Engine Start and Stop Control

Abstract

The present disclosure relates to engine start and stop control. A vehicle includes an engine and a braking system. The vehicle includes a controller configured to maintain an ignition state of the engine to prohibit a change in the ignition state between engine start and engine stop during pressurization of the braking system, wherein the pressurization of the braking system is induced and initiated prior to application of a brake pedal. The maintained ignition state is in response to receiving an indication of adverse road conditions from a source in the vicinity of the vehicle.

Description

Technical Field

[0001] The present disclosure relates to engine start and stop control of a vehicle. Background Art

[0002] Internal combustion engine vehicles can be started and stopped to save fossil fuels. The engine can be stopped by turning off the ignition switch or cutting off the fuel supply. The engine can be stopped when the vehicle is stopped at a stop signal. The engine can also be stopped in preparation for the vehicle to stop. For example, the engine can be stopped when the vehicle brake is applied and the vehicle speed is below a specific speed. During poor road conditions, engine stop and start can reduce the power available for auxiliary devices. Summary of the Invention

[0003] A vehicle includes an engine and a braking system. The vehicle includes a controller configured to maintain the ignition state of the engine to prohibit a change in the ignition state between engine start and engine stop during pressurization of the braking system, wherein the pressurization of the braking system is caused by an indication and starts before the application of the brake pedal. The maintained ignition state is in response to receiving an indication of poor road conditions from a source near the vehicle.

[0004] The controller may also be configured to: start the engine in response to the indication being lifted. The controller may also be configured to: stop the engine in response to the indication being lifted. The poor road conditions may be a reduced coefficient of friction. The reduced coefficient of friction may be caused by bad weather. During the maintaining of the ignition state of the engine, the vehicle may have a non-zero speed. The controller may also be configured to: maintain the ignition state in response to the reception only when the speed of the vehicle is less than a predetermined threshold. The paths of the vehicle and the source may intersect.

[0005] A vehicle includes a power steering system. The vehicle includes a controller configured to: maintain the ignition state of the engine of the vehicle to prohibit at least one of engine start and engine stop until the indication is lifted, such that there is sufficient energy available for the power steering system required by the indication. The controller maintains the ignition state in response to receiving an indication of poor road conditions from a source near the vehicle via dedicated short range communication (DSRC).

[0006] According to the present invention, there is provided a vehicle, including: an engine; and a controller configured to: in response to receiving an indication of poor road conditions from a source near the vehicle via dedicated short range communication, maintain the ignition state of the engine such that a change in the ignition state between engine start and engine stop is prohibited until the indication is lifted.

[0007] According to an embodiment of the present invention, the controller is further configured to maintain the ignition state in response to the reception only when the speed of the vehicle is less than a predetermined threshold.

[0008] According to an embodiment of the present invention, the path of the vehicle and the path of the source intersect.

[0009] A vehicle includes a controller configured to maintain an ignition state of an engine of the vehicle to prohibit at least one of engine start and engine stop until an indication is lifted, such that an auxiliary vehicle system caused by the indication is driven. The controller may be configured to maintain the ignition state in response to receiving an indication of a poor road condition from a source near the vehicle via dedicated short-range communication (DSRC) and the vehicle speed being lower than a predetermined threshold.

[0010] According to the present invention, there is provided a control method for a vehicle, including: in response to receiving an indication of a poor road condition from a source near the vehicle and the vehicle speed being lower than a predetermined threshold, maintaining an ignition state of an engine by a controller, such that a change between engine start and engine stop of the ignition state is prohibited until the indication is lifted.

[0011] According to an embodiment of the present invention, the control method further includes: in response to the reception, starting pressurization of a braking system before application of a brake pedal and the lift of the indication.

[0012] According to an embodiment of the present invention, the source is another vehicle. Description of the Drawings

[0013] Figure 1 is a schematic diagram of a vehicle;

[0014] Figure 2 is a timeline of an engine start and stop sequence;

[0015] Figure 3 depicts an indication of a poor road condition for a vehicle;

[0016] Figure 4 is a graph indicating an indication of system parameters and a timing of actuation;

[0017] Figure 5 is a flowchart of a maintained ignition state. Detailed Description

[0018] Embodiments of the present disclosure are described herein. However, it should be understood that the disclosed embodiments are merely examples and other embodiments may take various alternative forms. The drawings are not necessarily to scale; some features may be exaggerated or minimized to show details of particular components. Accordingly, the specific structural and functional details disclosed herein should not be construed as limiting, but merely as a representative basis for teaching one skilled in the art to utilize the invention in various forms. As will be understood by one of ordinary skill in the art, the various features shown and described with reference to any one of the figures may be combined with features shown in one or more other figures to produce embodiments that are not explicitly shown or described. Combinations of the features shown provide representative embodiments for typical applications. However, various combinations and modifications of the features consistent with the teachings of the present disclosure may be desired for a particular application or implementation.

