission ratio based on the shift lever selection. Alternatively, the shift lever 36 can be mechanically linked to the transmission 28 to adjust the transmission ratio.

[0024] The brake control device 20 includes a control unit that communicates electrically with the engine control module 14 and the vehicle system control device 18. The primary brake system 22 includes a hydraulic actuation system 40 that converts the movement of a brake pedal 38 into fluid pressure. The hydraulic actuation system 40 includes a booster and a master cylinder. The brake control device 20 communicates fluidly with the hydraulic actuation system 40.

[0025] The vehicle 12 includes the drive wheels 34 and the driven wheels 42. Each wheel 34, 42 includes a wheel brake assembly 44, such as a caliper or drum brake assembly. A series of hydraulic lines 46 extends between the brake control device 20 and the wheel brake assemblies 44. The wheel brake assemblies 44 convert the hydraulic pressure into a clamping force that acts on a rotating element of the wheels to produce friction braking. The brake control device 20 includes an anti-lock braking function to pulsate the hydraulic pressure. The brake control device 20 also includes an electric brake pump 47, which can be controlled during Auto Hold Braking (AHB) to increase the brake pressure within the hydraulic lines 46 when the engine is switched off.

[0026] The primary braking system 22 also includes sensors that provide information corresponding to current braking characteristics, for example a brake pedal position switch (BPS) to provide a signal for brake pedal position (S bp ), which corresponds to a brake pedal position (e.g., pressed or released). In other embodiments, the primary brake system 22 includes a position sensor (not shown) for measuring the pedal position. The primary brake system 22 also includes one or more sensors for providing output signals that indicate a braking force or braking torque, which can be measured or derived. In the illustrated embodiment, the sensors include pressure sensors (PS) for providing a signal for brake pressure (P). brk ), which corresponds to an actual brake pressure value within the brake system (e.g. brake line pressure or master cylinder pressure).

[0027] The vehicle system 10 includes the secondary braking system 24. The secondary braking system is a wheel-mounted electric parking brake system 24 according to one or more embodiments. A wheel-mounted electric parking brake system 24 includes an actuator integrated into the rear wheel assemblies 44. In other embodiments, the electric parking brake system 24 includes an actuator (not shown) mounted on the vehicle frame (not shown) configured to move or pull mechanical cables connected to the rear wheel assemblies 44.

[0028] The brake control device 20 is configured to provide an auto-hold brake pressure function, whereby the brake control device 20 controls or maintains a desired brake torque when the engine is switched off to prevent the vehicle from rolling when stopped on a hill. The brake control device 20 can control the electric brake pump 47 to adjust the pressure within the hydraulic system and / or control the electric parking brake system 24 to adjust the wheel torque. In a preferred embodiment, the auto-hold brake pressure function is activated in response to braking, during which the vehicle 12 is decelerated to a standstill. In one or more embodiments, the brake control device 20 provides a status signal (AHB_status) indicating whether the auto-hold brake function is activated.

[0029] The vehicle 12 includes an accelerator pedal 48 with a position sensor (APPS) to provide an accelerator pedal position signal (APP) that corresponds to a driver request for propulsion. The engine control module 14 controls the throttle valve of the engine 16 based on the accelerator pedal position signal. In one or more embodiments, the engine control module 14 generates a signal (T accel ), which, based on accelerator pedal position, allows conclusions to be drawn about an acceleration torque requested by the driver at the wheels.

[0030] The vehicle 12 includes an energy storage device such as a battery 50. The battery 50 supplies electrical energy to the vehicle's control units and devices, e.g., the electric pump 47 and the starter 26, as generally indicated by the dashed lines in Fig. The vehicle 12 can include a single battery 50, for example a conventional low-voltage battery, or multiple batteries, including a high-voltage battery. Additionally, the vehicle 12 can include other types of energy storage devices, such as capacitors or fuel cells. The vehicle 12 includes a sensor 52 that provides a signal (V) indicating the voltage present in the battery 50.

[0031] The vehicle 12 also includes a gradient sensor 54, which provides a signal (GS) indicating the vehicle's gradient or inclination. In one or more embodiments, the gradient sensor 54 is an accelerometer that provides the GS signal partly based on a gravity component. In other embodiments, the gradient sensor 54 is an inclinometer. In one embodiment, the vehicle system 10 includes a road level estimation function or algorithm that determines the road gradient based on the GS signal. In other embodiments, the vehicle includes a navigation system (not shown) that provides signals that can be used to estimate the road gradient.

