The invention relates generally to the calibration of engine parameters to adjust engine performance to desired levels. More particularly, the invention relates to the calibration of engine parameters to optimize the engine's volumetric efficiency under desired conditions.
Engine performance is often measured by considering a variety of metrics including power output and fuel economy. Depending upon the intended use of a vehicle, different weighting is given to what metrics should be optimized in order to achieve ideal performance. Changes are then made to the vehicle to optimize performance. For example, mechanical changes can be made to the engine or exhaust system of a motorcycle to improve the horsepower provided by the vehicle during racing. However, such mechanical changes can affect the vehicle's ability to efficiently process fuel.
In one embodiment, the present invention provides systems and methods for optimizing the volumetric efficiency of a vehicle under normal operating conditions. The vehicle system adjusts vehicle parameters such as the amount of fuel provided by the fuel injection system in a closed loop in order to achieve a target air-to-fuel ratio. A portable vehicle communication interface module is selectively attached to the vehicle without inhibiting normal operation of the vehicle. The vehicle is then driven under normal conditions for which the vehicle is being optimized (e.g., on a race course). When connected to the vehicle, the vehicle communication interface module records the adjustments made by the vehicle system. These recorded values are then used to update the calibration table that the vehicle system uses as default values.
By using the portable vehicle communication interface, the calibration data for the vehicle can be updated based on actual, real-world operating conditions. As such, the calibration data no longer needs to be estimated based on performance on the vehicle under controlled conditions, such as a dynamometer.
In another embodiment, the invention provides a method of calibrating a vehicle. The vehicle includes an engine, an engine control unit, a sensor that detects a value of an output parameter, and an actuator that controls the engine according to a value of an input parameter. The method includes transferring data from a vehicle communication interface module to a calibrating computer system. The vehicle communication interface module is selectively attachable to the vehicle and records data received from the vehicle during normal operation of the vehicle. The transferred data includes a plurality of adjusted actuator values and a corresponding combination of engine speed and throttle position for each of the adjusted actuator values. The adjusted actuator values are values that were generated by the engine control unit of the vehicle by accessing a stored data table defining a preset actuator value for each combination of engine speed and a value indicative of throttle position. In various embodiments, the value indicative of throttle position can include a percentage or proportional measure of actual throttle position, throttle control position, or a measured manifold air pressure value. The engine control unit then adjusts the actuator value based on a comparison between a current value of the output parameter as measured by the sensor and a target value.
After the data is transferred, the calibrating computer system determines a number of adjusted actuator values stored to the vehicle communication interface module that correspond to a first combination of engine speed and throttle position. If the number of stored values exceeds a threshold, the calibrating computer system calculates an updated data table entry based on the adjusted actuator values corresponding to the first combination. An updated data table is then transferred to the engine control unit of the vehicle.
In yet another embodiment the invention provides a calibration system for a vehicle. The vehicle to be calibrated stores a calibration table defining a plurality of fuel-injector settings each corresponding to a combination of a range of engine speeds and a range of values indicative of throttle position. The vehicle also operates in a closed-loop mode that adjusts the fuel-injector setting from the calibration table based on an air-to-fuel ratio detected by a sensor. The calibration system includes a vehicle communication interface module and a calibration computer.
The vehicle communication interface module includes a housing and a computer-readable memory. The housing is selectively attachable to the vehicle and, when attached, is supported by the vehicle without restricting normal operation of the vehicle. The computer-readable memory stores data received from the engine control module of the vehicle. The data indicates an adjusted fuel-injector setting and a corresponding combination of a current engine speed and a current throttle position.
The calibration computer is selectively connectable to the vehicle communication interface module and receives data stored to its memory. The calibration computer processes that data and determines if the number of adjusted fuel-injector settings for each of a plurality of combinations of a range of engine speeds and a range of throttle positions. For each combination where the number of stored adjusted values exceeds a threshold, the computer generates an updated calibration table entry for the first combination based on the adjusted fuel-injector settings corresponding to the first combination. An updated calibration table is then transmitted from the computer to the engine control module of the motorcycle. In some embodiments, the vehicle communication interface module is connected to both the computer and the engine control module and the updated calibration table is transmitted from the computer to the engine control module through the vehicle communication interface module.
