Performance indicatorsEngine Performance

Main objectives

Order of objectives

Intake

Timing

Compression

Exhaust

Engine assumptions

Task 1 – Single cylinder model

Task 2 – 2 litre naturally aspirated gasoline engine model

Engine

Balance

Firing order

Intake

Exhaust

Ignition timing

Cam duration, lift and phasing

Exhaust Valve Opening Timing modification – EVO

Exhaust Valve Closing Timing modification – EVC

Intake Valve Opening Timing modification – IVO

Intake Valve Closing Timing modification – IVC

Valve Overlap

Results

Task 3 – 1.4 litre turbocharged gasoline engine model.

Turbocharger characterization

Results

Task 4 – Comparison of powertrain alternatives on a hillclimb course.

Calculation flow

Assumptions

Input parameters and order

Resistant force

Torque and gears

Electric Drive

Perfect Drive

Comparison

Bibliography

Webgraphy

Electronic Documents

Data Sheets

Figure 1: Performance figures single piston

Figure 2: Naturally aspirated inline 4 model

Figure 3:Valve-timing diagrams (a) medium-performance engine, (b) high-performance engine

Figure 4: Naturally aspirated engine results

Figure 5: Turbocharged 1400 cc engine model

Figure 6: Fuel injected per cylinder

Figure 7: Turbo characterization

Figure 8: Intercooler / Turbo with pressure and temperatures diagram

Figure 9: Turbocharged engine results

Figure 10: Turbocharged engine BMEP

Figure 11: Hillclimb calculation flow

Figure 12: Resistant Curve calculation

Figure 13: Input of vehicle parameters and gear ratios

Figure 14: Gear ratio to polynomial curve and acceleration calculation

Figure 15: Perfect drive configurations

Figure 16: Hillclimb performance comparison

Figure 17: (Speed – Distance – Time) Hillclimb comparison

Table 1: Single piston engine configuration

Table 2: N/A Intake dimensions

Table 3: N/A Exhaust dimensions

Table 4: 2000 cc engine benchmarking

Table 5: Turbocharged cylinder configuration

Table 6: Turbocharged Intake dimensions

Table 7: Turbocharged Exhaust dimensions

Table 8: 1400 cc turbo engine benchmarking

Table 9: Battery energy caclulation

Table 10: Battery characteristics

Table 11: Perfect drive (gearbox vs direct drive)

Engine Performance

Performance evaluation of automotive engines is of great importance for their economic operation. The method or criteria for assessing the engine performance include the determination of engine power and torque, considering the engine stroke, engine speed, mean effective pressure and bore- all of these affect the horsepower, and its performance, and if possible, with efficiency, which means obtaining the greatest possible power with lowest possible fuel consumption.

Performance indicators

Common engine performance indicators include:

• Power (kW): The measure of how much torque can be done in a specified time.

• Torque (Nm): Engine’s rotational force, correlates with vehicle driveability

• Mean effective pressure (bar): permits the comparison of torque output per unit displacement

• Brake specific fuel consumption (g/kWhr): The mass of fuel in grams consumed per kWhr of power produced at a particular engine speed and load. The lower the fuel consumption, the less fuel has to be carried at any given point in a competition.
• Operating compression pressure.
• Ignition timing.
• Valves timing.
• Fuel mixture adjustment.
• Mechanical conditions.
  • Pistons’ rings and cylinders condition.
  • Bearings properly maintained.
  • Lubrication.

Main objectives

The objectives of this study are:

• Study engine size by configuration of bore, stroke, displacement and compression ratio.
• Measurement of power and torque along the engine speed range.
• Method of air induction.
• Evaluating the efficiency based on mechanical efficiency and thermal efficiency, considering the energy supplied to the engine and the energy delivered by the engine.
• Measurement of fuel consumption.

Order of objectives

Intake

As the air flows into the engine and it is mixed with fuel and burned to make power. Fewer restrictions will allow an engine to make more power. Restrictions slow the air down before it reaches the engine, and reduce the amount of air at any given point in time.

Timing

The mechanism that manages intake of air and the release of exhaust. By using different valve timing at different RPM, the engine can work better in a variety of different conditions.  Modifications that increase performance by tuning the way the engine performs in different conditions. Systems like VTEC system (Variable Timing Electronic Control) change the timing of the valves according to the speed engine in order to provide optimum valve performance to increase final power.

Compression

The compression ratio of the engine refers to how much the pistons compress the air that comes into the cylinders. High performance cars tend to have higher compression ratios. This allows the car to produce more power, but the downside of this is that cars with higher compression ratios usually require higher-octane fuel

Exhaust

The final step. Like the intake, reducing restriction in the exhaust almost always results in more power. High performance vehicles optimize the exhaust flow to have as little backpressure as possible. This allows the engine to expel the waste fumes as quickly as possible so it can burn more fuel faster.

Engine assumptions

Effective blow by gap: For each engine, a value of 0.001 mm has been chosen for each cylinder so a some pressure is lost at the combustion chamber through the piston ring but without losing more than 5% of the performance.

All parallel pipes have the same distance and diameter.

To find the values for piping and ratios, a process of iteration until converging has been used to run the different parameters into excel tables.

All caculations have been achieved with Matthew Harrison notes.

Task 1 – Single cylinder model

This first simulation runs a 500cc single cylinder engine with a range from 3000 to 7000 RPM.

Engine performance indicators required: