KR101230825B1 - Output shaft sensor breakdown diagnosis method automatic transmission car - Google Patents

Abstract

The present invention relates to a method for diagnosing a failure of an output shaft rotation sensor for an automatic transmission vehicle that can prevent misdiagnosis by determining whether an intermediate stage of the shift lever is stopped. A first step of checking input / output failure information of a part; A second step of determining whether the shift lever is N-> D intermediate stop if there is no failure information in the first step; In the second step, since it is determined that the vehicle is currently running, if it is not an intermediate stop, the vehicle speed is calculated by using the turbine speed Nt and the vehicle speed of X KPH or more is maintained for more than td seconds while maintaining No = 0. Including the third step to determine the failure.

Vehicle, automatic transmission, output shaft rotation sensor, diagnosis method

Description

Output shaft sensor breakdown diagnosis method automatic transmission car}

1 is a schematic view showing the position of a typical speed sensor

2 is a flowchart for explaining a conventional method.

Figure 3 is a graph showing the rotation speed waveform of the engine and turbine when the shift lever of the vehicle shifts from the D stage to the N stage.

4 is a graph showing the rotational speed waveforms of the engine and turbine when the vehicle is running in a stationary state.

5 and 6 are graphs for explaining the diagnostic logic according to the present invention.

7 is a flowchart illustrating a diagnostic method according to the present invention.

8 is a graph showing waveforms at an intermediate stop with gear neutral while driving a vehicle.

Fig. 9 is a graph showing waveforms when the vehicle is stopped in the stopped state.

10 is a flowchart for explaining a diagnostic method according to the present invention.

The present invention relates to a method for diagnosing a failure of an output shaft rotation sensor for an automatic transmission, and more particularly, to a method for diagnosing a failure of an output shaft rotation sensor for an automatic transmission for determining an intermediate stop of a transmission lever and preventing an error diagnosis. .

In general, the automatic transmission is equipped with one speed sensor for measuring the rotational speed of the input shaft and the output shaft, and the shift control through these signals.

Therefore, most vehicles measure vehicle driving speed by separately attaching a vehicle speed sensor (VSS) to an axle connected to a differential gear (hereinafter referred to as DIFF).

In order to measure the rotational speed while responding to changes in the tire diameter of the vehicle, two drive / driven gears are applied to the axle, and the ratio of the number of teeth is adjusted by the bite of the gear.

Recently, as the functions of the T / M Control Unit (TCU) and the speed sensor have been improved, the rotation speed and the end reduction gear ratio of the existing transmission output speed sensor (OSS) The transmission is equipped with a tire comparator input to the TCU, which allows the controller to calculate the vehicle speed accurately and output a signal to the speedometer / odometer.

In case of transmission equipped with vehicle speed sensor (VSS) separately, there is no way to cope with sensor failure, so it is reflected on the speedometer as it is. can do.

In addition, most transmissions have an input speed sensor (ISS), so there are at least two signal sources for calculating the vehicle speed.

2 is a flowchart for explaining a conventional method.

As an example, the conventional vehicle has the following conditions for determining a failure of the output shaft speed sensor in the case of the first gear ratio.

If the shift lever is the driving stage (D, 3, 2, L, or sport mode) and maintains the following conditions, it is determined whether there is a fault when there is no signal input for td seconds.

tds Engine Speed (Ne)> Ne_stall rpm, Throttle Opening (TH)> THs% (Vehicle Speed (VS)> V KPH)

The engine speed, Ne_stall, must be greater than or equal to the vehicle stall rpm (the maximum engine speed that can be reached when stopped by brake operation) to ensure that the engine speed is the actual driving speed, and that the actual driving intention (throttle opening degree, Ths) Further check that the driving state.

It is used only to confirm that the current vehicle speed, V is also running, or to have a separate signal source (eg CAN signal from ABS) independent of the output shaft speed sensor.

However, according to the conventional method, it is difficult to reach the fault determination condition and output the alternative vehicle speed during the fault diagnosis.

In other words, in order to diagnose the first-speed fault, the current fault diagnosis method must maintain a certain throttle or more to reach the engine stall rotation speed, and since the vehicle speed signal is not output to the instrument panel, the vehicle driver may experience severe discomfort. May not detect a fault and attempt to drive any more.

In addition, there is a possibility of incorrect diagnosis when the shift lever N> D intermediate stop occurs.

That is, the shift lever is designed such that physical hydraulic pressure is applied after an electric signal of driving is first generated for user safety. Therefore, the driving stage is marked as 'D' in the neutral stage, but the actual hydraulic pressure may occur in the so-called shift lever intermediate stop that is placed in the neutral ('N') stage.

