ISUZU's world - a global brand, a local impact
As one of the world's leading diesel engine and commercial vehicle manufacturers, Isuzu produces more than 1 million diesel engines annually. Isuzu's leading edge diesel technologies have enhanced the environmental benefits of diesel engines, and their integration into a new generation of diesel engines has helped accelerate the growing use of Isuzu diesel engines and commercial vehicles in more than 100 countries around the world.
Today, 75 percent of Isuzu's diesel engines by production volume and 65% by revenue, are sold outside of Japan. Isuzu's engines are highly regarded in markets around the world. Production volumes have been steadily expanding year on year. As of 2007, cumulative production volume of Isuzu diesel engines reached 20 million.
Committed to enhancing the environment, around the world
Isuzu sees the future of itself and the diesel engine in developing the potential of the clean diesel engine as an environment-friendly power source. As a result, Isuzu are heavily committed to environment preservation activities, and the research, development and production of cutting edge, environment-friendly diesel engines incorporating the fruits of our R&D in diesel technologies.
Super clean diesel engines: superior green results
As Isuzu pursue the goal of developing super-clean diesel engines that will dramatically enhance their operational characteristics, Isuzu is a powerful force for change in the new era. Super-clean diesel engines combine the traditional advantages of diesel over other internal combustion engines, with powerful performance and reduced exhaust gases and PM emissions, by integrating combustion optimization, after-treatment technology and comprehensive electronic control. The Isuzu Clean Air Solutions (I-CAS) system optimizes these three key technologies to minimize exhaust emissions, and boost power.
Isuzu leads the world in electronic control technology, having accumulated expertise in this field by developing its own engine control software. Striving to develop electronic control systems and maximize hardware capabilities, Isuzu is pioneering the field of homogenous premix combustion, which relies on precise control of the electronic common rail fuel injection system as a technology base. This is a complex technology that helps to eliminate PM and NOx in diesel emissions.
Uncompromising manufacturing quality
At the same time, uncompromising manufacturing quality has always been a core element of Isuzu's heritage. Isuzu is constantly raising the quality of its workforce and manufacturing system to ensure uniform global quality. The Manufacturing Division follows a strict quality control system and efficient manufacturing practises.
Today's vehicle chassis and engines have so many parts that it is very difficult to identify and fix the defective part or parts after completion. To prevent this from happening, Isuzu ensures that the job performed at each manufacturing step conforms 100% to quality standards, by having specialised line inspectors at key sections.
Trends in diesel engine technology
Beginning in the later half of the 1990s, there has been dramatic progress in the development of new diesel engine technology, producing a new breed of extremely clean and quiet diesel engines that overturns old views of diesel engines as being noisy and smelly. This dramatic progress is the result of three key technologies:
- Combustion optimization technology
- After treatment of exhaust gases
- Electronic control technologies
Of these, electronically-controlled common rail fuel injection, which enables super high-pressure fuel injection at all engine revolutions, is a major factor, contributing to major reductions in emissions as well as noise and vibration.
Improvements in after treatment are necessary to enable diesel engines to comply with the Post New Long-Term Emissions Regulations that will be introduced in Japan in 2009, and the equivalents of these regulations around the world. Isuzu is already DPD (Diesel Particulate Diffuser) technology and is working to develop catalysts for dissolving NOx out of exhausts.
By 2009, diesel engine powered vehicles should be as clean as gasoline engine powered vehicles, and at same time offer superior torque, fuel economy and lower CO2 emissions, setting the stage for diesel engines to replace gasoline engines as the most popular power plant as they are already set to do in Europe.
Reducing emissions with fuel injection technologies
New fuel injection technologies work to simultaneously reduce NOx, which occurs due to complete combustion, as well as PM which occurs due to incomplete combustion. A good example of this technology is the common rail system, which enables multiple fuel injection at higher pressures. Research is currently being carried out to enable even higher-pressure fuel injection, for even more efficient combustion in the engine.
Common rail system
Fuel under high pressure is stored in the common rail and uniformly supplied to each fuel injector. Injecting the fuel under higher pressures enables the engine to have more complete combustion, which reduces the creation of PM. At the same time, the use of multiple fuel injectors helps to prevent excessively high temperatures in the combustion chamber, thereby reducing the creation of NOx. The key to the common rail system is the precise electronic control of the fuel injection pressure, injection timing, the number of injections and the amount of fuel injected.
Air management technologies for controlling the engine intake system
Air management technology is an important component in diesel engines for controlling the intake system. Its goal is to reduce NOx and PM, and improve fuel economy by working with the fuel injection technology. Key examples of this technology include turbochargers and EGR systems, which charge the engine with intake air using the system's exhaust gases.
Turbocharger
It uses the engine's exhaust gas to power a turbine, which in turn charges the cylinders with high-density air which has been compressed. This enables a higher volume of air to be taken into the cylinder and improves combustion efficiency.
