FIELD OF THE INVENTION

The present invention relates to the field of internal combustion (10) engines. The present invention specifically relates to a method of configuring and controlling an engine with multiple power ratings.

BACKGROUND OF THE INVENTION

Internal combustion (10) engines have revolutionized the automobile industry. Basic thermodynamics and mechanical systems are the backbone of IC engines. In general, vehicle engine performance is a primary focus of automotive development, where the engine performance mainly depends on its configuration. Now a days, electronic controllers and electrical systems act as an indispensable part of the 10 engines. Fuelling systems of the 10 engines are controlled by an ECU, which looks into a series of inputs and injects fuel based on the fed in algorithm.

Currently, most BSIII and above IC diesel engines utilize common rail system with an electronic control system, which controls the fuel injection. Fuel injection pressure, injection timing and injection quantity are controlled independently in the common rail engines, which enhances the performance of the engines. Normally, such engines are calibrated for maximum power which is arrived at based on the performance requirements from the vehicle such as acceleration, grade ability and maximum speed and a torque curve is also defined for the arrived maximum power. Once the torque curve is defined, an optimum balance of injection pressure, timing and quantity is computed on the test bed to acquire the best Specific Fuel Consumption (SFC) at all torque values and engine speed at rpm.

Further, emission optimization is performed after completing optimization for SFC. Every power or torque curve is associated with an emission zone. Since the emission zone is a function of the power curve, thus it is different for different power curves. For emission optimization, initially the emission levels are checked in the emission zone. Then, injection quantity and timing is worked upon to meet the norms, especially NOx which is seen to be higher in diesel engines, which results in an increase in SFC levels in the emission zone. The finalized set of injection pressures, quantity and timing is stored In a database against each torque value and engine rpm value. Hence, the obtained final engine performance is not completely optimized for SFC because of the emission constraints.

Conventionally, only a single power curve is derived and used in the engine for all its applications, which results in reduction of fuel efficiency particularly when the vehicle is half loaded or unloaded. For example, consider the vehicle is a truck, then the engine power is decided based on the maximum grade-ability, maximum speed and acceleration achievable in the rated full load condition. After finalizing these boundary conditions, the engine fueling calibration is designed as explained above. While considering the part throttle performance of the engine, it is observed that the best SFC region is confined to a small region of the engine's operable span for a specific power curve.
With respect to the conventional approaches, it should be apparent that a need exists for achieving good fuel economy by making the engine to operate in the best SFC zone with respect to the vehicle conditions, which is partially accomplished by optimizing the driveline. Since the engine is optimized to a specific power rating, the SFC of the vehicle is not always effective in all vehicle conditions such as loaded condition, unloaded condition and half loaded condition. In case of such high variations in the operating loads, it is not possible for the vehicle to operate in the best SFC zone at all times. Therefore, it is desirable to provide a method of configuring and controlling an engine with multiple power ratings, which is capable of overcoming the aforementioned drawbacks.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a method of configuring and controlling an engine with multiple power ratings, which improves fuel efficiency and economy by operating the vehicle always in effective SFC zone even if the vehicle loads are varied.
Another object of the present invention is to provide a method of configuring and controlling an engine with multiple power ratings, which acts as a performance limiter by avoiding excessive speed or acceleration of the vehicle by the driver during less load or unloaded conditions.

According to one aspect, the present invention, which achieves this objective, relates to a method of configuring and controlling an engine with multiple power ratings comprising: calibrating an operating mode of an engine at the multiple power ratings for different load conditions of a vehicle. Several datasets can be configured and registered with vehicle variables relating to a specific power rating for each load condition with respect to lowest specific fuel consumption (SFC) corresponding to torque requirement and performance limitation of the engine. An actual load condition of the vehicle can be detected based on determination of real-time vehicle data. A dataset corresponding to the actual load condition can be identified and selected from the datasets. The engine can be automatically switched and controlled in accordance with the vehicle variables of the selected dataset to operate the vehicle at a desired power rating of the engine. Thus, the method improves fuel efficiency and economy by operating the vehicle always in effective SFC zone even when the vehicle loads are varied. It also avoids excessive speed or acceleration of the vehicle by the driver during less load or unloaded conditions.
Furthermore, the load conditions of the vehicle comprise full-load condition, half-load condition and unload condition. The vehicle variables of the datasets comprise engine power curve, fuel injection pressure, fuel injection timing, fuel injection quantity and airflow. The vehicle variables in each dalaset correspond to a specific power rating and performance of the engine. The datasets can be stored in an engine controller unit (ECU). The vehicle data can be detemiined based on a position of a variable switch at every drive cycle for detecting the actual load condition of the vehicle. The variable switch can be manually operated by the user to position it in relation to the load conditions of the vehicle.

