FIELD OF INVENTION
This invention relates to a system for heating gas pressure regulator by engine
exhaust gas.
PRIOR ART
Gaseous fuel is stored at higher pressure in storage tank for vehicle
application. However, before injecting the fuel in the engine, it is required to
reduce the pressure of gas as shown in Figure 1 indicating the following
cornpone11t s:-
1. Gas storage tank.
2. Pressure gauge
3. Pressure regulator with pressure sensor
4. Filter
5. Exclusive valve & seats
6. Intake manifold M/ F
7. lrljector Rail
As gaseous fuel flows through a pressure regulator to reduce the pressure
I)c,forcx injecting into the engine, the gas temperature reduces because of
cxparisior~ phenomenon. To avoid icing and freezing of fuel in the regulator,
heating of the regulator is carried out with the help of circulation of engine
coolant in the system. After warmed-up condition when coolant temperature is
high, such kind of methodology is beneficial.
However, it is associated with the following disadvantages:
ileating through coolant is beneficial only when the coolant has sufficient
temperatures to heat up the gaseous fuel after expansion in Gas pressure
r<:gulator. However, this does not help during warm up condition (when coolant
tc:mperature is low) at extreme low condition such as zero degree in LPG
rngincs. As LPG is liquefied below around -2 deg. Celsius, it
results in unstable combustion in engine at sub zero temperatures. Hence,
existing system cannot be used to extend the use of LPG engine at zero or sub
zero temperatures during warm-up phase.
Therefore, performance level of LPG engine cannot be matched with that of
gasoline engine at zero or sub zero temperature during warm up.
Hence, the present invention has been proposed to achieve a better
performance level of LPG engine during warning up a t low temperature.
OBJECTS OF THE INVENTION
The primary object of the present invention is to provide a system for heating
gas pressure regulator by engine exhaust gas which overcomes disadvantages
associated with prior art.
Anothcr object of the present invention is to provide a system for heating gas
PI-c:ssurc regulator by engine exhaust gas which is simple in construction.
Yet another object of the present invention is to provide a system for heating
gas pressure regulator by engine exhaust gas which is reliable & efficient.
SUMMARY OF THE INVENTION
According to this invention, there is provided a system for heating gas pressure
regulator by engine exhaust gas comprising of a gas storage tank supplying
sigh prcssure gas to pressure regulator, which is connected to a filter for
supplying low pressure gas to engine through a fuel rail mounted on intake
manifold, wherein the engine is provided with a valve to supply exhaust gas for
heating said pressure regulator.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Further objects and advantages of this invention will be more apparent from
the ensuing description when read in conjunction with the accompanying
drawings and wherein:
Fig. 1 shows: conventional system for LPG engine.
- 7 riig. -2 shows: improved system for LPG engine according to the present
invention.
Fig. 3 shows: connection between ECU and valve in accordance with the
present invention.
Fig. 4 shows: schematic view of present invention during warm-up.
Fig. 5 shows: schematic view of present invention following warm-up.
DETAIL DESCRIPTION OF THE INVENTION WITH REFERENCE TO THE
ACCOMPANYING DRAWINGS:-
This invention provides a system for heating gas pressure regulator by engine
c:xhai.tst gas. Now reference may be made to fig. 2, wherein engine exhaust gas
is used to heat up the cooled expanded LPG in the LPG regulator.
Electronically controlled valve is provided to regulate the flow of exhaust gas
during warm-up phase, which stops the supply of exhaust gas when the engine
coolant gains sufficient heat (fully warmed-up condition) to heat up the cooled
LPG. As the engine exhaust gas has sufficient heat just after the start of
engine, this heat can be used to heat up cooled expanded LPG during warm-up
phasc.
Thus, the exhaust gas from gas storage tank (1) flows through the LPG
pressure regulator (2) to heat up the LPG during warm-up condition in the
subzcro temperatures.
