Patent Application
20110264354
The present disclosure relates to vehicle control systems, and more particularly to a system and method for detecting a stuck vehicle accelerator and remedially controlling a powertrain system of the vehicle.
The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.
Internal combustion engines combust an air/fuel (A/F) mixture within cylinders to drive pistons that rotatably turn a crankshaft generating drive torque. The drive torque may be transferred to a driveline (e.g., wheels) of a vehicle via a transmission. Air may be drawn into an intake manifold of the engine through an inlet that may be regulated by a throttle. The throttle may be controlled either mechanically or electronically based on input from a driver of the vehicle. The driver input may include acceleration based on a position of an accelerator (e.g., a pedal).
A control system for a vehicle includes an error detection module and a remedial control module. The error detection module detects whether an accelerator of the vehicle is stuck is based on vehicle speed, a position of the accelerator, and one of a pressure applied to a brake of the vehicle and a status of a parking brake of the vehicle. The remedial control module, when the accelerator is stuck, at least one of resets the position of the accelerator and decreases torque output of a powertrain system.
A method for controlling a vehicle includes detecting whether an accelerator of the vehicle is stuck is based on vehicle speed, a position of the accelerator, and one of a pressure applied to a brake of the vehicle and a status of a parking brake of the vehicle, and when the accelerator is stuck, at least one of resetting the position of the accelerator and decreasing torque output of a powertrain system.
In still other features, the systems and methods described above are implemented by a computer program executed by one or more processors. The computer program can reside on a tangible computer readable medium such as but not limited to memory, nonvolatile data storage, and/or other suitable tangible storage mediums.
Further areas of applicability of the present disclosure will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the disclosure.
The present disclosure will become more fully understood from the detailed description and the accompanying drawings, wherein:
The following description is merely exemplary in nature and is in no way intended to limit the disclosure, its application, or uses. For purposes of clarity, the same reference numbers will be used in the drawings to identify similar elements. As used herein, the phrase at least one of A, B, and C should be construed to mean a logical (A or B or C), using a non-exclusive logical or. It should be understood that steps within a method may be executed in different order without altering the principles of the present disclosure.
As used herein, the term module refers to an Application Specific Integrated Circuit (ASIC), an electronic circuit, a processor (shared, dedicated, or group) and memory that execute one or more software or firmware programs, a combinational logic circuit, and/or other suitable components that provide the described functionality.
During vehicle operation an accelerator (e.g., a pedal) may become physically and unintentionally displaced. In other words, the accelerator may become “stuck.” For example, the accelerator may become stuck due to improperly placed and/or improperly designed floor mats or due to other loose objects obstructing the accelerator. The stuck accelerator may increase torque output of a powertrain and thus increase a speed of the vehicle above a desired speed. Moreover, when the accelerator becomes stuck a driver of the vehicle may then be unable to decrease the speed of the vehicle. More specifically, brakes may be insufficient to decrease the speed of the vehicle. In other words, the brakes may be unable to overpower the torque output of the powertrain to allow the driver to decrease the speed of the vehicle.
Accordingly, a system and method are presented that detect when the accelerator is stuck and then remedially control the powertrain to allow the driver to decrease the speed of the vehicle. More specifically, the system and method may detect whether the accelerator is stuck based on vehicle speed, accelerator position, brake pressure, and corresponding thresholds. For example, the brake pressure (and duration) may be used to prevent false detections (e.g., drivers that simultaneously command the accelerator and the brake, also known as “two-footed drivers”). Additionally or alternatively, the system and method may detect whether the accelerator is stuck based on vehicle speed, accelerator position, a status of a parking brake, and corresponding thresholds. The system and method, however, may also determine that the accelerator is stuck based on other combinations of inputs (e.g., input from the driver requesting override operation).
When the accelerator is stuck, the system and method may command a reset of the accelerator position (i.e., set the position to zero). When the accelerator position reset occurs, the current position of the accelerator pedal becomes the learned idle position and further displacement of the accelerator pedal results in incremental torque requests from the idle torque request. If the accelerator position reset occurs when the accelerator is fully displaced, however, no additional torque may be requested via the accelerator. Additionally, as the accelerator pedal releases back towards its normal idle position, the learned idle position of the accelerator pedal may update to the current physical accelerator pedal position.
