This disclosure generally relates to automatic-transmission and in particular relates to on-board diagnostics.

Background
A transmission is used to transmit power from an engine to a drive mechanism. The transmission uses the principle of mechanical advantage to convert the rotational speed, direction, and torque of a driving element into a different rotational speed, direction, and torque of a driven element. Most transmissions use a combination of gears in differing ratios to achieve this speed-torque conversion.

Vehicle transmissions often include more than one set of gear ratios (typically called “gears”) to allow the vehicle to operate in a variety of conditions. When the vehicle is at rest or travelling at a low speed, a gear ratio may be selected to deliver relatively high torque from the engine to the driveline. When the vehicle is travelling at higher speeds, a different ratio may be used to deliver higher rotational speeds at lower torque to the driveline. Gear ratio may be selected to optimize the delivery of power to the driveline having regard to the characteristics of the engine, and in particular, to the engine's delivery of power as a function of the engine's rotational speed. Changing the gear ratio of a transmission is commonly known as shifting or changing gears, and typically requires a brief decoupling of the engine from the driveline using a clutch arrangement.

State of the art automobile transmissions are controlled through a gear shift assembly connected to the transmission through a mechanical linkage. The gear shift is normally prominently positioned adjacent the driver's seat for easy access. In a vehicle having either an automatic or a manual transmission, to change the transmission gear position the operator moves the gear shift to a position corresponding to the intended gear position, e. g., park, neutral, drive, reverse, etc.

The automatic-transmissions lead to a gear-selection based on microcontroller measurements and has the probability to run into errors. The diagnostics rendered by the existing vehicle ECU are limited and a manual troubleshooting is required to a large extent to detect and diagnose the hidden errors. Accordingly, there lies a need to diagnose the gear-malfunction in automatic transmissions with an ease of operation and least manual effort.

Summary of Invention

This summary is provided to introduce a selection of concepts in a simplified version that is further described below in the detailed description. This summary is not intended to identify key features or essential features of the present invention, nor is it intended as an aid in determining the scope of the present invention.

The present subject matters refers a diagnostic system for a gear-shifter unit in a vehicle. The system comprises a plurality of sensors for sensing user selected gear positions, a microcontroller (MCU) for determining the sensed gear position, a MOSFET driver for rendering functional signals for driving an actuator based on determined gear position by the microcontroller. Further, a diagnostic unit (ECU) is configured to process the functional signals to determine the sensed gear positions and at least one state of a non-gear entity, determine an invalid state or a valid state pertaining to gear selection based on processing the functional signals, and alerting or aborting switching of gear in case of the invalid state.

An on-board diagnostics for a gear-shifter unit consists of Hall Effect Sensors, voltage regulator, MCU, Half bridge driver (e.g. a 6 channel half bridge Driver) and LEDs for a backlight illumination (e.g. for reverse gear operation). In an example, the hall-effect sensors may be an assembly of one magnet and three ‘magnetic-field’ detecting sensors.

The output from sensors yield particular-position of the gears as have been achieved through movement of the gear-shifter. The detected positions may be visible detectable positions such as Front, Neutral, Reverse, together with a signal as to whether these positions have been selected through a predetermined valid operation. As a part of same, the invisible gear positions (as taking place within the gear-console assembly as a part of automatic gear transmission) are also selected in addition to the visible gear-shifter positions.

The visible gear shifter positions and other invisible gear shifter related positions are communicated to the microcontroller for analysis and further directed to a half-bridge driver (MOSFET and transistor based gate-driver) for actuating the linear actuators to automatically select a particular-gear and ancillary devices (such as a reverse-lamp). In an example, the functional output signals may be of 800 mA and communicated at 12V to drive the linear actuators that in turn enables the automatic gear selection as part of automatic-transmission
Further, said functional output-signals for the actuators as outputted by the Half-Bridge Driver are in parallel sampled and accessible through a connector to port it to a diagnostic ECU (other than the main ECU) to thereby log the data, and detect the errors and enable stalling of the operations in case of invalid states. For example, the valid states as detected by the diagnostic ECU allow the operation while the invalid states as detected by the diagnostic ECU stall the operation.