Reference may be made to fig. 4, in which the system of the present invention
supplies the exhaust gas through the LPG pressure regulator. Exhaust gas
controls the LPG temperatures only when the engine (6) is not fully warmed-
LIP. Once engine is fully warmed-up, exhaust gas (E) circulation in the
regulator is stopped as shown in fig. 5. After warmed up condition, coolant
circulation in regulator is sufficient to maintain the desired state of LPG.
Therefore, only coolant circulation is present in LPG pressure regulator after
fully warmed-up condition of engine. Valve is designed in such a way that it
provides some impedance to flow of gas from regular path when it is opened.
This is required as the pressure difference between the inlet of exhaust gas to
regulator and the outlet of exhaust is not sufficient to meet the higher demand
of exhaust gas circulation in the regulator. Higher demand of exhaust gas
circulation is required when there is sudden load change resulting in sudden
iiyuefaction of LPG. Valve (V) is operated by stepper motor which is controlled
by ECU. When stepper motor receives signal to allow exhaust through gas
prcssurc regulator, the valve restricts the exhaust gas flow directly into
Exhaust manifold (5). Exhaust gas changes its direction (D) when the valve is
opened as shown in fig. 4.
As engine exhaust gas (E) has water vapors, water can be accumulated in the
hoses or regulator whenever exhaust gas exchanges heat with LPG in regulator.
'I'o avoid the water accumulation in the pressure regulator, lay-outing of the
hoses that supply exhaust gas is designed in such a way that exhaust gas
flows only downwards as indicated in fig. 4. This is achieved by mounting the
;;rcssdrc regulator in engine room at a height lower than engine exhaust port.
This ensures absence of water clogging in the new circuit which is provided to
heat up the gas pressure regulator by engine exhaust gas.
Now, reference may be made to fig. 3.
r-3,
i nc. cicctronically controlled valve comprising of solenoid valve (V), which is
operated by ECU control signals. Flow of exhaust gas or valve opening in the
pressure regulator depends upon the various parameters such as coolant
temperature, LPG temperature, engine speed and engine load. Such kind of
control helps in achieving the most desired state of LPG. ECU controls the
valve opening depending upon the requirement of engine. Valve opening time or
flow rate of exhaust gas is calibrated on the basis of various parameters such
as coolant temperature, LPG temperature, engine speed and engine load. Thus,
ECU controls the flow rate of exhaust gas by changing the opening time of
vaivc, as requirement of heat can't be directly determined. Therefore, ECU
opc.ratc.s the valve as per requirement receiving signals from different sensors
r-ogarding engine speed, engine load, coolant temperature and LPG
temperature.
Advantages:
1. Helps to achieve stable and smooth running of LPG engine at low
temperatures too.
2. Dedicated LPG engine with good startability and performance equivalent
to petrol at low temperatures, can be developed.
It 1s to be noted that the present invention is susceptible to modifications,
::claptations and changes by those skilled in the art. Such variant embodiments
cmploying the concepts and features of this invention are intended to be within
the scope of the present invention, which is further set forth under the
following claims:-

+ p, .? 0, ?-,=-I
1 \ 1 \ , ' ' ?
THE PATENTS CT.' 1970 "*
COMPLETE
SPECIFICATION
SECTION 10
TITLE
"A system for heating gas pressure regulator by engine exhaust gas".
APPLICANT
MARUTI SUZUKI INDIA LIMITED, A COMPANY REGISTERED UNDER THE
COMPANIES ACT, 1956, HAVING ITS REGISTERED OFFICE AT 1, NELSON
MANDELA ROAD, VASANT KUNJ, NEW DELHI-110070, INDIA.
The following specification particularly describes the invention and the
manner in which it is to be performed.
FIELD OF INVENTION
This invention relates to a system for heating gas pressure regulator by engine
exhaust gas.