[0032] The vehicle 12, according to one or more embodiments, includes a user interface 56 that communicates with the vehicle system control device 18. The user interface 56 may include a touchscreen display and / or an array of buttons and scales (not shown). The user can manually control the engine and brake system functions using the user interface 56. The user interface 56 provides input signals (ESS_enable, EPB_apply, AHB_enable) to the vehicle system control device 18, each of which indicates a user request to enable / disable the engine start-stop function, apply the electric parking brake 24, and enable / disable the auto-hold brake function.

[0033] The vehicle system control device 18 communicates with other vehicle systems, sensors, and control devices to coordinate their function. As shown in the illustrated embodiment, the vehicle system control device 18 receives a plurality of input signals (e.g., ESS_enable, AHB_enable, EPB_apply, P). brk , Engine speed (N e ), S bp, vehicle speed (Veh), gearshift lever status (PRNDL_status), etc.) from various vehicle systems and sensors. Although shown as a single control device, the vehicle system control device 18 may include multiple control devices that can be used to control several vehicle systems according to an overarching vehicle control logic or software. The vehicle control devices, including the vehicle system control device 18, the engine control module 14, and the brake control device 20, generally include any number of microprocessors, application-specific circuits, integrated circuits, memories (e.g., flash memory, read-only memory ROM, random-access memory RAM, erasable programmable read-only memory EPROM, and / or electrically erasable programmable read-only memory EEPROM), and software code to act collectively to perform a set of operations.The control units also include predefined data or "lookup tables" based on calculations and test data, stored within memory. The vehicle control units communicate with each other and with other vehicle systems via one or more wired or wireless vehicle connections using common bus protocols (e.g., CAN and LIN).

[0034] The vehicle system control device 18 communicates with the engine control module 14 to control the shutdown and restart of the engine 16 based on input signals corresponding to brake application and release conditions. The vehicle system 10 anticipates the vehicle's acceleration based on brake release conditions. By shutting down the engine 16, a stop-start system can improve fuel economy compared to conventional vehicles.

[0035] The engine stop-start (ESS) and auto-hold braking functions can operate independently. The driver can activate or deactivate engine stop-start (ESS) and / or auto-hold braking (AHB) using the user interface 56. Preferably, the vehicle system 10 coordinates the engine stop-start function with the auto-hold braking function to maximize the vehicle's fuel economy and improve driving comfort. The vehicle system 10 also coordinates the control of the electric brake pump 47 and the electric parking brake system 24 to provide the auto-hold braking function. The vehicle system 10 improves driving comfort by extending the duration for which a driver can release the brake pedal during an extended stop of the vehicle on an inclined surface.

[0036] Referring to Fig. Section 3 describes a method for controlling braking systems during engine shutdown according to one or more embodiments and is generally referenced by reference numeral 410. Method 410 can be implemented using software code which, according to one or more embodiments, is contained within the brake control device 20. In other embodiments, the software code is shared by different control devices (e.g., the engine control module 14, the vehicle system control device 18, and the brake control device 20).

[0037] In operating step 412, the vehicle system receives 10 input signals including ESS_enable, AHB_enable, Veh and P brkIn operating step 414, the vehicle system 10 evaluates the ESS_enable signal to determine whether the engine start-stop function is activated. The user can manually deactivate the engine start-stop function using the user interface 56. Additionally, the vehicle control units (e.g., the engine control module 14) can deactivate the engine start-stop function under certain vehicle conditions. If engine start-stop is not activated, the vehicle system 10 proceeds to operating step 416 to determine whether auto-hold braking is activated. In operating step 416, the vehicle system 10 evaluates the AHB_enable signal to determine whether the auto-hold braking function is activated. The user can manually deactivate the auto-hold braking function using the user interface 56. Additionally, the vehicle control units (e.g., the brake control unit 20) can deactivate the auto-hold braking function under certain vehicle conditions.If the auto-hold braking function is activated, vehicle system 10 proceeds to operating step 418 and provides normal auto-hold braking functionality, independent of the engine start / stop function. If the determination in operating step 414 is positive (i.e., the engine start / stop control is activated), vehicle system 10 proceeds to operating step 420.

