WO2021156887A1

WO2021156887A1 - Evaporative emission control system for a vehicle

Info

Publication number: WO2021156887A1
Application number: PCT/IN2021/050107
Authority: WO
Inventors: Anbukkarasu Anukkavoor Subramanian; Gnanakotaiah Gutti; Sadesh Balakrishnan; Vinoth Balaram Ranganathan; Shirinidhi S; Narayanan M; Ajay Kumar MYSORE KRISHNAMOORTHY; Varalakshmy R
Original assignee: Tvs Motor Company Limited
Priority date: 2020-02-03
Filing date: 2021-02-03
Publication date: 2021-08-12
Also published as: PE20221602A1; CN114981534B; MX2022008326A; CN114981534A

Abstract

The present invention relates to vehicle (100) configured with the evaporative emission control system. The evaporated fuel is introduced through evaporative fuel nozzle (111)located on the tube outlet (106) of the induction system in the predetermined distance(Dx) from the throttle valve (201) of the throttle body (105). The evaporative fuel nozzle(111) is having predetermined inner diameter (Da). Thus, the present subject matter does not require any sophisticated electronic control system for purging operation.

Description

EVAPORATIVE EMISSION CONTROL SYSTEM FOR A VEHICLE

TECHNICAL FIELD

[0001] The present subject matter relates to a vehicle. More particularly, the present subject matter relates to an evaporative fuel emission control system. BACKGROUND

[0002] Over the past few years, the investment and market viability of the fuel efficient vehicle are growing in a wide range because of high costs of fossils-based fuel and at the same time a need to be environment-friendly is leading to many innovations. Therefore, there exists a continuous challenge for automotive manufacturers to address the emissions including evaporative emissions as well as avoid discharge of the same into the atmosphere within minimum space / size of the vehicle as well as at a reduced cost and weight impact. BRIEF DESCRIPTION OF THE DRAWINGS

[0003] The detailed description is described with reference to an embodiment of an evaporative fuel emission control system for a vehicle with the accompanying figures. The same numbers are used throughout the drawings to reference like features and components. [0004] Fig. 1 illustrates the rear side view of the vehicle as per preferred embodiment of the present invention.

[0005] Fig. 2a illustrates the bottom cut section view of the tube outlet in assembled condition as per preferred embodiment of the present invention.

[0006] Fig. 2b illustrates the bottom cut section view of the tube outlet in assembled condition as per alternative embodiment of the present invention.

DETAILED DESCRIPTION

[0007] Various features and embodiments of the present invention here will be discernible from the following further description thereof, set out hereunder. It is contemplated that the concepts of the present invention may be applied to any type of vehicle consisting of at least 2 wheels including two, three or four wheeled vehicle employing the similar configuration within the spirit and scope of this invention. [0008] Typically, the hydrocarbon based fuels are primarily used for transportation. The hydrocarbon based fuel has propensity to vaporize at room temperatures within respective container and this emission needs to be purged to avoid undue pressure development in the container. Such emissions are often referred to as evaporative emissions. Ideally, fuel system should be completely closed to prevent any vapor escape, but as it is evident from the fact that under extreme conditions like heat and cold which affects the pressure inside the fuel tank generally fuel tank head space, hence there arises a need for venting and vacuum pressure relief functions to limit the positive and negative pressure inside the fuel tank respectively. Evaporative emissions are bound to exist under normal environment conditions and temperatures ranging from ambient temperatures to temperature encountered during various operating conditions of the vehicle. Thus, the evaporative emissions also add to the pollution in terms of unbumt and burnt hydrocarbons. There is a constant drive from manufacturers to bring down the extent of emissions to move towards being eco-friendly and greener transport solutions. While the challenge is particularly significant for a small multi wheeled vehicle where impact on compactness, weight and cost become critical.

[0009] Typically, manufacturers look for implementing an evaporative emission control system where the canister assembly is used to address these emissions to the extent feasible. Bigger the size of the canister assembly, higher the emissions can be adsorbed. Typically, a canister assembly is connected to the fuel tank via a breather pipe. The canister is typically filled with activated charcoal. The charcoal acts like a sponge and adsorbs and stores fuel vapors. The vapors are stored in the canister until the engine is started, is warm and is being driven. The purge control valve when open, it allows intake vacuum to siphon the fuel vapors into the engine. Hence, the escape of fuel vapors is avoided.

[00010] Under normal circumstances, the evaporative fuel emission control system having canister causes few problems known in the art. The most common problems with the evaporative emission control system having canister are a faulty purge control, increased hose length, pinching of hose pipe.