The advantages and details of the present invention will be apparent from the following detailed description and accompanying drawings, which are explanatory only and is not restrictive of the present invention.

Brief Description of the Accompanying Drawings

To further clarify the advantages and features of the present invention, a more particular description of the present invention will be rendered by reference to specific embodiments thereof, which is illustrated in the appended drawings. It is appreciated that these drawings depict only typical embodiments of the present invention and are therefore not to be considered limiting of its scope. The present invention will be described and explained with additional specificity and detail with the accompanying drawings in which:

Figure 1 illustrates a system overview, in accordance with the present subject matter;

Figure 2 illustrates a block diagram representation, in accordance with the present subject matter;

Figure 3 illustrates tabulated-details in accordance with a valid-state as a part of diagnostics, in accordance with the present subject matter;

Figure 4 illustrates tabulated-details in accordance with an invalid-state as a part of diagnostics, in accordance with the present subject matter; and

Figure 5 illustrates a method of operation in accordance with the present subject matter.

It may be noted that to the extent possible like reference numerals have been used to represent like elements in the drawings. Further, those of ordinary skill in the art will appreciate that elements in the drawings are illustrated for simplicity and may not have been necessarily drawn to scale. For example, the dimensions of some of the elements in the drawings may be exaggerated relative to other elements to help to improve understanding of aspects of the present invention. Furthermore, the one or more elements may have been represented in the drawings by conventional symbols, and the drawings may show only those specific details that are pertinent to understanding the embodiments of the present invention so as not to obscure the drawings with details that will be readily apparent to those of ordinary skill in the art having the benefits of the description herein.

Detailed Description

For the purpose of promoting an understanding of the principles of the present invention, reference will now be made to the embodiment illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the present invention is thereby intended, such alterations and further modifications in the illustrated system, and such further applications of the principles of the present invention as illustrated therein being contemplated as would normally occur to one skilled in the art to which the present invention relates.

It will be understood by those skilled in the art that the foregoing general description and the following detailed description are exemplary and explanatory of the present invention and are not intended to be restrictive thereof. Throughout the patent specification, a convention employed is that in the appended drawings, like numerals denote like components.

Reference throughout this specification to “an embodiment”, “another embodiment” or similar language means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, the appearances of the phrase “in an embodiment”, “in another embodiment” and similar language throughout this specification may, but do not necessarily, all refer to the same embodiment.

Various embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

Figure 1 illustrates an overview of the system, in accordance with the present subject matter. In an example, the vehicle is installed with a rotary gear-shifter 102 or rotary gear-knob defining gear shifter positions (in contact of automatic-transmission) such as P (Park), R (Reverse), N (Neutral), F (Forward). The user-operation upon request is given through movement of the knob in either-directions. The sensed gear positions are determined as Front, Neutral, Reverse

Figure 2 illustrates a block diagram representation of a diagnostic system 200, in accordance with the present subject matter. The user-operation upon the gear knob 103 is detected through a Hall Effect Sensor to thereby detect any of the R (Reverse), N (Neutral), D (Drive) positions. The Hall-effect sensor is provided for sensing gear position selected by the user.

The microcontroller (MCU) is provided for determining the sensed gear position. The output from Hall-Effect Sensor 202 which is interpreted by microcontroller 204, directed to Half-Bridge Driver 206 through a serial parallel interface (SPI) communication and functional output signal 208 is given to a diagnostic ECU through a Half Bridge Driver 206.

In an example, Half-bridge driver 206 may be a TB9102FNG IC s designed specifically for Automotive usage. 6High-side/ 6Low-side MOSFETs transistors are built-in for directly driving a load for example or a small DC Brushed motor for further driving a solenoid actuator through issuing the functional output signals. The driver comprises MOSFET transistors for driving a load for further driving a solenoid actuator through issuing the functional output signals. The driver may be used for automotive Air-condition system, Door Mirror control.

