Six Stroke Engine

Approaches of six stroke engine, working of 5 stroke engine, limitation of 4 stroke engine, advantages & limitations of 6 stroke engine.

1. Name: Stream: Semester: Roll No.: Md. Hamza Zakaria Mechanical Engineering 5 th Semester 60 Topic : Six Stroke Engine

2. Introduction To improve Efficiency, Reduce Emission, Brake thermal efficiency, Dramatic Reduction in pollution and Better Scavenging Six Stroke Engine have 2 power stroke - one by fuel, one by steam/air Few notable six stroke engine Design in this class are: The Velozeta six stroke engine Built by the College of Engineering at Trivendrum in India . The Crower stroke engine, invented by bruce Crower of the U.S.A. The Bajulaz engine by the Bajulaz S A Company of Switzerland.

3. Disadvantage of four stroke engine There are many losses in the internal combustion engine as below: Time loss(6%) Heat loss(12%) Blow Down loss(2%) High Fuel Consumption

4. APPROACHES IN SIX STROKE ENGINE The engine captures the waste heat from the 4 stroke Otto cycle/Diesel cycle & uses it to get additional power & exhaust stroke of the piston in the same cylinder. Designs either use steam/air as the working fluid for the additional power stroke. The additional stroke cools the engine & removes the need for a cooling system making the engine lighter & giving 40% increased efficiency over the normal Otto or Diesel Cycle. These six stroke engines have 2 power strokes: one by fuel, one by steam/air. The six stroke engine uses a 2 nd opposed piston in each cylinder which moves at half the cyclical rate of the main piston, thus giving six piston movements per cycle. Functionally, the second piston replaces the valve mechanism of a conventional engine and also it increases the compression ratio.

5. Working of six stroke engine Different working strokes of Six-Stroke Engine are as follows: S uction Stroke Compression Stroke Combustion Stroke (1 st Power Stroke) Re-Compression Stoke(1 st Exhaust Stroke) Water/Air Injection (2 nd Power Stroke) 2 nd Exhaust Stroke

6. MODIFICATION IN SIX STROKE ENGINE Crankshaft to Camshaft Ratio Modification 4-stroke engine, gear at crankshaft rotate 720 ◦ for 360 ◦ Camshaft to complete a cycle 6- stroke engine , gear at the Crankshaft must rotate 1080 ◦ to rotate camshaft 360 ◦ & complete cycle Their gear ratio is 3:1. Camshaft Modification 6-stroke engine 360 ◦ of cam is divided into 60 ◦ . Exhaust cam has 2 lobes for to 2 exhaust stroke (4 th stroke & 6 th stroke to push out steam). Cam follower modification B ottom shape of regular follower has flat pattern, which is suitable with normal camshaft for 4-stroke engine When reducing duration of valve opening from 9000 to only 6000 shape of follower must be changed from flat to roller/spherical shape.

7. Advantages of the six stroke engine Thermal efficiency reaching 50% (30% for the actual Internal combustion engine ). Fuel consumption reduced by more than 40 %. Reduction of chemical, noise and thermal pollution up to 65%. Two expansion (work) through six stroke. Direct Injection and optimal fuel combustion at every engine speed. We would get the better scavenging in fifth stroke Lower engine temperature - easy to maintain the optimum engine temperature level for better performance

8. Disadvantages of six stroke engine High Initial cost Due to change in gear structure. High Manufacturing cost in six stroke engine. Engine size Increases Due to additional stroke in engine, fifth stroke and sixth stroke . Complex head design. Complex cam design for exhaust (due to 2 exhaust strokes ). Thermodynamically the engine is stable, yet the designing of parts becomes more and more complex as the torque requirement increases