Economax

The Economax Engine Cooling System represents a major step forward in engine cooling technology. To fully appreciate the radical improvements facilitated by Economax, it is useful to review current cooling technology.

Over the last 100 years engine design and efficiency has improved significantly. In stark contrast engine coolants have remained mostly unchanged since the 1930’s and are still based on a mixture of Ethylene Glycol (EG), water and corrosion inhibitors. All such mixtures have inherent physical and chemical limitations that restrict engine performance and effect reliability.

Physical limitations of water based coolants Within an engine cooling system the hottest surfaces are those adjacent to the combustion chamber, specifically the cylinder liners and cylinder head. Evans have proven that in these areas EG-Water mixtures regularly cross the thermal boundary that separates efficient Nucleate Boiling (B in Fig.1) from inefficient Critical Heat Flux.

CHF is synonymous with the condition ‘Departure from Nucleate Boiling’ or DNB. When DNB occurs in an engine cooling system a layer of steam bubbles form adjacent to the engine hot-spots (A in Fig.1). Because steam dissipates less than 1/30th of the heat that water does, local metal temperatures over-heat rapidly.

This over-heating leads to several problems including; thermal distortion of the cylinder head and liners, pre-ignition (aka engine knock), liner pitting, boil-over and after-boil. Over-heating is the most common cause of engine down-time and responsible for >50% of catastrophic engine failures.

Chemical limitations of water based coolants Although water is cheap and readily available, it is also the root cause of corrosion within engine cooling systems (see Fig.2). Hence the necessity to add corrosion inhibitors. Corrosion inhibitor formulations have changed many times over the years, but not always for the better.

Nitrite, silicate, borate and azole based products have been around for many years, with Organic Acid Technology (OAT) inhibitors appearing more recently. OAT formulations are often branded as ‘Long-Life’ based on their five year life-span, compared with 1-2 years for standard antifreeze formulations.

Although OAT-EG-Water mixtures are now used in most new car engines, they have proven less successful in Heavy Duty Diesel Engine (HDDE) cooling systems. After several years of trying OAT based products many OEMs and fleet operators reverted to nitrite and/or Hybrid OAT (HOAT) formulations. One reason for this u-turn was that OAT formulations offer little protection against liner pitting - a major problem in HDDE.

To maintain effective inhibitor levels it is often necessary to retro-dose with Supplemental Coolant Additives or SCAs. It is common for SCA’s to be under or over dosed leading to accelerated corrosion rates, cylinder liner pitting or blocking up of radiator channels with congealed inhibitor. 

 Physical limitations of water based coolants                            Chemical limitations of water based coolants 

                  

 

Reduces fuel consumption by up to 9%

The Economax Engine Cooling System is proven to reduce fuel consumption by up to 9%. For HGVs covering considerable motorway mileage, fuel savings of 4 to 8% can be expected. Engines used in slow moving and semi-static environments, where ram air cooling is negligible, can achieve fuel savings in excess of 9%. Detailed corroborative data is available on request.

 

Development of 4LIFE Waterless Coolants and the Economax Engine Cooling System

Jack Evans, founder of Evans Cooling Systems and Tom Light, Evans Chief Engineer, have spent a lifetime designing high performance cooling systems for internal combustion engines. Both are well known and highly respected throughout the Nascar racing fraternity and responsible for many unique cooling innovations. Ferrari and General Motors are just two notable OEM’s that have benefited from Evans experience and design skills.

Stage 1

During their research Jack and Tom identified that, although it was possible to tune an engine to achieve maximum output, a limiting factor was removing the extra heat generated by burning more fuel. Specifically the physical limits of water based coolants were being exceeded – please refer to ‘Physical limitation of water based coolants’ overleaf.

Stage 2

Over an extended period the Evans 4LIFE Waterless Coolant was formulated, tested and perfected. With a boiling point above 180°C efficient heat transfer was restored and all the issues associated to over-heating eliminated - even at maximum engine output. To compliment their high boiling point Evans 4LIFE Waterless Coolants have been proven to last for an engine lifetime.

Stage 3

Having formulated an engine coolant that eliminated Departure from Nucleate Boiling (see fig.1 overleaf), Evans examined the benefits of raising coolant temperatures above the conventional 95°C. Further research established that higher coolant temperatures actually improved engine efficiency, lowered fuel consumption and reduced thermal stress. After thorough investigation and verification of lube oil capabilities a new maximum coolant temperature of 110°C was confirmed.

Stage 4

To accommodate the benefits identified in Stage 3 it was necessary to design a Hi-Flo Thermostat that would open at 102°C and a Fan-Miser Module to raise the fan on-off temperatures to 110-104°C. This compares with 85°C and 95-89°C respectively for water based cooling systems. The final Economax ECS comprises; 4LIFE Waterless Coolant, Hi-Flo Thermostat and Fan-Miser Module.

Stage 5

Following many successful Nascar trials an Economax ECS was fitted to a 12.7 litre Series 60 Detroit Diesel truck engine, operated by Joe Umstead on sub-contract to North American Van Lines. Since conversion Joe’s truck has covered over a million miles without a hitch.

Stage 6

More recently Evans have been fitting Economax ECS to fleet vehicles, large and small. In addition to fuel savings of 4-7% all operators have reported improved engine reliability and reduced maintenance demands. Trials are currently being run within several very large fleets and two significant OEM’s. One OEM is considering a joint venture with Evans to retrofit all their existing engines and fit Economax ECS to all new engines.

Stage 7

Appointment of USA based distributors and conversion centres to supply and fit Economax ECS. There are now more than 75 stockists and 6 conversion centres, with more opening all the time.

Stage 8

Introduction of the Economax ECS to China, UK, Europe etc. Since being established in 2003 Evans China has converted more than 200,000 engines and recently commissioned a new factory to cope with increasing demand. Evans UK operates from a purpose built facility in Swansea and has a network of installers distributed throughout Britain and Ireland. Sales to Europe will be co-ordinated by Evans UK.