Now the present functional output signals are rendered by the half bridge driver 206 are directed to other ECU or the diagnostic ECU to determine the gear “Position” as requested by user and accordingly execute a decision. The functional output signals issued by the half bridge driver comprises one or more of
a) Forward Gear Signal
b) Neutral gear Signal
c) Reverse gear signal

The functional output signals issued by the half bridge driver and corresponding to the non-gear entity comprises one or more of:
a) Reverse Redundant signal;
b) Reverse Lamp relay signal;
c) LED signal for backlight illumination; and
d) Diagnostic Signal pertaining to circuit malfunction.

In an example, there are 6 Functional output signals as issued by the half bridge driver circuit as follows: –
1. Forward Signal – This signal Active High indicates Forward position is selected by user.
2. Neutral Signal - This signal Active High indicates Neutral position is selected by user.
3. Reverse Signal - This signal Active High indicates Reverse position is selected by user.
4. Reverse Redundant Signal – This signal Active High indicates Forward or Neutral Position is selected by user as this signal will be Active High if Forward or Neutral Position is selected.
5. Reverse Lamp Signal - This signal Active High indicates Reverse position is selected by user as this signal will be Active High if Reverse position is selected to operate Reverse Lamp Relay.
6. Diagnostic Signal – This signal Active High indicates Short to Battery or Short to Ground status of Functional Output signals.

A diagnostic unit (ECU) is configured to process the functional signals to determine the sensed gear positions and at least one state of a non-gear entity. The diagnostic ECU is configured to determine an invalid state or a valid state (as shown in Fig. 3 and Fig. 4) pertaining to gear selection based on processing the functional signals. The ECU is configured to sound alert or abort switching of gear in case of the invalid state.

Figure 3 illustrates tabulated-details through Table 1 in accordance with a valid-state as a part of diagnostics, in accordance with the present subject matter. A Valid State may be a state that is as per “Functionally OK” grade and in line with an expected outcome from the product. For example, in valid state, Diagnostic Signal will be LOW (0) as product is working as per functional requirement.

The invalid state corresponds to one or more of: a) opposite states of front gear and reverse redundant, b) opposite states of neutral gear and reverse redundant, and c) opposite states of reverse gear and reverse LED illumination. The valid state corresponds to one or more of:
a) similar states of front gear and reverse redundant
b) similar states of neutral gear and reverse redundant
c) similar states of reverse gear and reverse LED illumination
Example of Valid State - If User Selection is Forward position then RR and Forward Signal should only be high – Valid State. Such example among other VALID examples have been illustrated in Table 1
Figure 4 illustrates tabulated-details through Table 2 in accordance with an invalid-state as a part of diagnostics, in accordance with the present subject matter. “Not Valid State” may be state which is not as per “Functionally OK” grade and accordingly not in line with expected outcome from the product. In not valid state, Diagnostic Signal will be HIGH (1) as product is not working as per functional requirement.

Example of Not valid State - If User Selection is Forward position then RR and Forward Signal should only be high – Valid State but only forward output signal is high – it is Invalid State. Such example among other INVALID examples have been illustrated in Table 2.

Figure 5 illustrates a method of operation in accordance with the present subject matter. The method comprises:

At step 402, the user selected gear positions are sensed by a plurality of sensors. The Hall effect sensor is provided for sensing gear position selected by the user.

At step 404, the sensed gear position are determined by a microcontroller (MCU). The sensed gear positions are determined as Front, Neutral, Reverse

At step 406, functional signals by a MOSFET driver are rendered for driving an actuator based on determined gear position. The driver comprises a 6 channel half bridge driver connected to the MCU through a serial peripheral interface (SPI) communication and configured to provide functional output signal to the diagnostic unit.