[00011] Thus, when evaporative fuel is introduced from the canister assembly to the engine there exists a problem of un-intended action of purge control valve during the idling of engine as conventionally an evaporative fuel nozzle is located on the throttle body or after throttle body i.e. between the engine and throttle body. This arrangement thereby activates the purge control valve due to suction pressure of engine during idling or low throttle valve opening. During idling and specific low throttle operating conditions the purging is unintended which can help in reducing overall emission from engine. Also, it is known that the vehicle emits highest amount of pollution during cold start when the catalytic converter has not reached the light off temperature. Thus, to control the unintended action, the purge control valve requires dedicated electronic control systems that actuates the purge valve under all operating conditions. This leads to additional controls like electronic components and controls which are sophisticated and high in cost.

[00012] Keeping in light the preceding aspects and the challenges involved in designing a compact vehicle configured to have an evaporative emission control system, it is a desirable to provide an evaporative emission control system for a vehicle which is easy to assemble or dis-assemble giving it flexibility to overcome packaging constraints, meet layout requirement and as well as operate efficiently. [00013] Hence, there exists a challenge of designing an efficient evaporative emission control system, which can satisfactorily accommodate all essential elements including canister assembly, hose piping and purge control valve in a vehicle without any adverse change in design and manufacturing set-up of the vehicle while overcoming the need of an electronic control system & other problems known in art. [00014] The present invention has been made in view of the above circumstances. [00015] It is an aspect of the present invention to provide an evaporative emission control system which reduces the number of parts and cost.

[00016] It is yet another aspect of the present invention to provide an evaporative emission control system which ensures efficient purging operation without any use of electronic means to control the purge control valve. [00017] It is an aspect of the present invention to have evaporative emission control system which is easy to service.

[00018] The present subject matter relates to a vehicle configured with the evaporative emission control system where the fuel tank is attached on the frame assembly. The fuel tank is connected to the canister assembly through a breather pipe. Further, the canister assembly is connected to engine through the purge control valve, where the purge pipe connects canister assembly to engine. The purge pipe comprises the first purge pipe and second purge pipe. The first purge pipe connects the canister assembly to the purge control valve and second purge pipe connects the purge control valve to the engine. The purge pipe is operatively connected to a tube outlet at a predetermined location in between said air cleaner and said throttle body. Further, the purge pipe is connected to the tube outlet through an evaporative fuel nozzle. In alternative embodiment the evaporative fuel nozzle is aligned in the direction of flow of air in the tube outlet. In present invention, the evaporated fuel is introduced through evaporative fuel nozzle before the throttle body on the tube outlet of the induction system and clean air from air cleaner is sent to the engine from the tube outlet.

[00019] The evaporative fuel nozzle configured to have predetermined inner diameter (Da) which ranges from 0.8 milli meter to 2.5 milli meter. At the same time the evaporative fuel nozzle is located on the tube outlet before the throttle body at a pre-determined distance (Dx). The predetermined distance (Dx) ranges from 40 milli meter to 80 milli meter. Thus, the predetermined distance (Dx) and inner diameter (Da) of evaporative fuel nozzle together solve the problem of un-intended action of purge port during the idling of engine, As, it is counterintuitive in nature to place evaporative fuel nozzle in proximity of engine without use of dedicated electronic means. As per an aspect of the present invention, the design so configured causes the suction pressure of engine during idling not to activate the purge control valve without the use of any electronic means. Thus, the service time i.e. to assemble and disassemble the dedicated electronics controls for purge control valve during servicing is avoided. Hence it is easy to service. [00020] The aforesaid and other advantages of the present subject matter would be described in greater detail in conjunction with the figures in the following description.

[00021] Exemplary embodiments detailing structure and layout of an evaporative fuel emission control system in accordance with the present invention will be described hereunder with reference to the accompanying drawings. Various aspects of different embodiments of the present invention will become discernible from the following description set out hereunder. Rather, the following description provides a convenient illustration for implementing exemplary embodiments of the invention. It is to be noted that terms “upper”, “lower”, “right”, “left”, “front”, “rear”, “forward” “downward”, “upward”, “top”, “bottom” and like terms are used herein based on the illustrated state or in a standing state of the vehicle. Furthermore, a vehicle longitudinal axis (YY’) refers to a front to rear axis relative to said vehicle, while a vehicle lateral axis (XX’) refers to a side to side, or left to right axis relative to the vehicle. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting.