In addition, the vehicle data can be determined based on one or more voltage signals of a sensing unit at every drive cycle for detecting the actual load condition of the vehicle. The sensing unit is configured to determine the load conditions of the vehicle and to generate the voltage signals corresponding to the load conditions of the vehicle. The sensing unit comprises a load cell or a gradient sensor or a combination of both. The vehicle data can also be determined based on vehicle performance data in the ECU and vehicle configuration data by Original Equipment Manufacturer (OEM) for detecting the actual load condition of the vehicle. The vehicle performance data comprise vehicle speed, vehicle acceleration, engine speed in rotation per minute (RPM), gear position, clutch position, brake position and accelerator pedal position.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be discussed in greater detail with reference to the accompanying Figures.

FIG. 1 illustrates a flow diagram depicting selection of engine power rating by an ECU in case of manual switch or load cells, in accordance with an exemplary embodiment of the present invention;

FIG. 2 illustrates a flow diagram depicting automatic selection of engine power rating by an ECU based on vehicle performance inputs, in accordance with an exemplary embodiment of the present invention; and

FIG. 3 Illustrates a flowchart depicting a method of configuring and controlling an engine with multiple power ratings, in accordance with an exemplary embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The IC engines are usually calibrated for one set of performance condition, i.e. the engine usually operates for single power rating. The present invention provides a system and methodology for defining multiple power ratings for the same engine. The shifting between power ratings can occur dynamically based on load or performance by means of manual switching or automatic switching of power ratings, which results in an Improvement of fuel consumption. The design of hardware and software architecture confirms to all system specifications, requirements and application. The software modification to take care of methodology of the present invention has been applied on an existing electronic control unit (ECU), particularly Common Rail System ECU, of the IC engine without any hardware modification.

Initially, the engine is calibrated with different power ratings for different load conditions. Power curves and fuelling data at each power rating of the engine can be stored in a database in an engine controller unit (ECU) or control unit. The number of power ratings defined for an engine is constrained only by the size of the database of the control unit. The detection of vehicle load condition and shifting between the power ratings of the engine can be executed using a manual switch or load cells or gradient sensor and/or by means of automatic switching. In such manual switching or load cells, a three-position variable resistance switch can be connected to the engine ECU. A 5V input can be supplied from the ECU to the switch and the voltage drop across the switch is taken as the input by the ECU to determine the switch state-In case of manual switch, the driver operates the manual switch to select the power rating of the engine in relation to the vehicle load condition. The manual switch acts as a trigger for detecting the vehicle load condition. Similarly, the load cells are used to determine the vehicle load condition and then the engine can be automatically switched between the different power ratings based on the determined load condition. The gradient sensors are used to sense the gradient and looking at the acceleration of the vehicle in order to derive the vehicle load condition from the vehicle performance. Then, the engine can be automatically switched between the different power ratings based on the derived load condition. This system dynamically shifts the engine between different power ratings based on application or vehicle load.

Referring to FIG. 1, a flow diagram depicting selection of engine power rating by an ECU in case of manual switch or load cells is illustrated, in accordance with an exemplary embodiment of the present invention. Initially, vehicle load can be interpreted by means of either load cells or manual switch. The ECU embeds and stores several datasets pertaining to different power ratings of the engine. Each dataset relating to a single engine power rating are configured based on a specific vehicle load condition, which includes, but are not limited to full-load condition, unload condition and half-load condition.