[0019] Many vehicles employ start-stop functions to improve fuel economy. Static start-stop can be performed when the vehicle is stationary, while roll start-stop can be performed when the vehicle is in motion (e.g., rolling). Since starting a vehicle engine requires high current, strict implementation of the start-stop function can cause vehicle performance to lag. This high current draw can limit the power available for other powered components. For example, power steering may require 95A, which may be difficult to obtain during engine start-up. Additionally, engine shutdown can cause auxiliary loads to draw power from a storage location rather than from the alternator. This draw on power storage can limit the power available for auxiliary loads (e.g., braking systems, power steering, auxiliary systems) and may be depleted over time or otherwise become unavailable. The start-stop function may be prohibited during adverse road conditions to ensure the availability of auxiliary systems necessary to cope with the adverse conditions.

[0020] An indication of adverse road conditions may be received from another nearby vehicle. For example, the other vehicle may detect adverse road conditions and send an adverse indication to the vehicle such that start-stop is prohibited until the indication subsides or the vehicle has passed through the adverse road conditions. Adverse road conditions may be caused by inclement weather, road construction, or other circumstances.

[0021] Referring to Figure 1, the vehicle 10 may include an engine 12, an ISG 14, a battery 16, an electrical bus 18, and a controller 28. The engine may be directly mechanically connected to the ISG 14. The ISG may be electrically connected to the battery 16 and the electrical bus 18. The battery 16 may be connected to the electrical bus 18. The controller 28 may communicate with the engine 12, the ISG 14, and the battery 16. The electrical bus 18 may supply power to vehicle systems such as an electric power steering unit 20, a brake booster pump 22, or other vehicle systems. Other systems may include a transmission system or energize an active or magnetic suspension of the vehicle. For example, a magnetic suspension may require energy to ensure maximum contact of the wheels with the road surface. The power steering unit 20 allows the driver to properly steer the vehicle in adverse road conditions. The brake booster pump 22 ensures that brake pressure is available and the brakes are responsive in adverse road conditions.

[0022] The power steering unit 20 or the brake booster pump 22 may be energized during system transients to reduce energy consumption. The brake booster pump 22 may pressurize a hydraulic braking system including brakes 26. The vehicle 10 may include a receiver 24 to receive an indication of adverse road conditions from a source.

[0023] Referring to Figure 2, an engine automatic stop event may include multiple stages. "Automatic stop start" marks the beginning of the engine automatic stop event. "Prepare for engine automatic stop" is the time period during which the vehicle system and the engine prepare for the upcoming engine stop. "Cut off fuel" marks the time point when fuel stops flowing to the engine. "Engine stop" is the time period during which the engine speed decreases to 0. "Low fuel restart" marks the time point such that if a restart is requested at this time point during the "engine stop" stage, it will be necessary to engage the starter to start the engine (if a restart is requested during the "engine stop" stage and before "low fuel restart", the engine can be restarted by reopening the fuel flow). "Engine speed = 0" marks the time point when the engine speed is close to or equal to 0. "Engine automatic stop" is the time period during which the engine is shut down. "Starter engage" marks the time point when the starter begins to start the engine to make the engine start (in response to detecting an engine automatic start condition). "Starter start engine" is the time period during which the engine cannot start by its own power. During restart, electric power steering, brake pressurization, or other auxiliary loads may be disabled because restarting drains the battery. That is, power steering or other auxiliary systems may be disabled for 700 ms to allow the engine to reach idle speed and power steering has 2 ms - 300 ms to re-engage. "Starter disengage" marks the time point when the engine can start by its own power. "Engine speed increase" is the time period during which the engine speed increases to its operating speed (a speed equal to or higher than the target idle speed). Finally, "automatic start end" marks the time point when the engine speed reaches its operating speed.

[0024] Refer to Figure 3 , a source 50 is shown. The source 50 can be a vehicle, an infrastructure component, or other device with dedicated short-range communication (DSRC) capabilities. DSRC can use or can include various communication protocols (e.g., Wi-Fi, V2X, or cellular). Any communication protocol can be used to communicate between the source 50 and the vehicle 10. The source 50 can be a vehicle configured to send V2V communication to the vehicle 10. The source 50 can send an indication 54 of a poor road condition 52. The indication 54 can refer to "true" or "false". The indication 54 can be an indication of a reduced coefficient of friction associated with the source 50. The indication 54 can be a classification of the road surface condition (e.g., icy, slippery). An indication of the forward distance can be communicated between the vehicle 10 and the source 50 to delay the start and stop prohibition.

