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21/01/2026

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21/01/2026

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19/01/2026

18/09/2025

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30/03/2025

Aston Martin Oman wishes you and your loved ones a blessed Eid Al-Fitr

May this Eid bring happiness and peace to you.

‎.أستون مارتن عُمان تتمنى لكم ولأحبائكم عيد فطر مبارك

‎.نتمنى أن يحمل هذا العيد السعادة والسلام إليكم

13/03/2025

19/02/2025

What are VVTI and VTEC?💨🛠️🔧👇

An engine operates by burning a fuel-air mixture, which expands and exerts pressure. If more air is introduced, the pressure on the piston increases, resulting in greater power output. This process is known as cylinder charging.

However, in a naturally aspirated (non-turbo) engine, there is a limit to how much cylinder charging can be increased under atmospheric pressure. Various methods have been developed to improve cylinder charging efficiency.

Why does cylinder charging decrease?

In a 4-stroke engine, the fuel-air mixture enters through the intake valve during the intake stroke. The intake valve opens to allow air to enter the cylinder and closes at the end of the stroke. However, since an engine completes a cycle in just milliseconds, the time available for the intake valve to remain open is very short, especially at high RPMs.

When an engine runs at high speeds, there isn't enough time to fully fill the cylinder with air, leading to reduced pressure on the piston during combustion. This, in turn, reduces power and efficiency.

Additionally, at higher altitudes, atmospheric pressure decreases, reducing the density of air. This means there is less oxygen per unit volume, which results in incomplete combustion and lower power output.

Since the Engine Control Unit (ECU) adjusts fuel injection based on air intake to maintain the correct fuel-air ratio, reduced air density leads to lower fuel injection, further reducing power.

Due to these challenges, manufacturers have developed various cylinder charging technologies to improve engine performance.

Cylinder Charging Systems

A common technique used in almost all engines is valve overlap, where the intake valve opens slightly before the exhaust stroke ends. This allows more air to enter the cylinder. However, the overlap period is very short, limiting its effectiveness.

To improve airflow, manufacturers introduced dual intake valves, leading to 12-valve engines (for 4-cylinder engines). While this increased efficiency, the presence of only one exhaust valve created backpressure, slightly restricting airflow.

To solve this, engines were upgraded to 16-valve designs (2 intake valves and 2 exhaust valves per cylinder). While this improved performance, at high RPMs, cylinder filling was still not optimal.

Variable Valve Timing (VVT)

To address the high-RPM air intake issue, manufacturers introduced Variable Camshaft Timing (VCT). In this system, the camshaft timing is adjusted dynamically using oil pressure, allowing the intake valve to open earlier and stay open longer. This improves air intake, increasing cylinder filling at high RPMs.

This system is controlled by electronic systems and is known by different names depending on the manufacturer:

Toyota – VVTI (Variable Valve Timing with Intelligence)

Honda – VTEC (Variable Valve Timing and Lift Electronic Control)

Mitsubishi – MIVEC (Mitsubishi Innovative Valve timing Electronic Control)

Difference Between VTEC and VVTI

VVTI (Toyota) adjusts the timing of the camshaft, altering when the valves open and close.

VTEC (Honda) changes both timing and valve lift, meaning it can also adjust how much the valve opens.

Benefits of Variable Valve Timing

By optimizing cylinder filling only when necessary, these systems:
✔ Improve fuel efficiency
✔ Increase power output
✔ Enhance overall engine performance

Despite these advancements, no manufacturer has yet been able to achieve atmospheric pressure inside the cylinder during the intake stroke in a naturally aspirated engine.

To further improve cylinder charging, forced induction systems like turbochargers, superchargers, and nitrous oxide (NOS) are used. These systems are classified as forced air induction systems.

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Dr.mechanics 🛠️🔧

09/12/2024

📌 Here are the Different Types of Sensors used in Vehicles:

1. Mass Air Flow Sensor:

A mass (air) flow sensor (MAF) is a sensor used to determine the mass flow rate of air entering a fuel-injected internal combustion engine.

