There is also an English Patent for the Lenoir gas generator available which is in printed form. It was issued to John Henry Johnson, a patent attorney, who had filed it for Jean Joseph Etienne Lenoir.

The description can be summarized as follows:

The motor is similar in its general construction and arrangement to the ordinary steam engine. The working cylinder A is provided with two slide valves T and T¹ which open alternately and at the proper times the ports a, a¹ and a² for conducting the mixture of air and gas to each side of the piston as well as the ports b, b¹ and b² for the emission of the products of combustion.

The introduction of atmospheric gas takes place through the port a, which is in communication with an open nozzle.

The movement of the piston p is transmitted to the main crank shaft B by aid of the connecting rod C¹ which is secured to the crank  of the main shaft. The two eccentrics D and D1 actuate the slide valves T and T¹. A small pulley E imparts motion by means of a strap to the governor or regulator of the machine.

The cylinder is provided at each end upon its two covers the igniters G and G¹ in communication with an electric distributer H, carried by the main driving shaft and is itself in connection with a Rhumkorff coil which is in communication with any convenient battery or generator of electricity.

In starting the engine, the piston p is first cause to travel a certain distance thereby producing a  vacuum behind it and allows air and gas to enter such void space through the ports a and a¹ respectively. According to Lenoir's specification the slide T and the orifices are arranged such that the air enters the cylinder prior to the gas, so that air and gas are not becoming entirely mixed together. They will exist in the space behind the piston in distinct strata (Emphasis added). After the slide T closes the port leading to that end of the cylinder the igniter G suddenly producing an electric spark causes the gas to explodes, heating the air and its combinations, which extends considerably. The pressure produced operates upon the piston so as to force it to the opposite side of the cylinder, the residuum of the combustion or the products thereof escaping by the exhaust slide valve T¹ and passage b.

The fly wheel assists the piston in its course towards the end of the cylinder and the slides T and T¹ changing their positions the air and gas are introduced to the other side of the piston just at the moment that the second igniter G1 produces a spark which ignites the gas and causes the piston to return to the opposite end of the cylinder thus completing a double stroke.

 The following statement is quite interesting as we will see later in our discussion of the Otto patent N° 532:

Lenoir further states: I found desirable liquid or solid Hadro-Carbons may be employed in this engine for heating and expanding the air and its combinations in which case the substances from which the inflammable gases or vapours are to be obtained are placed in a small boiler and in direct communication with the escape pipe of the engine. The boiler is first heated and as soon as the hydro-carbon is converted into vapour gas, it is place in communication with the working cylinder. The vapour so produced is ignited in exactly the same manner as the inflammable gas before mentioned and similar effects will follow.