At step 408, the functional signals are processed to determine the sensed gear positions and at least one state of a non-gear entity. The functional output signals issued by the half bridge driver comprises one or more of
a) Forward Gear Signal
b) Neutral gear Signal
c) Reverse gear signal

The functional output signals issued by the half bridge driver and corresponding to the non-gear entity comprises one or more of:
a) Reverse Redundant signal;
b) Reverse Lamp relay signal;
c) LED signal for backlight illumination; and
d) Diagnostic Signal pertaining to circuit malfunction.

At step 410, an invalid state or a valid state pertaining to gear selection is determined based on processing the functional signals. The invalid state corresponds to one or more of:
a) opposite states of front gear and reverse redundant
b) opposite states of neutral gear and reverse redundant
c) opposite states of reverse gear and reverse LED illumination

The valid state corresponds to one or more of: a) similar states of front gear and reverse redundant, b) similar states of neutral gear and reverse redundant, and c) similar states of reverse gear and reverse LED illumination

At step 412, the switching of gear is alerted or aborted in case of the invalid state.

Embodiments of the present invention have been described in detail for purposes of clarity and understanding. However, it will be appreciated that certain changes and modifications may be practiced within the scope of the present invention. Thus, although the present invention is described with reference to specific embodiments and drawings thereof, the embodiments and drawings are merely illustrative, and not limiting of the present invention.

We Claim:

1. A diagnostic system for a gear-shifter unit in a vehicle comprising:
a plurality of sensors (202) for sensing user selected gear positions;
a microcontroller (MCU) (204) for determining the sensed gear position;
a MOSFET driver (206) for rendering functional signals for driving an actuator based on determined gear position by the microcontroller;
a diagnostic unit (ECU) (208) configured to:
process the functional signals to determine the sensed gear positions and at least one state of a non-gear entity;
determine an invalid state or a valid state pertaining to gear selection based on processing the functional signals; and
alerting or aborting switching of gear in case of the invalid state.
2. The diagnostic system as claimed in claim 1, wherein the plurality of sensors comprise Hall effect sensor for sensing gear position selected by the user.
3. The diagnostic system as claimed in claim 1, wherein the sensed gear positions are determined as Front, Neutral, Reverse
4. The diagnostic system as claimed in claim 1, wherein the driver comprises a 6 channel half bridge driver connected to the MCU through a serial parallel interface (SPI) communication and configured to provide functional output signal to the diagnostic unit.
5. The diagnostic system as claimed in claim 3, wherein the functional output signals issued by the half bridge driver comprises one or more of
a) Forward Gear Signal
b) Neutral gear Signal
c) Reverse gear signal
6. The diagnostic system as claimed in claim 4, wherein the functional output signals issued by the half bridge driver and corresponding to the non-gear entity comprises one or more of:
a) Reverse Redundant signal;
b) Reverse Lamp relay signal;
c) LED signal for backlight illumination; and
d) Diagnostic Signal pertaining to circuit malfunction.
7. The diagnostic system as claimed in claim 1, wherein the driver comprises MOSFET transistors for driving a load for further driving a solenoid actuator through issuing the functional output signals.
8. The diagnostic system as claimed in claim 1, wherein the invalid state corresponds to one or more of:
a) opposite states of front gear and reverse redundant
b) opposite states of neutral gear and reverse redundant
c) opposite states of reverse gear and reverse lamp relay signal
9. The diagnostic system as claimed in claim 1, wherein the valid state corresponds to one or more of:
a) similar states of front gear and reverse redundant
b) similar states of neutral gear and reverse redundant
c) similar states of reverse gear and reverse lamp relay signal
10. A method for diagnosing a gear-shifter unit in a vehicle comprising:
sensing (402) user selected gear positions by a plurality of sensors;
determining (404) the sensed gear position by a microcontroller (MCU);
rendering (406) functional signals by a MOSFET driver for driving an actuator based on determined gear position by the microcontroller;
executing a diagnostic unit (ECU) configured to:
process (408) the functional signals to determine the sensed gear positions and at least one state of a non-gear entity;
determine (410) an invalid state or a valid state pertaining to gear selection based on processing the functional signals; and
alerting or aborting (412) switching of gear in case of the invalid state.