DESC:Field of Invention
The invention is related to system for improving fuel economy. The invention is more particularly related to improvement in fuel economy by assisting vehicle driver or rider in recommending transmission ratio with respect to vehicle running condition.
Background
Vehicle fuel economy and engine performance are depend on various factors. Transmission plays major roll in full economy. At any particular speed condition, load condition etc. it is necessary to that the vehicle should be in optimum transmission ratio to obtain better economy. For that it is necessary for rider to change transmission ratio according to the vehicle running condition. It is an additional task for the rider to monitor speed or other conditions of vehicle and shift transmission ratio accordingly. Vehicles are provided with instrument cluster, also known as instrument cluster panel etc. are generally equipped with various indicators such as speedometer, fuel level indicator, battery status etc. Similarly in recent vehicles, manufacturers are also started providing transmission ratio recommendation indicator. Main purpose of providing transmission ratio recommendation indicator is to assist rider about transmission ratio in such a way that it optimizes engine performance, to improve fuel efficiency etc. Rider of the vehicle while driving the vehicle at different load conditions and with his/her varying driving habits may select a transmission ration which may not be giving desired /optimum engine performance and thus leading to low fuel economy. Thus it is important aspect that the rider should be recommended with optimum transmission gear ratio to improve fuel economy of the engine. This recommendation of transmission ratio is generally depend on various factors or parameters related to vehicle in running condition.
Existing recommendation systems primarily takes two parameters, namely the engine load and the engine rpm. Engine load is derived either from an accelerator pedal position or throttle position or Manifold Pressure sensor or airflow sensors or is estimated on the basis of in-cyclic rpm signatures. The drawback of basing the strategy on engine load is that the strategy will be insensitive to road ients and vehicle payload conditions.
Following equation is a governing equation for a moving vehicle.
Wheel Torque = (Road load + ma + mg sin (theta)) X Dynamic Rolling Radius of Tyre
Where “Road load” is a force required to overcome the resistance offered by the flat road, “ma” is the force required to accelerate a vehicle having mass m and with an acceleration a. Last component that is “mg sin (theta)” is force required to overcome a gradient which can also be called as mass gradient. Theta is the road slope or inclination while vehicle is driving uphill or downhill.
Following equation is used to calculate the Wheel Torque from Engine Torque/Load.
Wheel Torque = Engine Load X Transmission ratio
Most of the transmission ratio recommendation strategy are based on wheel tractive force calculated from engine load and does not take care of vehicle acceleration or road gradient or payload on vehicle
Also, most of the transmission ratio recommendation systems do not consider engagement state of clutch, due to which system is unable to differentiate about engaged and disengaged state of clutch. This leads to erroneous recommendation of transmission ratio in disengaged condition of clutch.
Further, known transmission ratio recommendation system fails to prevent upshift recommendation at the highest gear and downshift recommendation at the lowest gear which may confuse the rider.
Hence there was need of sensitive, simple, error free transmission ratio recommendation system so as to reduce complexity.
Objective of present invention
Objective of present invention is to improve fuel economy by providing transmission ratio recommendation system for rider or driver by recommending transmission ratio.
Yet another object of the present invention is to provide a system which is more sensitive and accurate in comparison to known prior arts.
Another object of the present invention is to provide transmission ratio recommendation system which is compact and can be integrated in instrument cluster.
Yet another object of the present invention is to provide transmission ratio recommendation system with simple, error free and reduced complexity.
Summary of Present invention
