Con­ven­tional Com­bus­tion Engines:

Inter­nal com­bus­tion engines use fuel and air to com­bust, gen­er­at­ing the force that moves each pis­ton in its cylin­der, thus pow­er­ing the vehi­cle. Since Otto invented the mod­ern four-stroke cycle engine in 1876, liq­uid fuels, namely petrol and diesel, have become the pre­ferred fuels, due to their phys­i­cal prop­er­ties of high energy con­tent, ease of stor­age and han­dling. Rel­a­tively, only a small quan­tity of fuel is required and stored onboard to give the vehi­cle an accept­able range.

In con­ven­tional petrol engines the liq­uid fuel is pre­mixed with air in the car­bu­ret­tor, while in diesel and fuel-injection engines, the fuel is injected into the com­bus­tion cham­ber by injec­tors. Pres­sure fed via a fuel pump, the fuel is ‘atom­ised’ or turned into a fine spray through an injec­tion nozzle.

Air flow into and out of the cylin­der is con­trolled by valves. The atom­ised liq­uid fuel changes to a gaseous state known as ’ vapor­i­sa­tion ’ and its mol­e­cules attach to the air oxy­gen mol­e­cules, ‘volatil­i­sa­tion ’ . Liq­uid fuels can­not burn until they are volatilised. Dur­ing the com­pres­sion stroke the valves close and the con­tain­ment of the cylin­der is com­pressed. Due to the den­sity and com­po­si­tion of petrol or diesel, the com­pres­sion causes a quan­tity of the vapor­ised and volatilised fuel to return into an un-combustible liq­uid state.

In a petrol engine, igni­tion of the air / fuel mix­ture is accom­plished by a spark plug. In the diesel, com­bus­tion takes place auto­mat­i­cally as soon as the fuel is injected. The volatilised fuel ignites and the force of the explo­sion dri­ves the piston.

This first explo­sion pow­ers the vehi­cle. The release of heat from this first explo­sion vapor­ises and volatilises addi­tional liq­uid fuel and re-ignites due to the auto-ignition tem­per­a­tures, result­ing in waves of com­bus­tion. The com­bus­tion wave explo­sions gen­er­ate suf­fi­cient heat to release NOx emis­sions from the dis­so­ci­ated atmos­pheric nitro­gen. The ambi­ent air is typ­i­cally com­posed of 20% oxy­gen, required for com­bus­tion, 78% nitro­gen and 2% of N2 compounds.

The remain­ing un-burnt fuel hydro­car­bons that are not burnt-up are released to the atmos­phere as unde­sir­able emis­sions. The emis­sions of hydro­car­bons and NOx have caused severe dam­age to our envi­ron­ment, ozone layer and the health and wel­fare of humans, plants, and ani­mals. The engine effi­ciency of petrol engines range from 25% to 30% and some diesels can achieve effi­cien­cies up to 42%. This means that only a small per­cent­age of the energy in the fuel is con­verted to mechan­i­cal power. The remain­der is wasted into the atmos­phere or as heat into the vehicle’s cool­ing system.

How the ECO-GAS Tech­nol­ogy Works

LPG vapour fuel is injected into the engine’s intake man­i­fold, homo­ge­neously mix­ing to the engine’s intake of atmos­pheric air. The liq­uid diesel fuel is injected into the cylin­ders as before. Under the com­pres­sion cycle, the air mixed with the LPG fuel heats to hot­ter tem­per­a­tures due to the alter­nate fuel’s higher ‘heat of vapor­iza­tion’. The increased tem­per­a­tures dur­ing the com­pres­sion cause the diesel fuel to stay in a gaseous state and forces more droplets of diesel fuel to vapor­ize and vola­tize. Com­pres­sion of the air / fuel mix­tures never reaches auto-ignition, so pre-ignition is not a concern.

Igni­tion, as pre­vi­ously, is accom­plished auto­mat­i­cally as diesel fuel is injected into the engine. In addi­tion to the increased vapor­i­sa­tion and pre-combustion tem­per­a­tures, the gaseous fuel, due to its ‘sto­i­cho­me­t­ric flame speed’ of 0.43 of LPG (propane), higher volatil­ity and higher auto-ignition tem­per­a­ture (high octane), causes a quicker and more spon­ta­neous com­bus­tion result­ing in increased power and econ­omy with­out engine modification.

The power increases are due in part to the increase in vol­u­met­ric effi­ciency from the require­ment for less oxy­gen in the air / fuel / alter­nate fuel mix­ture charge and main­tains the engine’s exist­ing sto­i­cho­me­t­ric ratios. Although the gaseous alter­nate fuel should increase the tem­per­a­ture of com­bus­tion of the fuel mix­ture over ded­i­cated liq­uid fuel com­bus­tion, this has not been mea­sur­able and is believed to be negligible.