Other aspects of the invention will become apparent by consideration of the detailed description and accompanying drawings.
Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways.
A vehicle communication interface module (VCI) 105 is shown attached to the handlebars of the motorcycle 101. The VCI 105 is a portable, detachable device that can be selectively connected to the ECM 104. The VCI 105 can be attached to the handlebars of the motorcycle 101 as shown in
When attached to the motorcycle 101, the VCI 105 is communicatively coupled to the ECM 104. Data is transmitted from the ECM 104 to the VCI 105 and stored to the internal memory of the VCI 105. This data is indicative of performance characteristics of the motorcycle 101 and may include data generated by sensors installed in the vehicle engine or data indicative of adjustments made by the ECM 104 during operation as described in further detail below. The VCI 105 is discretely sized so that it can be attached to the motorcycle 101 without interfering with the normal operation of the vehicle. The motorcycle 101 can be driven in an environment, such as a race course, while the VCI 105 is attached. As such, the VCI 105 is able to capture vehicle performance data under real-world conditions without requiring a simulated environment such as a dynamometer.
Although the VCI 105 is capable of collecting such performance data while the motorcycle 101 is being operated under real-world conditions, such as a race track, the VCI 105 can also be used to collect data when the motorcycle 101 is operated on a dynamometer. In such cases, the VCI 105 can be connected to both the ECM 104 and the calibration computer 203 (described below) to act as a pass-through interface which provides data that is stored directly to the calibration computer 203.
As illustrated in
In some embodiments, the calibration computer 203 is connected directly to the ECM 104 when data is to be transmitted to the ECM 104. In other embodiments, the calibration computer 203 is connected to the ECM 104 through the VCI 105, which acts as a pass-through interface for transmitting data from the calibration computer 203 to the ECM 104. In some embodiments, the updated data tables transmitted from the calibration computer 203 are stored on both the ECM 104 and the VCI 105.
The ECM 104 includes a memory 205 that stores predefined parameters that are used to control the operation of the motorcycle 101. The memory 205 also stores instructions that are executed by a processor 207 to control the operation of the engine 103. The VCI 105 includes a memory for storing performance data received from the ECM 104 and, as described above, a button 107 and a LED 109. The VCI 105 also includes logic that controls the operation of the LED 109 and manages the storage of data received from the ECM 104.
The calibration computer 203, in one embodiment, is a desktop computer that includes a memory 217, a processor 219, and a user interface 221. The user interface 221 includes a keyboard, a mouse, and a monitor. The calibration computer 203 runs a software package such as the SCREAMIN' EAGLE PRO SUPER TUNER™ package offered by HARLEY-DAVIDSON®. The software package processes the data recorded to the VCI 105 and also communicates updated calibration information to the ECM 104. Although the calibration computer 203 in this example is a standard desktop computer, the calibration computer, in other embodiments, can be a device designed specifically for calibration and tuning operations such as those described herein.
As described above, the ECM 104 stores predefined parameters that are used to control the operation of the engine 103 of the motorcycle 101.
The ECM 104 uses the volumetric efficiency value stored in the table and the known throttle position to determine how much fuel to provide to the engine through the fuel injection system. Although the table of
In other embodiments, the ECM 104 uses the data from the table of
Similarly, although the data table of
The data table of
The ECM 104 adjusts the volumetric efficiency value when operating in a closed-loop mode in order to achieve the target air-to-fuel ratio. As such, when operating in closed-loop mode, the volumetric efficiency defined in the data table of
When the motorcycle 101 is started (step 401) it initially enters into an open-loop operating mode. The ECM 104 determines the engine speed and the position of the throttle (step 403) and accesses the data table of
When the ECM 104 enters the closed-loop mode, it begins to adjust the values accessed from the stored volumetric efficiency table based on a comparison between the observed air-to-fuel ratio and the target air-to-fuel ratio as defined in the data table of
Various techniques can be used to determine how much the volumetric efficiency value should be adjusted including, but not limited to, implementing a proportional-integral-derivative (PID) controller or other mathematical calculation. However, in this embodiment, the volumetric efficiency value is adjusted proportionately to the difference between the air-to-fuel ratio and the target. For example, if the air-to-fuel ratio is 10% lower than the target, the volumetric efficiency is increased by 10%.
