Indian Electric

With regards of the electric vehicle revolution in India, our Honourable Road Transport & Highway Minister, Mr. Nitin Gadkari has given a very clear statement to the automotive OEM’s saying,” Move to electric cars by 2030 or be bulldozed”. And with the imminent BS VI switch to be made in 2020, the statement has OEM’s baffled by the workload and the instability that it might cause in the market.

What I believe is that rather than just focusing on technology, we should also focus on changing the mindset of people and their views on alternate propulsion, only then I believe that the ‘Electric Revolution’ will have any real impact. To explain my point better, I must say that, it took about a 100 years for the IC engine technology to penetrate to almost every remote village in India, but we can’t afford to wait a 100 more years for the electric infrastructure to do the same.

 Many countries like Norway and Iceland have already started seeing massive adoption rates of electric cars in favor of gasoline-powered vehicles. In fact, in Norway, about 35% of the total car’s sales are dominated by electric vehicles. This feat was only possible by the collaboration of different automotive companies and the government for the infrastructure and incentives, in contrast to having a ‘Bull-doze Policy’.

I strongly believe that with the right collaboration and the technical know-how, any country and not just India can successfully complete the electric transition. And I sincerely hope that different countries and the OEM’s will help each other out to change the tide of human race cause after all we all have to share the same planet until Elon Musk happens.

 

ALS- Anti Lag System

An anti-lag system, commonly known as misfiring system, is used to minimize the turbo lag produced by the turbocharged units. They were first put to use in the Formula One cars until fuel restrictions made them unsuitable for usage.  Currently, they are used in the rally race cars and were put to use in some of the prototypes road cars like the Procar P2.

A typical ALS system works when the throttle is closed. Some un-burnt fuel is introduced into the exhaust manifold by the means of retarded ignition in the combustion chamber. The temperature of the manifold leads to combustion of the AF mixture which ultimately keeps the compressor of the turbocharger spooled up. Some of the AF mixtures continues burning in the turbine and down the exhaust system resulting in flames and explosions which can be seen and heard coming out of the muffler.

There are typically four methods through which the above phenomena can be achieved.

1.Throttle Bypass

• A throttle solenoid system combined with ignition retardation and slight fuel enrichment (required for cooling) are the major components of the Throttle bypass system.
• When the throttle is closed the bypass valve opens up due to the pressure built up in the inlet section and a late ignition is engineered by the ECU of the vehicle.
• This late ignition causes very little expansion of gasses so the pressure and temperature will be very high when the exhaust valve opens.
• At the same time, the torque provided to the crankshaft is very small but is just enough to keep the engine running.
• The higher exhaust pressure and temperature combined with the increased mass flow are enough to keep the turbocharger spooled up at high speeds, thus reducing turbo lag.
• When the throttle is opened, the system resumes to its natural operating procedures.
• This system is very harsh on the engine components as they have to face very extreme temperatures.
• The ALS is shut down if the coolant reaches extreme temperatures.

2.Secondary Air Injection

• These are also known as a drag style anti-lag system.
• They are more commonly used to build boost on the line just before the race begins.
• When the throttle is closed, air to the turbocharger is transferred through a bypass using a solenoid valve which is situated just before the butterfly valve.
• When the air reaches the turbocharger through the bypass, it is enriched with fuel coming from the combustion chamber due to a late ignition, and the opening of the solenoid valve engineered by the ECU of the vehicle.
• Due to high temperature in the exhaust system, this mixture ignites which helps in keeping the turbocharger spooled up, hence, diminishing turbo lag.

3. Turbo and Intercooler Bypass D-Valve

• In this method, we attain the objective by using a D-valve.
• The D-valve is just installed prior to the throttle body enabling the air to bypass the intercooler and the turbocharger provided there is a negative pressure gradient.
• This leads to more air reaching to the compressor wheel of the turbocharger spooling it up, hence, diminishing turbo lag.
• When there is a positive pressure gradient formed the valve automatically closes.

4. Two Step Anti Lag

• In this method, a rev limiter is used to hold the engine at a certain RPM where it is able to produce the maximum usable boost.
• The basic premise of using a two-step anti-lag system is to build positive boost pressure from a static engine, releasing full or increased power to the wheels when the car starts to move off.
• This can be used in accordance with the above-mentioned methods.

Automobile Layout

The various Automobile Layout can be broadly classified into the below categories:

• Front Wheel Drive Layout
• Rear Wheel Drive Layout
• Four Wheel Layout

The Front Wheel Drive Layout

This type of layout is popularly known as the FF layout. In this layout, only the front wheels of the vehicle are driven and the rear wheels are situated on a dead axle.

In the current market scenario, the FF’s are the most popular layout used in the automotive industry. Usually, the engine is mounted transversely on the driven shaft with the engine situated in front of the driven axle.