Objectives mentioned above are achieved by providing a fuel economy improvement system comprised of a controller to receive various input parameters and compares with predefined condition to decide recommendation of required transmission ratio. The said parameters includes current gear position, vehicle speed, change in vehicle speed (vehicle acceleration), clutch engagement-disengagement state. As an embodiment, other input parameters like engine load are also included in scope of invention.
The Controller receives current gear position from gear position detection means, clutch position from clutch switch and vehicle speed from vehicle speed detecting means. The vehicle acceleration is derived from the change in vehicle speed. Transmission ratio recommendation system recommends rider either upshift or downshift through transmission ratio recommendation indication means with respect to output received from controller.
Said transmission ratio recommendation system may be integrated in vehicle instrument cluster.
Transmission ratio recommendation system do not recommend upshift or downshift when current transmission ratio satisfying predefine condition or matching with transmission ratio required for particular vehicle running condition according to present invention.
According to another embodiment of the present invention, in addition to the current gear position, vehicle speed, change in vehicle speed (vehicle acceleration) and clutch engagement-disengagement state, present transmission ratio recommendation system may also consider engine load as an input parameter. Engine load may be obtained by various known methods or it may be sourced from any other controller on the same vehicle. Controller may be inclusive of predefined upshift and downshift maps may be based on engine load and vehicle acceleration. There may be an upshift and downshift map for each gear. Vehicle speed may be selected for particular engine load and vehicle acceleration on the basis of said map. Said vehicle speed may be considered as one of the parameter in said transmission ratio recommendation system.
The said transmission ratio recommendation indication means may also comprises of transmission ratio indication means which may be capable of indicating current transmission ratio.
In another embodiment of the present invention, the said transmission ratio recommendation means may also comprises transmission ratio indication means which may be capable of indicating recommended transmission ratio.
No recommendations are made by transmission ratio recommendation system in neutral gear or when clutch is in disengaged condition. Also, when clutch is in released condition and rider selected a neutral transmission ratio, transmission ratio recommendation system do recommend upshift or downshift.
Said transmission ratio recommendation system do not recommend upshift transmission ratio when transmission is already in top most transmission ratio. And in another embodiment of the present invention, this top most transmission ratio may be represented as override condition. The said override condition may be indicated by transmission ratio indication means in alphanumeric manner, for example as letter “O” or “H” where “O” represents override condition and “H” represents highest transmission ratio.
Similarly no downshift recommendation made by said transmission ratio recommendation system when transmission is already is lower most transmission ratio.
In another embodiment of the present invention the said transmission ratio indication means capable of indicating current transmission ratio and recommended transmission ratio simultaneously in distinguishing manner. In one of the embodiment of the present invention indication of current transmission ratio may be realized by displaying digit continuously, while recommended transmission ratio realized by displaying digit discontinuously or by blinking.
Brief description of drawings
Fig. 1 is perspective view of typical two wheeled vehicle structure along with instrument cluster.
Fig. 2 is a perspective view of instrument cluster along with feature of present invention.
Fig. 3 is a block representation of system according to present invention.
Fig. 4 shows process of transmission ratio recommendation according to present invention.
Fig. 5 is a perspective view of the embodiment of present invention.
Fig. 6 shows process of transmission ratio recommendation according to one of embodiment of the present invention.