Resetting the accelerator position, therefore, may effectively override the stuck accelerator pedal and allow the driver to brake and stop the vehicle. Additionally or alternatively, when the accelerator is stuck and the driver requests override control (e.g., via a push-button ignition, a rotatable key-in ignition, or a separate emergency switch), the system and method may command idle operation of the powertrain. The idle operation of the powertrain may allow the driver to brake and stop the vehicle and may also provide a smoother transition to stop the vehicle as compared to a traditional emergency stop that immediately turns off the powertrain system. For example, commanding idle operation instead of turning off the powertrain system allows the driver to continue using hydraulic components such as hydraulic brakes (i.e., power brakes) and hydraulic steering (i.e., power steering).
Referring now to
The engine 12 draws air into an intake manifold 14 through an inlet 16 that may be regulated by a throttle 18. For example, the throttle 18 may be electronically controlled (e.g., electronic throttle control, or ETC). Air in the intake manifold 14 is distributed to a plurality of cylinders 20. While six cylinders are shown, the engine 12 may include other numbers of cylinders. The air in the cylinders 20 may be combined with fuel from fuel injectors 22 to create an A/F mixture. The A/F mixture may be compressed by pistons (not shown) and ignited to rotatably turn a crankshaft 26 generating drive torque. For example, the A/F mixture may be ignited by spark from spark plugs 24. However, as previously described, other methods of fuel injection and/or combustion may be used depending on the type of powertrain.
An engine speed sensor 28 measures a rotational speed of the crankshaft 26 (e.g., in revolutions per minute, or RPM). The drive torque may be transferred from the crankshaft 26 to a driveline 30 (e.g., wheels) of the vehicle via a transmission 32. For example, the transmission 32 may be coupled to the crankshaft 26 via a torque converter (e.g., a fluid coupling) (not shown). A transmission output shaft speed (TOSS) sensor 34 may measure a rotational speed of an output shaft (not shown) of the transmission 32. For example, the measurement of the TOSS sensor 34 may indicate the speed of the vehicle. However, the vehicle speed may be measured or modeled using other suitable methods. Exhaust gas resulting from combustion may be expelled from the cylinders 20 into an exhaust manifold 36. The exhaust gas may then be treated by an exhaust treatment system 38 that decreases emissions before being released into the atmosphere.
A control module 40 controls operation of the powertrain system 10. Specifically, the control module 40 may control the throttle 18, the fuel injectors 22, the spark plugs 24, the transmission 32, and/or the exhaust treatment system 38. The control module 40 may also receive signals from the engine speed sensor 28 and the TOSS sensor 34. The control module 40 may also implement the system and/or method of the present disclosure. Specifically, the control module 40 may also receive input from a driver of the vehicle. For example, the control module 40 may receive input from the driver of the vehicle via one of a plurality of devices (collectively referred to as a “driver input module 42”).
The driver input module 42 may include an accelerator 44, a brake 46, a parking brake 48, an ignition control module 49, and/or a shift control module 50. Specifically, the driver input may be based on a position of the accelerator 44 (e.g., a pedal) and a pressure applied to a brake 46 (e.g., a pedal). For example, a position sensor 45 may measure a position of the accelerator 44 and a pressure sensor 47 may measure a pressure applied to the brake 46. Furthermore, the driver input module 42 may include a parking brake 48 and an ignition control module 49.
For example, the status of the parking brake 48 (e.g., a handle or a pedal) may include either a first state (e.g., “ON,” or engaged) or a second state (e.g., “OFF,” or disengaged). Additionally, for example, the ignition control module 49 may include a push-button ignition or a rotatable key-in ignition. Moreover, both the push-button ignition and the rotatable key-in ignition may transition from first states to second states by a push or a turn from the driver, respectively.
Additionally or alternatively, the ignition control module 49 may include an emergency switch that may be actuated and deactivated by the driver by switching the emergency switch from a first state to a second state and vice-versa. The shift control module 50 may include a shift lever that may control various modes of the transmission 32. For example, the shift control module 50 may include a park/reverse/neutral/drive/low (PRNDL) shifter that allows the driver to select one of a park mode, a reverse mode, a neutral mode, a drive mode, and a low speed/load mode, respectively. Additionally, for example, the shift control module 50 may include an alternative manual shift selection mode (e.g., manumatic) that allows the driver to tap-up (e.g., upshift) or tap-down (e.g., downshift) to control shifting of the transmission 32.
