Text: Jude Morte / Photos: Jude Morte | posted September 30, 2008 17:02
More than just a tank and an emulator
The green yet greenback-reducing solution is the very liquefied petroleum gas (LPG) that cooks your adobo. It has been proven in the country over the last three years that LPG can power automobiles, with nearly every taxi in the metro running on the said fuel. The fact that auto LPG is much cheaper than petroleum products, along with extending engine life due to the absence of carbon deposits - which reduces soot formation, engine abrasion and chemical degradation of oil over time ? is a two-fold long term benefit. But the aforementioned taxis tote Japanese inline four cylinder gas engines; how about the rest of the motoring public that have vehicles with V6 and V8 petrol setups?
One solution, according to Total Philippines Corporation and SKN (a Makati-based company that specializes in converting petrol V8-powered autos for LPG use), is to modify the current open loop LPG system normally used for four cylinder units. An open loop LPG system ?piggybacks? itself to a conventional gasoline engine via an emulator to transfer signals correctly from the ECU and a regulator (or vaporizer) that uses heat from the car's cooling fluids to vaporize the propane into gas form, as well as cutting the flow of gas if the engine stops or stalls. It also has a restrictor valve added to the pipe between the mixer and the vaporizer, which the installer will use to tune the system. By adjusting this valve, the installer can tune how much of the vacuum the vaporizer experiences, so can control how much gas can join the airflow and so keep the engine electronics in sync with the auto LPG electronics.
SKN claims that its emulators - electromechanical piggyback auto LPG fuel distributors that are connected to the ECU - are the difference. When the car is operating on LPG, the fuel injectors will not be sending any information to the other sensors in the car - this will light up the "check engine" light and give incorrect diagnostic readings. The emulator ?fakes? the proper signals so the ECU can operate properly. For V8 engines, SKN uses two emulators (one for each bank of four cylinders). ?The ECU tells the emulator what to instruct the injectors to do; the emulators are pre-programmed already for a particular vehicle. We don?t cut off the ECU; doing that causes problems and costs more money in the long run. Also, tuning the ECU is done manually for minimal engine risk,? said SKN general manager Ravi Idnani.
V6 and V8 engines require rather large amounts of fuel to run, and the normal 30-40 liter LPG tanks used in taxis fall short of the needed LPG delivery requirements. SKN?s V6 and V8 LPG tanks are 60 liters, and are installed either in the trunk or where the spare tire is placed (normally at the rear underchassis). SKN also realizes that these tanks could come in contact with the tarmac sooner or later due to its location, and before they arrive in the country they are tested rigidly for seven months. ?Just to prove that the LPG tanks are leakproof, we rolled them (with LPG filled to the brim) down 12 flights of stairs in a hotel in a Cebu. There was one dent, but no leaks. We made it collide with a train, and there were no leaks. We lit up the tank, and it only exploded when the internal pressure rose to three times the normal pressure inside the tank (8 bar). Each and every component in our kit is made under one roof in India, in order to ensure quality. If each component of an LPG kit is outsourced from a different country and put together, there are potential quality and safety concerns,? said Idnani.
A third difference maker is Total?s AutoLPG itself. Total Philippines saw what SKN was doing and became partners with the latter, providing auto LPG that (according to representatives from the French-based gas company) has the lowest flammability range of any natural gas, since the two compounds that compose LPG ? propane and butane/isobutane ? have boiling points well below zero degrees Celsius. That means that even at very low temperatures, it will vaporize as soon as it is released from its pressurized container. This results in a clean-burning fuel that doesn't require a lot of equipment to vaporize it and mix it with air. In short, there?s no risk of fire.
In order to discern if LPG is a great fit for vehicles with more than four cylinders, Total and SKN gave this writer the opportunity to test drive the latter?s LPG-powered 2000 Ford Expedition Eddie Bauer for a week, using both Total unleaded gasoline and LPG. There were huge gaps in terms of power between gas and LPG use (see test results*), but the fuel costs between the two fuels are obvious. ?It?s not as powerful as gasoline. We?re talking about fuel delivery, vapor vs. liquid. But when you?re running at a maximum of 130-140 kph, you have enough torque and power to get you from point A to point B and save on fuel costs,? said Idnani.
Vehicle: Total/SKN 2000 Ford Expedition Eddie Bauer
0-60 kph (gas): 7.93 seconds
0-60 kph (LPG): 16.97 seconds
Top speed (gas): 150 kph
Top speed (LPG): 111 kph
City driving (gas): 5.15 km/liter
City driving (LPG): 5.5 km/liter
Highway driving (gas): 6.2 km per liter
Highway driving (LPG): 5.7 km per liter
Full tank* (gas): 100 liters, P4,000.00 total
Full tank* (LPG): 48 liters, P777.00 total
*liters at peso equivalent
The other solution ? and it applies for four cylinder and V6 setups at the moment ? is closed loop LPG technology. In the aforementioned open loop systems, vaporizer diaphragms and the restrictor valve bed in over time, thus tuning deviates (and becomes frequent), with significant drops in power and economy. The closed loop system does away with the restrictor valve, and uses an electronic controller that operates in much the same way as in petrol fuel injection systems. It utilizes an oxygen sensor to effectively measure the air-fuel mixture by measuring the oxygen content of the exhaust and control valve on the converter or in the vapor line to adjust the mixture. The result is very little drop-off in power and fuel efficiency.
Offered (by the time this story is posted) by South Korea-based EROOM, the closed loop LPG system has been retrofitted in 51,200 vehicles (and counting) in Korea. ?This was borne out of an obligation to overcome the worldwide pollution issue, which is becoming worse with each passing day. We feel that we have a commitment to improve mankind?s future by contributing to the creation of a global village where people can live in a clean environment,? said Wonsoo Do, EROOM Philippines, Inc. (Philippine representative of EROOM Co. Ltd. of Korea) president.
Recently a select number of motoring media were given the chance to experience closed loop LPG technology with EROOM Scribes were made to test ? from Mandaluyong to Tagaytay and back ? several vehicles equipped with EROOM closed loop Auto LPG. Among them were a third generation (1999-2003) Nissan Cefiro 2.0L V6, an eighth generation (1998-2002) Toyota Corolla 1.6L, a 1999 Honda City 1.5L m/t and a 2001 Honda Civic 1.6L a/t. This writer had the ?01 Civic as his stablemate for the rest of the day, and the performance was good as advertised. The Civic displayed little drop off in power and torque (particularly on acceleration from rest), but tended to hesitate when letting off the gas and jumping on the right pedal again. It also tended to take its sweet time bordering on 1900-2000 rpm when traveling on steep 35-degree inclines.
Then again, most LPG-retrofitted vehicles rarely traverse mountain passes and inclines. Reports from those who got behind the wheel of the Cefiro ? such as Business Mirror motoring editor Popong Andolong, Manila Bulletin motoring assistant editor Anjo Perez and ManilaStandardToday motoring reporter Dino Directo ? were roughly the same as what this writer experienced with the Civic. Installation of the kit may be a bit costlier (EROOM claims that their Cefiro LPG kit is P5000-P9000 more than current open loop V6 setups), but for those who crave quicker engine response from their auto LPG system, the additional investment is worth the risk.
The auto LPG systems available in the country give motorists options in contributing to a cleaner earth, and keeps them in the (figurative) loop.