MITSUBISHI PAJERO DID LPG Gas Conversion

MITSUBISHI PAJERO DID
LPG Gas Conversion
A Joint Project between:
Impco Fuel Systems
& Diesel On Gas
Project Date: June 2003

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Project Overview

• The “Diesel on Gas” system

The system enables an otherwise unmodified Diesel engine to run reliably on
a pre specified amount of LPG in conjunction with a proportionally reduced
amount of Diesel. LPG gas is stored in an auxiliary tank usually located
underneath the rear of the vehicle. The liquid LPG turns into gaseous form
inside a LPG gas converter. The gas is induced into the engine via the patent
pending Diesel ON Gas mixer which is situated before the turbo charger. A
series of valves between the converter and the mixer cut off the LPG vapour
flow during vehicle braking and deceleration. This function is controlled by the
D.O.G. microprocessor control module. The other function of the control
module is to monitor engine parameters during operation and to revert back to
Diesel operation should any of the preset parameters be exceeded.
The chosen gas substitution rate always remains constant in reference to the
applied engine load irrespective of engine rpm. This function is completely self
compensating due to the novel internal makeup of the D.O.G. mixer and
requires no further electronic or mechanical input. It allows the safe
application of high gas substitution rates of over 50% to be applied in direct
injection Diesel engines. This feature is unique and exclusive to the D.O.G.
system. Other Diesel/gas fumigation systems will rarely exceed substitution
rates above 20%.

• Project
objectives

To test and evaluate the “D.O.G.” system on a current model Mitsubishi
Pajero DID Diesel. Categories for performance evaluation included
performance, emission and fuel consumption at different driving conditions.

• The
vehicle

Fig 1




2003 model
Mitsubishi Pajero DID
5 speed manual.
Engine:
3 Liter, 4 cyl. Diesel
121kw
Fuel capacity:
90 Liter

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• Installation
details

Fig 2



63 Liter LPG tank located in
emergency seat well.











Fig 3



Engine bay view.











Fig 4




Location of Diesel/gas mixer in
air intake between air filter and
turbo charger intake

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Fig 5



Microprocessor control module






Fig 6






Valve control module and LPG gas
converter.










• Operational
benefits

The test has shown the following benefits and advantages of the system:

⇒ Reduced engine noise
⇒ Increased performance and drivability
⇒ Lower fuel cost
⇒ Seamless changeover between dual fuel and Diesel mode
⇒ Significantly reduced emissions
⇒ Reduced engine load
⇒ Lower exhaust temperature at same load (up to 25%)
⇒ Extended operating range
⇒ No interference with engine management system

---

Project Overview

• The “Diesel on Gas” system

The system enables an otherwise unmodified Diesel engine to run reliably on
a pre specified amount of LPG in conjunction with a proportionally reduced
amount of Diesel. LPG gas is stored in an auxiliary tank usually located
underneath the rear of the vehicle. The liquid LPG turns into gaseous form
inside a LPG gas converter. The gas is induced into the engine via the patent
pending Diesel ON Gas mixer which is situated before the turbo charger. A
series of valves between the converter and the mixer cut off the LPG vapour
flow during vehicle braking and deceleration. This function is controlled by the
D.O.G. microprocessor control module. The other function of the control
module is to monitor engine parameters during operation and to revert back to
Diesel operation should any of the preset parameters be exceeded.
The chosen gas substitution rate always remains constant in reference to the
applied engine load irrespective of engine rpm. This function is completely self
compensating due to the novel internal makeup of the D.O.G. mixer and
requires no further electronic or mechanical input. It allows the safe
application of high gas substitution rates of over 50% to be applied in direct
injection Diesel engines. This feature is unique and exclusive to the D.O.G.
system. Other Diesel/gas fumigation systems will rarely exceed substitution
rates above 20%.

• Project
objectives

To test and evaluate the “D.O.G.” system on a current model Mitsubishi
Pajero DID Diesel. Categories for performance evaluation included
performance, emission and fuel consumption at different driving conditions.

• The
vehicle

Fig 1




2003 model
Mitsubishi Pajero DID
5 speed manual.
Engine:
3 Liter, 4 cyl. Diesel
121kw
Fuel capacity:
90 Liter

---

Fuel consumption testing

• Test
regime

To obtain accurate and valid fuel consumption data, the vehicle was tested on
both Diesel and dual fuel modes, comparing 3 different drive cycles over a total
distance of over 9000km. The drive cycles where defined as:

1. City drive cycle
2. Constant 110km/h drive cycle
3. Constant 100km/h drive cycle

Both the City and the 100km/h drive cycle are commonly used by Motor
magazines to illustrate and establish the average fuel consumption of a vehicle.
The 110km/h test was added because it reflects the speed limit in many states
and is therefore more practice oriented.

• Variable fuel substitution mode

A driver operated switch allowed selection between 40% and 60% substitution.
This allowed for a comparison of benefits and operating characteristics between
both fuel substitution ratios.

• Fuel cost calculation

The cost per km calculations are based on an average Diesel fuel price of $0.88
and a LPG fuel price of $0.36

• Thermal
efficiency
calculation

Thermal efficiency on dual fuel operation was compared against standard Diesel
efficiency performance values. Efficiency was established by comparing the total
heat value of amount of fuel consumed over the same distance on Diesel and
dual fuel. All calculations are based on a net heat value of 42.5MJ/kg for Diesel
and 46.1MJ/kg for LPG.