2. Throttle Position Sensor:

A throttle position sensor is a sensor used to monitor the throttle body valve position for the ECU of an engine. The sensor is usually located on the butterfly spindle/shaft so that it can directly monitor the position of the throttle.

3. Oxygen Sensor:

An oxygen sensor, also known as an O2 sensor or lambda sensor, is a device that measures the amount of oxygen in a car's exhaust gas and helps the engine run efficiently.

4. Engine Knock Sensor:

The knock sensor is located on the outside of the engine block. It is intended to record knocking noise in all engine operating states to prevent engine damage.

5. Camshaft Position Sensor:

A camshaft position sensor is a vital component of a car's engine that measures the camshaft's position and rotation and sends this information to the engine control module (ECM).

6. Coolant Temperature Sensor:

A coolant temperature sensor (CTS) (also known as an ECT sensor or ECTS (engine coolant temperature sensor) is used to measure the temperature of the coolant/antifreeze mix in the cooling system, giving an indication of how much heat the engine is giving off.

7. NOx Sensor:

NOx sensors monitor the level of nitrogen oxide emitted by a diesel vehicle to ensure compliance with emissions regulations.

8. Manifold Absolute Pressure Sensor:

A manifold absolute pressure (MAP) sensor measures the pressure or vacuum in a car's intake manifold and provides information to the engine's electronic control unit (ECU).

Follow us EngineersPost Website for more interesting topics.

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25/11/2024

Yesterday I showed you the Q3 2024 global sales for electric vehicles. Today it’s time for the year-to-date figures (January-September 2024).

- Tesla keeps leading with 124,000 units ahead of BYD. That’s less than the 276,000 units that separated both companies in Jan-Sep 2023. The American maker posted a 2.6% decline vs +11.6% for BYD. Will the Chinese outsell Tesla by the year end?
- Geely is the big winner of the year with its volumes up by 51%, climbing two positions in the ranking and outselling Volkswagen Group (-4.7%) and Hyundai-Kia (-8.1%). Geely is being boosted by the success of the Volvo EX30, Galaxy subbrand and ZEEKR.
- BMW Group was the best performer among the big non-Chinese BEV makers. It recorded a 19% increase in contrast to -22% from Mercedes (Smart included) and -6% from Audi (included in VW Group).
- GAC along with Mercedes were the worst performers of the top 10. GAC’s is feeling the impact of a product revamp at AION and Hyptec brands. The German maker struggles with the luxury models like EQE and EQS (too different from Mercedes DNA?).
- Stellantis also struggles with volumes down by 17% following lower sales of the Fiat 500, and the delays on the introduction of the Citroen e-C3 in Europe.
- Outside the top 10: Leapmotor doubles its sales and seems that has finally taken off in China; GM is the other non-Chinese winner with sales up by 56% thanks to the positive response of American public to Chevrolet Blazer EV, Cadillac Lyriq. In contrast, Ford lost 17% with a flopped F-150 Lightning and lack of enthusiasm around the European made Explorer EV.
- Xiaomi impressed with almost 70k units sold so far. The upcoming SUV will accelerate even more the growth; Vinfast (+107%) seems to take off in Vietnam and the Philippines thanks to the small VF 3.

Source: OEMs, estimates

03/10/2024

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30/09/2024

Every tread tells a different story—your story.​

Engineered for excellence, every Bridgestone tyre tread is crafted to match your driving style perfectly. Choose the one that elevates your ride and conquer the road.


لكل نمط مداس إطار قصة، فما هي قصتك؟ تم تصميم كل نمط من أنماط إطارات #بريدجستون ليتناسب تماماً مع أسلوب قيادتك. اختر الإطار الذي يرتقي بقيادتك ويقهر الطرقات.
#بريدجستون #القيادة

11/09/2024

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