Since the diesel liq­uid fuel is vir­tu­ally vapor­ised and volatilised pre-combustion, and since com­bus­tion is more rapid and com­plete, there is one explo­sion con­sum­ing the fuel and releas­ing its energy. No ‘com­bus­tion waves’. An audi­ble qui­et­ing of the diesel knock can be ver­i­fied with a stetho­scope. Since there are no addi­tional explo­sions of the com­bus­tion wave, excess heat is not gen­er­ated in after waves of com­bus­tion, reduc­ing the for­ma­tion of NOx and the engine’s cool­ing sys­tem is not strained dis­si­pat­ing the excess heat. Cool­ing sys­tem tem­per­a­tures remain as before, because of ther­mostats, elec­tronic cool­ing fans, etc. Engine oil tem­per­a­tures can decrease by up to 20 degrees Cel­sius with the ECO-GAS sys­tem in oper­a­tion. Exhaust with ‘lower’ hydro­car­bons and NOx emis­sions are released to the atmosphere.

As vir­tu­ally no fuel is present in the exhaust gas, there is no after burn in the exhaust. Exhaust tem­per­a­tures can decrease on vehi­cles fit­ted with the ECO-GAS sys­tem and an increased vapour con­tent of the exhaust is observ­able, a fur­ther indi­ca­tion of more effi­cient combustion.

Addi­tion­ally, the prop­er­ties of the LPG gaseous fuel dis­solves car­bon and tar deposits in the com­bus­tion cham­ber after a period of oper­a­tion. Com­bus­tion cham­ber deposits are respon­si­ble for sig­nif­i­cant increases in emis­sion, heat gen­er­a­tion and inef­fi­cient com­bus­tion. Dual fuel sys­tem oper­a­tion cleans the com­bus­tion cham­ber even in older or high mileage vehi­cles and returns them to a cleaner more effi­cient condition.

Fuel sav­ings are gen­er­ated because the com­bus­tion is more com­plete with less energy being wasted to heat or turned into harm­ful emis­sions. Less liq­uid diesel fuel is required to main­tain the same oper­a­tion lev­els, yet torque is increased, pro­vid­ing more sat­is­fac­tory engine per­for­mance, improved accel­er­a­tion, and greater load haul­ing capa­bil­i­ties. In some man­ual fuel injec­tion engines, a slight adjust­ment can be made to reduce the diesel liq­uid fuel to the engine.

The ECO-GAS — Diesel Boost Emis­sions System:

• The ECO-GAS sys­tem is an add-on fuel sav­ing sys­tem which increases econ­omy and low­ers exhaust emis­sions. The sys­tem injects a small mea­sured quan­tity of LPG fuel simul­ta­ne­ously with the exist­ing use of the diesel fuel. The ECO-GAS sys­tem is defined as ‘DUAL FUEL’, a sys­tem that con­verts a vehi­cle to run on two fuels at the same time.
• Equip­ping a vehi­cle with a ECO-GAS sys­tem involves no mod­i­fi­ca­tions to the engine or to any part of the fuel or emis­sion con­trol sys­tems, as the ECO-GAS sys­tem is fully automatic.

The ECO-GAS sys­tem com­prises the fol­low­ing components:

• A reser­voir / tank to store the LPG fuel onboard the vehi­cle. Since only a small amount of fuel is needed, the capac­ity of LPG required to increase the vehi­cle range between refu­el­ing is small, for exam­ple, a typ­i­cal pas­sen­ger car only requires a 15 to 30 lt LPG reser­voir which has lit­tle or no effect on the vehicle’s cargo capac­ity and presents no safety con­cern of addi­tional fuel storage.
• A fill­ing valve to refuel the LPG tank is fit­ted either in the rear bumper wing, tow bar, or under the flap of the orig­i­nal fuel refill­ing point.
• A fuel sup­ply pipe from the reser­voir or tank to a sec­ond elec­tri­cal safety shut­tle valve in the engine bay and to the ECO-GAS con­trol system.
• A small gas sup­ply hose is fit­ted to the engine intake or manifold.
• A small dig­i­tal fuel level dis­play gauge with on / off switch is installed inside the cab.
• The appro­pri­ate ECO-GAS con­troller is installed in the engine com­part­ment. The con­troller unit vapor­izes / treats and con­di­tions the LPG gas vapour fuel for inject­ing into the engine intake. The sys­tem uses the vehicle’s engine cool­ing sys­tem to gen­tly heat the Eco-Gas unit to pre­vent any con­den­sa­tion or freezing.