[00022] Figure 1 illustrates rear side view of the vehicle (100). The power generated by an engine (108) is transferred to the rear wheel (107) through a transmission system (not shown). The engine (108) is supported & mounted on the frame assembly (FA). The canister assembly (101) intended for trapping and adsorbing the evaporated fuel, is formed in a substantially cylindrical shape which incorporates the adsorbent for adsorbing the evaporated fuel and is configured in a lateral direction (XX’) at the rear portion of the vehicle (100). The canister assembly (101) comprises a drain joining port (101c), an atmospheric air introduction port (lOld), a purge port (101a) and a breather port (101b). The breather port (101b) is positioned at the lower portion of a front end portion of the canister assembly (101). The front end portion having purge port (101a) of the canister assembly (101) which is further connected to the purge pipe (104a, 104b) via purge control valve (107) for supplying said evaporated fuel to the engine (108). The drain joining port (101c) is provided at the lower position relative to the atmospheric air introduction port ( 101 d) . The drain tube (115) is configured to be joining to the drain joining port (101c). The drain tube (115) droops downwardly, and discharges the excess fluid component introduced within the canister assembly (101) to the outside of said vehicle (100). The excess fluid is introduced in the canister assembly (101) may be due to raising of said vehicle (100) which side slipped. The drain tube (115) is extended vertically facing the ground as viewed from the left side of said vehicle (100). An atmospheric air introduction port (10 Id) is provided on the rear end of the canister assembly (101). An atmospheric air introduction pipe (116) is connected to the atmospheric air introduction port (10 Id), for introducing atmospheric air to the inside of said canister assembly (101) at the time of desorption of the evaporated fuel and maintaining the pressure difference between fuel tank (114) and the atmosphere. [00023] The canister assembly (101) is connected to the fuel tank (114) via a breather pipe (103). The one end of a breather pipe (103), which discharges the evaporated fuel within the fuel tank (114) to the canister assembly (101), is jointed on the fuel tank (114) and other end to the breather port (101b) of the canister assembly (101). The canister assembly (101) is connected to the tube outlet (106) through purge pipe (104). The purge pipe (104) comprises of the first purge pipe (104a) and the second purge pipe (104b). The first purge pipe (104a) extends from the purge port (101a) in a lateral direction (XX’) from the upper portion of the front end of the canister assembly (101) and is connected to the purge control valve (107). Further, a second purge pipe (104b) is connected from the purge control valve (107) to the tube outlet (106) through evaporative fuel nozzle (111). The evaporative fuel nozzle (111) is connected to a portion of said tube outlet (106) such that it slightly protrudes from the portion of the tube outlet (106). The evaporated fuel from the canister assembly (101) supplied to the engine (108) via purge control valve (107) which is opened by the intake negative pressure of a throttle body (105). The throttle body (105) is operatively connected to engine (108) through a pipe intake (113). [00024] The throttle body (105) has a throttle valve (201) (as shown in fig. 2), wherein; the fuel and the purified air is simultaneously supplied to the engine (108). The purified air is supplied via the tube outlet (106) from the air cleaner (102). The air cleaner (102) is supported to the frame assembly (FA) so as to be suspended above the engine (108). The tube outlet (106) extends downwardly from the rear portion on the air cleaner (102) and bends towards the engine (108), and is joined to the throttle body (105) through A clamp (112). Further, the purge control valve (107) and canister assembly (101) is positioned between fuel tank (114) and the air cleaner (102).

[00025] The air inlet tube (110) is configured to extend in lateral direction (XX’) of the vehicle (100). The one end of the air inlet tube (110) is connected to the air cleaner (102) and other end to the rear panel duct (not shown). Typically, the air inlet tube (110) is directed to the space between air cleaner (102) and rear side panel (not shown). The filtered air from air cleaner (102) passes through the tube outlet (106) and reaches to the throttle body (105). The charge pipe (109) is configured to have a fuel injector port (not shown). The fuel injector port (not shown) is connected to the fuel tank (114) through charge pipe (109) from where the fuel from fuel tank (114) is introduced. Thus, during the suction action of the engine (108) and based on the user input for the throttle body (105) actuation, the hydrocarbon fuel vapor from canister assembly (101) is sent back to engine (108) through the purge pipe (104) to the tube outlet (106). The evaporated fuel is mixed with the fuel injected through fuel injector (not shown). The fuel is combusted in the engine (108) together with the air-fuel mixture. At this time, the outside air is introduced into the canister assembly (101) from the atmospheric air introduction pipe (116), which thereby facilitates the desorption of the evaporated fuel.

