A Closer Look at Emissions Standards in 2011 and Beyond

The new Honda GX120, GX160 and GX200 mid GX engines meet EPA Phase 3 exhaust and evaporative emissions standards – the most stringent emission regulations in the world. As background, the EPA has finalized a new emission control program to reduce hydrocarbon emissions from small spark-ignition engines by approximately 35 percent.

These new exhaust emissions standards will take effect in 2011 or 2012, depending on the size of the engine. The final rule also includes new standards to reduce evaporative emissions from these fuel systems. Ultimately, these standards will serve to reduce the ozone and carbon monoxide levels produced by these engines.

The design configuration of the new Honda mid GX models reduces pollutants such as hydrocarbons (HCs) and nitrous oxide (NOx) while maintaining the same level of output power as the previous Honda GX models they replace. “The engines reduce HCs by reducing oil consumption via a redesigned piston shape and piston ring along with a modified carburetor setting. In addition, the engine designs reduce NOx emissions through an adjustment in ignition timing which reduces combustion temperature and pressure,” explained Rudolph.

Reduction of Noise and Vibration and in the New Honda Mid GX Models

In the new mid range GX160 engines, the composition of the push rods has been changed from steel to aluminum. Because the cylinder heads also are constructed from aluminum, this design change equalizes the linear expansion coefficient (the ratio at which the length of the push rod changes from reaction to engine heat) of the push rods. This improvement reduces the valve clearance (caused by the thermal expansion of the push rods and the cylinders) which reduces the tappet noise. The new engines also exhibit three primary design enhancements that contribute to class-leading low noise operations. Enhancements to the muffler, the breather valve and the case cover (GX160/200 models only) result in lower noise levels:

Turning to the issue of vibration, any engine generates vibration through the reciprocal movement of the pistons. In the new mid GX models, the piston weight has been reduced and the crank weight has been adjusted according to the piston weight and connecting rod weight. As a result, the crankshaft rotates to counterbalance the reciprocal movement force of the pistons – reducing primary engine vibration.

All three new mid GX models – the GX120, the GX160 and the GX200 – carry the Honda industry-competitive, three-year warranty.

Comprehensive details about this warranty offering and other consumer information can be found at www.honda.com.