[0038] In operating step 420, the vehicle system 10 evaluates the vehicle speed signal (Veh) to determine whether the vehicle speed is below a speed threshold. In one embodiment, the speed threshold is approximately five mph. If the vehicle speed is below the speed threshold, the vehicle system 10 proceeds to operating step 422 and evaluates the AHB_enable signal to determine whether auto-hold braking is activated. If auto-hold braking is not activated, the vehicle system 10 proceeds to operating step 424 and provides the engine stop-start function, independent of auto-hold braking. If the determination in operating step 422 is positive, this would mean that both the engine stop-start function and the auto-hold braking function are activated, and the vehicle system 10 proceeds to operating step 426 to coordinate their functions.

[0039] In operating step 426, vehicle system 10 evaluates the brake pressure signal (P). brk ) to determine whether the brake pressure is above an engine shutdown brake pressure threshold (Pbrkepd) lies. Pbrkepd embodies a minimum braking pressure required to hold a vehicle stationary after the engine has been stopped. In one embodiment, Pbrkepd, as disclosed, for example, in U.S. Patent No. 8,998,774, can be calculated. The vehicle system 10 can determine torque values ​​based on the brake pressure values, which includes the following: (T brk ), which is a P brk represents corresponding torque, and (T hold ), who has one Pbrkepd represents the corresponding torque value. In operating step 428, the vehicle system evaluates 10 T brk to determine if T brk greater than T holdIf the determination in either of the two operating steps 426 and 428 is negative, the vehicle system 10 proceeds to operating step 430 and activates the electric brake pump 47 to increase the brake pressure (P). brk ) to increase. If the determination in operating step 428 is positive, the vehicle system 10 proceeds to operating step 436.

[0040] In operating step 436, the vehicle system 10 compares the total braking torque (T brk ) with a target braking torque value (T sp ) to determine if T brk greater than T sp is. T sp corresponds to the sum of T hold and T creep The motor 16 provides creeping torque during idle operation, T creep However, it decreases to zero when the engine is switched off. Therefore, the vehicle system increases the brake pressure (P) 10 times before the engine is switched off. brk ), to T creepto compensate and prevent the vehicle from rolling backward. If the determination in operating step 436 is negative, the vehicle system returns to operating step 430. If the determination in operating step 436 is positive, the vehicle system 10 advances to operating step 438 and switches off the motor 16.

[0041] In one variation of the above, the vehicle system 10 can provide a notification to the driver via the user interface 56 if the determination in operating step 436 is negative. The notification can prompt the driver to increase pressure on the brake pedal to trigger automatic engine shutdown. In such an embodiment, activation of the pump is unnecessary due to the brake pressure supplied by the driver. In a further alternative embodiment, the vehicle system 10 may take no action if the determination in operating step 436 is negative. In such an embodiment, the engine may simply continue to run.

[0042] If the auto-hold braking system is activated and the engine is automatically switched off, the vehicle system 10 evaluates the driver's intention regarding further vehicle propulsion according to various methodologies, as disclosed, for example, in the concurrently pending application 14 / 339,887, which is incorporated herein in its entirety by reference. Now, referring to Fig.Section 4 describes a method for evaluating an intention regarding vehicle propulsion based on the movement of a gearshift lever according to one or more embodiments and is generally referenced by reference numeral 510. Method 510 can be implemented using software code which, according to one or more embodiments, is contained within the engine control module 14. In other embodiments, the software code is shared by various control devices (e.g., the engine control module 14, the brake control device 20, and the vehicle system control device 18).

[0043] In operating step 512, the vehicle system receives 10 inputs, including an engine speed N. eThe vehicle system uses two statuses: one for the Auto Hold brake function (AHB_status) and one for the gearshift lever (PRNDL_status). In operating step 514, the vehicle system evaluates AHB_status to determine whether the Auto Hold brake function is engaged. If the evaluation is negative, meaning the Auto Hold brake function is not engaged, the vehicle system returns to operating step 512. If the evaluation is positive, the vehicle system proceeds to operating step 514.

[0044] In operating step 514, the vehicle system evaluates 10 N e to determine whether the engine was automatically switched off. If the determination is negative, then, for example, N eIf a non-zero number is received, indicating that the engine is not switched off, vehicle system 10 proceeds to operating step 518. In operating step 518, vehicle system 10 controls the braking system to provide normal auto-hold braking function. Then, vehicle system 10 returns to operating step 512.