Detailed description of drawings
Fig. 1 shows typical two wheeled vehicle 101 in top view comprising frame structure102, handle bar 103, engine 104, and instrument cluster 105. Instrument cluster 105 is generally located above head tube (not shown) and between left 106 and right 107 grip portions of handle bar 103. The instrument cluster 105 may be comprised of speedometer 201, fuel gage indicator 202, odometer 203, clock 204 and various other indicators as shown in Fig. 2.
According to the present invention, Instrument cluster 105 also comprises transmission ratio recommendation indication means 304 in Fig. 3 may comprised of upshift and downshift indication means 205, 206 recommending rider to either upshift or downshift with respect to vehicle running condition.
Fig. 3 indicates block representation of transmission ratio recommendation system 301. Instrument cluster block 302 indicated in Fig. 1 comprises a controller 303 to receive and process various input signals. Controller receives inputs such as current gear position, vehicle speed and clutch state. Transmission ratio detection means 108 (i.e. Gear Position sensor) detects current transmission ratio when vehicle is in running or in standstill state. Vehicle speed detecting means 109 detects vehicle speed and clutch engagement-disengagement status may be determined from clutch switch 110. Controller 303 derives vehicle acceleration from vehicle speed.
When vehicle is in running condition then there can be two cases according to the strategy disclosed in present invention. In first case where clutch switch 110 is in pressed condition and other is that the clutch switch in released condition. Details are explained in following paragraphs.
Fig. 4 describes these two case according to which transmission ratio recommendation system operates. According to first case that is if clutch switch is in pressed condition that means clutch is disengaged or if the gear is in neutral condition, no power is getting transmitted from the engine to the transmission and further to wheels. In this condition, according to present invention transmission ratio recommendation indication means does not indicate any recommendation.
When clutch switch is in released condition that means clutch is engaged and when the gear is not in a neutral condition, power is getting transmitted from engine to the transmission box and ultimately to the wheels. In this condition, according to present invention control unit receives vehicle speed and current gear position and calculates vehicle acceleration using vehicle speed.
Further, the said controller capable to compare the vehicle speed with a predefined threshold speed. For a currently selected transmission ratio by rider, if the current vehicle speed is greater than a threshold (T1) and the vehicle acceleration is greater than zero, then transmission ratio recommendation means recommends an upshift. And it is indicated through transmission ratio recommendation indication means 501.
Similarly, the said controller also capable to compares the vehicle speed with a predefined threshold speed (T2). For a currently selected transmission ratio by rider, if the vehicle speed is found to be lesser than T2 and the vehicle acceleration is less than zero, a downshift is recommended. Where thresholds T1 and T2 are a function of the current gear engaged.
For example, the range of speed of vehicle when first transmission ratio is in operation is 10 kmph to 20 kmph. If the vehicle speed reaches greater than 20 kmph with acceleration is greater than zero and vehicle operating in first transmission ratio (selected by rider) then according to the present invention the said transmission ratio recommendation system recommends upshift. Similarly, if vehicle started slowing down that is with negative acceleration and speed reaches below 20 kmph and vehicle already running in third transmission ratio (selected by rider), then according present invention the said transmission ratio recommendation system recommends down shift.
According to one of the embodiment of the present invention, instrument cluster may also comprised of transmission ratio indication mean 501 capable to indicate current transmission ratio as shown in Fig. 5.
According to another embodiment of the present invention, current transmission ratio and recommended transmission ratio may be indicated simultaneously on transmission ratio indication means. Current transmission ration may be indicated by displaying current transmission ratio digit constantly. While recommended transmission ratio may be indicated by blinking recommended transmission ratio digit. Gear should be blink like arrow, best on the speed of vehicle (Speed logic will recommend to move or down the gear).
For example, if current transmission ratio is 2nd, then the transmission ratio indication means will display digit “2” constantly. And if according to the present invention recommended transmission ratio is 3rd, then digit “3” will start blinking on transmission ratio simultaneously with current transmission ratio.
According to present invention, logic or strategy used in the method of recommendation of transmission ratio uses vehicle acceleration and vehicle speed which makes the logic more sensitive to the output vehicle reaction as opposed to an input engine load. This makes the strategy sensitive to road gradient and vehicle payload conditions.
Strategy of the present invention mainly rely on the vehicle acceleration, vehicle speed and the mass gradient. Also, accounting for mass gradient improves the quality of recommendation of transmission ratio.
According to another embodiment of the present invention as shown in Fig. 6, in addition to the current gear position, vehicle speed, change in vehicle speed (vehicle acceleration) and clutch engagement-disengagement present transmission ratio recommendation system may also consider engine load as an input parameter. Predefined upshift and downshift maps may be based on engine load and vehicle acceleration. There may be an upshift and downshift map for each gear. The said map may output speed values. These speed values may act as THRESHOLD_1 and THRESHOLD_2 in process explained to recommend upshift or downshift transmission ratio in Fig. 4.
Since instrument cluster comprised on transmission ratio recommendation indication means, it is more convenient to implement the logic in the instrument cluster itself.
The present fuel economy improvement system delivers substantial improvement in fuel economy in case the rider follows the recommendation indicated to rider.
Modifications and variations to the fuel economy improvement system described in the present specification may be apparent to skilled readers of this disclosure. Such modifications and variations are deemed within the scope of the present invention.
,CLAIMS:1. 1. A fuel economy improvement system for a vehicle (101) comprising,
a controller (303) to receive various input parameters and compares with predefined conditions, characterised in that the said controller decides recommendation of required transmission ratio based on the comparison of said parameters with predefined conditions wherein said parameters at least include current gear position, vehicle speed, change in vehicle speed or vehicle acceleration, clutch engagement-disengagement state.