The Advantages of a Front Wheel Drive Layout are:

• The FF layout is chosen primarily because of its compact packaging providing more volume for passengers and the cargo.
• As the engine and the driven shaft is on the same side, the central tunnel is not required to accommodate the propeller shaft.
• As there are fewer components required, the overall weight of the vehicle is reduced leading to increased performance during acceleration and braking. This also leads to better fuel economy and lower cost of production.
• Rather than using the tunnel for the propeller shaft, which is obsolete in the FF layout, the tunnel can be used for housing the exhaust system to provide better ground clearance.
• As the steered wheels are the one driven, the car attains a natural tendency to understeer. This makes the car easier to control the car on low traction surfaces like mud, snow, sand etcetera.
• Also as the engine is located in front of the driven wheel, the center of mass of the vehicle shifts to the front improving the traction and the directional stability on low traction surfaces like mud, sand, etcetera.

The Disadvantages of a Front Wheel Drive Layout are:

• For the vehicles possessing high horsepower, the understeering can become a noticeable problem. This problem is tackled using diver aids such as four-wheel drive system, active front suspension etcetera. The Audi Quattro system is one the most common system found in the current market scenario.
• In an FF layout, the problem of Torque Steer occurs. *Torque Steer is the tendency of the vehicle to pull to the right or left during hard acceleration.
• Only smaller displacement engines like the inline 4 cylinder or the VR6 engines are generally used as the space available is too cramped to install a larger displacement engine than a V8.
• The FF layout makes heavy use of the front tires, even when compared to the wear caused to the rear wheels in a rear wheel drive layout.
• Under heavy braking, as the already heavy front, causes the weight to transfer forward, this leads to decreased traction of the rear tires.

Exhaust Brakes and Advantages of Engine Braking

The discovery of the Exhaust Braking System was built upon the disadvantages of the Compression Release Exhaust Brakes used in the diesel engines as discussed earlier. The main disadvantage being the ‘Machine Gun’ Noise produced during the operation of the compression release exhaust braking system. And like the later, this mechanism is restricted to diesel engines only.

In the Exhaust Brake mechanism, a restriction is produced into the pathway of the exhaust gas causing the exhaust gas to be compressed in the exhaust manifold and in the cylinder. The restrictions can be magnified by using equipment like particulate filter and EGR.

As the exhaust gases are the only thing getting compressed and there is no fuel flow being applied, hence, the engine produces negative torque. In simple words, the engine works in the opposite direction. Also, the amount of negative torque generated is directly proportional to the back pressure of the engine. This negative torque is then used to slow down the vehicle provided the vehicle is in some gear except the neutral and the clutch is fully(for best results)/ partially engaged.

** Back Pressure: It is the pressure opposed to the flow of fluid in a confined place such as pipes (Source: Wikipedia)

Some of the advantages and disadvantages of Engine Braking system are:

• It submissively reduces the wear on a mechanical braking system of the vehicle.
• It can be used to control speed while driving on very steep slopes.
• Improper engine braking technique can lead to loss of traction.
• Engine braking in two-stroke engine leads to engine damage as during the process it not only will starve of fuel but also lubricant required for the smooth working of the engine.

Compression Release Exhaust Brakes

The compression release exhaust brakes is a method of engine braking used in the diesel engines in contrary to the Deceleration Fuel Cutoff System(DFCS) used in the petrol.

Like the DFCS the clutch should be completely released with the transmission in gear and the accelerator pedal should be completely released for the system to work. When activated the motion of the fuel injection rocker arm is transferred to the exhaust valve. This process takes place during the Top Dead Center(TDC) and releases the compressed air into the cylinder so that the energy is not transferred to the crankshaft. This leads to slowing down of the vehicle.

This process is widely used by the truck drivers around the world to maintain a constant speed and even to slow down the vehicle without the use of the traditional braking system.

But putting the advantages aside, unlike the DFCS of the petrol engines, the process produces huge amounts of unwanted ‘Machine Gun’ noise due to the release of the compressed gas into the atmosphere. Hence the use of the compression release exhaust braking system has been heavily regulated by the governments of the respective countries.

To tackle the problem of the ‘Machine Gun’ noise the mechanism of ‘Exhaust Brakes’ were introduced which would be discussed in the next post with a brief about advantages of using engine braking over the traditional braking systems.

Deceleration Fuel Cutoff System

Engine braking is the process of slowing of the car with the use of the negative torque produced by the engine instead of some other mechanical braking mechanism like the friction braking system or the magnetic braking system.

Now, deceleration fuel cutoff system is a type of the engine braking which are in use in gasoline powered vehicles.

The whole process is based on the simple phenomena of creation of partial vacuum in the ignition chamber in the engine block.

In the process, when the accelerator pedal of the vehicle is released the butterfly air valve present in the air intake of the engine closes up and the Electronic Control Unit (ECU) send a set of commands to the fuel injectors to stop injecting fuel in the combustion chamber.

This leads to creation of a partial pressure in the combustion chamber which provides a resisting force to the driving wheels provided the car is in any gear except the neutral gear and also the clutch is fully engaged to the engine flywheel.

This ultimately slows down the car without any use of mechanical brakes and also reducing the consumption of fuel and increasing the life of the braking system installed in the system.

Also an obvious use of this particular system can be demonstrated in the case of failure of brakes as an emergency maneuver