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4-stroke cycles compressed to single crankshaft revolution (Atkinson cycle) Fully valve controlled gas exchange Diesel or Otto engine Turbo charger and.

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Presentation on theme: "4-stroke cycles compressed to single crankshaft revolution (Atkinson cycle) Fully valve controlled gas exchange Diesel or Otto engine Turbo charger and."— Presentation transcript:

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2 4-stroke cycles compressed to single crankshaft revolution (Atkinson cycle) Fully valve controlled gas exchange Diesel or Otto engine Turbo charger and supercharger (piston compressor) 2-cylinder Z engine provides equal power output to a 4-cylinder 4-stroke engine HCCI combustion Internal EGR Easily balanced mass forces Good torque characteristics Ignition controlled by multiple variables High downsizing degree Excellent transient behaviour Driving fun

3 What is Z engine? 4/2-stroke, 2-cylinder engine Revolutionary working principle combines the best aspects of 2- and 4- stroke engines Part of the compression cycle is made outside of the working cylinder, so all of the cycles of 4-stroke engine can be done in a single crankshaft revolution Compact size Light weight Small emissions Low manufacturing costs

4 Exhaust cycle Exhaust valves opens 60° BBCD and closes 120° ABCD  2 x 180° = 360° pulses for the turbo charger Exhaust gases hot enough for 3-way catalyst

5 Injection Fuel injected during 110° - 120° ABDC, when the exhaust valves are closing Long mixing time before the ignition, 60° – 70° Injection pressure 200 – 700 bar, duration 5° – 12° Hollow cone spray Small spray penetration Small droplets Fuel injected to hot exhaust gas  Partial fuel reforming High temperature and low pressure during injection  Rapid fuel evaporation Gas temperature an pressure during the start of the injection: 700 – 800 K, 1,5 – 2,5 bar Temperature drop of the gas in the cylinder during injection: 200 – 400 K Heat for fuel evaporation from exhaust gas

6 The temperature and pressure curves between 80° - 40° BTDC

7 Intake cycle (scavenging) Intake valves opens 60° BTDC and closes 45° BTDC Intake pressure 4 – 15 bar  Velocity of intake gas: 300 – 500 m/s Intern EGR 15 – 45%, acts as an intern heat exchanger Hot, active radicals in EGR can be used to assist ignition No overlapping of intake and exhaust valves  No losses of intake gas Fuel evaporation cools the mixture: more air to the cylinder Electric heater in the intake channel for start

8 The theorethical valve flow

9 Final Compression Mechanical compression ratio: 14 – 15:1 Primary compression is made in piston compressor, secondary in work cylinder: 3-5:1 Short compression time  Low amount of heat transfer Fuel evaporation before final compression and high intercooling rate  Low compression temperature, more air in to the cylinder Compression temperatures at TDC: 800 K at part load, 700 K at full load  The compression temperature descend when load increases Lower gas temperature  Lower compression pressure, higher bmep

10 Ignition delay curve of HCCI mixture

11 PV diagram of the Z engine

12 Combustion and work cycle SAHCCI (Spark Assisted Homogenous Charge Combustio Ignition) Controlled By: Temperature at TDC, lambda, injection amount and timing, intercooling rate, valve timing Pressure and temperature at TDC controlled by adjusting intake air pressure and temperature Low temperature at TDC: no self ignition Start of combustion: 5-15° ATDC Short combustion duration: high efficiency Lambda : low Tmax, low NOx Active radicals assist the ignition Active radicals lower CO and HC No knock, as ignition at the right side of NTC area

13 Manufacturing costs compared to 4-cylinder turbodiesel engine equipped with Common Rail + DeNOx-catalyst + particulate filter = 2800 € 2 working cylinders less = € Compressor needed = € Low injection pressure, 2 low cost nozzles = € No DeNOx catalyst = € No particulate filter = € Together = € lower production costs per engine!

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