At this time, if the engine speed exceeds Ne_stall while the throttle continues to open more than THs, the output shaft cannot be rotated because it is a neutral stage, and only the input shaft rotates without load, so the TCU can recognize the condition as a sensor failure.

The present invention has been invented to solve the above problems, the object of which is to determine the output shaft speed sensor no signal failure diagnosis more quickly than the existing logic in the 1-speed driving state of the vehicle and the problem of the wrong diagnosis according to the middle stop of the lever The present invention provides a method for diagnosing a failure of an output shaft rotation sensor for an automatic transmission vehicle which can prevent the occurrence of the error.

Referring to the characteristic configuration of the present invention for achieving the above object is as follows.

A method for diagnosing a failure of an output shaft rotation sensor for an automatic transmission vehicle according to the present invention may include: a first step of checking input / output failure information of another part without a brake being operated in a first speed driving state; A second step of determining whether the shift lever is N-> D intermediate stop if there is no failure information in the first step; In the second step, since it is confirmed that the vehicle is currently running, if it is not an intermediate stop, the output shaft rotation sensor is maintained when the vehicle speed of X KPH or more is maintained for more than td seconds while calculating the vehicle speed through the turbine speed (Nt) and maintaining No = 0. Including the third step of determining that the failure.

Referring to the present invention having such characteristics in detail as follows.

The present invention is to prevent the error diagnosis by adding a logic for determining whether or not the progress of the fault diagnosis and whether to output a replacement vehicle speed by determining whether the shift stage N> D intermediate stops by comparing the turbine speed and the engine speed.

In addition, by determining whether the vehicle is driven by the turbine speed, the fault determination is faster than the existing logic considering the rotation value of the engine stall rpm or more.

It is also possible to output a vehicle speed alternative signal at turbine speed during fault diagnosis.

Therefore, the present invention uses the physical characteristics of the engine speed and the transmission input shaft speed in the case of the neutral stage in order to output the replacement vehicle speed after recognizing whether the shift lever N> D intermediate stops and before the failure diagnosis is confirmed.

The engine speed and the transmission input shaft speed converge in almost the same value within a short time because the vehicle is not loaded in the neutral stage, and the torque multiplication increases in the torque converter to overcome the vehicle inertia when entering the driving state. As it occurs, slip (rotation value difference) occurs between engine and transmission input shaft, so measure it and use it as the criterion for middle stop.

 For example, if the shift lever signal is D 'and there is no transmission output shaft rotation signal, it is necessary to determine whether the output shaft speed sensor is faulty or not.

3 is described in detail with reference to the graph showing the rotational speed waveform of the engine and turbine when the shift lever of the vehicle shifts from the D stage to the N stage.

First, TCU (Transmission Control Unit) has gear ratio for each gear stage, which is the source of T / M, and input / output shaft rotation speed (Nt, No) through speed sensor, brake operation in brake switch, ECU (Electronic Control Unit) ), The engine speed Ne and the throttle opening degree TH can be known in real time. If the vehicle is running, the real-time vehicle speed (VS) is calculated based on the Nt value and the gear ratio.

On the other hand, the speed difference between Nt and Ne is called slip (SLIP = | Ne-Nt |) in the torque converter.

In the case where Nt increases from 0, it is a case where the driving stage stops-> starts or shifts to N stages.

In addition, when the engine is unloaded (neutral), the engine has a lower engine idle speed (Idle rpm, Ne_idle) than the normal driving and stall rotation by the neutral stage control. Turbine rotation converges very quickly to engine speed in a short time, overcoming its own weight of rotational inertia.

Ne 이다.That is, Ne_idle (engine idle) at the neutral stage (N) <Ne_stall, Nt

Ne.

4 is described in detail with reference to a graph showing the rotational speed waveforms of the engine and the turbine when the vehicle is running in the stationary state.

The driving force and torque multiplication section when driving the vehicle is the largest when overcoming the initial inertia of the vehicle, and at this time, the speed ratio of the input (Ne) output (Nt) maintains the section in which the difference (τ) becomes larger by the torque ratio. .

In addition, when the speed change stage is 1 speed, the torque converter keeps the engine shaft and the turbine shaft to be slipped without being directly connected, so the torque is increased when acceleration is required. In the case of the driving stage, Ne can rise above the stall speed when the brake is not operated, and as the throttle opening increases, the slip amount also increases.When the brake is operated, the slip amount increases in proportion to the braking force and the throttle opening Increases, the engine does not exceed stall speed

Therefore, since the turbine shaft inertia of the TM (transmission) cannot be greater than the vehicle inertia, the slip amount at the time of inertia overturning at the driving stage is larger than the neutral stage, and the slip amount at the neutral stage can be set according to the vehicle type.

