 |
|
|
|
What is an ECM ? How does it work?
|
|
ECM is the acronym for Electronic Control Module. This is the brain of the MPFI system. It controls the amount of fuel to be injected into the engine and the ignition timing based on the inputs received from various sensors. It consists of a micro computer analog to digital converter.
|
| Top |
|
Why is a 16-bit computer better than a 8-bit ?
|
|
In a 16 bit computer the processing time is much less as compared to 8 bit. It takes the decision much faster resulting in quicker responses (More crucial during high speed operating condition or even during widely varying condition).
|
| Top |
|
What are the advantages of an Electronic Power Steering?
|
|
The advantages of the Electronic Power Steering are based on a number of parameters like more power, more dependability, more safety and more intelligence. It also occupies less space and has low maintenance cost.
The EPS is controlled by electronic gadgets and incorporates a "Self Diagnosis" feature,in case of any problem.
More Power
EPS consumes less than 2% of an engine's power as compared to the 5% consumed by ordinary power steering. This enables the EPS fitted car to turn in an even more power-packed performance making the EPS extremely useful for small cars.
More Dependability
Ordinary Power Steering is based on a hydraulic system, which may at times result in loss of power assistance to the steering due to the wear and tear of the mechanical parts. The EPS with its electronic parts is a more dependable system as it totally eliminates the possibility of power loss due to the absence of these parts and results in virtually zero maintenance.
More Intelligence
EPS is also known as a Variable Power Steering, which essentially means that the system quickly adapts according to driving conditions and provides requisite power. For instance, more power is needed in operations such as parking and slow traffic conditions, while considerably less power is needed while steering at higher speeds.
The EPS is built to provide only as much power as needed for a particular operation, thus exerting less load on the engine while ordinary power assisted steering provide constant power assistance irrespective of the application, which results in greater demands on the car's engine.
More Safety
The EPS's ability to vary the power provision significantly enhances safety. Power delivery at higher speeds needs to be calibrated so as to provide dependability of movement at higher speeds also.
|
| Top |
|
Why is the Maruti fuel injector better able to cope with fuel adulteration, as compared to, say, the Santro?
|
|
Poor fuel quality, e.g. due to adulteration, affects the engine performance significantly and may damage the engine. The deterioration of engine performance or engine damage depends upon the amount of adulteration. The performance of the components like fuel pump, fuel injector and intake valves are affected due to gum deposition. Beside this, adulteration results in poor combustion and sometimes leads to knocking, which subsequently damages the piston and piston rings. The most affected components are fuel injector, fuel pump and intake valve.
The diameter of the fuel injector nozzle is very small--around 1 mm. When gum formation starts on the fuel injector, it cannot inject the required quantity of fuel. This will result in poor starting, poor fuel economy and poor pickup. As the gum formation on injector increases, it may be difficult to start the engine.
The design of fuel injector plays an important role in performance and it can be made deposit-proof to some extent. Maruti MPI models (Maruti 800 MPI, Alto, WagonR etc.) use DENSO fuel injectors which have four holes as compared to the Santro’s single hole injector. This four-hole nozzle plate is positioned in such a way that it does not allow any deposit, which makes the injector deposit-proof to certain extent. That is the advantage of Denso fuel injector used in all Maruti MPI models, as compared to other competitor model injectors.
Besides this, seat leakage in the Santro injector is 8 times more than in the Maruti Injector. More seat leakage means more chance of deposits, and subsequent clogging of the injector. The Maruti fuel pump is also designed for Indian fuel quality. The commutator used in the Maruti pump is Carbon-type, which is less prone to failure under adulterated fuel conditions. The current requirement in a Carbon commutator is significantly lower than in the copper-type. It makes the pump more efficient and more durable. Santro fuel pump commutator is made of copper, which is affected by the adulteration and other elements like silicon and phosphorous in the fuel. So, the Maruti fuel pump is more advanced and reliable as compared to SANTRO.
|
| Top |
|
What is the use of spoilers?
|
|
Spoilers, acting in a manner opposite to wings, were first added to the back of racing cars, to induce negative lift. Racing cars were becoming speedy enough that lift was generated, reducing the ground contact of the tyres, and affecting control.
Spoilers give negative lift to press the car back to the ground and improve control. Later, they were also introduced in high performance production sports cars, for the same reason.
However, at Indian city driving speeds, the spoiler is unlikely to offer significant aerodynamic performance. At these speeds, tyre pressure will affect braking distance more. Like sunglasses on film stars, which were originally prescribed to protect eyes weakened by Klieg lights, spoilers are now used mainly for aesthetics.
|
| Top |
|
What is DDLI (double distributor less ignition)? What are its advantages?
|
|
In the vehicle ignition system with the distributor, the distributor assy has two functions:
1. It provides the input signal to the ECU regarding position of the Cam so that the input can be provided to ignition coil for generation of high voltage.
2. It distributes the high voltage generated by the coil to the required spark plug.
In case of distributor less ignition system, there is no distributor. Instead:
1. One Cam sensor is used to provide the input signal to the ECU
2. The coils mounted on the plug-top provide the high voltage to the spark plugs directly.
The advantages are: Better output available at the spark plug resulting in better ignition and starting.
|
| Top |
|
