Liquid Petroleum Gas (LPG) Advantages and Disadvantages of LPG


Introduction to LPG

Propane and Butane are the two flammable gaseous obtained from oil wells, they also obtained from the petroleum refining process. This two gases compressed and cooled to form liquid known “liquid petroleum gas”. They are widely used as fuel for cooking, heating. Also used in IC engine, buses, and cars and referred to as autogas. Clean LPG is odorless gas, for safety concern and in order to detect the leaks, powerful odorant like ethanethiol is added to LPG.

Advantages and Disadvantages of Hydrogen as Fuel in IC Engine


Advantages of hydrogen fuel

  • Renewable energy.
  • Easy production - Hydrogen can produce by many chemical processes including simple electrolysis of water.
  • Reduce the dependency on fossil fuel.
  • High energy content per liter (only when stored as liquid form)
  • Physical delay of fuel is almost zero.
  • Good load response.
  • Clean combustion of fuel and low emission.
  • Since there is no carbon in the fuel, there is would be no carbon monoxide and hydrocarbons in the exhaust gas.
  • Even fuel leakage to the environment does not consider as pollution.

Alcohol as IC Engine Fuel - Advantages and Disadvantages of Alcohol Fuels

spirit lamp

Introduction to alcohol fuels

Alcohol is the one of the main liquid fuel alternative to the gasoline in combustion engines. Alcohol fuels are attractive because they can be obtained from nature as well as it can manufacture very easily. The methanol, ethanol, propanol, and butanol are the main type of alcohol fuel. In which ethanol is the most widely used alcohol because of its abundance and leas toxicity. More complex alcohol is not popular as fuel because they are not commercially viable.

In theory, the alcohol is get completely oxidized in the engine and get convert it into the carbon dioxide and water. But in reality, the alcohol burn incompletely and there will be many toxic by-products like carbon monoxide, aldehydes etc. The theoretical chemical reaction (oxidization) happening to the alcohol fuels is given below

alcohol oxidization equation

Advantages of alcohol as fuels

  • Abundance in availability; obtained naturally and synthetically.
  • Reduce the dependence fossil fuels.
  • Emission is very low when compared to a petrol engine.
  • Alcohol is ultraclean and sulphur free.
  • Alcohol has high flame speed.
  • Alcohol contains oxygen, so it requires less amount of air for stoichiometric combustion.
  • Alcohol possesses high latent heat of vaporization, which results in low intake temperature. This reduces the work input of compression stroke and increases volumetric efficiency.
  • Alcohol possesses high octane number, it can run high efficiently by high compression ratio.
  • The combustion of alcohol gives more moles of exhaust gas, which results in more pressure and power in the expansion stroke.

Disadvantages of alcohol fuels

  • Low calorific value, almost half of that of gasoline. For equal thermal efficiency more volume alcohol is required.
  • Alcohol fuels have poor ignition characteristics.
  • Alcohols are hygroscopic, absorb water content from the air. That increase the difficulty of transportation and storage.
  • High chance of vapor lock in fuel delivery system.
  • Aldehydes are one of the by-products of incomplete combustion of alcohol. The aldehyde emission would be serious when as much alcohol is consumed as gasoline.
  • Danger of storage tank due to the low vapour pressure of alcohols. A simple air leak can create a combustible mixture.
  • The low vapour pressure also results the poor cold weather starting characteristics.
  • Alcohol produces invisible flames, which is considered as dangerous in fuel handling. This problem can be overcome by adding fuel additives.
  • Lower exhaust temperature results longer time to heat the catalytic converter. Catalytic converter takes some time to get its efficient operating temperature.
  • Alcohol is more corrosive on copper, brass, aluminium etc. this cause deteriorate action on engine, gasket, fuel line and fuel tank. This put some restriction (selection of material) in the engine design and manufacturing process.
  • The strong odor alcohol cause headaches, dizziness, and many people find it is offensive.
  • The alcohol fuel production by fermentation of biomass like corn (bioalcohols) may alter the food production principles.

Variable Valve Timing VVT - Discrete Vs Continuous, Cam Phasing and Variable Duration


🔗What is Valve timing diagram of engine?
🔗Variable valve timing VVT of internal combustion engine - Advantages

Discrete variable valve timing and continues variable valve timing

The early type of VVT used stepped or discrete adjustment. For example “Cam switching”, one valve timing used below 3000rpm and another valve timing used above 3000rpm. The modern advance VVT uses “continuous variable valve timing" adjustment. Continuous VVT offer a continues or infinite number of adjustment of valve timing in the operating speed range of engine, and therefore they can be optimized to use all engine condition and speed. For example “Oscillating cam”.

Variable Valve Timing VVT of Internal Combustion Engine – Objectives and Advantages


🔗Valve timing diagram of four stroke SI engine
🔗Lead, lag, and overlap of valve timing and their advantages

What is variable valve timing?

The variable valve timing (VVT) is the process of altering the valve timing during the running of engine. Here the valve timing is modified as the function of engine speed and load. This process often used to improve performance, fuel emission, and fuel economy. The strict exhaust gas emission regulation is the one of the main reason for automotive manufacturers to adopt VVT systems.

Lead, Lag, and Overlap In the Valve Timing Diagram and Their Advantages

lag, lead and overlap Valve timing diagram four stroke SI engine

🔗Valve timing diagram of four stroke SI engine
🔗Working of four stroke spark ignition engine with PV diagram

Valve lead in engine

Theoretically, the engine valve opens and closes at TDC (Top Dead center) and BDC (Bottom Dead Centre). However, in a practical situation, opening and closing of engine valve occur at some degree (time) before or after TDC and BDC. The term “lead” and “lag” used to represent where the actual opening and closing of valve occurred.