FIELD OF THE INVENTION
The present invention relates to user information methodology in an automobile
in respect of open/ close status of fuel lid which allows preventive action against
safety hazards. More particularly, the invention relates to a fault-data detection
system in an alternative fuels vehicle in a running mode based on visual
indication of close/open status of the fuel lid.
BACKGROUND OF THE INVENTION
Automobiles are driven by internal combustion engines (ICE). For driving the
ICE, commonly used fuels are Gasoline, Diesel, and CNG (or its variants).
These fuels are filled in a specific fuel tank. The fuel tank can be refilled through
various Petrol/Diesel pump stations in case of normal Petrol/Diesel vehicles.
In addition, for CNG vehicles, there is a separate kind of tank used and these
special tanks can be refilled only at CNG stations. However, no specific safety
measures are available in prior art in respect of refuelling the automobiles in the
fuel-filling stations. Thus different safety measures are self-devised by the
fuelling stations.
The CNG filling is usually done at a very high pressure of around 200bar. The
storing of CNG at this high pressure including storage in fuel tank demands
maintenance of high-standard of safety.
If the automobiles engine is in running state, and the vehicle operator
accidentally or deliberately tries to drive-out the vehicle from the refuelling point, during or after CNGfilling while CNGfilling hose is still connected, the same may
lead to a serious accident. The reason being that the high pressure CNGshall still
be particularly available in the hose, which may spread out in the adjacent
environment very qUickly leading to possible fire hazards.
Hence as a practice, it is essential to turn off the engine before CNGfilling and
restarting the vehicle only after the hose is detached. This is manually ensured
by the vehicle operator or the pump. However, an inadvertence to follow the
practice, might lead to a major accident at these refuelling stations.
Nevertheless, prior-stopping of the engine during CNGfilling can be checked and
ensured easily for types of vehicle having refuelling nozzle located at the front
hood of the car. But, the process of checking becomes more difficult for vehicles
having the nozzle in the side of the vehicle body (as today's engines are much
more silent), leading to visibility offset.
The fault detection process of prior art is therefore completely manual without
haVing any mechanised or automated control feature. Hence there is a need to
introduce a robust system which is not depending on the user, but to the system
itself (and can shut down the engine automatically during CNGfilling).
As a safety against fire hazard, at the time of CNGfilling, follOWing regulatory
requirement is defined in Automotive Indian Standards (AIS 028, c1ause-2.2.5):
"Filling connections in motor vehicles shall be fitted with a system that prevents
the engine starting when the dust plug or dust protection cap is removed. This
system shall isolate the starting device of the vehicle." This will ensure that
vehicle can not be driven while CNGpipe is still attached to the vehicle However, the standard does not cater for the potential safety hazard for vehicles
when brought for refilling, with the engine in running mode. In case of CNG
filling process, if switching off the vehicle as per gUidelines is not followed by the
user at CNGstation, this may lead to inadvertent safety hazard.
The vehicles for alternative fuels applications specifically warrant:
1. a superior technical detection system, enabled to provide accuracy to the
safety needs for fuel system in particular at the time of fuel filling.
2. proposing a fault-detection system such that safety needs is implemented in
particularly for the alternative fuels power train of the alternative fuels
systems.
A technical solution to the above-disadvantages has been disclosed by the
applicant in Indian patent application 899jKOL/2010.
Although the fault-detection system for alternative fuels vehicles can be
automated to prevent engine from running during CNGfilling as conceptualized
hereinabove, there still remains a further possible hazard for example, a
alternative fuels based vehicle gets stranded at traffic signal or due some other
circumstances, with the fuel-lid accidentally remaining opened say for reasons
not attributable to refuelling, the vehicle operator while restarting the engine
shall be disabled to start the engine, without detecting the cause of restartfailure.
The operator will be subsequently enabled to detect that the open-status
of the fuel lid· is disallowing restarting of the engine which however, is
undesirable for the vehicle-manufacturer including the users. OBJECTS Of INVENTION
It is therefore an object of the invention to propose a system for fault detection
in a alternative fuels system of a vehicle in a running-mode and transmission of
fault data to a user related to fuel lid open/close.
Another object of the invention is to propose a method of fault detection in a
alternative fuels system of a vehicle in running mode and communication of the
fault to the user.
SUMMARY Of THE INVENTION
The invention is about the fuel lid open/ close status display in these systems.