PRIOR ART
Gaseous fuel is stored at higher pressure in storage tank for vehicle
application. However, before injecting the fuel in the engine, it is required to
reduce the pressure of gas as shown in Figure 1 indicating the following
cornpone11t s:-
1. Gas storage tank.
2. Pressure gauge
3. Pressure regulator with pressure sensor
4. Filter
5. Exclusive valve & seats
6. Intake manifold M/ F
7. lrljector Rail
As gaseous fuel flows through a pressure regulator to reduce the pressure
I)c,forcx injecting into the engine, the gas temperature reduces because of
cxparisior~ phenomenon. To avoid icing and freezing of fuel in the regulator,
heating of the regulator is carried out with the help of circulation of engine
coolant in the system. After warmed-up condition when coolant temperature is
high, such kind of methodology is beneficial.
However, it is associated with the following disadvantages:
ileating through coolant is beneficial only when the coolant has sufficient
temperatures to heat up the gaseous fuel after expansion in Gas pressure
r<:gulator. However, this does not help during warm up condition (when coolant
tc:mperature is low) at extreme low condition such as zero degree in LPG
rngincs. As LPG is liquefied below around -2 deg. Celsius, it
results in unstable combustion in engine at sub zero temperatures. Hence,
existing system cannot be used to extend the use of LPG engine at zero or sub
zero temperatures during warm-up phase.
Therefore, performance level of LPG engine cannot be matched with that of
gasoline engine at zero or sub zero temperature during warm up.
Hence, the present invention has been proposed to achieve a better
performance level of LPG engine during warning up a t low temperature.
OBJECTS OF THE INVENTION
The primary object of the present invention is to provide a system for heating
gas pressure regulator by engine exhaust gas which overcomes disadvantages
associated with prior art.
Anothcr object of the present invention is to provide a system for heating gas
PI-c:ssurc regulator by engine exhaust gas which is simple in construction.
Yet another object of the present invention is to provide a system for heating
gas pressure regulator by engine exhaust gas which is reliable & efficient.
SUMMARY OF THE INVENTION
According to this invention, there is provided a system for heating gas pressure
regulator by engine exhaust gas comprising of a gas storage tank supplying
sigh prcssure gas to pressure regulator, which is connected to a filter for
supplying low pressure gas to engine through a fuel rail mounted on intake
manifold, wherein the engine is provided with a valve to supply exhaust gas for
heating said pressure regulator.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Further objects and advantages of this invention will be more apparent from
the ensuing description when read in conjunction with the accompanying
drawings and wherein:
Fig. 1 shows: conventional system for LPG engine.
- 7 riig. -2 shows: improved system for LPG engine according to the present
invention.
Fig. 3 shows: connection between ECU and valve in accordance with the
present invention.
Fig. 4 shows: schematic view of present invention during warm-up.
Fig. 5 shows: schematic view of present invention following warm-up.
DETAIL DESCRIPTION OF THE INVENTION WITH REFERENCE TO THE
ACCOMPANYING DRAWINGS:-
This invention provides a system for heating gas pressure regulator by engine
c:xhai.tst gas. Now reference may be made to fig. 2, wherein engine exhaust gas
is used to heat up the cooled expanded LPG in the LPG regulator.
Electronically controlled valve is provided to regulate the flow of exhaust gas
during warm-up phase, which stops the supply of exhaust gas when the engine
coolant gains sufficient heat (fully warmed-up condition) to heat up the cooled
LPG. As the engine exhaust gas has sufficient heat just after the start of
engine, this heat can be used to heat up cooled expanded LPG during warm-up
phasc.
Thus, the exhaust gas from gas storage tank (1) flows through the LPG
pressure regulator (2) to heat up the LPG during warm-up condition in the
subzcro temperatures.
Reference may be made to fig. 4, in which the system of the present invention
supplies the exhaust gas through the LPG pressure regulator. Exhaust gas
controls the LPG temperatures only when the engine (6) is not fully warmed-
LIP. Once engine is fully warmed-up, exhaust gas (E) circulation in the
regulator is stopped as shown in fig. 5. After warmed up condition, coolant
circulation in regulator is sufficient to maintain the desired state of LPG.
Therefore, only coolant circulation is present in LPG pressure regulator after
fully warmed-up condition of engine. Valve is designed in such a way that it
provides some impedance to flow of gas from regular path when it is opened.