After adjusting the volumetric efficiency value, the ECM 104 outputs the adjusted value to a communication bus (step 419). When the VCI 105 is connected to the ECM 104, the VCI 105 detects the data on the communication bus. If the record mode of the VCI 105 has been activated (step 421), the ECM stores the adjusted volumetric efficiency value, the current engine speed, and the current throttle position to the VCI 105 (step 423) before repeating the closed-loop operation and continuing to store additional data. If not, the adjustment value is not recorded and the ECM returns to the beginning of the closed-loop (step 409).
The data stored to the VCI 105 is then used by the calibration computer 203 to update the data table of
Before changing a value on the data table, the calibration computer 203 determines whether sufficient data was collected. After the data has been parsed into the appropriate groupings, the calibration computer 203 begins by examining the first groups (e.g., all adjusted values recorded when the engine speed was between 750 and 1000 RPM and the throttle position was between 0.0 and 2.2%) (step 505). If the number of stored values for the first group is less than a defined threshold (step 507), the calibration computer proceeds to the next group without changing the value in the data table (step 509).
If, however, the number of stored values for the group is greater than the threshold, the calibration computer 203 calculates an average of the stored values for that group (step 511) and replaces the value in the table for that group with the calculated average value (step 513). The calibration computer 203 repeats this process of evaluation and replacement until all of the groups in the data table have been considered. When the calibration computer reaches the last group (step 515), the user is prompted to approve or reject one or more of the proposed changes to the data table (step 517). As such, if a value appears to change drastically, a user might assume that an inaccurate outlier value is responsible for the change and decline to update the data table for that value.
After the updated data table has been approved by the user, the calibration computer 203 determines whether the ECM 104 is connected. If so, the updated data table is transmitted from the calibration computer 203 to the ECM 104 and stored (step 521). If the ECM 104 is not connected, the calibration computer 203 instructs the user to properly connect the ECM 104. After the data table has been updated, the ECM 104 uses the updated data table when operating the motorcycle 101 in open or closed-loop mode as illustrated in
Only three values were recorded while the engine was operating between 3000 and 3250 RPM and the throttle was set between 60.0% and 65.0%. Because this number does not exceed the threshold (i.e., four), the value for this combination of engine speed and throttle position is not overwritten in the data table of
Four values were recorded while the engine was operating between 3000 and 3250 RPM and the throttle was set between 15.0% and 20.0%. As such, the calibration computer 203 calculates an average of 93.6 (
It is to be noted that, unless explicitly stated otherwise in the claims, the intended scope of the invention extends beyond the specific examples described above. For example, although the examples above describe a system that monitors adjusted volumetric efficiency values during real-world operating conditions, the invention could be applied to monitor other values that are adjusted by the ECM when operating in a closed-loop mode. Similarly, although the interfaces between the various components of the system (e.g., the VCI, the ECM, and the calibration computer) are described as selectively connectable wired connections, other embodiments might utilize wireless connections as a communication interface between the components. Various features and advantages of the invention are set forth in the following claims.
The present application claims the benefit of U.S. Provisional Application No. 61/227,391; entitled “Method and Apparatus for Automatic Engine Calibration to Optimize Volumetric Efficiency;” filed on Jul. 24, 2009; the entire contents of which are herein incorporated by reference.
Number | Date | Country | |
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61228391 | Jul 2009 | US |