2. The fuel economy improvement system as claimed in claim 1, wherein said controller (303) considers engine load as one of the input parameter.

3. The fuel economy improvement system as claimed in claim 1, wherein said controller receives current gear position from gear position detection means (108), clutch position from clutch switch (110) and vehicle speed from vehicle speed detecting means (109); the vehicle acceleration is derived from the change in vehicle speed.

4. The fuel economy improvement system as claimed in claim 1, wherein said system further comprising a transmission ratio recommendation system (301) capable to recommend rider either upshift or downshift gear or transmission ratio through a transmission ratio recommendation indication means (304) with respect to output received from said controller(303).

5. The fuel economy improvement system as claimed in claim 1, wherein said transmission ratio recommendation system (301) is integrated in a vehicle instrument cluster (105).

6. The fuel economy improvement system as claimed in claim 1, wherein said controller (303) is inclusive of predefined upshift and downshift maps based on engine load and vehicle acceleration.

7. The fuel economy improvement system as claimed in claim 6, wherein the controller (303) is inclusive of separate upshift and downshift maps for each gear or transmission ratio.

8. The fuel economy improvement system as claimed in claim 6 or 7, wherein controller (303) selects vehicle speed for particular engine load and vehicle acceleration on the basis of said map.

9. The fuel economy improvement system as claimed in claim 7 or 8, wherein top most transmission ratio is represented as an override condition.

10. The fuel economy improvement system as claimed in claim 9, wherein the said override condition is indicated by transmission ratio indication means in alphanumeric manner.

11. The fuel economy improvement system as claimed in claim 4, wherein transmission ratio indication means (304) capable of indicating current transmission ratio and recommended transmission ratio simultaneously in distinguishing manner.

12. The fuel economy improvement system for a vehicle claim 11, wherein said indication of current transmission ratio is realized by displaying digit continuously through transmission ratio indication means and recommended transmission ratio realized by displaying digit discontinuously or by blinking through transmission ratio indication means.

13. The fuel economy improvement system as claimed in claim 1 and 4, wherein said controller (303) is capable to compare the vehicle speed with a predefined threshold speed (T1) such that for selected gear or transmission ratio, if the current vehicle speed is greater than a threshold (T1) and the vehicle acceleration is greater than zero, then transmission ratio recommendation means recommends an upshift.

14. The fuel economy improvement system as claimed in claim 1 and 4 , wherein said controller (303) is capable to compare the vehicle speed with a predefined threshold speed (T2) such that for selected gear or transmission ratio, if the current vehicle speed is lesser than a threshold (T2) and the vehicle acceleration is less than zero, then transmission ratio recommendation means recommends an downshift.

15. The fuel economy improvement system as claimed in claim 13 and 14, wherein thresholds T1 and T2 are functions of the current gear or transmission ratio engaged.

16. The fuel economy improvement system as claimed in claim 1, wherein output of the controller (303) decides the transmission ratio which is depend on the torque required to rotate wheel; the said torque is a function of road load, vehicle acceleration, and a mass gradient; wherein mas gradient is a function of vehicle weight and inclination of road.