Referring now to
The error detection module 60 determines whether the accelerator 44 is stuck based on the received signals. More specifically, the error detection module 60 may determine that the accelerator 44 is stuck when the vehicle speed is greater than a vehicle speed threshold (VSTH), the position of the accelerator 44 is greater than an accelerator position threshold (APTH), and the pressure applied to the brake 46 is greater than a brake pressure threshold (BPTH) for a predetermined period. Alternatively, the error detection module 60 may determine that the accelerator 44 is stuck when the vehicle speed is greater than the speed threshold VSTH, the position of the accelerator is greater than the position threshold APTH, and the state of the parking brake 48 is the first state (e.g., ON, or engaged). The error detection module 60, however, may also determine that the accelerator 44 is stuck based on other combinations of the inputs. For example, when a driver of the vehicle indicates an emergency (e.g., via the ignition control module 49), the error detection module 60 may determine that the accelerator 44 is stuck. Otherwise, the error detection module 60 may determine that the accelerator 44 is not stuck.
The remedial control module 70 communicates with the error detection module 60 to determine whether the accelerator 44 is stuck. For example, the remedial control module 70 may receive a status signal from the error detection module 60 indicating whether the accelerator 44 is stuck. For example, the status signal may include either a first state (“YES”) or a second state (“NO”). The remedial control module 70 may also receive an emergency signal from the ignition control module 49 indicating that the driver of the vehicle is requesting override control of the powertrain system 10.
Specifically, the driver of the vehicle may request override control of the powertrain system 10 when the accelerator 44 is stuck. For example, the driver may request override control by one press of a push-button ignition or one clockwise turn of a rotatable key-in ignition. Additionally or alternatively, for example, the driver may request override control by actuating the separate emergency switch (e.g., an ON/OFF button). Additionally or alternatively, for example, the driver may request override control by changing a selection of the shift control module 50 (e.g., change of PRNDL or a tap-up/tap-down in the manumatic mode).
The remedial control module 70 may reset the accelerator position (i.e., set the accelerator position to zero) when the accelerator 44 is stuck. When the accelerator position reset occurs, the current position of the accelerator 44 becomes the learned idle position and further displacement of the accelerator 44 results in incremental torque requests from the idle torque request. If the accelerator position reset occurs when the accelerator 44 is fully displaced, however, no additional torque may be requested via the accelerator 44. Additionally, as the accelerator 44 releases back towards its normal idle position, the learned idle position of the accelerator 44 may update to the current physical accelerator position.
When the accelerator 44 is stuck and the emergency signal is not received, however, the remedial control module 70 may decrease the torque output of the powertrain system 10. More specifically, the remedial control module 70 may decrease the torque output of the powertrain system 10 to a torque output as low as idle operation. For example, the remedial control module 70 may merely decrease the torque output of the powertrain system 10 when the driver is lightly applying the brake (e.g., brake pressure<threshold). The remedial control module 70, however, may decrease the torque output of the powertrain system 10 to idle operation (i.e., command idle operation) when the driver is heavily applying the brake (e.g., brake pressure>threshold).
For example, idle operation of the powertrain system 10 may include commanding the throttle 18 to a predetermined position, commanding the fuel injectors 22 to inject a predetermined amount of fuel, and commanding the fuel injectors 22 and the spark plugs according to predetermined timings. In other words, idle operation of the powertrain system 10 may include controlling the A/F ratio of the engine and combustion timing to maintain a relatively low engine speed and engine output torque.
Referring now to
At 104, the control module 40 may determine whether the accelerator 44 is stuck. If true, control may proceed to 108. If false, control may return to 100. At 108, the control module 40 may determine whether the driver has requested override control. If false, control may proceed to 112. If true, control may proceed to 116.
At 112, the control module 40 may decrease torque output of the powertrain system to a torque output as low as idle operation. For example, the decreased torque output may be based on a brake pressure applied by the driver (e.g., heavy brake pressure may result in idle operation). Control may then return to 100. At 116, the control module 40 may reset the accelerator position (e.g., set the accelerator position to zero). Control may then return to 100.
The broad teachings of the disclosure can be implemented in a variety of forms. Therefore, while this disclosure includes particular examples, the true scope of the disclosure should not be so limited since other modifications will become apparent to the skilled practitioner upon a study of the drawings, the specification, and the following claims.