[0025] Refer to Figure 4, shows a timing diagram 200. The timing diagram 200 includes a vehicle speed indication 202, an indication 54 of poor road conditions, and energization of an auxiliary load 220. The vehicle speed 202 can change over time. An indication 54 of poor road conditions can be received at time 204. At time 206, the vehicle speed 202 can be less than a predetermined vehicle speed threshold 208, which would typically allow engine start and stop. The indication 54 can prohibit engine start or stop to ensure that the auxiliary system 220 can be energized. The auxiliary system can be part of a power steering pump 20 or a braking system 22.

[0026] Referring to Figure 5 , shows a flowchart 300. The flowchart begins at step 302. At step 304, the controller 28 performs engine start and stop as necessary. For example, a rolling start and stop or a static stop and start can be performed. At step 306, the vehicle 10 can establish communication with a source 50. The vehicle 10 and the source 50 can perform a handshake to establish a communication link. At step 308, the vehicle 10 receives an indication 54 of poor road conditions 52. The indication 54 can prohibit the engine start and stop function for a predetermined period of time or until another indication that the poor road conditions have been lifted is sent. For example, the indication 54 can include a delay period based on the distance between vehicles, or the expected time for the vehicle to reach the poor road conditions 52. Then, at step 312 the vehicle 10 can apply pressure to the brakes, at step 314 the vehicle 10 can energize the power steering, or at step 316 the vehicle 10 can energize other auxiliary loads. At step 318, the controller 28 determines whether the indication 54 has been lifted or the delay period has passed. At step 320, the vehicle performs engine start and stop as necessary. At step 322, the process ends or returns to the start to continue.

[0027] The words used in the specification are descriptive rather than restrictive, and it should be understood that various changes can be made without departing from the spirit and scope of the present disclosure. As previously mentioned, the features of various embodiments can be combined to form further embodiments that may not be explicitly described or shown in the present invention. Although various embodiments may have been described as providing advantages or being superior to other embodiments or prior art implementations with respect to one or more desired characteristics, those of ordinary skill in the art should recognize that, depending on the specific application and implementation, one or more features or characteristics may be compromised to achieve the desired overall system attributes. These attributes can include, but are not limited to: cost, strength, durability, life cycle cost, marketability, appearance, packaging, size, maintainability, weight, manufacturability, ease of assembly, etc. Therefore, embodiments that are described as less satisfactory than other embodiments or prior art implementations in one or more characteristics are not outside the scope of the present disclosure and may be desirable for a particular application.

Claims

1. A vehicle, comprising: An engine; A braking system; And A controller configured to: in response to receiving an indication of a poor road condition from a source near the vehicle, maintain the ignition state of the engine to prohibit a change in the ignition state between engine start and engine stop during pressurization of the braking system, wherein the pressurization of the braking system is caused by the indication and starts before the application of the brake pedal.

2. The vehicle according to claim 1, wherein, The controller is further configured to: start the engine in response to the indication being lifted.

3. The vehicle according to claim 1, wherein The controller is further configured to: stop the engine in response to the indication being lifted.

4. The vehicle according to claim 1, wherein, The poor road condition is a reduced coefficient of friction.

5. The vehicle according to claim 4, wherein, The reduced coefficient of friction is caused by bad weather.

6. The vehicle according to claim 1, wherein, During the maintaining of the ignition state of the engine, the vehicle has a non-zero speed.

7. The vehicle according to claim 1, wherein The controller is further configured to: maintain the ignition state in response to the reception only when the speed of the vehicle is less than a predetermined threshold.

8. The vehicle according to claim 1, wherein, The path of the vehicle and the path of the source intersect.

9. A vehicle, comprising: An engine; And A controller configured to: in response to receiving an indication of a poor road condition from a source near the vehicle via dedicated short-range communication, maintain the ignition state of the engine such that a change in the ignition state between engine start and engine stop is prohibited until the indication is lifted, and In response to the reception, start pressurization of the braking system before the application of the brake pedal.

10. The vehicle according to claim 9, wherein, The controller is further configured to: start pressurization of the braking system before the lifting in response to the reception.

11. The vehicle according to claim 9, wherein, The controller is further configured to: start the engine in response to the indication being lifted.

12. The vehicle according to claim 9, wherein, The controller is further configured to: stop the engine in response to the indication being lifted.

13. The vehicle according to claim 9, wherein, The poor road condition is a reduced coefficient of friction.

14. The vehicle according to claim 13, wherein, The reduced coefficient of friction is caused by bad weather.

15. The vehicle according to claim 9, wherein, During the maintaining of the ignition state of the engine, the vehicle has a non-zero speed.

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