This is required as the pressure difference between the inlet of exhaust gas to
regulator and the outlet of exhaust is not sufficient to meet the higher demand
of exhaust gas circulation in the regulator. Higher demand of exhaust gas
circulation is required when there is sudden load change resulting in sudden
iiyuefaction of LPG. Valve (V) is operated by stepper motor which is controlled
by ECU. When stepper motor receives signal to allow exhaust through gas
prcssurc regulator, the valve restricts the exhaust gas flow directly into
Exhaust manifold (5). Exhaust gas changes its direction (D) when the valve is
opened as shown in fig. 4.
As engine exhaust gas (E) has water vapors, water can be accumulated in the
hoses or regulator whenever exhaust gas exchanges heat with LPG in regulator.
'I'o avoid the water accumulation in the pressure regulator, lay-outing of the
hoses that supply exhaust gas is designed in such a way that exhaust gas
flows only downwards as indicated in fig. 4. This is achieved by mounting the
;;rcssdrc regulator in engine room at a height lower than engine exhaust port.
This ensures absence of water clogging in the new circuit which is provided to
heat up the gas pressure regulator by engine exhaust gas.
Now, reference may be made to fig. 3.
r-3,
i nc. cicctronically controlled valve comprising of solenoid valve (V), which is
operated by ECU control signals. Flow of exhaust gas or valve opening in the
pressure regulator depends upon the various parameters such as coolant
temperature, LPG temperature, engine speed and engine load. Such kind of
control helps in achieving the most desired state of LPG. ECU controls the
valve opening depending upon the requirement of engine. Valve opening time or
flow rate of exhaust gas is calibrated on the basis of various parameters such
as coolant temperature, LPG temperature, engine speed and engine load. Thus,
ECU controls the flow rate of exhaust gas by changing the opening time of
vaivc, as requirement of heat can't be directly determined. Therefore, ECU
opc.ratc.s the valve as per requirement receiving signals from different sensors
r-ogarding engine speed, engine load, coolant temperature and LPG
temperature.
Advantages:
1. Helps to achieve stable and smooth running of LPG engine at low
temperatures too.
2. Dedicated LPG engine with good startability and performance equivalent
to petrol at low temperatures, can be developed.
It 1s to be noted that the present invention is susceptible to modifications,
adaptations and changes by those skilled in the art. Such variant embodiments
employing the concepts and features of this invention are intended to be within
the scope of the present invention, which is further set forth under the
following claims:-

WE CLAIM:
1. A system for heating gas pressure regulator by engine exhaust gas
comprising of a gas storage tank supplying high pressure gas to pressure
regulator, which is connected to a filter for supplying low pressure gas to
engine through a fuel rail mounted on intake manifold, wherein the
cnginc is provided with a valve to supply exhaust gas for heating said
pressure regulator.
2. A system as claimed in claim 1, wherein the valve is electronically
controlled valve.
3. A system as claimed in claim 1 or 2, wherein the valve is solenoid valve
operated by stepper motor, which is controlled by Electronic Control
Unit.
4. A system as claimed in any of the preceding claims, wherein the pressure
regulator is mounted in engine room at a height lower than the engine
exhaust port to make the exhaust gas flow downwards, which ensures
absence of water clogging in the fuel circuit.
5. A system as claimed in any of the preceding claims, wherein the valve
regulates the flow of exhaust gas during warm-up phase, which stops the
supply of exhaust gas when the engine coolant gains sufficient heat to
heat up the cooled LPG.
6. A system as claimed in any of the preceding claims, wherein the valve
provides some impedance to flow of gas from regular path when it is
opened.
7. A system as claimed in any of the preceding claims, wherein the
electronic control unit controls the flow of exhaust gas or valve opening
lirne in the pressure regulator according to the requirement of the
engine, which is calibrated on the basis of various parameters such as
coolant temperature, LPG temperature, engine speed and load.
8. A system as claimed in any of the preceding claims, is associated with
the advantageous features such as herein described.
9. A system for heating gas pressure regulator by engine exhaust gas
substantially as herein described with reference to the accompanying
drawings.