This a feature aimed at assisting the user by alerting him about the above
possible scenarios in the system. Additionally, the communication of such
detected faults is communicated to the user by glowing a lamp is to be used on
pre-defined pattern (for e.g. blinking, continuous ON, off depending on the fuel
lid open/ close status). Thus, the vehicle operator is enabled to recognise the
causeof engine-stoppage in a running mode.
The system referred in this disclosure cover all kind of vehicles running in CNG,
for example:
1. Vehicles that can be driven by both conventional fuels and alternative fuels
(like CNG).
2. Vehicle that can be driven by alternate fuels (CNG)only (Also, covers vehicles
with small fuel tank (Gasoline/Diesel) for limp-home purpose). Accordingly, there is provided a diagnostic system for detection of fuel-lid status
during running of a vehicle and real-time communication of the detected status
to allow the vehicle operator to immediately diagnose the cause of engine
malfunction. According to the invention, the vehicle comprising an engine
activable by operating an ignition switch, a starting motor providing initial
rotation to the engine, a plurality of engine sensors to acquire vehicle operation
data, at least one fuel tank with a fuel lid, a fuel level/pressure sensor, a fuel-lid
switch an electronic control unit CECU),and a signal transmission line connecting
a display means and the ECU,the system is configured to receive signal from the
fuel lid switch in respect of open or close status of the fuel lid; upon sWitchingon
the ignition switch monitoring status of all the devices including peripheral
devices of the engine/fuel system; checking the fuel-filling status if the engine
speed is above a threshold value; communicating to the display device that the
open status of the fuel lid causing stoppage of restart of the engine, and
manually changing the open status of the fuel lid to restart the engine.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Figure 1 - shows a schematic diagram of the fault detection system in an
engine system of a vehicle in running mode according to the
invention.
Figure 2 - shows a flow-chart for implementing the detection steps in the
fault detection system.
DETAIL DESCRIPTION OF THE INVENTION
As shown in figure-l, during a normal start-up, the engine [9], is turned ON by activating the Ignition switch [3] (hereafter referred to as IGSW), and engage
the starter motor [10] through the IGSW (3) or through a controller [1]
(hereafter referred to as ECU). The starter motor [10] then rotates the engine
(9) and generates an initial engine speed (hereafter referred to as RPM)which is
required by the engine (9) to start automatically for firing. During this time, the
fuel is delivered to the engine (9) through the dedicated fuel lines [12]. The ECU
(1), based on a plurality of sensors [5] and logics incorporated inside the ECU,
determines the spark timing, fuel quantity, and fuel injection timing. This allows
the engine to gain the required RPMand thereafter it rotates without Starter
motor's assistance.
As shown in figure-2, the invented system comprises:
- an ECU (1) (Electronic control unit) and/a CNG ECU for driving CNG
system (Optional);
- a Speedometer or similar display device (2);
- an Ignition switch (3);
- a Fuel lid switch (4);
- a plurality of Sensors (5);
- a CNGtank (6);
- a CNGreceptacle (7);
- a CNGfuel level/pressure sensor (8);
- an Engine (9);
- a Starter motor (10);
- a Fuel Lid (11);
- a Fuel line (12); and
- a Communication line (13) (CAN/Serialline) During implementation of this invention, a sensing mechanism is provided in the
fuel lid [12] which sends signal to the designated ECU. Based on the sensing
results, the fuel lid is detected as either open or close. This explains the user
intent of getting the fuel filled through receptacle [7].
Similarly, the Ignition switch status is also sensed constantly and the data is
made available to the ECU. The ECU constantly monitors these signals and stores
the parameters in software flag FLSW and IGSW respectively.
As shown in figure-2, the sequence for system operation is as under:
Let VSPD: Vehicle Speed
RPM: Engine RPM
VEHRUN: Status of Vehicle running (Indirect measure)
FLSW: Fuel lid status
CNGFIL: CNG filling detected
IGSW: Ignition switch status
ENGOFFREQ: Engine OFF request. In case it is TRUE, the engine running will be
inhibited by fuel cut etc. In case it is FALSE, no action will be taken by the ECU
for this logic.
Fuel Filling can be detected by reading the FLSW values.
In yet another possible implementation, the CNG filling can be monitored by
continuously checking the CNG pressure coming through CNG pressure sensor
[8]. In case, the previous value is less than the current value, it can be said that
the filling is going on.
For e.g.: d(CNG Filling volume)/dT > K,
K is any variable that can be calibrated depending on the logic.