[00026] Figure 2(a) illustrates the bottom side cut section view of the tube outlet (106) assembled with the throttle body (105). The tube outlet (106) has a center axis C-C\ The center axis C-C’ passes longitudinally through the center of the tube outlet (106). An imaginary plane A-A’ is passing through the center of the throttle valve (201) such that it is substantially perpendicular to the center axis C-C’ and intersecting at point PI. Further, an imaginary plane B-B’ is passing longitudinally through the center of the evaporative fuel nozzle (111) such that it is perpendicular to the center axis C-C’ and intersect at point P2. The plane B-B’ is substantially parallel to the imaginary plane A-A’. The imaginary plane B-B’ is positioned within predetermined distance (Dx) from the imaginary plane A-A’. The predetermined distance (Dx) includes a range from 40 milli meter to 80 milli meter between point PI and P2.

[00027] Further, the evaporative fuel nozzle (111) adapted to have predetermined inner diameter to allow the evaporative fuel to be injected into the tube outlet (106). The predetermined inner diameter (Da) includes a range from 0.8 milli meter to 2.5 milli meter. The evaporative fuel nozzle (111) integrally formed with the tube outlet (106) gets activated by the engine suction pressure during operating of the engine (108) only while the throttle body (105) is actuated based on the input from the user of the vehicle (100).

[00028] Figure 2(b) illustrates the bottom side cut section view of the tube outlet (106) assembled with the throttle body (105) as per alternative embodiment. The tube outlet (106) has a center axis C-C\ The center axis C-C’ is passing longitudinally through the center of the tube outlet (106). An imaginary plane A-A’ is passing through the center of the throttle valve (201) such that it is substantially perpendicular to the center axis C-C’ and intersecting at point PI. Further, an imaginary plane B-B’ is passing longitudinally through the center of the evaporative fuel nozzle (111) such that it passes through the center axis C-C’ and intersect at point P2. The evaporative fuel nozzle (111) is inclined with respect to the tube outlet (106) to introduce the evaporative fuel in the direction of the flow of air in the tube outlet (106). The imaginary plane B-B’ is positioned within predetermined distance (Dx) from the imaginary plane A-A’. The predetermined distance (Dx) includes a range from 40 milli meter to 80 milli meter between point PI and P2.

[00029] If the evaporative fuel nozzle (111) is positioned outside the predetermined range it will result in the uncontrolled emissions. Locating evaporative fuel nozzle beyond the maximum distance, results in the suction pressure to be low to initiate the purging operation at the canister assembly (101) end hence the purging will not happen even in the required stage leading to more loading of the canister assembly (101). As the tube outlet (106) is configured to have varying cross section such that the inner diameter of the tube outlet (106) near to the throttle body (105) is less as compare to the inner diameter of the tube outlet (106) away from the throttle body (105). In other words, the tube outlet (106) configured to have conical shape. Furthermore, when the evaporative fuel nozzle (111) is located at a distance less than the minimum distance it leads to adverse manufacturability issues. As the evaporative fuel nozzle is integrally formed with the tube outlet thus to locate the evaporative fuel nozzle at the extreme end of the tube outlet requires complex manufacturing process controls during molding process. In addition to above, the un-intended purging will take place during idling and other specific low throttle operating points due to the engine suction pressure leading to higher hydro carbon emission from the engine. Hence, to avoid frequent purging operation separate electronic devices are otherwise required but albeit at cost. Thus, the present invention locates the evaporative fuel nozzle of predetermine diameter within predetermined range to avoid unintended purging during idling and low throttle operating points.

[00030] The present subject matter does not require any sophisticated electronic control system to control purging operation which reduces the cost and complexity of design. Further, the service time to disassemble and assemble the electronics controls while servicing of purge control valve is eliminated. Thus, the cost, complexity of design, weight and service time is reduced which is particularly significant for a small multi wheeled vehicle where impact on compactness, weight and cost become critical.

[00031] While the present invention has been shown and described with reference to the foregoing preferred embodiments, it will be apparent to those skilled in the art that changes in form, connection, and detail may be made therein without departing from the spirit and scope of the invention.

