Using this technology, the engine can save 20% fuel in minutes!

In the early days of automobile development, people were keen on increasing horsepower by increasing displacement in order to improve automobile performance. With the economic crisis and energy shortage, people began to realize the importance of energy conservation and emission reduction. Cylinder deactivation technology finds a balance between energy conservation and power. Today, Mechanical Front will tell you about engine variable displacement technology, commonly known as engine cylinder deactivation technology.

Cylinder deactivation variable displacement technology

A technology that uses on-board computer control technology to adjust the number of cylinders that are opened and closed, stop supplying fuel to the cylinders and close the valves, reduce the number of cylinders in operation, and thus improve the fuel economy of the vehicle and reduce energy consumption.

V8 engine closed one side valve open

The history of cylinder deactivation technology

The first engine to apply cylinder deactivation technology was the Cadillac L62 V8-6-4 engine. At that time, the technology was called DoD (Displacement on Demand). The V-type engine could change from an 8-cylinder to a 6-cylinder or 4-cylinder operating mode. The fuel-saving effect was obvious, but due to the technical limitations at the time, it was shelved.

Cadillac L62 V8-6-4 engine

With the recognition of the cylinder deactivation energy-saving concept, many automobile manufacturers have begun to develop their own cylinder deactivation technology. Mitsubishi's MD, Chrysler's MDS, Honda's VCM, Volkswagen's ACT, etc., have all launched their own cylinder deactivation engines. Next, let's talk about the principle of cylinder deactivation engines.

The principle of cylinder deactivation engine

OHV tappet separation

As we all know, muscle cars are popular in the United States. For muscle cars with low speed requirements, OHV bottom camshaft technology is widely used. Many Chrysler HEMI 5.7L engines use MDS technology. The ECU controls the hydraulic system and pushes the bayonet through the hydraulic system. The bayonet can make the tappets become one, thereby pushing the valve.

Chrysler MDS tappet separation

Improvement of valve lift

Valve lift technology is no secret to most car manufacturers. By improving valve lift technology, the valve can be closed and the cylinder can be closed. For example, Volkswagen's ACT, the main model is EA211, a 1.4L TSI inline four-cylinder, which opens and closes the cylinder by moving the camshaft position. Its essence is the same principle as valve lift.

Volkswagen's ACT, the main model is EA211, a 1.4L TSI inline four-cylinder

Link rocker arm synchronization and separation

Honda's VCM (Variable Cylinder Management) variable cylinder management is mainly used in J series engines and is applied to some models of the eighth-generation Accord. Many Honda V6 3.5L engines are now equipped with cylinder deactivation technology.

The ECU controls the hydraulic system, which combines the rocker arm connecting rod with the hydraulic system to form an integrated whole, thereby controlling the opening and closing of the valves.

Valve separation

Since the OHV bottom-mounted camshaft can separate the tappets and rocker arm connecting rods, why can't the valve stems be separated? Bosch's cylinder deactivation technology uses a hydraulic system to separate and combine the valve stems to achieve valve opening and closing.

Bosch valve separation and combination to achieve valve opening and closing

Models with cylinder deactivation technology

It will soon be installed in the new Audi A3/S3 models, changing from 4 cylinders to 2 cylinders. Audi's imagination is really big; Lamborghini officially announced the launch of the new Huracan LP 610-4 model. The biggest highlight of the new car is that its 5.2L V10 engine adopts cylinder deactivation technology; overseas ATS and CTS are equipped with 3.5L V6 engines, which have start-stop technology and cylinder deactivation technology; Chrysler HEMI 5.7L engine uses MDS technology, and the engine has cylinder deactivation technology; Honda's eighth-generation Accord 3.5L V6 engine has cylinder deactivation technology, and there is also Honda's Crosstra, etc.

Chrysler HEMI Grand Cherokee

The eighth-generation Accord is equipped with a 3.5L V6 engine

Summary: To realize the opening and closing of the valves of cylinder deactivation technology, it is nothing more than to make some changes to the valve train (camshaft, valve push rod, valve). The above are four classic mechanical cylinder deactivation structures. With the development of current electronic technology, electronically controlled valves will replace these mechanical structures in the future.