Turbocharger with intercooler
This adds a cooling device to rapidly cool intake air which gets heated as it gets compressed by the turbocharger. By charging cylinders with high-density intake air, the system is able to improve the engine's combustion efficiency, as well as the vehicle's fuel economy, while lowering its CO2 emissions.
Variable Geometry Turbocharger System (VGS)
VGS works to precisely and efficiently control the turbocharger system, based on intake air volume conditions, to address one of the weaknesses of turbo systems which is their performance at low engine revolutions when there is very little engine exhaust.
Exhaust Gas Recirculation (EGR)
Essentially mixes exhaust gas with intake air, to lower the concentration of oxygen in the combustion chamber and thereby smooth the combustion process and reduce the formation of NOx.
Cooled EGR
Adds a cooling device to the EGR path, helping to lower the combustion temperature, further reducing the amount of NOx formation and improving fuel economy.
One-way cooled EGR
It incorporates a one-way valve to prevent intake air entering into the cooled EGR path. This ensures air flows in one direction only, and eliminates waste of EGR gases so they are all sent into the combustion chamber.
4-valves per cylinder
The 4-valves per cylinder design of diesel engines, with 2 intake and 2 exhaust valves per cylinder, essentially improves intake and exhaust efficiency of the engine, and also reduces pumping loss in the intake and exhaust cycles. At the same time it enables the fuel injection nozzle to be positioned in the center of the combustion chamber which allows uniform fuel injection and mixing formation, and also reduces PM and soot formation while improving engine output and fuel economy.
4-valves gives improved intake and exhaust efficiency enables the positioning of the combustion chamber in the center of the piston for more ideal combustion configuration.
Variable swirl
Formed when the intake air swirls around the center of the cylinder, in direct injection diesel engines swirl dramatically contributes to the mixture of fuel and air. Variable swirl systems include a mechanism to vary the generation of swirl according to the engine's operating conditions, resulting in decreased emissions and improved fuel economy.
After-treatment technologies
After-treatment technology aims to remove emissions from the air that the engine itself can't take out, by cleaning PM and NOx out of the exhaust emission immediately before exhaust is emitted from the vehicle. More specifically, DPD (Diesel Particulate Diffusers) is an after-treatment technology to clean and revive a ceramic filter by burning PM caught in the filter using Isuzu's own exhaust gas temperature control system, which precisely controls fuel injection of the electronically-controlled common rail system and exhaust throttle. Other technologies aim to reduce PM and NOx by using a chemical transformation activated by catalysts.
Oxidizing Catalysts
Oxidizing catalysts use precious metals like Platinum and Palladium as catalysts which take advantage of the oxygen present in the exhaust gases to oxidize unburnt matter, especially hydrocarbons that are present in PM, changing it into water and CO2.
DPD (Diesel Particulate Diffuser)
The DPD or PM Catalytic Converter is an after-treatment technology to clean and revive a ceramic filter by burning PM caught in the filter. It is applied in relation to the individual engine characteristics, to thoroughly remove environmental impact substances.
NOx absorption/reduction catalysts
Technology that aims to reduce NOx to harmless water and nitrogen by using catalysts. This type of catalysts is more prone to combine with sulphur than with NOx, which shortens the lifetime of the catalysts.
Urea-Selective Catalytic Reduction (SCR)
These systems act to suppress NOx generation using the same principles as ammonia-based nitrogen generation systems used in large power plants. This process is extremely effective at reducing NOx and has no harmful effect on fuel economy, and so has great future prospects.
Increasing environment-friendly fuels
An important new environment-friendly fuel is low-sulphur diesel. By way of example, diesel fuel sold in Japan is made from the crude oil of the Middle East and had high concentrations of sulphur, but since legislation was introduces in the early 1990s to reduce this, the concentration of sulphur has been reduced to 1/100 of original levels to the 50ppm limit mandated by law, and in some cases is actually as low as 10ppm. Low-sulphur diesel improves oxidation catalyst performance, lengthens the lifetime of catalysts, and is also an effective way of reducing PM.
Another possibility with diesel engines is that they can use a variety of fuels compared to gasoline engines. When Rudolf Diesel, the engine's inventor, demonstrated his engine at the Paris Exposition, it was running on peanut oil. Currently there is a lot of ongoing research into the mix of fuel that incorporate bio-diesel, due to the high price of crude oil and the need to further lower CO2 emissions, and these technologies are currently in use in Germany and France.
Blended bio-diesel fuels
Although there is no current chemical definition for blended bio-diesel fuels, generally they refer to the process of treating animal and vegetable oils and mixing them with diesel for use in diesel powered vehicles. Because animal and vegetable oils have a high viscosity and can't be used as fuels as is, they are treated with methyl ester to convert them into a substance that is closer in composition to diesel.