4 Advantages of Variable Valve Timing (VVT) Engines

There is a piece of modern technology for car engines called variable valve timing (VVT). It helps to boost the efficiency and overall performance of engines which utilize this technology.

Keep reading to see how variable valve timing works and what its main advantages are.

Read Also: 5 Main Parts of an Engine

How Variable Valve Timing Works

Variable valve timing manages the opening and closing of the air intake valve and the exhaust valve. These are the valves responsible for allowing outside air to flow inside and to replace exhaust emissions; respectively.

The timing and speed at which these valves open are crucial for the engine to perform well. Although it is possible for the engine to exist without this technology, you would see a great decrease in your fuel economy if this were to happen.

The variable valve timing system is comprised of various mechanical and hydraulic components to create the lift effect for the valves. This is how the engine can respond quickly to the demands of the driver. At times when engine performance is not needed, you can still maintain great efficiency in the engine.

Today, you will find the top three Japanese car manufacturers using this technology, including Honda, Toyota, and Nissan among others. The way these processes work can vary slightly in each type of car.

For example, the variable valve timing system inside the engine of a Honda uses a camshaft to lower its RPM. The computer monitor in the engine calculates all of the conditions of the vehicle in order to make this happen.

It looks at the engine’s speed and the throttle pedal’s position in order to decide if switching to a high-performance camshaft is necessary or not. If it decides that it is necessary, hydraulic pressure is then activated to change the camshaft to a high performing one in order to accommodate the high RPM of the car.

Top 4 Advantages

Everyone wants to have a high performing engine whether we admit it or not. Out of all the components and machinery in a vehicle, the engine is the most important.

If you can get it to do its job well, you can ensure that your vehicle stays healthy for a good long time. On top of that, you will enjoy many advantages as the driver of a vehicle utilizing VVT. To sum up what those advantages are, below are the top four pros of a variable valve timing engine.

1) Higher RPM

high RPM

The main advantage of having a variable valve timing technology is the increase it will provide in your engine’s revolutions per minute. When you step on the gas pedal to accelerate the vehicle, your engine will be capable of a higher RPM which generally translates to more power (to a point).

Variable valve timing has a lot to do with making this happen. That roaring sound you hear when you step on the gas pedal is the variable valve timing system hard at work to keep your engine running strong.

2) Better Fuel Economy

bad gas in car symptoms

Engine efficiency has a lot to do with the timing of the exhaust valve and intake valve. If these valves can be managed and timed properly from the variable valve timing technology, then the engine will be able to produce the same power without needing so much fuel.

If your engine doesn’t require as much fuel, then you will see your gas mileage increase. This means fewer trips to the gas station and more money saved on fuel costs.

3) Lower Carbon Emissions

car exhaust smoke

Any time your engine provides a better fuel economy, you will see reduced carbon emissions too. Variable valve timing technology does not get enough credit for its eco-friendly nature.

If a higher RPM and better fuel economy weren’t enough to convince you that this technology is beneficial, then hopefully its ability to reduce carbon emissions will change your mind. If you live in a state which has required emissions testing, then this technology will increase your chances of helping you pass the test.

4) Increased Engine Lifespan

variable valve timing engine

If you continue to maintain an efficient and high performing engine, then you can expect to get a great number of years out of it. A lot of people will wait until their engines go bad before they decide to replace their vehicle.

If you have variable valve timing in your engine, then it will help keep it strong for as long as possible. Of course, there are other factors involved in keeping an engine healthy too. Make sure you regularly get oil changes and use the right kind of fuel.

See Also: How Long Do CVT Transmissions Last?


7 thoughts on “4 Advantages of Variable Valve Timing (VVT) Engines”

  1. Good article. However, the key answers I was looking for are not described.
    What action is taken on the intake and exhaust valve at low speeds and high power demand or at high speeds and cruising, Or at any other engine operating conditions?

    • That depends highly on the specific implementation of VVT on the vehicle. Each manufacturer has a different implementation of VVT and they call that system different things (e.g. i-VTEC, VCT, AVCS, etc). Some systems simply switch between two cam profiles (classic VTEC, for instance), others have a whole range of settings based on a table stored in the ECU.

      Typically, cam profiles are relaxed at idle and low load, and the timing advances at higher loads and wide open throttle. Delayed timing may help with fuel economy or smooth idle. More advanced timing gives you more power, to a certain extent.

      Many vehicles also start to open the intake valves while the exhaust valves are still open to produce a scavenging effect at high loads. In other words, the force of the exhaust gases rushing out of the combustion chamber helps pull in fresh air from the intake.

      If you’re looking for information on a specific vehicle, you can often find really nice technical writeups in the forums for that make or model (for instance, NASIOC for the Subaru Impreza, WRX, and STI). Facebook has a lot of helpful groups as well, and YouTube is another great source for seeing engine teardowns and walkthroughs of technical systems.

      Some vehicles have variable lift as well as variable timing. This changes how far the valves open, not just how long they stay open. Hope this helps.

  2. Does Peugeot have this? I experience too much consumption with my 1st and 2nd peugeot 307. While is it like that? I will appreciate a quick response

    • Yes your 307 probably has VVT. There are many factors that could cause poor fuel consumption. Some examples are old spark plugs on a gasoline engine, bad O2 sensors, and a dirty engine air filter.

    • That’s a good question. There’s really no “best” VVT implementation. Even if there were, the answer would likely change in a year or two as technology advances.

      With any design, there are trade offs between cost, complexity, efficiency, and durability that have to be made. These days, manufacturers are experimenting with variable valve duration and variable compression designs.

      Many VVT implementations are very similar and generally pretty good. They’re given different names depending on the manufacturer, such as i-VTEC (Honda) and AVCS (Subaru). If you’re interested, I recommend looking up each implementation to see how they work. YouTube videos from people like Engineering Explained will help you visualize what’s going on under the hood.


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