• Conclusion

Dual fuel operation at 40% substitution rates resulted in a fuel cost saving of
around 25% and an increase in thermal efficiency of over 15% under all driving
modes. Combined fuel consumption was lower than with Diesel operation. 60%
substitution showed a lower thermal efficiency gain with a higher consumption
and only a minimal reduction in fuel cost when compared to the lower substitution
rate. Further tests will be conducted with a substitution rate of 50%. Calculated
savings at this setting are expected to be around 30%.

---

City cycle


Fig 7

Fuel consumption comparison
Standard Diesel:
(City drive cycle)
12.7Liter/100km
(NRMA figures)
14

12
10
4.41
5.31

8
LPG

/
100km
12.7
6
Diesel
Dual fuel 40% LPG:
i
ter
4
L
7.51
7.37
11.9Liter/100km
2
0

Diesel
Dual Fuel 40%
Dual Fuel 60%
Dual fuel 60% LPG:
LPG
LPG
12.7Liter/100km


Fig 8

Fuel cost comparison
Standard Diesel:
(City drive cycle)
11.2cent/km
12

10
Dual fuel 40% LPG
8
8.2cent/km (26.5% saving)
m
1.58
1.9
LPG
t
/
k
6
n
11.16

Diesel
Ce
4
Dual fuel 60% LPG
6.59
6.47
2
8.4cent/km (24.7% saving)
0

Diesel
Dual Fuel 40%
Dual Fuel 60%

LPG
LPG



Fig 9

Thermal efficiency comparison
Dual fuel 40% LPG
(City drive cycle)
15.6% efficiency increase

15.6%
11.5%
Dual fuel 60% LPG
11.5% efficiency increase
Efficiency increase
Fuel energy/km



Diesel
Dual Fuel 40%
Dual Fuel 60%

LPG
LPG

---

Constant 110km/h


Fig 10

Fuel consumption comparison
Standard Diesel:
(Constant 110km/h)
10.8Liter/100km

14
Dual fuel 40% LPG:
12
10
10.4Liter/100km
0km
3.77
6.78
8
LPG

/
10
6
10.8
Diesel
Dual fuel 60% LPG:
i
ter
4
L
6.63
5.12
11.9Liter/100km
2
0

Diesel
Dual Fuel 40%
Dual Fuel 60%

LPG
LPG



Fig 11

Fuel cost comparison
Standard Diesel:
(Constant 110km/h)
9.5cent/km

10
Dual fuel 40% LPG
8
7.2cent/km (24.3% saving)
1.35
m
6
2.41
LPG

t
/
k
n
9.47
4
Diesel
Dual fuel 60% LPG
Ce
5.82
4.5
2
6.9cent/km (25.0% saving)
0

Diesel
Dual Fuel 40%
Dual Fuel 60%

LPG
LPG



Fig 12

Thermal efficiency comparison
Dual fuel 40% LPG
(Constant 110km/h)

13.0% efficiency increase
13.01%
6.66%

Dual fuel 60% LPG
Efficiency increase
6.7% efficiency increase
100%
86.99%
93.34%
Fuel energy/km



Diesel
Dual Fuel 40%
Dual Fuel 60%

LPG
LPG

---

Constant 100km/h


Fig 13

Fuel consumption comparison
Standard Diesel:
(Constant 100km/h)
9.4Liter/100km
(NRMA figures)
10

8
Dual fuel 40% LPG:
2.39
6
LPG
8.4Liter/100km
9.4
r
/
100km
Diesel

4
i
t
e
6.02
L

2

0

Diesel
Dual Fuel 40% LPG




Fig 14

Standard Diesel:
F u e l c o s t c o m p a ris o n
8.3cent/km
(C o n s ta n t 1 0 0 k m /h )

9
Dual fuel 40% LPG
8
7
6.2cent/km (25.7% saving)
6
m
0 .8 5

5
L P G
t
/
k
4
8. 26
D ies e l

Cen
3
5 . 2 9
2

1
0

D ie s el
D u a l F u el 4 0 %

L P G



Fig 15

Thermal efficiency increase
Dual fuel 40% LPG
(Constant 100km/h)
17.4% efficiency increase

17.4%


Efficiency increase
Fuel energy/km




Diesel
Dual Fuel 40% LPG

---

Average consumption


Fig 16

Fuel consumption comparison
Standard Diesel:
(Average consumption)
11.1Liter/100km
(NRMA figures)
12

10
Dual fuel 40% LPG:
3.4
8
LP G
10.2Liter/100km
6
/
100km
11.05
Diesel

i
ter
4
L
6.77
2

0

Dies el
Dual Fuel 40% LP G



Fig 17

Standard Diesel:
Fue l cost comparison
9.7cent/km
(Av e rage consumption)

12
Dual fuel 40% LPG
10
7.2cent/km (25.8% saving)
8
m

1.22
LP G
t
/
k
6
n
9.7
Dies el

4
Ce
5.95
2

0

Dies el
Dual F uel 40%

LP G



Fig 18

Dual fuel 40% LPG
Thermal efficiency comparison
(Average consumption)
16.3% efficiency increase

16.3%


Efficiency increase

Fuel energy/km



Diesel
Dual Fuel 40% LPG

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