List of references:

Longitudinal axis (YY)

Lateral axis (XX)

Frame assembly (F) Central axis (C-C’) Imaginary plane A- A’

Imaginary plane B-B’

Inner diameter (Da)

Vehicle (100) Front portion (F)

Rear portion (R)

Canister assembly (101) Purge port (101a)

Breather port (101b) Drain port (101c)

Air introduction port (10 Id) Air cleaner (102)

Breather pipe (103)

Purge pipe (104a, 104b) First purge pipe (104a) Second purge pipe (104b) Throttle body (105)

Tube outlet (106)

Purge control valve (107) Engine (108)

Charge pipe (109)

Air inlet tube (110) Evaporative fuel nozzle (111) Clamp (112) Pipe intake (113)

Fuel tank (114)

Drain tube (115)

Atmospheric air introduction pipe (116) Throttle valve (201)

Claims

We Claim:

1. An evaporative emission control system for a vehicle (100), the vehicle (100) comprises: a frame assembly (FA) extending from a front portion (F) to a rear portion (R) along the vehicle longitudinal axis (YY); a fuel tank (114) supported on said frame assembly (FA); an engine (108) supported on a frame assembly (FA), said engine (108) including cylinder head, said cylinder head connected to a throttle body (105), said throttle body (105) is connected to an air cleaner

(102) through a tube outlet (106), said air cleaner (102) supported by said frame assembly (FA); a purge pipe (104), said purge pipe (104) providing passage for evaporated fuel from canister assembly (101) to a tube outlet (106) through a purge control valve (107); wherein said purge pipe (104) is operatively connected to said tube outlet (106) at a predetermined location in between said air cleaner (102) and said throttle body (105). 2. The evaporative emission control system for a vehicle (100) as claimed in claim 1, said purge pipe (104) is connected to the tube outlet (106) through an evaporative fuel nozzle (111).

3. An evaporative emission control system for a vehicle (100), the vehicle comprises: a frame assembly extending from a front portion (FA) to a rear portion (R) along the vehicle longitudinal axis (YY); a fuel tank (114) supported on the frame assembly (FA); an engine (108) supported on a frame assembly (FA), said engine (108) including a crankcase, and a cylinder head, said cylinder head connected to a throttle body (105), said throttle body (105) is connected to an air cleaner (102) through a tube outlet (106), said air cleaner (102) supported by the frame assembly (FA); a purge pipe (104), said purge pipe (104) providing passage for evaporated fuel from canister assembly (101) to tube outlet (106) through a purge control valve (107); wherein said purge pipe (104) is operatively connected to the tube outlet (106) at a predetermined location through an evaporative fuel nozzle (111) in between the air cleaner (102) and the throttle body (105), wherein said evaporative fuel nozzle (111) is inclined with respect to the tube outlet (106) to introduce the evaporative fuel in the direction of the flow of air in the tube outlet (106).

4. The evaporative emission control system for a vehicle (100) as claimed in claim 2 or claim 3, said evaporative fuel nozzle (111) configured to have predetermined inner diameter (Da).

5. The evaporative emission control system for a vehicle (100) as claimed in claim 4, said predetermined diameter (Da) ranges from 0.8 milli meter to 2.5 milli meter.

6. The evaporative emission control system for a vehicle (100) as claimed in claim 1 or claim 3, wherein said tube outlet (106) having a center axis C-C’, said center axis is passing longitudinally through the center of said tube outlet (106). 7. The evaporative emission control system for a vehicle (100) as claimed in claim 1 or claim 3, said throttle body (105) configured to have a throttle valve (201).

8. The evaporative emission control system for a vehicle (100) as claimed in claim 7, wherein said throttle valve (201) having an imaginary plane A-A\ 9. The evaporative emission control system for a vehicle (100) as claimed in claim 8, said imaginary plane A-A’ is passing through the center of the throttle valve (201) such that it is substantially perpendicular to the center axis C-C’ and intersecting at point PI.

10. The evaporative emission control system for a vehicle (100) as claimed in claim 2 or claim 3, said evaporative fuel nozzle (111) having an imaginary plane B-B\

11. The evaporative emission control system for a vehicle (100) as claimed in claim 10, said imaginary plane B-B’ is passing longitudinally through the center of the evaporative fuel nozzle (111) such that it passes through the center axis C-C’ and intersect at point P2.

12. The evaporative emission control system for a vehicle (100) as claimed in claim 11, said imaginary plane B-B’ is substantially parallel to the imaginary plane A-A’.

13. The evaporative emission control system for a vehicle (100) as claimed in claim 12, said imaginary plane B-B’ is positioned within predetermined distance (Dx) from the imaginary plane A-A’.

14. The evaporative emission control system for a vehicle (100) as claimed in claim 13, said predetermined distance (Dx) includes a range from 40 milli meter to 80 milli meter between point PI and P2. 15. The evaporative emission control system for a vehicle (100) as claimed in claim 2 or claim 3, wherein said evaporative fuel nozzle (111) integrally formed on the tube outlet (106).