Seminar Report Presented by

VISHNU. T

Dept of Mechanical Engineering

Govt Polytechnic College, Palakkad

MULTI AIR ENGINE TECHNOLOGYMULTI AIR ENGINE TECHNOLOGY

ABSTRACTABSTRACT

Downsizing and turbo charging in combination with UNIAIR electronic valve control and gasoline direct injection are now commonly regarded as key technologies for SI engines to cope with the challenges of fuel economy enhancement and driveability improvement.

The Multiair technology is an innovative system for intake valves electronic control which, by regulating the intake air at every combustion cycle, allows both a substantial consumption reduction and a remarkable improvement in the engine readiness and fun-to-drive.

IntroductionIntroduction• Multiair is a fundamental breakthrough in

petrol engine design that will dramatically cut fuel consumption, as well as significantly boosting power and torque, cutting carbon dioxide emissions by between 10 and 25 percent, and up to a 60 percent reduction in other engine pollutants.

• This higher output will allow Fiat to replace larger engines with smaller, more efficient ones, and the company's 1.0 liter and 1.4 liter engines will be the first to get the new technology, along with a new 900cc twin cylinder engine.

MULTI AIR TECHNOLOGY EXPLAINEDMULTI AIR TECHNOLOGY EXPLAINED

MULTI AIR TECHNOLOGY EXPLAINEDMULTI AIR TECHNOLOGY EXPLAINEDThe beauty of Fiat’s “Multiair” system is its

simplicity; it essentially achieves what Valvetronic does by using hydraulic fluid running through narrow passages connecting the intake valves and the camshaft so the two can be decoupled.

This system is modulated by an electronically controlled solenoid, and there are effectively two modes:

When the solenoid is closed, the incompressible hydraulic fluid transmits the intake-cam lobe’s motion to the valve, as in a traditional engine.

When the solenoid is open, the oil bypasses the passage, decoupling the valve, which then closes conventionally via spring pressure.

MULTI AIR TECHNOLOGY EXPLAINEDMULTI AIR TECHNOLOGY EXPLAINEDFor example, to shut the valves early, as

in a part-load situation, the solenoid would be closed initially and then open partway through the intake cycle.

The tricky business is correctly timing the switching of the solenoid, and Fiat has painstakingly optimized the responsiveness of the electronic controls.

Aside from the fuel-economy and emissions benefits, Fiat claims Multiair can also enable a 10-percent horsepower boost.

MULTI AIR TECHNOLOGY EXPLAINEDMULTI AIR TECHNOLOGY EXPLAINED

MULTI AIR TECHNOLOGY EXPLAINEDMULTI AIR TECHNOLOGY EXPLAINED

MULTI AIR TECHNOLOGY EXPLAINEDMULTI AIR TECHNOLOGY EXPLAINED

MULTI AIR TECHNOLOGY EXPLAINEDMULTI AIR TECHNOLOGY EXPLAINED

Multiair technologyMultiair technology

Figure 1 - Operating principle of the system, applied to intake valves

Multiair technologyMultiair technology

Figure 2 – Different actuation modes

FeaturesFeaturesThe application of the Multiair technology offers the potential to improve almost all the critical areas of SI engines:Throttleless load control reduced fuel consumptionOptimal charge trapping efficiency increased performanceFast and direct valve control improved dynamic response and fun to driveAdvanced combustion control reduced fuel consumption and emissionsPerformance and driveability increase potential is significant, thanks to:Torque and power increase, due to optimal volumetric efficiency over the whole engine speed range, increasing both torque and power valuesImproved fun to drive due to the faster response to driver pedal request during acceleration

BenefitsBenefits

BenefitsBenefits

• Maximum power is increased by up to 10 per cent thanks to the adoption of a power-orientated mechanical camshaft profile.

• Low RPM torque is improved by up to 15 per cent through early intake valve closing strategies that maximise the air mass trapped in the cylinders.

• Elimination of pumping losses brings a 10 per cent reduction in fuel consumption and CO2 emissions, both in naturally aspirated and turbocharged engines with the same displacement.

• MultiAir turbocharged and downsized engines can achieve up to 25 per cent fuel economy improvement over conventional naturally aspirated engines with the same level of performance.

BenefitsBenefits• Optimum valve control strategies during engine warm-up

and internal exhaust gas recirculation, realised by reopening the intake valves during the exhaust stroke, result in emissions reductions ranging from 40 per cent for unburnt hydrocarbons and carbon monoxide (HC/CO), and up to a 60 per cent cut in oxides of nitrogen, (NOx).

• Constant upstream air pressure, atmospheric for naturally aspirated and higher for turbocharged engines, together with extremely fast air mass control, cylinder-by-cylinder and stroke-by-stroke, result in a superior dynamic engine response, and enhanced driving pleasure.

• MultiAir is applicable to all internal combustion engines, regardless of the fuel used.

• It can be adapted for diesel engines to reduce their NOx emissions and make particulate filters significantly more effective.

SummarySummary

• The beauty of “Multiair” system is its simplicity; it essentially achieves what Valvetronic does by using hydraulic fluid running through narrow passages connecting the intake valves and the camshaft so the two can be decoupled.

This system is modulated by an electronically controlled solenoid, and there are effectively two modes:

• When the solenoid is closed, the incompressible hydraulic fluid transmits the intake-cam lobe’s motion to the valve, as in a traditional engine.

• When the solenoid is open, the oil bypasses the passage, decoupling the valve, which then closes conventionally via spring pressure.

SummarySummary

• For example, to shut the valves early, as in a part-load situation, the solenoid would be closed initially and then open partway through the intake cycle.

• The tricky business is correctly timing the switching of the solenoid, and Fiat has painstakingly optimized the responsiveness of the electronic controls.

• Aside from the fuel-economy and emissions benefits, it is claimed that Multiair can also enable a 10-percent horsepower boost.

SummarySummary

• Components of 4WD vehicles can be serviced in basically the same manner as the same components on a 2WD vehicle.

• Some AWD vehicles have a third differential, called an interaxle differential, instead of a transfer case.