Computer Box In Your Car: All You Need To Know

Our present is far advanced than the obsolete trinkets of the past. But we still have a long way to go for capitalizing on the vast scope of future. The computer box, technically known as the ECU (Electronic Control Unit) is a fitting example of how far we have come from the days of horse-drawn carriages.

This ECU played a very important role in making the elusive dream of modern technologically evolved car possible. Today, most of the incredible benefits that we enjoy in our dream ride are mainly because of this computer box only.

We can say that it is essentially the brain of our vehicle. It makes sure that everything is working smoothly at all times. And makes it possible for the automobile to function optimally and safely round the clock. It keeps an eye on both inside and outside agents and manages the functioning of the car accordingly.

Mechanical Age of Cars

Before stepping into the future, we have to appreciate the technological advancements of the present. And for that, we need to time travel all the way back to the 1800s. Only then we can appreciate how privileged we are to have this groundbreaking technology at our disposal.

It Started With The Carburetor

In the early 1800s, the computer was in the picture but not in the petite frame that they are available today. Back then they were a lot bulky and space consuming so no one imagined of them being included in their car.


The process of fine-tuning the air-fuel mixture was usually performed with the help of carburetors. There was no technology advances enough back then to facilitate the direct engines or fuel engines which is a common occurrence in the cars of today.

A spark distributor was used to make sure that the spark was getting equally distributed to all the cylinders. This was done by managing the spark timing in an efficient manner. There was no computer or electronic aid within the car circuitry to offer even a better fuel pressure.

Car Technology Early Beginnings

The carburetor engines were not able to sufficiently mist the fuel. And the lack of abundant pressure made it impossible for the fuel to combusted properly. There was not much electrical help within the car structure. Most of the tasks were performed using little electronic support including the solenoids, vacuum hoses, and basic electrical contacts.

Back then people heavily relied on the skillful mechanic to keep their car running smoothly all year long. The screwdrivers and wrenches were all the help one can get from outside when the car stops performing with the initial vigor.

The ease and comfort of the sensor network and many other crucial adjustments that we take for granted today were not available in those times. And that is why it was a lot harder to manage a smooth and hassle-free journey day after day with the same vehicle.

Ignition System Distributor

Before the presence of fuel injections, there was the one and only ignition system distributor. The car relied on it heavily to provide a steady stream of fuel in a highly useful manner. It used to manage a lot of functions within the car.

Even today, the vintage cars and similar models rely on this system only to offer that familiar level of performance. Firstly, it makes it a point to transfer the right amount of voltage from the coil to the correct cylinder. This task is accomplished with the help of rotor and the cap.

The rotor spins within the cap. This rotor is in turn connected to the coil. As it spins, it passes by a lot of contacts which are further present at the tip of these cylinders. The high voltage spark is transferred from the coil onto the rotor which passes it equally between the various cylinder contacts.

Basic Structure

The high voltage pulse passes from the contact points onto the spark plug wire. Then it moves towards the spark plug on the required cylinder. This is why the tune-up process of this kind of cars involve replacement of the cap and the rotor after an appropriate amount of time.

This is because they wear out during the process and need to be replaced with a fresh batch to maintain the performance to the initial levels. The spark plug wires also need to be replaced since they wear out and lose their original electrical insulation properties.

The above-described mechanism is not efficient at all and that is why today we have the luxury of ECU to monitor these key activities. A sensor informs the ECU about the exact position of the piston. It will then manage the current transition to the coil accordingly.

Evolution of the ECU System and Computer Box

The modern day cars that we see and enjoy today were not created overnight. It was a series of hit and misses that ultimately led to the transition from carburetor engines to the ECU-controlled engines. It began somewhere in the middle of the 19th century when people actually started reinventing the traditional car engine model.


Below is a series of major milestones that define the conception and ultimate development of a well-defined ECU system:

1.  Breakless Ignition

The evolution of the engine systems began with the introduction of the breakless/electronic shaft. It basically used the optical/magnetic sensor on the surface of the distributor shaft. This way the contact points were totally removed from the picture that was implemented for the triggering process of the coil.

These electronic ignitions improved the entire engine system in a lot of significant ways. The spark plug life got increased to a minimum of fifty thousand miles. The tune-up times were also increased manifolds. The emission levels dropped got reduced to more acceptable levels.

Their design conception and development process got the momentum by the end of 1940 itself. They first became commercially available somewhere in the 1960s in a select few vehicles. The first standard-fit electronic ignition was introduced in the market by the FIAT offered the in its ’68 Dino car model.

Detailed Look

This was not available in the US at that time. It was the 1971 Jaguar XJ which became the first car to actually offer this nature of ignition systems within the US in the year 1971. This revolution in the engine design gain momentum with the help of Chrysler which made it the electronic ignition standard somewhere in the year 1973.

Ultimately the GM, Ford, and AMC also became a part of the elite club in the year 1975 and started offering electronic ignition in their automobile models too. But, technically these breakless ignitions were not as computerized as they could have been.

Basically, they just made the system a bit better than the previous version. This just included the replacement of few obsolete components with the more durable and tough parts. It was the strict emission control standards that brought this revolution in the automobile industry.

2. Computerized Ignitions

With the automobile emission laws being stricter than ever, the computerized ignition was the next invention that everyone desperately needed. The very first of this kind was developed by the Chrysler group and included in their 1976 models as the Electronic Lean-Burn System.