5 and 6 are graphs for explaining the diagnostic logic according to the present invention, Figure 7 is a flow chart for explaining the diagnostic method according to the present invention.

When described in detail with reference to the accompanying drawings as follows.

Here the variable is defined as

t: Time required for No to change from 0 to more value at driving stage ('D')

td: Duration of monitoring for fault determination (set value)

S_neu: Maximum value of slip when the slip value converges below a certain value at the neutral stage (test value)

S_neu = MAX [[Ne-Nt] / Ne * 100] When the shift stage of the TM (transmission) is at the neutral stage.

tn_max: Maximum statistical value of the time when the slip amount converges below S_neu at Nt = 0 when shifting from the driving stage to the neutral stage (test value)

X: Use vehicle speed abnormal value when Nt = Ne_idle at 1 speed at vehicle driving speed (set value)

The OSS fault diagnosis process is as follows.

① Entry condition: 1 speed, driving stage, brake not working, no information on I / O failure of other parts. If the No signal remains in the output state, carry out ②.

② Determine whether the shift lever is in the middle of N-> D. The middle stop logic performs the process as shown in FIG. At this time, if it is not middle stop, execute ③.

③ After confirming that the vehicle is currently running, calculate the vehicle speed through the turbine speed (Nt) and maintain No = 0, and if the vehicle speed more than X KPH continues for more than td seconds, it is judged as OSS failure.

The detailed description of FIG. 7 is as follows.

In the case of the intermediate stop of the shift stage, when the hydraulic state is changed from the D stage stop to the neutral stage (see Fig. 9) and the stop-> engine and turbine behavior at the start (see Fig. 4) is similar, the output speed sensor is broken. In this case, Ne, Nt, and No waveforms are similar, so there is a possibility of misdiagnosis.

When the vehicle is changed to the neutral stage while driving (see Fig. 8), a speed ratio different from the current speed ratio is generated, so that the synchronization failure is judged, and thus it is possible to diagnose whether there is a problem with the transmission.

Accordingly, when the transmission is neutral and the load is applied, it is possible to distinguish the difference between the engine / turbine speed by the big and small, so that the process of distinguishing the D stage signal shift neutral phenomenon is shown in FIG. 10.

0 을 유지하였으면 주행단으로 판단. 그렇지 않으면 ②를 실행① X KPH or greater than No = 0, or Ne> Ne_idle and Nt> Ne_idle, or Nt

If it stays at 0, it is judged as the driving stage. Otherwise run ②

(2) If Ne> Ne_idle, No = 0, and Nt> 0 are satisfied, and the tn_max time elapses and the slip amount decreases below S_neu, it is judged to be neutral. Otherwise judged by the driving stage

③ If it is not neutral, calculate the vehicle speed by using Nt value and TCU input value (1 speed gear ratio, end gear ratio, tire radius) and start output to outside (speedometer, odometer).

As described above, the present invention determines whether the shift stage N> D is stopped by comparing the turbine rotational speed and the engine rotational speed, thereby determining whether to proceed with a fault diagnosis and outputting a replacement vehicle speed. It works.

In addition, the present invention can determine the vehicle running by the turbine speed is faster than the existing logic that considers the rotation value of the engine Strp rpm or more, and can determine the speed, the vehicle speed alternative signal to the turbine speed during the diagnosis time There is a specific effect that can be output.

Claims (2)

A first step of checking the input / output failure information of another part without the brake being operated in the first speed driving state; A second step of determining whether the shift lever is N-> D intermediate stop if there is no failure information in the first step; In the second step, it is confirmed that the vehicle is currently running if it is not an intermediate stop, and if the vehicle speed of X KPH or more is maintained for td seconds or more while calculating the vehicle speed through the turbine speed (Nt), the output shaft rotation sensor malfunctions. It is configured to include a third step of determining, In the second step, determining whether the middle stop X KPH or greater, or Ne> Ne_idle and Nt> Ne_idle, or Nt before No = 0 occurs

A fourth step of judging by the driving stage if it is maintained at 0; If it is not determined as the driving stage in the fourth step, both Ne> Ne_idle and No = 0 and Nt> 0 are satisfied, and if tn_max time elapses and the slip amount decreases below S_neu, it is judged as neutral stage. A fifth step of judging by the driving stage; In the fifth step, if the neutral stage is not included, the sixth step includes calculating the vehicle speed using the Nt value and the TCU input value (1 speed gear ratio, end gear ratio, tire radius) and starting output to the outside (speedometer, odometer). A method for diagnosing a failure of an output shaft rotation sensor for an automatic transmission, characterized in that. delete

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