Here, the ECU stores the three datasets for three different power ratings, which are respectively configured for the full-load condition, the unload condition and the half-load condition, only for the purpose of explanation and not by the

way of any limitations. Each dataset is provided with a set of vehicle variables, namely, but not limited to power curve, fuel injection pressure, fuel injection timing, fuel injection quantity and airflow. The set of vehicle variables defined in each dataset are predetermined corresponds to specific power rating and performance of the engine. The engine ECU executes data selection using either manual switch or load cells and decides the engine to be operated on which power rating.

In case of manual switch, the engine ECU determines position of the switch to recognize a vehicle load condition. Each position of the switch indicates the specific vehicle load condition, i.e. full-load, unload or half-load condition. The checking of switch position is carried out after each drive cycle. The switch can be manually operated by the user for positioning the switch in relation to the vehicle load condition. After determining the switch position, the ECU selects a dataset assigned to the recognized vehicle load condition. The ECU operates the engine at power rating and corresponding performance with respect to the selected dataset. Thus, the engine operates the vehicle based on the preset variables of the selected dataset though out the drive cycle.
In case of load cells or gradient sensor, the ECU recognize a vehicle load condition based on voltage output from the load cells or gradient sensor. The voltage outputs from the load cells or gradient sensor is calibrated for a series of vehicle load conditions, i.e. full-load, unload or half-load condition. The checking of voltage output from the load ceils is carried out after each drive cycle. After sensing the voltage output from the load cells, the ECU selects a dataset assigned to the recognized vehicle load condition. The engine operation is carried out in similar fashion as by using the switch. In this case, the selection of power rating and corresponding performance of the engine can be performed based on the voltage output from the load cells or gradient sensor.

Referring to FIG. 2, a flow diagram depicting automatic selection of engine power rating by an ECU based on vehicle perfomance Inputs is illustrated, in accordance with an exemplary embodiment of the present invention. Initially, vehicle performance data and vehicle configuration data can be collected to calculate an instantaneous operating point or condition of the engine and a vehicle load condition. The vehicle load condition can be detected based on the calculation of vehicle performance data like vehicle speed, acceleration pedal position and gear position, which are currently available for the engine ECU. The vehicle performance data include, but are not limited to vehicle speed, engine rotation per minute (RPM), gear position, clutch position, brake position, vehicle acceleration and acceleration pedal position.

Further, the vehicle configuration data is stored in a database by Original Equipment Manufacturer (OEM). The engine operating condition can be represented as torque in relation to the engine rpm. Several datasets pertaining to different power ratings of the engine can be stored in the database. The calculated vehicle load condition and the calculated engine operating condition can be compared with the datasets of different power ratings. A dataset assigned to the calculated vehicle load condition can be selected with respect to specific fuel consumption (SFC) for the engine operating condition along with torque requirement and performance limitation of the engine.

The ECU operates the engine at the set power rating and corresponding performance with respect to preset variables, like rail pressure, timing and quantity control, defined in the selected dataset. Thus, the ECU selects the power rating automatically based on vehicle performance data. If the selection of engine power rating is performed automatically, then there is no need for extra hardware requirement. In case of any hardware or software errors like switch malfunction, switch short circuit, data error from the load cell etc., the engine reverts to the default data representing the maximum power rating set for the engine.

Referring to FIG. 3, a flowchart depicting a method of configuring and controlling an engine with multiple power ratings is illustrated, in accordance with an exemplary embodiment of the present invention. As illustrated in step 310, an operating mode of an engine can be calibrated at the multiple power ratings for different load conditions of the vehicle. Then, as depicted in step 320, several datasets can be configured and registered with vehicle variables relating to a specific power rating for each load condition with respect to lowest specific fuel consumption (SFC) corresponding to torque requirement and performance limitation of the engine. An actual load condition of the vehicle can be detected based on determination of real-time vehicle data, as specified in step 330. Thereafter, as shown in step 340, a dataset corresponding to the actual load condition can be identified and selected from the datasets. Finally, as indicated in step 350, the engine can be automatically switched and controlled In accordance with the vehicle variables of the selected dataset to operate the vehicle at a desired power rating of the engine.
The vehicle variables in each dataset correspond to a specific power rating and performance of the engine. The vehicle data can be determined based on the position of the variable switch at every drive cycle for detecting the actual load condition of the vehicle. Similarly, the vehicle data can be detennined based on voltage signals of the load cell or gradient sensor at every drive cycle for detecting the actual load condition of the vehicle. The load cell or gradient sensor is configured to determine the load conditions of the vehicle and to generate the voltage signals corresponding to the load conditions of the vehicle. The vehicle data can also be determined based on vehicle performance data in the ECU and vehicle configuration data by OEM for detecting the actual load condition of the vehicle.