It can be assumed that whenever CNG is filling (based on above formula), and if
the IGSW is in ON state, it is a safety hazard.
The implementation is explained as follows:
During fuel filling if it is detected and that the fuel lid is Open, ECU will continue
to monitor these values.
If FLSW=OPEN
Or CNG filling is detected through some other measure.
CNGFIL=DETECTED
When fuel filling is not detected, and that the fuel lid is Closed. ECU will continue
to monitor these values.
If FLSW=CLOSE
Or CNG filling is not detected through some other measure.
CNGFIL=NOTDETECTED
Hence,
When IGSW=OFF, the ECU will not process further information.
Once, IGSW= ON, the ECU initialise the system and monitor various sensor
signals and peripheral status (for e.g. Starter Motor engaged or not, and so on). Engine Running is considered when engine RPM is greater than 250. The ECU
will continue to monitor these values and ignore the fuel filling status:
RPM>250
CNGFIL not considered
If engine RPM is less than 250 RPM and/or Vehicle speed VSPD < = 10kmph, the
ECUwill check the fuel filling status through CNGFIL.
RPM<=250 and/or VSPD<=10kmph
Read CNGFIL
If the filling is detected, ECU will send signal to Display device (via Can or Serial
line) and control the Lamp behaviour satisfying the following conditions:
IGSW=ON
CNGFIL=DETECTED
RPM<= 250
VSPD<=lOkmph
The display device is connected to this ECU via commonly available CAN line
and/or Serial line. After calculations of the signal values by the ECU, the
lamp/LED available on the display device (for e.g. Speedometer) is controlled by
sending the signal on CAN/Serial-line.
This designated lamp can be used in several methods (by blinking, continuous
ON, off, self-diagnosis during system initialisation) which will indicate the status
of fuel lid at any point of time depending on algorithm implemented. The
designated lamp mayor may not be exclusive for this purpose. Provision is kept for understanding the malfunction as well. The sensing can be
in both direct and/ or indirect manner and is sUitably informed to the user using
same or another LED/Lamp.
Salient Points of Invention
1. Informs the user about fuel lid open/ close status at any point of time
2. If fuel lid found open, the starting device does not allow the engine to
start for safety purpose. In such situation, our system informs the user so
that he can resolve the problem himself.
The systems referred in this disclosure cover all kind of vehicles running in CNG,
for example:
1. Vehicles that can be driven by both conventional fuels and alternative
fuels (like CNG).
2. Vehicle that can be driven by alternate fuels (CNG) only (Also, covers
vehicles with small fuel tank (Gasoline/Diesel) for limp-home purpose).
WE CLAIM
1. A method in a diagnostic system for detecting and displaying the cause of
engine-restart failure in a alternative fuels compliant vehicle during an
intermediate stoppage mode of the vehicle, the system comprising a
vehicle engine activable by operating an ignition switch, a starting motor
providing initial rotation to the engine, a plurality of engine sensors to
acquire vehicle operation data, at least one fuel tank with a fuel lid, a fuel
level/pressure sensor, a fuel-lid switch an electronic control unit (ECU),
and a signal transmission line connecting a display means and the ECU,
the display means being enabled to display different visual patterns to
indicate plurality of operational status, the method comprising the steps
of:
- detecting fuel-filling status based on data to be transmitted to the ECU
from the fuel lid SWitch,or by comparing the CNG pressure acquired
through the CNGpressure sensor;
- eliminating the data if exhibiting close status of the fuel lids;
- initializing the system if status of ignition switch indicates 'ON' position;
- monitoring through the ECUthe operating values acquired from said
plurality of engine sensors including the operational status of the
peripheral devices;
- monitoring engine running status which when detected to be less than
250 rpm and fuel filling status showing refuelling mode, transmitting a first pattern signal to the display device representing open-status of the
fuel-lid and disabled status of the ignition SWitch;and
- in addition, monitoring vehicle running status which when detected to
be less than 10kmph and fuel filling status showing refuelling mode,
transmitting a first pattern signal to the display device representing
open-status of the fuel-lid and disabled status of the ignition switch
- transmitting representing open-status of the fuel-lid, disablement of the
ignition SWitch,and non-detection of refuelling status.
2. A method in a diagnostic system for detecting and displaying the cause of
engine-restart failure in a alternative fuels compliant vehicle during an
intermediate stoppage mode of the vehicle, as substantially described and
illustrated herein with reference to the accompanying drawings.