Later the Ford introduced their first EEC (Electronic Engine Control) system with their 1978 Lincoln Versailles. And the GM Motors followed this suite with their own version of the new computerized systems in their 1981 models.

The initial introductions of the computerized ignition systems were a step in the right direction. But they still had to be sculpted in a lot of ways before they can solve their purpose as they are supposed. All these systems were found lacking in one way or the other but it sure helped in transitioning to the automobile industry from the mechanical age to the computerized age.

In the Right Direction

The primitive computers were capable enough to compute the correct spark timing for any given situation. This helped in improving the performance of the entire car in a lot of different ways. It was followed by applying vacuum to the distributor for the advancement of the ignition timing as and when required.

One of the popular features of this generation of cars was the “feedback” carburetors. This would get the feedback from the oxygen mixture in a timely manner. That will in-turn help the on-the-fly adjustment of the air and fuel mixture.

This is not much as compared to the technology of today. But back then it was a breakthrough that helped in shaping the present automobile technology. It became a milestone movement that helped in giving more control to the car owner.

3. Electronic Fuel Injection

It did not take much time to introduce the electric fuel injections into the market. In fact, they were introduced somewhere in 1957 on a commercial scale. With this introduction, the ignition or feedback carburetors were removed from the average car structure.

This marked the beginning of computer age in the automobile domain. And it greatly helped in making the average car a safe and sound vehicle for the car owners as well as the environment. This gave the necessary acceleration that the car industry needed for a long time.

Electronic Fuel Injector

Mechanical fuel injections were introduced first by the GM motors in the car models somewhere during 1957 in their car models. They basically repurposed the mechanical fuel injections used in the aircraft engines into the ones suitable for the average car.

4. Electrojector

The Bendix organization came up with a fuel injection system and called it Electrojector. It was fitted with a transistorized electronic control system. It was the first of its kind and was specifically designed for a production car.

The debut of this innovative system was supposed to be made with American Motors Corporation’s 1957 Rambler Rebel in the price bracket of $395. A few prototypes of this concept were created but they turned out to be horribly wrong. So much so that they were not installed in any of the car models for which they were initially manufactured.

It was the Chrysler that introduced this Electrojector in as many as 35 of their 1958 production cars. But soon they realized how incapable this system was. That is why they replaced them all of these Electrojectors with the carburetors. It is still debatable whether they can be counted as the first ECUs that the world ever experienced or not.

5. Electronic Fuel Injection System

It was somewhere in late 1960 that the Bosch came up with the Jetronic electronic fuel injection system. They got everything about the primitive ECUs just right with this attempt and the final prototype was finally ready to be launched.

This system worked by making use of the date from a pressure sensor along with the engine speed for the purpose of controlling the fuel injection rate. It was the first computer-based system and it worked to perfection.

Consequently, Bosch made the right move of licensing it to a lot of automakers. Volkswagen was the first to put it into production in the year 1968. It officially launched this system with the Type III Fastback and Squareback. They marketed them as the first few car models with their own computer which got a lot of buzzes.

a) Hybrid Digital Designs

In the mid-1980s, the hybrid digital and analog designs received a lot of fame. This system basically made good use of the analog techniques for the measuring and processing purposed. It then utilized the lookup table that is stored within the digital ROM chip. This finally lets to the generation of precomputed output values.

The systems of today are able to generate this output value in a dynamic manner that is more accurate and efficient. If we are able to understand the working of this system well then it can be quite easy to handle. But this system works well only with a brand new engine.

As the wear and tear on the engine increases, the precomputed values generated will not be optimal for the new functioning anymore. This will create a huge gap between the functioning of the fuel injection system which will make the car malfunction sooner than later.

b) Modern Designs

The latest ECUs is as high-tech as it can get. They basically have a microprocessor that processes the information gathered from the sensor network. And then respond in an optimal manner. They get inputs from the engine in real-time to offer the most suitable output quickly.

Modern ECU

This ECU basically acts as the firmware that performs the function of connecting the hardware of the system with the software. The prime hardware components of the car involved in the ECU functioning are electronic components on a printed circuit board (PCB along with the ceramic substrate or a thin laminate substrate.

A microcontroller chip (CPU) is the main component of this circuit board. The software portion of this system consists of the microcontroller or other chips on the P.C.B. These are typically present in the EPROMs or flash memory so the C.P.U. can be re-programmed quite easily later on.

Working Details

The reprogramming process of the CPU can be done by replacing the chips or by uploading the updated codes. This whole structure is also known as the (electronic) Engine Management System (EMS). It receives inputs from the number of outside sources.

The EMS can control various aspects of the basic engine functioning. It can also directly communicate with the transmission control units. The direct interface can also be performed with the electronically controlled automatic transmissions, the traction control systems, and other relevant channels.

Most of the modern day cars make use of the Controller Area Network or CAN bus automotive network for enabling good communication between the various systems. The cruise control, anti-skid brake control, transmission control and anti-theft control are the other advanced features that are also available with modern ECUs.


The computer box in our car is responsible for making our journeys convenient and safe without any hassles. The cars have evolved a lot since the introduction of the ECUs and they keep on escalating the pace of development of automobile technology. Most of the technological comforts that we enjoy today are provided one way or the other by the computer boxes only.

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