Moreover, the IC engine can be operated at the multiple power ratings so that the engine is capable of operating at different power curves. Since the engine is configured with the multiple power ratings, the vehicle can be operated at best SFC even when there are variations in the vehicle load conditions. Thus, it is highly beneficial for fuel economy in the commercial vehicle when there is high range of variations in operating loads. Hence, the method improves fuel efficiency and economy by operating the vehicle always in effective SFC zone even if the vehicle loads are varied. The fuel economy can be improved by enhancing the operating region at best SFC in the low load condition, and by avoiding excessive acceleration of the vehicle by the driver to cut off the power In low load conditions. It also acts as a performance limiter by avoiding excessive speed or acceleration of the vehicle by the driver during (ess load or unloaded conditions.
The above description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the claimed invention. Various modifications and alterations to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the claimed invention. Thus, the claimed invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

CLAIM:

1. A method of configuring and controlling an engine with multiple power ratings,comprising:

calibrating an operating mode of an engine at the multiple power ratings for different load conditions of a vehicle;

configuring and registering a plurality of datasets with one or more vehicle variables relating to a specific power rating for each load condition with respect to lowest specific fuel consumption (SFC) corresponding to torque requirement and performance limitation of the engine;

detecting an actual load condition of the vehicle based on determination of real-time vehicle data;

identifying and selecting a dataset corresponding to the actual load condition from said plurality of datasets; and

automatically switching and controlling the engine in accordance with said vehicle variables of the selected dataset to operate the vehicle at a desired power rating of the engine.

2. The method as claimed in claim 1,wherein the load conditions of the vehicle comprise full-load condition, half-load condition and unload condition.

3. The method as claimed in claim 1,wherein said vehicle variables of said plurality of datasets comprise engine power curve, fuel injection pressure, fuel injection timing, fuel injection quantity and airflow.

4. The method as claimed in claim 1,wherein said vehicle variables in each dataset correspond to a specific power rating and performance of the engine.

5. The method as claimed in claim 1,wherein said plurality of datasets is stored in an engine controller unit (ECU).

6. The method as claimed in claim 1,wherein the vehicle data is determined based on a position of a variable switch at every drive cycle for detecting the actual load condition of the vehicle.

7. The method as claimed in claim 6,wherein said variable switch is manually operated by the user to position it in relation to the load conditions of the vehicle.

8. The method as claimed in claim 1,wherein the vehicle data is determined based on one or more voltage signals of a sensing unit at every drive cycle for detecting the actual load condition of the vehicle.

9. The method as claimed in claim 8,wherein said sensing unit is configured to determine the load conditions of the vehicle and to generate the voltage signals corresponding to the load conditions of the vehicle.

10. The method as claimed in claim 8,wherein said sensing unit comprises a load cell and a gradient sensor.

11. The method as claimed in claim 1, wherein the vehicle data is determined based on vehicle performance data in the ECU and vehicle configuration data by Original Equipment Manufacturer (OEM) for detecting the actual load condition of the vehicle.

12. The method as claimed in claim 11, wherein the vehicle performance data comprise vehicle speed, vehicle acceleration, engine speed in rotation per minute (RPM), gear position, clutch position, brake position and accelerator pedal position.

13. A system of configuring and controlling an engine with multiple power ratings, configured to perform the method as claimed in any one of the preceding claims 1 to 12.