Automotive electronics, Slides of Automatic Controls

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AUTOMOTIVE ELECTRONICS

COURSE CODE: BEC714C

COURSE OBJECTIVES

This course will enable students to :

1. Understand the basics of Automobile Dynamics and

Design Electronics to complement those features.

2. Design and implement the Electronics that attribute

the reliability, safety, and smartness to the

Automobiles, providing add-on comforts.

EVOLUTION OF AUTOMOTIVE ELECTRONICS

• (^) Electronics have been relatively slow in coming to the

automobile because of the relationship between the

added cost and the benefits.

• (^) The first electronics (other than radio) were

introduced into the commercial automobile during the

late 1950s and early 1960s.

• (^) These features were not well received by customers,

so they were discontinued from production

automobiles.

• (^) Two major events occurred during the 1970s that

started the trend toward the use of modern electronics

in the automobile:

1. the introduction of government regulations for

exhaust emissions and fuel economy, which required

better control of the engine than was possible with

the methods being used; and

2. the development of relatively low cost per function

solid-state digital electronics that could be used for

engine control.

THE AUTOMOBILE PHYSICAL CONFIGURATION

 (^) The early configuration is depicted in Figure 1.1, in which many of the important automotive systems are illustrated. These systems include the following:

1. Engine
2. Drivetrain (transmission, differential, axle)
3. Suspension
4. Steering
5. Brakes
6. Instrumentation
7. Electrical/electronic
8. Motion control
9. Comfort/convenience
10. Entertainment/communication/navigation

Systems of the Automobile

Cutaway View of a 6- Cylinder, Overhead- Valve, Inline Engine

The major components of the engine include the following:

1. Engine block
2. Cylinder
3. Crankshaft
4. Pistons
5. Connecting rods
6. Camshaft
7. Cylinder head
8. Valves
9. Fuel control system
10. Ignition system
11. Exhaust system
12. Cooling system

Engine Block

• (^) Mechanical power produced in the engine by the

combustion (Burning) of fuel inside the cylinder in

the engine block and a mechanism consisting of

piston and connecting rod coupled to the crankshaft.

• (^) The piston is connected to the crankshaft by

connecting rod as shown in fig.

• (^) Crankshaft and connecting rod mechanism converts

up and down motion of piston into rotary motion and

the torque needed to drive the wheels

Piston, connecting rod and crankshaft mechanism

Valve Operating Mechanism

 (^) The valves are operated by off-center (eccentric) cams on the camshaft, which is driven by the crankshaft  (^) The camshaft rotates at exactly half the crankshaft speed because a complete cycle of any cylinder involves two complete crankshaft rotations and only one sequence of opening and closing of the associated intake and exhaust valves.  (^) The valves are normally held closed by powerful springs.  (^) When the time comes for a valve to open, the lobe on the cam forces the pushrod upward against one end of the rocker arm.  (^) The other end of the rocker arm moves downward and forces the valve open.

strokes for a 4-stroke/cycle SI engine, which are called:

1. Intake
2. Compression
3. Power
4. Exhaust

INTAKE

• (^) During the intake stroke (Figure 1.5a), the piston is moving from top to bottom and the intake valve is open. As the piston moves down,
• (^) a partial vacuum is created, which draws a mixture of air and vaporized gasoline through the intake valve into the cylinder.
• (^) In modern, electronically controlled engines, fuel is injected into the intake port and is timed to coincide with the intake stroke.
• (^) The intake valve is closed after the piston reaches the bottom. This position is normally called Bottom Dead Center (BDC).