[0045] If the determination in operating step 516 is positive, i.e., the engine has been automatically switched off, vehicle system 10 proceeds to operating step 518. In operating step 518, the vehicle system evaluates PRNDL_status to determine whether the gearshift lever 36 is being moved from one gear position to another. If the determination is negative, i.e., the gearshift lever 36 is not being moved from one gear position to another, vehicle system 10 proceeds to operating step 522. In operating step 522, vehicle system 10 controls the braking system to provide normal auto-hold braking functionality and holds the engine in auto-stop condition according to normal stop-start functions. However, the engine may be automatically restarted due to other conditions, such as a change in battery charge level, power consumption, or other auto-start requirements. Vehicle system 10 then returns to operating step 512.

[0046] If the determination in operating step 520 is positive, i.e., the gearshift lever 36 is moved from one gear position to another, the vehicle system 10 proceeds to operating step 524. In operating step 524, the vehicle system 10 evaluates PRNDL_status to determine whether the gearshift lever 36 has been moved away from PARK. In other words, the vehicle system 10 determines whether the gearshift lever 36 was in PARK before the current movement.

[0047] If the determination in operating step 524 is negative, i.e., the gear selector 36 is moved from a gear position other than PARK, the vehicle system 10 proceeds to operating step 526. If the gear selector 36 is moved from a gear position other than PARK with the engine off, it can be inferred that there is a high probability that the gear selector 36 will be moved into PARK. In operating step 526, the vehicle system 10 keeps the engine in the auto-stop condition. This may include suppressing a request to automatically restart the engine, which would normally be issued due to the gear shift. However, the engine may restart automatically due to other conditions, such as a change in battery charge level, power consumption, or other auto-start requests. The vehicle system 10 then returns to operating step 512.

[0048] After moving the gear selector 36 to PARK, the auto-hold braking function can remain activated, and the braking system can continue to provide auto-hold braking. In a preferred embodiment, the auto-hold braking function is maintained until an additional condition is met. In various embodiments, the additional condition can include the application of an electric parking brake, the detection of driver exit (e.g., by detecting the opening and closing of the driver's door or by detecting driver exit via a driver's seat occupancy sensor), the turning off of an ignition switch, or the elapse of a calibratable time interval.

[0049] If the determination in operating step 524 is positive, i.e., the gear selector 36 is moved from PARK to another gear position, the vehicle system 10 proceeds to operating step 528. It can be deduced that when a driver moves the gear selector 36 from PARK to another gear position, the driver intends to resume driving and request power. In operating step 528, the vehicle system 10 automatically restarts the engine. Then, the vehicle system 10 returns to operating step 512.

[0050] Variations of the above are of course possible. For example, embodiments according to the present disclosure can be implemented in all vehicles, including hybrid vehicles, that have an engine configured to automatically shut down according to one operating condition and to automatically restart according to a second operating condition during a driving cycle.

[0051] As can be seen, this disclosure provides a system and method for controlling an engine in a vehicle that can avoid unnecessary engine restarts due to switching to PARK with the Auto Hold brake function activated. Avoiding unnecessary engine restarts can provide various benefits, including improved fuel economy, reduced wear and tear on vehicle components, and improved driver satisfaction.

[0052] Although the most suitable mode has been described in detail, those skilled in the art will recognize various alternative concepts and embodiments within the scope of the following claims. Furthermore, the features of different implementations of the embodiments can be combined to develop further embodiments of the invention. While various embodiments could have been described as advantageous or preferable over other embodiments or implementations of the prior art with respect to one or more desired characteristics, those skilled in the art will recognize that one or more features or characteristics can be restricted to achieve desired properties of the overall system, which depend on the specific application and implementation.These characteristics may include, but are not limited to, cost, strength, durability, life-cycle costs, marketability, appearance, packaging, size, operational readiness, weight, manufacturability, ease of assembly, etc. The embodiments described herein as less desirable than other embodiments or implementations of the prior art with respect to one or more characteristics are not outside the scope of disclosure and may be desirable for certain applications. Furthermore, the features of different implementations of the embodiments may be combined to develop further embodiments of the invention.

Claims

[1] Vehicle comprising the following: an engine with auto-stop and auto-start conditions; a braking system with an auto-hold function configured to automatically apply braking torque after the vehicle has decelerated to a complete standstill, regardless of the brake pedal position; and a control device configured to automatically apply braking torque in response to the activation of the engine's auto-stop condition, and to control the engine into an automatic restart in response to the movement of a gearshift lever from PARK, with the automatic restart of the engine being controlled before the gearshift lever reaches an end position. [2] Vehicle according to claim 1, wherein the control device is further configured to maintain the auto-stop condition when the brake pedal is released.

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